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Articles from 1995 In October


Wakeup call on wakes

Wakeup call on wakes

Air traffic has increased greatly over the last 20 years. The most straightforward ways to deal with this increase are: increase the number of aircraft that can land at our existing airports; build more airports; or build bigger airplanes.

Building more airports is a non-starter. Such construction would cost many billions of dollars (and no one wants an airport next door). Landing more aircraft seems possible, but will definitely require that air traffic controllers reduce the spacing between aircraft.

George C. Greene, a researcher at NASA Langley Research Center, Hampton, VA, says the current state of our understanding of wake turbulence makes spacing reductions difficult. And the situation will become even more complex if aerospace companies produce new, super-heavy aircraft.

Today, many airports are capacity-constrained. So putting the maximum number of people into a given airport may involve a tradeoff between size and wake turbulence. "If you could replace a couple of heavy aircraft with a single one, there could be a tremendous economic incentive to buy it. But if the airplane doesn't buy you more people on the ground per hour, because of wake turbulence, then it doesn't make as much sense."

In flight, aircraft generate a vortex off each wingtip. Each coil-like cylinder of rapidly spiraling air develops when air from the high-pressure region below the wings curls around the tip of the wing into the low-pressure area above the wing. The core of the vortex is at a lower pressure than the air circulating around it.

Vortices trail out behind the aircraft and cause wake turbulence. If another aircraft flies into the vortices, it can experience a roll violent enough to cause an accident.

Goals and problems. Wake turbulence studies for NASA's Terminal Area Productivity Program (TAP), which is now underway at NASA Langley, are part of the joint NASA/FAA Wake Vortex Program. TAP seeks to achieve clear-weather airport capacities in instrument-weather conditions.

Researchers at NASA Langley want to increase airport capacity as much as 15% by finding ways to safely reduce wake-vortex-imposed separation standards. Doing so requires vortex hazard characterization, development of vortex-detection technology, and system concept development.

If successful, their work will result in the demonstration of a concept called Aircraft Vortex Spacing System (AVOSS). Ultimately, AVOSS will feed data into the Terminal Radar Area Control (TRACON) automation system. "What the AVOSS system is about," says NASA researcher Leonard Credeur, "is to try to determine what the wake vortex is doing today, right now, when this next airplane is going to land.

"Controllers now do separation by distance," says Credeur. "Actually, wake vortex is a time-based phenomenon. It takes a certain time for a wake vortex to blow out of an aircraft's approach corridor, descend out of the way, or decay." NASA seeks to define an acceptable level of wake strength that translates to a time separation for one specific type of airplane following another: for example a DC-9 following a Boeing 757.

The NASA researchers point out that pilots must be involved to help define what constitutes a wake hazard. "If you've got a young, bold pilot, he may think a big upset's okay; a more conservative pilot may favor a smaller number," Greene observes. "It's difficult to get pilots to agree, since many haven't experienced a serious vortex encounter."

AVOSS will include several subsystems. One, a weather subsystem, will use several measurement techniques to determine what's happening to the weather now, and what will happen in the next 30 minutes. "AVOSS will probably require wind information from the surface to about 1,500 ft," says NASA Langley Aerospace Technologist David A. Hinton. Algorithms now being written at Langley will convert sensor data into wake-vortex behavior predictions. This predictive subsystem will produce an estimate of the time separation required between aircraft for safe landing.

"The real killer problem is the knowledge base needed to write the predictive subsystem. Once we have that, hopefully the software won't be very intensive," says Hinton.

On the ground, a real-time sensor subsystem will detect, track, and quantify vortices. Data from this sensor subsystem go to the predictive subsystem to refine its output. If measured conditions on the field don't correspond to the predicted conditions, the air traffic control system will go back to conservative default aircraft spacings.

Below about 200 ft, Hinton explains, "there are ground interactions that cause more-rapid vortex decay, and also make predicting transport more difficult." More data on vortex behavior must be collected in the low-altitude region. Getting the atmospheric data won't necessarily involve a technical stretch.

"There are several ways of doing it. Existing sodar systems will ping the atmosphere and give you the winds every 20 meters through 400 or 500 meters above the ground. You can buy radar profilers that do the same thing up to several kilometers above the ground. And there are acoustic systems that measure temperature aloft over the first few hundred meters" says Hinton.

It may prove possible to track wake turbulence with radar. "People have confidence that they'll be able to find the vortices with lidar and get a signature," says Robert T. Neece, senior research engineer at NASA Langley. "Lidar's likely to have trouble in fog or light rain; whether or not radar could provide an all-weather capability remains a question."

Theory predicts that researchers should be able to detect vortices with X-band radar, and achieve higher resolution than is possible at longer wavelengths. Also, weather radars now in use operate at that frequency. "We might be able to incorporate an X-band wake vortex detection function into an existing radar," says Neece.

The present thrust of Neece's research is to demonstrate vortex reflectivity at X-band. "Within six months we're going to have to determine what we're going to do relative to X-band. That may not determine what we're going to do with radar. There's a possibility that we may use radar to complement lidar."

In some weather conditions, radar may provide the best means of detecting vortices. In clear air, Bragg scattering is the source of vortex reflectivity. To get Bragg scattering, eddys with a diameter of about a half-wavelength at the radar frequency must exist in the vortices. But if there are water droplets in the vortices, they can provide reflectivity. Thus, Neece explains, if clear-air vortex-detection capability can't be demonstrated, a radar could still provide that capability in foul weather.

To make a radar a good detector for wake vortex, Neece remarks, requires a large antenna to get the necessary resolution. "You must do some things to improve your signal/noise ratio. And beyond that the main changes will be in how you process doppler data," says Neece. Asked what constitutes the most interesting or challenging part of the radar problem, he responds: "It's trying to discover a vortex signature. How do we identify a vortex within this radar data? Once we crack that nut, we'll have it."

Equipment designed to observe vortices in real time is needed because the ATC system, the pilot community, and the travelling public might find it difficult to trust a purely algorithmic solution to the wake-vortex problem. So AVOSS will combine the predictive subsystem with the sensor subsystem. The NASA researchers point out that an AVOSS might be feasible without a dedicated wake sensor. But the system would require more conservative wake predictions, and the gain in airport capacity it could offer would be less than that achievable with a system that includes a sensor.

Real-world information. Data on wakes are now being gathered for NASA at a facility built by MIT's Lincoln Laboratories at the Memphis International Airport. It employs a 10.6-micron continuous-wave laser and a signal processor to track vortices in real time, and watch them decay. The Memphis facility also includes a radar profiler, a sodar, and a 150-ft tower instrumented with wind vanes, temperature and humidity sensors, barometers, and other devices.

The two primary carriers at Memphis, FEDEX and Northwest Airlines, provide aircraft data for every arrival. So researchers can track each airplane that lands, and each vortex, and correlate it with ATC data. The flight's operator then tells researchers what the airplane weighed--an important parameter in estimating initial vortex strength. This approach generates a data set that describes the aircraft that made the wake, the weather, and the wake's behavior.

"Roughly 100 wakes have been tracked. We're now starting to process them," says Hinton. "We're looking at a demonstration of the predictive algorithms in 1999. We plan to go to the field this year with a Version One predictor. We will run that predictor on roughly a daily basis here at Langley, using data transmitted back from Memphis. After we get the laser tracking data, probably a month or two later, we'll do a comparison to see how well we track."

As the modelling proceeds, Hinton and his colleagues expect to see field data and the predictive algorithms converge. "I believe we'll be converging by 1999. I have a lot of confidence we'll be able to converge on a product that will be useful to the AVOSS system," Hinton asserts.

Looking at weather represents a new engineering approach to wake-turbulence studies. "On the operational side, in the past," says Greene, "it hasn't been recognized how important weather effects are on vortices. On the science side it was always recognized as important, but it has taken a long time to get these ideas merged. You can predict the initial strength of a vortex. The hard thing is to predict its decay."

Improving our understanding of wake turbulence can enable existing capacity-limited airports to safely handle more traffic at a reasonable cost. By the end of the century, if NASA's researchers are successful, aerospace engineers and air traffic controllers will have a new battery of sensors and data with which to battle this aviation hazard.

Wireless Communications: The next generation

Wireless Communications: The next generation

Thanks to coming advances in wireless communications, you may never have to miss another important phone call because you were at a meeting.

Analog Devices, Inc., Norwood, MA is developing wireless local loop (WLL) technology that would replace the wired PBX phone in your office. The system would include a cellular base station in your office building or manufacturing facility, and an antenna that would be able to pick up and broadcast conversations.

"Essentially," says Rupert Baines, a communications engineer and marketing manager, "you could take your office phone to the meeting with you, or to the cafeteria, or anywhere else in the building."

The technology is based on the DECT (Digital European Cordless Telephone) standard, already used by about 100,000 subscribers overseas, but not yet in the U.S.

Panasonic, Inc. has also developed technology for turning office phones into cellular phones, and vice versa. Its BusinessLink Personal Communications System includes a switch that goes behind the PBX system. "We re-direct the circuit to our switch and associate it with a wireless handset," says engineer John Avery. The result: You can take your office phone out of the building and it converts to a cellular phone. Come back to the building and it reverts to a regular office phone again.

These are just two of the many breakthroughs in wireless communications that have spawned the era of the "virtual" office--making your car and your home as efficient places to conduct business as the traditional four-walled-and-carpeted office.

Offering faster processing speeds, better quality picture and sound, a slew of new features, and weight and cost savings, the next generation of wireless products will go far beyond the capabilities of today's systems. "We've barely scratched the surface," predicts Samuel May, a wireless communications specialist with the Yankee Group, Boston. "The big movement involves designing systems using innovative engineering that may someday make today's standards--CDA, TDMS, or AMPS--transparent to users. You will be able to use wireless anywhere, the standards simply won't matter."

Innovation lies behind the products that will pave the way for next-generation wireless, personal communications systems (PCS). Let's take a closer look at some of the engineering feats that will make this happen.

Radio functions in software. One group of communications engineers are betting on a new branch of radio services that don't depend on hardwiring. Called software radio, it is based on advances in multi-band antenna, radio frequency (RF) converters, digital signal processors (DSPs), and the use of intermediate frequency (IF). Aimed at cellular networks, software-radio architecture offers several advantages over wired radio.

For instance, many users can share one radio channel, and, with multichannel users, comes considerable cost savings. Programmability also leaves room for more flexibility between different standards, as well as offering designers different ways to optimize a wireless network.

"We expect software-radio architecture will lead designers to higher levels of complexity needed for the next generation of wireless communications, such as PCS," says Joe Mitola, a consulting scientist with Mitre Corp., McLean, VA. "It will be designed into base stations for integrating the modes needed to make multimedia happen." Using voice, fax, data, or multimedia, a mobile software-radio terminal will directly interface to the user, while the base station will interface to the public switching telephone network.

Despite its name, a software radio actually uses a lot of hardware. The building blocks for a typical system include: a power supply, an antenna, a multiband RF converter, a chip with on-board A/D/A/ converters, a general-purpose processor, and the memory for performing the radio functions. So, why call it "software" radio? "Everything is programmable," explains Analog Devices' Baines. "That includes RF bands, channel access modes, and channel modulation and demodulation schemes. The key is using programmable components, such as high-speed DSPs and ADCs."

Consisting of printed circuit boards, Analog Device's evaluation system is up and running. Measuring 8.5 x 11.5 inches, it contains a receiver converter, a digital down converter, and off-the-shelf A/D and DSP evaluation boards. Cutting out a lot of the hardwiring also means that the A/D/A converters can be placed closer to the antenna, thus significantly reducing the potential for interference problems.

"Several process stages previously used to stabilize, amplify, and filter the signal are eliminated,"Baines adds. "While you gain more flexibility by cutting out all of the hardwired stuff that came between the antenna and the A/D/A converter, the closer the converters are to the radio, the less problems you're going to have with noise and distortion."

A key component in the software radio prototype is Analog Device's new 12-bit ADC, the AD9042. With a sampling rate of 41 Msps, it boasts speeds 60% faster than current chips on the market. It also requires one-third less energy, taking 575 mW off a single +5V power supply. "The chip is designed for direct intermediate-frequency sampling and oversampling of wideband signals," explains Baines. "This makes it an excellent candidate for the tough requirements of software radios, such as the next-generation, wireless base stations that can understand multiple standards (AMPS, CDMA, or TDMA) merely by changing a program in the DSP."

The converter uses a two-stage architecture with six- and seven-bit converters. It is based on a cascaded-magnitude amplifier design that does not require any laser trimming or calibration to achieve the 12-bit accuracy. Recent successful tests included a broadband signal containing up to 48 different tones.

Leaping hurdles. Still, despite its advantages, many challenges stand in the way of commercialized software radio. "The ADC and DSP cores needed for this kind of architecture consume a lot of power," cautions Mitre's Mitola. "Design engineers must think of more innovative ways to keep these chips cool. In addition, these systems will need ten times more ASIC processing power than hardwired systems." Other design obstacles: engineering the needed wideband low-loss antennas, and complexities resulting from mixing and matching software tools.

Even considering such design limitations, the consensus is that this technology may prove vital in future wireless links. While it currently revolves around base stations, some experts believe software radio will eventually find its way into the handheld set, with low cost as a very tempting goal. "I do expect we will see small, cheap software radios that fit in your palm," predicts Joseph Kennedy, director in charge of software radio engineering at Engineering Research Associates, Vienna, VA. "You'll be able to connect with any air standard out there."

An antenna with smarts. The first application for software-radio technology is on the market in the form of a "smart" antenna for the 800 MHz commercial mobile cellular radio band. And Kennedy and his colleagues at Engineering Research Associates will introduce a highly accurate signal-location system based on a self-adapting antenna. "This type of antenna technology simply could not be realized in a hardwired radio," says Kennedy, who heads the CAPITAL project.

Basically, the system tracks and analyzes traffic flow by monitoring cell phone signals from cars. Since cellular phones are popular consumer products, their signals represent a fairly good indication of traffic flow. "Looking at the technology options, we decided that it would be more cost effective to devise a signal-location system geared to mobile cell phones, rather than install roadside traffic monitoring systems," Kennedy explains.

The CAPITAL project involves a mainframe software system that resides at several locations in the Washington, DC, area. A given cell-phone signal is pinpointed by comparing its time of arrival at different locations. The system also uses Global Positioning System (GPS) data, as well as advanced signal-processing functions made possible by having the radio implemented as a software algorithm.

Rather than simply receiving a signal, the antenna function in the software radio remains active, scanning frequency bands and analyzing the nature and power of a complex welter of signals. Reception and discrimination of a signal is enhanced by generating a "null" function at other angles, which screen out noise.

These sophisticated signal-processing functions must sort out a given cell phone from the massive flow of radio signals. Combining all of the signal-processing location methods allows CAPITAL to pinpoint a single cell-phone signal to within 10 meters. At that resolution, individual vehicles and their movements can be resolved and traffic flow statistically analyzed.

The design is targeted at cell phone base stations to increase the number of available channels. To make this happen, Kennedy points out key differences between the smart antenna and conventional phase-antenna arrays. "Conventional antennas use steer beams or null, and designers are primarily interested in increasing power," he notes.

Rather than concentrating on power, Kennedy and his project team are focusing on maximizing the Carrier-to-Interference (C/I) ratio. "It's the interference from adjacent cells that hurts the performance of today's cellular phones," he explains. "If you increase the C/I, you will have more channels available in a geographical area. We've also included multi-path conversion, which plays a big part in cellular evolution."

Field tests are currently under way, including police and paramedic services to locate someone in distress. Anyone experiencing difficulties could simply leave their phone on after making an emergency call; the antenna would inform an emergency vehicle of the exact location.

With the complexity of wireless networks comes a load of problems stemming from new standards and protocols needed to keep up with the exploding market. Even for expert network designers, understanding the performance and behavior of a particular network, and then building the infrastructure to get a project up and running, can be extremely time-consuming.

Designing the networks. "It takes months just to write the Fortran code for the infrastructure alone," says Marc Cohen, co-founder of Mil 3, Inc., Washington, DC. His firm offers designers a sophisticated network toolset to simulate and analyze the performance of wired and wireless communications systems.

Based on a three-level hierarchical structure, Mil 3's product, OPNET, makes it easier to analyze and simulate complex networks. It resulted from a thesis project spawned by Cohen's brother, Allain, and a fellow student at MIT. "After graduation, we decided to commercialize it," says Cohen. The result: a software simulator that features over 300 functions. The client list includes more than 700 companies that range from small office-equipment design to fast packet-switch satellites.

"Each environment has its own set of problems," says Cohen. "Even in a small office you are up against a large amount of signal interference and complex propagation issues. If you're are in the city, high-density buildings create added multipath and reflection problems."

Running on X Windows, and supported by SUN, DEC, IBM, and Silicon Graphics workstations, OPNET presents the user with icons and menus that combine detailed network analysis with radio-frequency techniques. "In the past, these issues have been treated separately," Cohen relates. "By combining them in the same package, you get a more powerful analysis of the performance of your network."

The highest hierarchical level, the Network Editor, graphically captures the physical topology of a network. "You can create nodes that represent the different communicating sites in the network," Cohen explains. "each node fits into a class that defines its attributes, such as a switch's processing speed, a workstation's traffic-generation rate, or a gateway's buffer capacity."

The nodes communicate using several kinds of communications links. For wireless modeling, the company offers an OPNET Modeler/Radio link. It includes a feature developed by NASA that calculates satellite orbits specified by their six-element ephemeris data sets. It also takes into consideration the effects of solar and lunar gravity, atmospheric drag, and solar radiation pressure.

On the second level, the Node Editor graphically captures node architectures as diagrams of data flow between modules that represent hardware and software subsystems. The modules are divided into two categories. For dedicated functionality, traffic generators, transmitters, and receivers are configured on the menu. In the user-programmable behavior module, the functions performed by queues and processors are user-specified.

The third tier consists of a Process Editor. It's based on a state-transition diagram for supporting different protocols, applications, algorithms, or queuing policies. The states and transitions graphically define the progression of a process in response to events. For each state, a library of about 300 functions exists to implement the general logic for your applications. Simulation results can be plotted as time series, scatter plots, histograms, or probability functions.

Booming applications. The explosion of applications and customers in need of detailed network analysis has even stunned Cohen. "We were amazed at the variety of uses engineers are finding for the tool," he adds.

Network simulation is the key engineering tool for engineers at COMSAT Laboratories, McLean, VA, a pioneer in the development of future communications satellite technology. "With the rapid emergence of point-to-multipoint services, such as video conferencing, there is a growing need for on-board fast packet switches," says D.J. Shyy, a research engineer at COMSAT. "The programmability allows us to develop accurate models of multicast fast packet switches." The switches were examined under different traffic patterns and loading scenarios. The engineer analyzed queuing behavior, call-splitting capabilities, and congestion control.

Hughes Aircraft Co. also uses the system to develop intelligent communications controllers for multimedia tactical networks. The controllers integrate various satellite and HF communications systems under a common control concept for providing a flexible network service. OPNET not only models a variety of radio and network characteristics, but also functions as a development tool for constructing the advanced protocols for Hughes' customers.

Meanwhile, engineers at Adroit Systems, Inc., Alexandria, VA, use OPNET to model linked air-ground networks. These networks involve disparate heterogeneous systems that range from local area networks (LANS) and wide area networks (WANS) to high-rate TDM RF links.

It's all in the chips. To compete in such a highly competitive market, electronics companies must load more horsepower and memory on a chip. "Designing for the wireless market is different ball game," says Thomas Brooks, DSP marketing manager at Texas Instruments, Dallas. "DSP cores that are optimized for wireless communications bring end-product advantages, such as higher performance and lower power dissipation per function to the OEM."

Equally important, the push for digital technology remains strong. "You get more calls per channel, more capabilities, and privacy and safety features that are better controlled in a digital environment," Brooks adds. "Plus, with performances of up to 50 MIPS, the OEM has the ability to incorporate such value-added features as a speaker phone, noise cancellation, voice dialing, and short messaging."

Texas Instruments currently has under design chips with larger memories, core architectures, and intelligent peripherals. "The larger on-chip memory means having the ability to adapt to new industry standards and using fewer components per system," says Brooks. TI's designers also use thin packaging, glueless interfaces between the DSPs, analog components, and the speaker/microphone for designing smaller, lighter equipment at a lower cost.

Motorola also will come out with more wireless-specific DSPs. The latest line includes the DSP56300. It features speeds of 66/80 MIPS at 3.3V. "We're designing for the future with a component like this," says Mark Reinhard, vice president and director of technology for Motorola's Semiconductor Products Inc., Schaumburg, IL. "The migration path will be up to 100 MIPS and 1.8V within two years."

While digital technology, with its flexibility and programmability benefits, will reign as the key processing technology, demands for mixed-mode processing have many companies keeping analog on the market. "We expect analog to be around for at least another 20 years," says Russell McDonald, manager of TI's mixed-signal sector. Currently under development is a new power-saving chip, the Advanced RF Circuit Telephone Interface Circuit or ARTIC-136. It will hit the market in early 1996. A GMS Baseband Interface Circuit is planned for later in the year.

Analog Devices also hopes to attract the mixed-mode market with its AD7015. The company claims that the device is the first complete 3V codec for Global System Mobile Communications (GSM) handsets. It integrates all of the mixed-signal components: the voiceband codec, which connects the microphone and ear piece to the DSP, and the baseband codec, which connects the DSP to the radio, filters, amplifiers, and auxiliary converters. Previous designs have required several devices and 5V supplies.

Such developments, backed by innovative engineering, will play a major role in building the infrastructure and dynamics for the next generation of wireless technology. The results will propel wireless into the next century.

Application digest

Application digest

Pipe light to front panels with optics

Richard Present, Manager, Strategic Market Develoment, Dialight Corp.

Surface mount light-emitting diodes (LEDs) are point sources of light packaged for manufacturing compatibility. They require secondary optics to channel their light, usually at right angles, from the printed circuit boards on which they are mounted to the front panels of electronic enclosures. By contrast, through-hole LEDs use integral reflectors, lenses, and diffusants for this purpose.

The most common type of secondary optics are light pipes made of fiber-optic materials or molded lenses that act as conduits for light. Engineers use light pipes when LEDs are located at a distance from the front panel or emit light in a different direction. They're also useful when an application requires high-density arrays or uniquely shaped indicators. Light pipes provide added protection against electrostatic discharge because their polycarbonate construction isolates the LEDs.

Because they can't withstand surface-mount process temperatures, light pipes are attached after discrete LEDs are soldered on the board. The advantages of this approach outweigh the inconvenience of performing an additional post-process operation. These include greater flexibility in selecting LED size and shape, better access to the LEDs for rework and inspection, and the fact that alignment is less critical than with through-hole LEDs.

Light pipes interact only minimally with the front panel, so they do not pose a design burden. They offer changeable viewing surfaces, accommodating both backlighting and direct viewing in horizontal or vertical arrays. When properly designed, a single molded part can redirect light from multiple LEDs to different front-panel indicators without optical crosstalk. This reduces the installed cost per indicator position.

To be effective, light pipes must deliver as much of the limited light output of LEDs as possible to the front panel. This requires critical ray tracing to optimize their optical transmission performance. Molding techniques must be precise to minimize inconsistencies, impurities, and air bubbles in the plastic. The potential for light loss inherent in a surface-mountable component must be addressed.

To speak with a Dialight applications engineer, call (908) 223-9400.


Use robots for material handling problems

Rick Ware, President, Rankin Corp.

A system designed to transport blood samples demonstrates the flexibility that robots offer design engineers. Yamaha Robotics' engineering team based the design of this equipment on a modular automation system consisting of Yamaha two-axis FLIP robotic components operating in XY and XZ configurations. Each is governed by a DRC two-axis controller.

Robot models employed for the XY-axis configuration--the BLSII and BFS--provide standard stroke lengths of 1250 mm and 1050 mm respectively. For the XZ axis configuration, robot models employed are the 650-mm-stroke BFS and the 350-mm-stroke FS.

To enable the robots to grip and hold sample racks as they move from one testing station to another (each rack holds 10 blood vials), engineers used standard component parts to develop special finger tooling.

Developed, built, installed and programmed within 90 days--thus enabling the user to meet tight production deadlines--the system handles an average of 200 vial "parts"/minute. Because of the inherent flexibility of its modular design, the system has been adapted for other clinical laboratory applications by the user. Meanwhile, the programmable, high-precision components help keep system operating and maintenance costs low.

To speak with a Yamaha Robotics applications engineer, call: (800) 82-YAMAHA.

Washington Beat

Washington Beat

Engineering jobs, bonuses rise,
but inflation outpaces base pay

"The unemployment crisis for the profession seems to have ended." So says R.A. Ellis, director of research for the American Association of Engineering Societies (AAES) in Washington, DC. AAES surveys find the number of unemployed engineers has dropped "to more normal levels." Engineers with jobs rose to pre-recession levels during three quarters in a row through the first half of 1995. In manufacturing, 43.2% of engineers got bonuses last year, compared with 13.2% in 1993. The median base salary for engineers in industry this year is $56,800, up $200 from last year. That, however, is a loss when you figure in the 2.86% rise in living costs over the period. Typical salaries for new hires rose from $34,900 to $35,350. The median pay for engineers with 10 years experience stayed at $52,900. For engineers with 25 years experience, the median salary climbed from $68,200 to $68,650. Pay levels in the Pacific area improved markedly, while those in the South Atlantic region fell.


'Electronic nose' among tools for checking auto emissions

A new research program at the National Institute of Standards and Technology (NIST) will help manufacturers design and test low-emission cars and trucks. Among tools to be used in developing emission standards is an "electronic nose." It is an array of microsensors, detectors and a microprocessor on a device the size of a credit card. A new facility at NIST for calibrating primary flow meters will analyze auto exhaust using infrared light and microwaves.


Designers advance protection against whiplash injuries

With safety agencies showing renewed concern over whiplash injuries, auto engineers are designing new head restraints. General Motors has invented a pivoting restraint that attaches to a plate in the seat back. In a rear-end collision the restraint arcs forward and upward toward the back of the occupant's head. Swiss designers are developing a different type of restraint. An electronic sensor detects the occupant's position and signals an electric motor to adjust the restraint to a position that gives the best neck protection. In only a few cars can head restraints be positioned correctly for an average-size male, according to a study of 164 new car models. The Insurance Institute for Highway Safety, headquartered in Arlington, VA, made the study using a device that measures a restraint's height below and distance behind the head. It judged restraints in only five cars "good" and rated 117 models "poor." Makers of test dummies also are redesigning their products to show potential harm to the neck.


Panel opposes Discovery funds for advanced spacecraft design

Don't use funds from Discovery--a program of small planetary missions--to pay for advanced spacecraft design. It's "inappropriate," states a report from the Committee on Planetary and Lunar Exploration of the National Research Council. Strap- ped for resources, Discovery should rely mainly on current technology, the report adds. Space scientists should tap proven military technology as it becomes available. The use of new technology, the committee warns, could heighten the risk of failure. "In an environment of declining status and budgets for space exploration," it explains, "the failure of any given mission is no longer tolerable." The result: "engineering conservatism." Engineers must seek the "perfect" design. Suppose an advanced design is needed? Then, the report says, support should come from NASA's Office of Space Access and Technology, which is performing such services for earth-observation satellites. NASA, however, should avoid imposing "arbitrary constraints" on principal investigators of Discovery missions. For example, the report declares, NASA should not preselect the launch vehicle, the spacecraft bus, the payload, or the data rate.


Military motion sensors moving into civilian transportation

Motion detectors used to guide missile interceptors travelling up to 20,000 mph can help navigate cars travelling at 65 mph. So concludes a report by the Ballistic Missile Defense Organization. Many of the detectors use magnetohydrodynamic (MHD) technology developed in the organization's Wideband Angular Vibration Experiment. The MHD principle describes how conductive fluids and magnetic fields interact. ATA Sensors of Albuquerque, NM, has developed the MHD Effect Rate Gyroscope. A low-cost angular rate sensor, it measures vibrations from mdeg/sec to kdeg/sec in the frequency band from dc to more than 100 Hz. For 1997-model autos, the Charles Stark Draper Laboratory, Inc., of Cambridge, MA, is marketing a Silicon Micromachined Angular Rate Sensor. Originally, the sensor was part of an inertial guidance system for miniature interceptors. The report sees promise for both sensors in antilock braking and inertial navigation systems, airbag deployment, and control of steering, traction, and power.

Compact system detects lightning

Compact system detects lightning

Waltham, MA--There's more to lightning than meets the eye. Although cloud-to-ground lightning puts on quite a show, even in broad daylight, you typically can't see intracloud lightning during the day. That's important, because the number of intracloud flashes per minute reflects storm intensity, and intracloud lightning precedes cloud-to-ground lightning.

This system uses optical and electric-field sensors to observe intracloud and cloud-to-ground lightning, determine the intensity of approaching storms, and obtain an approximate measure of the distance to the storm. By doing so, the F-10 AllSky Lightning Detection System permits users to protect themselves, and vulnerable equipment, from lightning strikes.

To detect intracloud and cloud-to-ground lightning optically, the F-10 relies on a sensor that consists of a 45-degree conical mirror, a mirror on an annular disc that faces the conical mirror, and a biased photodiode positioned beneath the center of the annular disc. A hole in the conical mirror allows the diode to look at the sky directly above it. Ralph Markson, president of Airborne Research Associates, which manufactures the F-10, explains that engineers house the mirrors and photodiode inside a plastic cylinder. The clear plastic cylinder permits light to enter and reach the diode.

Basically, this sensor unit serves to gather the maximum possible amount of light and deliver it to the photodiode. When the photodiode generates an output signal with a rise time of 10 to 20 aeseconds, a one-shot latches for 20 mseconds. This action produces an output that can drive a small beeper.

Electric-field sensing enables the F-10 to distinguish between lighting and phenomena like strobe lights and welding arcs. To measure changes in the thunderstorm cloud's electrical field, Markson and his colleagues use a conventional flat-plate antenna. Induction on the antenna produces an input to a charge detector. If that charge exceeds a threshold level, which users can change using a varistor, it produces a usable output signal.

By adjusting the varistor, users effectively change the range at which the system can detect lightning-induced changes in electric field. At its most sensitive setting, the system can detect events 100 miles away; at its least sensitive, it detects lightning three to five miles away. Electric-field monitoring, says Markson, is always sensitive to the location of the flat plate antenna. If users place it under power lines, for example, the antenna cannot detect lightning at all.

In the F-10, signals from the optical detector and flat-plate antenna can both enter a coincidence circuit. If the circuit sees simultaneous inputs, it produces an output. If only one input arrives, the coincidence circuit does not allow an output signal, thus effectively acting as a filter to prevent nuisance alarms.

When users employ the F-10 in this combined detection mode, says Markson, "the F-10 becomes, in a sense, a synthetic weather radar." Each lightning flash generates an output from the electric-field and optical detectors, and from the coincidence circuit. The rate at which the F-10 detects flashes indicates the height of the convective clouds. Cloud height controls the storm's intensity and thus indicates the degree of danger it represents. Airborne Research has demonstrated that by detecting intracloud discharges the F-10 can provide 5 to 30 minutes of warning before a storm's initial ground strikes occur.

Other Applications
  • Protecting open boats

  • Primary/secondary education

  • Airport weather systems

There are several ways to use the output of the F-10. Trained personnel can make all decisions to sound alarms or close down lightning-sensitive operations. But two versions of the F-10, called the F-10/RA and the F-10 SI, can use the system's outputs to fire audible alarms (such as sirens), place phone calls to specified personnel, or start standby generators.

Basic F-10 systems sell for $2,500. The F-10 RA and F-10/SI are priced at less than $4,000. Users include golf courses, park districts, and the Kennedy Space Center.

Additional details...David McLaughlin, Marketing Manager, Airborne Research Associates, 260 Bear Hill Road., Waltham, MA 02154.

Linear motor outperforms steam-piston catapults

Linear motor outperforms steam-piston catapults

Hudson, MA--In a large shed off a back road in this rural Massachusetts town, engineers are developing the world's highest-thrust linear motor. For Naval aviation, it may mean the end of the age of steam.

By 2005, naval architects may begin replacing the enormous steam catapults on aircraft carriers with EMALS--the electromagnetic aircraft launch system. "We're hoping to replace heavy machinery with electronics," says Wolfgang Schlegel, EMALS program manager at Kaman Electromagnetics Corp. Under a Navy contract, the program has reached its Critical Component Demonstration phase, with daily firing of a test rig to prove the reliability and controllability of its constituent parts: a control system, a cycloconverter power conditioner, and the linear motor itself.

Developed originally for powering electromagnetic rail guns, the pulse alternator comprises a massive flywheel rotating at 6,000 rpm. At a signal, the test article delivers as much as 2 MW of electrical power to drive the linear motor. The cycloconverter transforms the high-frequency ac power to lower-frequency ac for the motor's use. Finally, the linear motor consists of modular arrays of NdBFe magnets and a full scale stator segment. In use aboard an aircraft carrier, a turbine engine would provide input power for an 8-MW pulse alternator, allowing 200-kt catapult firings of 100,000-lb aircraft every 45 seconds.

The test fixture consists of a 450-lb carriage riding on parallel rails. Centered between the rails at their midpoint stands a series of three modular stator segments. An array of encapsulated magnets affixed to the carriage interacts with the stator as the carriage passes by. At one end of the fixture, a large pneumatic ram pushes the carriage past the stator, where it's accelerated further. At the opposite end, a group of hydraulic dashpots and/or sacrificial foam blocks decelerate the carriage at the end of a run.

By throttling the ram to deliver the carriage to the linear motor segments at various speeds, engineers emulate every phase of a carrier launch without the expense of building a full-scale catapult. A line of proximity sensors alongside the rails adjacent to the stator records the system's precision in controlling acceleration. So far, says Schlegel, "We've got closed-loop control and response time--we're working in microseconds."

One indicator of the power of the system: 4 ft of stator area accelerates the 450-lb carriage to 7 kts. The test series is continuing, with 200-kt shots the final goal.

If approved for production, EMALS would bring a host of improvements to ship design and Naval aviation. With a maximum design thrust of 290,000 lbs, EMALS offers 28% greater launching capability than steam catapults. This improvement may allow flight operations regardless of whether the carrier is turned into the wind. That thrust is fully controllable, allowing compensation for wind gusts and more precise matching of thrust to aircraft weight than is possible with steam. Closed-loop control of thrust will produce less wear and tear on pilots as well as aircraft. By one study, the reduced stress from "soft starts" could extend airframe life as much as 31%.

Prototype magnet and stator sections have already passed testing for longevity in harsh, saltwater environments. Schlegel says that, since EMALS will be constructed in modular sections, it should achieve economies of scale in manufacturing, as well as granting designers greater flexibility in putting assisted-launch capability onto unconventional platforms. For example, ski-jump-style carriers could be given the ability to launch heavier aircraft or heavily laden STOVL aircraft could be launched from portable EMALS erected on small islands or clearings.

Other Applications
  • Automotive crash testing

  • Torpedo launching

  • Spacecraft launching

Because the system is powered by a turbine engine, it's independent of the carrier's nuclear or oil-fired power plant, thus increasing tactical flexibility. The system converts about 70% of input energy into aircraft kinetic energy compared to a steam catapult's 6% efficiency. Moreover, Kaman engineers envision accelerating an aircraft with only the first 2/3 of the modular stator segments. The remaining third will decelerate the shuttle once the plane becomes airborne. Deceleration will recover some of the input energy and further boost system efficiency.

In the future, engineers hope to develop an electric arrestor system, replacing the currently used hydraulic dampers with high-capacity eddy-current brakes. In that case, decelerating incoming aircraft could help accelerate others taking off. Until then, the short-term payoff is that four EMALS launchers will take up no more space than that needed by current steam systems, but will cut topside weight by 1,000 tons--a naval architect's dream.

Additional details...Contact Peter Mattila, Kaman Electromagnetics Corp., 2 Fox Rd., Hudson, MA 01749, (508) 562-2933.

Experience shows the way to latch onto success

Experience shows the way to latch onto success

Concordville, PA--Not many companies can boast double-digit growth in the '90s. Even fewer can look back on 50 years in business. Latch and access-hardware manufacturer Southco claims both distinctions.

The company had its humble beginnings making specialty fasteners in a previously abandoned building in Essington, PA. Today, Southco has more than 1,200 employees in ten countries and OEM customers in 40 countries. The firm has averaged at least 20% annual sales growth throughout the '90s.

A tour of the Brandywine division and corporate headquarters confirms that the firm is on the move: Though tidy, the offices are crowded; a temporary office annex awaits an addition to the facility, planned for 1996. That growth is not limited to domestic business. In April of '94, Southco Korea Ltd. opened in Seoul. This May, the firm opened a new European Headquarters in Worcester, UK, and was visited by Princess Anne at its gala opening.

Valued employees. At once traditional and dynamic, Southco's corporate culture hasn't changed much since 1945. One indication of the firm's emphasis on stability is the fact that Southco and its parent company have had only five CEO/presidents since its founding in 1899, and had one lay-off since 1945. Although the company has added 600 employees in the past four years, President and CEO Steve Kelly emphasizes that it has not grown into a "bloated bureaucracy" with an army of anonymous employees. "There's no mahogany row here," he says, pointing out the absence of secretaries and buzzers.

However, Southco's products, like the end-products they go into, have had to change dramatically. The company's extensive offering of latches, hinges, magnetic catches, blind rivets, and other fasteners is constantly changing to reflect manufacturing improvements and to suit such varied applications as automotive, electronic, and marine industries. More than half of the Fortune 500 companies are Southco customers, says Bob Ganskopp, vice president of marketing and sales.

Southco has undergone some changes in sales philosophy over the years, as well. Where the sales force was once deliberately isolated from the shop floor, there are now training programs and a dedicated facility called "Southco University" intended expressly to familiarize territory managers with a range of issues. Today, all new Southco salespeople are also engineers.

Kelly estimates that a 5 to 8% time investment in training pays off with a 10 to 12% improvement in productivity. Continuous training and a low employee turnover rate are critical to Southco's success, he adds. "It all comes back to people. They have the knowledge and wisdom that comes here and stays."

Among the company's veteran designers are many patent-holders. For example, Robert Bisbing, the firm's most prolific patent-holder, has 56 patents to his credit. The Inventors Club, created to honor patent-holders, has 20 members. Inventors Club engineers often act as mentors for younger engineers. Club member and Manufacturing Technologies Manager Bill Frame is a 43-year veteran of the company. "I could retire," he says, "But I like the technical work, and working with the young engineers."

One such engineer, Lynn Ziemer, joined Southco three years ago and was recently awarded her second iF award from the Industrie Forum Design Hannover in Germany for her design contributions to the Flush Simplicity(TM) latch. "I came to Southco for the advanced design tools and the family atmosphere," says Ziemer.

Part of the credit for Southco's market strength goes to the Design Partnership program, says Kelly. Intended to connect OEM engineers with Southco's Modifications Group, the program is helping large firms cope with a shrinking work force by providing a dedicated engineering team to help customize hardware. About 30% of Southco products are custom designs--many of them variations on the firm's 100-plus standard products.

To help customers reduce installed cost and integrate access hardware or fasteners into their products, Southco engineers use FEA and CAD software such as ANVIL 5000 from MCS, Scottsdale, AZ. "All of our CAD users worldwide are currently being trained on how to use 3-D drafting, hard metric design, and dimensioning," says Corporate Drafting Coordinator Jeffrey Stevens. Engineers also use failure mode effects analysis (FMEA) and stereolithography to improve design.

Southco's Plastics Technology Center, Bridgeport, NJ, is dedicated to developing new products and manufacturing technologies. The firm's manufacturing capabilities include CNC machining, injection molding, stamping, turning, heat treating, cold heading, die casting, powder coating, and assembly.

All domestic Southco facilities are ISO 9001 certified. Early on in the registration process, Southco decided to go for a single, global certificate rather than individual site certification. This all-or-nothing approach highlights the importance of each facility to operations of the company as a whole, says ISO Coordinator Marjorie Graham. "We feel very strongly that this is not a certificate to just hang on the wall. It's a system that will allow us to continually improve," says Graham. The firm also plans to be certified to the automotive industry's QS9000 standards by April '97.

Among other benefits, ISO 9001 certification helps Southco maintain flexible manufacturing, says Graham. "We've seen enormous benefit internally. Our processes are better-defined, and we can take a process from one facility and move it very smoothly to another facility," she adds.

Product uniformity is critical, especially to customers that rely on automated assembly. Even slight product variations--though they might seem like improvements--can spell disaster. "We want to make sure our processes are consistent," explains Kelly. "For example, certain products are assembled in the U.S., the U.K., and Australia, and they are all the same."

Southco also uses "cell manufacturing" to foster quality and product uniformity. The company manufactures, assembles, stocks, and ships any given product from a vertically integrated facility. The method cuts costs and lead times without affecting product quality, says Production Operations Manager Albert Frattarola. Scrap metal and waste oil are recycled to further reduce costs.

Although catch phrases such as "employee empowerment" aren't used at Southco, technicians are encouraged to run their segment of a facility like a company within a company, says Frattarola. In the Brandywine facility, for example, there are no dedicated janitors. Instead, each operator maintains his or her equipment.

Southco uses operator experience to further manufacturing improvements. For example, insert machine operators and machinists at the Albany, NY, plastics department recently teamed to reduce scrap by more than 50% and increase production by 20%. Their suggestions led to a system that detects non-conforming parts, as well as safety and maintenance enhancements.

What will the next fifty years hold for Southco? Says Kelly: "With our long-term commitment to internal and external partnering and to the process of constant improvement, I am confident that we will continue to view the competition in the rearview mirror."

Behind the boom in automation

Behind the boom in automation

Randall Webber has been the president of Humphrey, a manufacturer of pneumatic controls, since 1988. He is a member of the company's board of directors and chairman of South Haven Coil, a Humphrey subsidiary. Webber joined the company in 1976 as controller, and was subsequently promoted to treasurer, vice president of operations, executive vice president, and general manager. Just prior to joining Humphrey, Webber was controller for Wells Electronics. He was also a former senior accountant for Peat, Marwick, and Mitchell.

The drive to upgrade the nation's factories has been a major force in fueling the recent economic expansion. The CEO of a company that supplies the surging automation market analyzes the factors behind this growth.

Design News: Has the boom in automation investment peaked?

Webber: We may see some cooling off, but there are trends that point to a strong demand for automation technology for many years to come. Not only are major users, such as the automotive industry, continuing to install new equipment, but industries that many of us thought were on the decline are being reborn--thanks to automation.

The textile industry is a prime example. U.S. textile companies have received a boost from a new trend to custom-manufacture clothes. Shoppers can now get jeans that are tailor made--with the help of automated measurement and manufacturing equipment.

Q: What other automation markets look particularly strong?

A: Over the last few years, the resurgence of the auto industry has spawned new investments in equipment by a wide range of companies that make components, materials, and systems for the car companies. Demand also has increased for equipment for the semiconductor manufacturing industry. That has been fueled, of course, by the development of new and more powerful chips by companies such as Intel.

In the medical field, automated test equipment, such as that used for handling blood and other fluids, has become very important. This is in response not only to health hazards, such as AIDS, but also the move toward more decentralized testing labs. Still another big opportunity for automation is the packaging industry, as food, drug, and consumer goods companies develop more and more new products. Then, of course, because of the intensity of worldwide competition, manufacturers everywhere have no choice but to upgrade their equipment. In short, no matter where you look, there are just so many more opportunities today for automation suppliers than 20 years ago.

Q: Has the U.S. caught up with Japan in manufacturing?

A: We can still learn an awful lot from Japan about the manufacturing process, simply because they were so far ahead of us, particularly in such areas as robotics. Because their manufacturing processes are so good, they turn out high-quality products. In the case of Humphrey, we have benefited tremendously from our 30-year relationship with Koganei, a Japanese producer of pneumatic actuators and control valves.

But I believe the U.S. has now made great strides in catching up with Japan when it comes to manufacturing technology. Just look at the auto industry and the tremendous investment it has made in new plants and equipment. This has resulted in a marked improvement in the quality of our cars, as well as a sharp reduction in product development cycles.

Q: Can you point to any areas of automation where the U.S. is now superior?

A: A very obvious one is the use of computers in production operations. I believe the U.S. is far ahead of Japan. Our Japanese partner, for example, has 60 people totally dedicated to scheduling the factory. At Humphrey, our extensive use of computers for manufacturing resource planning enables us to get by with just six people. The same holds true for order processing, which can take two or three days in Japan. Our system, in contrast, takes just minutes to generate a work order because of our greater commitment to computers in the factory. Order a cylinder this morning, for example, and it could ship this afternoon.

Q: What are some of the most important steps Humphrey has taken to boost productivity?

A: It has to be our network of continuous improvement teams, who meet regularly to solve problems and conceive ideas for doing the job better. At key places throughout the factory, we post the operating results of the company, including such things as shipments, sales, profits, and production waste. As far as I'm concerned, such information and communications are crucial. You just cannot keep employees in the dark. We can't be successful unless everyone in our factory--from engineers to sales staff to production workers--join hands and work together. And to insure this commitment, we issue quarterly bonuses tied to company performance. Everyone has to realize that they must be able to cope with constant change and that the challenges never stop. Our whole drive is to eliminate supervision and have the employees run the company's day-to-day operations.

Mirror-image minivans?

Mirror-image minivans?

Take the redesigned 1996 Plymouth Grand Voyager SE, the new-in-1995 Honda Odyssey LX, and the popular Ford Windstar for test drives, and one might become confused, at least when it comes to styling. The new Voyager looks remarkably like a Windstar. Also, each of the models I drove offers dual airbags, side-impact protection and ABS as standard equipment. But, after a week in each vehicle, important distinctions among the three became apparent.

PASSENGER ROOM COMPARISONS

VEHICLE
GRAND AREA

ODYSSEY
LX

VOYAGER
SE

WINDSTAR
GL WAGON

Front Head

39.9

39.8

39.3

Front Leg

40.6

41.2

41.8

Middle Head

39.3

40.1

38.9

Middle Leg

38.5

36.6

39.2

Back 3 Head

37.6

38.1

38.1

Back 3 Leg

34.1

35.8

35.3

With its 3.3-l MPI V-6 engine, the Grand Voyager SE offers a smooth, comfortable ride. Its convenient 20-gallon fuel tank allows for long periods between fill-ups, as does the Windstar with its 20-gallon tank. Odyssey's 17.2-l fuel tank most likely is a byproduct of the smaller vehicle size, but don't let the size fool you when it comes to cargo space.

None of the three vehicles is fuel thrifty. Gas mileage averages out to be almost identical. The Honda comes in at the high end with 20 mpg city/24 mpg highway, the Plymouth claims 18 mpg city/24 mpg highway, and the Windstar averages out at 17 mpg city/24 mpg highway.

The Odyssey LX has the best fuel mileage by a bit, and also costs the most at $23,889, by the same margin. Its 2.2-liter, 16-valve engine produces 140 hp and 145 lb-ft of torque. A 4-wheel, double-wishbone suspension and 4-wheel disc brakes with ABS make the minivan handle like a passenger car. But at times the 4-cylinder engine seemed to need a power boost, such as when the air conditioning runs at full tilt.

The Plymouth, with the SE Luxury Package, sells for $23,855, just $34 less than the Odyssey. The package includes: air conditioning, rear window defroster/wiper de-icer, 7-passenger seating, power door locks, power windows, a climate group with sunscreen/solar glass, rear heat and ac, dual-zone temperature control, overhead console, integrated child seat, engine upgrade to 3.3l MPI V6, and driver-side sliding door.

At $22,280, Windstar offers even more amenities than the others. Included in the Preferred Equipment package are radio controls and headset mounts in the middle row of seats, and a remote keyless entry system with a panic button. However, it's the new-for-1996 traction control that sets Windstar apart from the two other vehicles.

The All-Speed Electronic Traction Control provides better traction for acceleration on slippery surfaces by determining how best to regain traction at the "driven" wheel. The system uses brake and engine management to transfer power to the wheel with the most traction.

The traction control system also measures the speed of each front wheel independently so, if one of Windstar's wheels hits an icy patch, the system will apply the brakes to the slipping wheel, allowing the torque to be transferred through the differential to the wheel with greater traction.

The 1996 Windstar GL model features a 3.0-liter SEFI engine as standard. However, you might want to consider a 3.8-liter V-6 engine rated at 200 hp at 5,000 rpm and 230 lb-ft of torque at 3,000 rpm as an upgrade. Ford promotes this engine as offering 10 years/100,000 miles without the need for major servicing when driven under normal conditions.

Family safety. Each model has its own special offerings when it comes to safety. On the 1996 Grand Voyager SE, for example, Plymouth engineers reduced the turning circle (on the long-wheel-base version) by more than three feet. They also increased visibility with a 32% larger windshield. The windshield wipers contain their own "de-icer" for safer driving in winter conditions. The de-icer, an electronic grid like the rear window defroster, covers a small area of the glass at the base of the wiper pattern where the wipers park.

SPECIFICATIONS

FEATURE

Windstar

Odyssey

Voyager

Wheelbase (in.)

120.7

111.4

119.3

Length (in.)

201.2

186.7

199.6

Height (in.)

68.0

64.7

68.5

Width (in.)

75.5

70.5

75.6

Seating capacity

7

6

7

Engine as driven

3.8 SPI

2.2 SOHC

3.3 V6

Displacement (cu.in.)

3.8

131.6

201.5

[email protected] RPM

200 @ 5,000

140 @ 5,600

158 bhp @ 4850

Torque (lb-ft @ rpm)

230 @ 3,000

145 @ 4,600

203 @ 3,250 rpm

Transmission

4-sp auto

4-sp auto

4-sp auto

Curb weight (lbs)

3,487

3,435

3,766

Price as driven

$22,280

$23,889

$23,855
HANDLING IMPRESSIONS

FEATURE

Windstar

Odyssey

Voyager

Handling

Good

Very good

Very good

Ride Comfort

Very good

Very good

Good

Acceleration

Very good

Good

Good

Quietness

Good

Good

Very good

Roominess

Excellent

Very good

Excellent

Visibility

Very good

Excellent

Very good

Overall quality

Very good

Very good

Excellent

The first minivan manufacturer to offer integrated child safety seats, Plymouth now offers a multiple-position recliner. And, for overloaded parents, the maker claims the child safety seats buckle up with just one hand (I didn't have a fidgeting child to test it out on). Also, for safety's sake, the Odyssey LX includes more than 293 degrees of outward visibility from the driver's seat. The wiper design, with two 600-mm wiper blades and arms that move in mirror image, ensures complete coverage to the A-pillars. Insetting the windshield 7 mm, rather than having it flush with the windshield post, helps prevent rainwater from flowing onto the side windows, further preventing vision obstruction.

The Odyssey's parking break lever mounts on the floor on the right side of the driver's seat. To ensure that someone walking through the aisle doesn't bump the lever and release it, the lever must first be raised before the release button can be pushed. The Ford Windstar brake contains a similar design, while the Voyager's hand-petal/hand-release brake to the left of the steering wheel gets it out of the aisle all together.

In the Grand Voyager redesign, Chrysler dropped the sill about one-and-a-half inches, and ramped the floor down to it, which lowered the step-in height. The driver's height remains the same as in the previous version.

Everyone I asked reacted positively to the Voyager's driver's side sliding door. It seems so obvious, yet it took a decade for an automaker to make the "go anywhere" family vehicle accessible from both sides for loading passengers and cargo. Actually, the Odyssey offered the first four-door minivan design in 1995, but the Voyager's slider is more convenient, particularly in tight parking spaces. It should be pointed out, however, that the 4-door design on the Odyssey allows second-row passengers to roll down their windows.

All-new hinging and latching mechanisms on both of the Voyager's sliding doors help make the door open and shut effortlessly. Inclined tracks allow gravity to assist door closing on a level surface.

The Voyager also has "wheels" on the bench seats. These Easy-out Roller Seats(TM) wheel into storage and are easy to remove. Each seat is latched to floor-mounted strikers. When unlatched, eight rollers lift each seat so that it can be rolled forward and backward. An ergonomic lever at the back of each seat riser releases the floor latches and raises the seat on its rollers in a single motion. To ensure that the seat is properly latched, a red indicator projects out of each handle until latching is complete.

Honda's engineers get kudos for their third-row retractable bench seat. Because the seat retracts completely into the floor, providing a flat, open cargo area, the seat adjustment can be made just about anywhere. A 7-liter storage compartment in the rear of the vehicle forms a convenient place to stow the third-seat head restraints.

For example, suppose the kid's soccer practice ends early and three neighborhood children need rides home. Pull the extra bench out of the floor in the Honda and off everyone goes. Those in the Plymouth or the Ford need a dry place to store the benches when not in use, making removal near the garage the only practical solution.

The Odyssey provides 150-plus feet of interior volume, more than the Windstar or the Plymouth, which surprised me. On the downside, only 9.8 cubic feet of that storage area is located behind the third seat. When all seats are occupied, there isn't much room left for cargo. The Voyager and the Windstar have more than double the space behind the third seat.

On the other hand, the Odyssey is the only vehicle with a deep storage well behind the third seat to help keep loose items from rolling about. Other benefits: a low step-in height and 64.7-inch-high roof, making it easier to load.

The Windstar GL cargo area offers 144 cubic feet with the seat folded down. There are 22.0 cubic feet behind the third row seat.

The new Voyager has 11% more passenger and 27% more cargo space than last year's model. It contains 22.2 cubic feet behind the rear seat, and totals 141.9 cubic feet with the seats removed. Chrysler claims that, with both benches folded flat, it's the only minivan that can carry a 4-x 8-ft sheet of plywood with the seats in and the liftgate closed.

The long-wheelbase Voyager measures 1.6 inches shorter than the Windstar, but has almost 20% more cargo space. Short-wheelbase versions with nearly 15 inches less length even exceed Windstar's cargo space.

A comparison of the three minivans wouldn't be complete without mentioning cupholders and storage compartments, for they abound. Voyager, Odyssey, and Windstar designers took into consideration the thirst of a family on the road and incorporated cup holders all over the place, but the Voyager's are unique. They adjust to various size containers. As the drawer containing the containers is opened, movable arms swing out to create two openings, each deep and large enough for the largest drink containers, including cups with handles. Each arm swings in on a three-position ratchet to grip smaller containers, even holding a juice box in place. Pushed inward past the smallest position, the ratchet releases, and the arms swing out again to the largest position.

Every family requires storage compartments, and in this regard the Grand Voyager beats the Odyssey and Windstar hands down. Under the rear armrests are two large storage bins. Tucked neatly beneath the front passenger seat is a drawer with its own lock. A center console offers a slide-away coin holder, a cubbyhole, and a compartment for storing CDs and cassettes. An overhead console will hold sunglasses and a garage-door opener.

Several friends asked if I found the bulky minivans difficult to park. Parallel parking the Honda seemed a breeze with its smaller size and excellent visibility. The others felt a little more awkward; gauging just where the back bumper ends when parallel parking had a more precarious feel. Still, all are manageable.

Honda Accord owners who need more space may enjoy owning an Odyssey. The Voyager attracts cargo haulers with its driver's-side sliding door and roomy interior. The Windstar, while very comparable, will probably lose some potential customers because it doesn't offer back-seat accessibility on the driver's side, but it does have traction control available for safety-conscious buyers. In the end, no single vehicle stands alone in the winner's circle.

Engineering News

Engineering News

Plastics create a winter sports wonderland

Newton, MA--Even as summer sports enthusiasts wind down their activities, sports-equipment makers are gearing up for the winter sports season. Drop into your local sports store and check out some of the latest designs. It will prove to be a big eye opener. Now, take a closer look. You will soon discover that many of the latest designs rely on plastics, and for good reason.

Take snowboards, for example. If the past two winters are any indication, sales of snowboards should soar. Two companies in particular hope to capitalize on the increased popularity of this sport.

Snowboarders, like skiers, prefer different styles of boards depending on where they will be used. Western snowboarders, for instance, might want more flexible boards for use in deep, powdered snow. Eastern terrain, by contrast, is icier, requiring stiffer boards.

Customized boards. U.S. Snowboard Technologies (USST), South Hampton, NH, designs its snowboards to customer specifications on a computer that develops nose radii, side cuts, and other dimensions, along with recommended laminate layers. Typically, the boards feature a wooden core surrounded with coextruded ABS/fiberglass sheet, rubber, and fillers. Wood cores consist of various combinations of maple, birch, and hickory.

Because of their laminated construction, the boards require an epoxy adhesive that will keep the layers in place through all types of terrain. USST found a solution in Ciba-Geigy's Araldite(R) AW 136R/HY 994H epoxy and Araldite LY 5085/HY 5046U resin hardener systems, especially when the customer wants a "see-through" surface.

Both adhesives, products of Ciba-Geigy's Formulated Systems Group, East Lansing, MI, offer excellent wet-out of the fiberglass and other reinforcing layers. They perform well under static and dynamic loading and withstand exposure to temperature extremes, water, and ice.

"We might use 160 grams of epoxy on one board and 310 grams on another to alter the flex pattern, without changing the weight of the fiberglass," says Horst Heuback, USST operation manager. "The more epoxy used, the stiffer and less flexible the board will be."

After the computer designs the board, USST pre-cuts the fabricating materials. Cores are milled to a precise size, shape, and length, also with a computer-programmed assist. ABS/fiberglass sheet is cut to the computer-specified dimensions, along with rubber and other board inserts used to secure the bindings in place.

After each board is laid up, it is put on a press and cured at 240F and 280 psi. Using a heating platen on the top and bottom enables USST to speed the curing cycle from 30 to 10 minutes.

Better bindings. Bindings make up another crucial part of snowboards. To improve the design of its bindings, Switzerland-based Fritschi Co. takes advantage of Verton(R) RF structural nylon composites from LNP Engineering Plastics, Exton, PA. The long-fiber skeletal structure of the material results in greater impact resistance even in sub-zero temperatures.

  • Plastics give engineers the opportunity to provide more flexible, longer-lasting designs for sports gear

  • Polymers can withstand cold-weather abuse, and weigh less than metal counterparts

  • Use of plastic enables sports equipment makers to keep up with latest fashion trends

Also, using the injection-moldable compound instead of a metal die cast enabled Fritschi to develop colors that keep pace with fashion trends, saving considerable painting/finishing costs. And, with a density almost half that of aluminum, but with greater relative strength, Verton RF provides significant weight savings.

Fashion statement. Fashion concerns also play an important role in the buying decision. At the higher end of the market, skiers expect the product to provide topnotch performance--and look good while doing it.

French manufacturer Salomon achieved this balance through its Monocoque concept--essentially a shell that sheathes the ski, including its sides. To meet the demands of this design, Salomon selected Rilsan(R) polymide resin from Elf Atochem North America Inc., Philadelphia. A film of Rilsan about 0.8-mm thick envelops the contour of the ski and allows the use of a sublimation printing process that burns the company's graphics into the surface.

Canadian ice caper. In Canada, winter and hockey are synonymous. Therefore, the ability to give a skilled hockey player the slimmest advantage can result in big sales for a producer of skates. Sport Maska Inc., Montreal, thinks its new CCM 752 "Tack" skates offer much more than that--thanks to an assist from rugged, lightweight materials from DuPont Engineering Polymers, Wilmington, DE.

The company claims players gain added efficiency and quickness with the skate's advanced heel stabilizer wedge made of an engineering thermoplastic elastomer. "It improves the skater's efficiency by allowing more forward flexing than traditional skates, while providing increased lateral and tendon support," explains Craig Ryan, Sport Maska product manager.

Sport Maska designers reconciled requirements for flex and stiffness with a co-injection molded component made from two grades of Hytrel(R) polyester elastomer having different flexural characteristics. This allowed them to put stiff or flexible material where each is most needed in the part structure.

The skate's blade support, injection molded from Zytel(R) ST super-tough nylon, weighs far less than a metal support. It features a fatigue strength that can take repeated dynamic loading during the starts, stops, and thrusts of hockey, while providing low-temperature impact resistance to withstand hits from pucks or errant sticks.

The uppers employ a ballistic nylon fabric reinforced with Kevlar(R) aramid fiber. The fabric weighs about one-third less than a comparable all-nylon fabric, according to Sport Maska designers.

Upscale toddler sled. And, for the toddler set, comes a sled from J.R. Wright Engineering & Sales, Scottsdale, AZ, designed to be "the Mercedes of toddler sleds," says President John Wright. It had to be light and easy to push or pull, and fold down for storage or to transport in a compact car. It had to be low-maintenance, with no wood to give splinters or rails to rust. And, most important, it had to offer comfort and safety. After six or seven years of design and prototyping, the Fawn Tracker was born.

Made from a strong, tough blend of Texin(R) thermoplastic polyurethane and Makrolon(R) polycarbonate engineering resin from Bayer Inc., Pittsburgh, the sled resembles a racing stroller with runners. Sleek and colorful, the Fawn Tracker is popular at ski resorts, or with families who live in areas where heavy snowfall makes using a stroller difficult. Even cross-country skiers pull their kids behind the sleds.

Over 90% of the sled, including the frame and runners, consists of the Texin 4215 thermoplastic polyurethane/polycarbonate blend. Although the sled is shipped fully assembled, individual pieces are joined with twist grip locks, snaps, or brass pins. A seat belt and fabric seat complete the design.

"I considered polypropylene and nylon, but I was concerned about breakage due to their lack of shear strength," Wright explains. "I knew that the Texin blend was more expensive, but the superior performance was worth the added price."


Rapid prototyping comes to tool-making

Austin, TX--Injection-molding tools in two weeks?

DTM Corp. says that's the promise of its RapidTool(TM) process, which uses technology initially developed to make sample parts directly from CAD data. Now, the company is merging its Selective Laser Sintering technology with conventional furnace-firing to create insets--cores and cavity sets--for prototype injection molding.

"Customers can quickly create tooling allowing them to produce prototypes that replicate the actual manufacturing process," says DTM President John Murchison. "This can dramatically affect the manufacturing process by compressing the product-development cycle."

The company just announced a beta program for the process, which is expected to be commercially available by the end of this year. Xerox Corp. and the University of Louisville prototyping consortium will be beta-testing the technology.

DTM's SLS process creates 3-D parts from powdered materials by a computer-directed modulated laser beam. RapidTooling first uses SLS to generate an initial iron model of the tool. In a second step, the part must be heated in a furnace to 1100C so copper infiltrates the model to create an iron/copper composite.

While conventional tool-making can take eight to 10 weeks, RapidTool creates insets in four or five days. Another week or so would then be needed for polishing and insertion into a mold base. An inset for a 6-x 8-in tool, several inches deep, would cost less than $2,000--a fraction of traditional methods.

The process is designed for tooling prototypes, but could also be used for limited production runs.


R&D honors best inventions of '95

Des Plaines, IL--A super-bright lightbulb, high-precision machine tool, and wristwatch that communicates with a PC were among this year's winners of R&D 100 Awards. The competition, sponsored by R&D magazine, cites the year's 100 most technologically significant products.

The Solar 1000 microwave sulfur lamp is a golfball-sized device based on a process called molecular emision. Sulfur in the bulb, stimulated by microwave energy, emits broadband light to mimic ordinary sunlight. At its Washington, DC, headquarters, DOE replaced 240 200-watt mercury lamps with just two of the new bulbs. The Solar 1000 was developed by the U.S. Department of Energy; Fusion Lighting, Rockville, MD; and Lawrence Berkeley National Lab, CA.

The winning machine tool, VARIAX, uses a space frame structure based on a series of interconnected triangles. Three pairs of triangulated crossed-legs containing motor-driven ballscrews support the upper and lower platforms. The upper platform houses the spindle, which holds the cutting tool. By extending and retracting the six legs, the spindle can be lowered, raised, or tilted.

Because forces on the VARIAX structure are axial, the machine center is five times more rigid than conventional metal-cutting machines, according to its developers, Giddings & Lewis, Fond du Lac, WI. Accuracy: 0.0003 in, compared to 0.003 from most conventional machines.

Timex Corp., Middlebury, CT, garnered an award for its Timex Data Link, a watch that can carry up to 70 personal data entries. Using Data Link software codeveloped with Microsoft Corp., the wearer can point the watch at a PC and press some buttons--and the data entries are automatically sent from the computer and stored in the watch.

Among the other winners:

Contraband Detector, Quantum Magnetics, San Diego, a magnetic-sensing security system that employs quadrupole resonance (a variety of magnetic resonance) to scan for specific atoms found in drugs and explosives.

  • Ignition system from ENOX Technologies, Natick, MA, which cuts NOx emissions from stationary natural-gas engines by 90%. It adds more air to the air/fuel mixture while simultaneously enhancing combustion efficiency with a continuous ignition source.

  • One-step automatic process for fabricating composite aircraft parts, Cincinnati Milacron, which downloads computer data to a fiber-placement machine. The device uses seven servo axes to accurately position and control up to 24 individual fiber strands.

For 1996 entry forms, fax R&D 100 at (708) 390-2618.


Controllers put excitement in exhibits

Newton, MA--If you think museums are just the past under glass, go to Chicago's Museum of Science and Industry. Under its MSI 2000 plan, designers there have created a veritable theme park for the intellect.

Best evidence: "Take Flight," a collection of more than 25 multimedia exhibits illustrating the science and engineering behind commercial aviation. As its centerpiece, Take Flight includes a retired Boeing 727 cantilevered off the East Court balcony. Visitors can board the gutted and reconfigured aircraft for interactive demonstrations of navigation instruments, aeronautical-engineering concepts, and air logistics planning.

Five times daily, 12 projectors, 75 spotlights, and eight speakers transform the Court into "Flight 727." With all systems now electrically or pneumatically operated, the plane's engines turn; and its lights, flight-control surfaces and landing gear deploy appropriately during a seven-minute simulation of a flight from San Francisco to Chicago.

According to MSI engineer Joe Schacter, the entire Take Flight exhibit took over two years work by more than two dozen contractors employing over 1,000 designers, engineers, and riggers. Underscoring the dynamic nature of the exhibits, not one of them is hard wired: Each employs programmable controllers to simplify set up, operation, and reconfiguration.

For example, ProMux(R) controller boards and MicroDAC controllers from Grayhill, Inc., LaGrange, IL operate all the 727's moving surfaces. Tom Wolcott, an engineer with Design Craftsman, the Midland, MI contractor that produced the display, explains the choice came down to experience and economics. "To coordinate all the surfaces, we'd need to wire up a dozen or more separate timers. It was simpler and less expensive to purchase the controllers, hook them to I/O boards, and move on from there."

ProMux boards control up to 24 modules, communicating at speeds to 38.4 baud. MicroDAC controllers handle as many as 32 analog or digital I/O modules and reach 115.2 baud. Both systems have RS-422/485 communications capability in multi-drop or repeat configurations. Either can be programmed via a host PC using Basic or C (ProMux) or Microsoft C, Borland C or Quick Basic (MicroDAC). Programming simplicity and clarity counts as an asset in the MSI application, since designers can't predict how visitors will interact with the exhibits. Bill Hogan, an Electronics Design Technician praises the reliability of the industrial-quality controllers. "The boards run 8-10 hours a day, flawlessly," he says.

According to MSI's Schacter, the public has responded favorably to the new exhibits: attendance figures have risen 25% compared to the same period last year.


Oven motor beats the heat

St. Louis, MO--You push a button, and 45 seconds later, a vending machine delivers fresh-cooked French fries. The new French Fry Vendor(R), made by National Vendors for Ore Ida Foods, Inc., Boise, ID, may be great for potatoes, but it's tough on motors.

The machine's cooking basket and fan are controlled by a 0.5-horsepower, 56-frame motor from MagneTek, St. Louis, MO. During the cooking cycle, air temperature inside the machine reaches 460F. In order to bake off any residue, air temperature during the cleaning cycle hits 850F.

The application required a custom-designed motor that could operate on two speeds: 1,725 rpm for loading and unloading the fries in a cooking basket, and 3,450 rpm to cook the fries and for the self-cleaning cycle. "We created a motor that's almost two motors in one--a four-pole on low speed for loading and unloading fries, and a two-pole on high speed during cooking and cleaning," explains Greg Hall, MagneTek market specialist. "We used a switching device instead of tap winding to ensure that the motor could run slowly enough," he adds.

The high-temperature operating environment created a different challenge for MagneTek. Engineers realized that when the machine reached 850F, heat could be transferred through the motor shaft to the bearings. They solved this problem by using a stainless-steel shaft in place of conventional carbon steel.

MagneTek engineers also had to eliminate the danger of the open drip-proof motor overheating in an enclosed environment. Because an "air-over" cooling design wasn't possible, engineers designed the motor with reverse ventilation. This cools the motor as well as creating static pressure to keep hot air out of the motor, explains Hall. A specially balanced rotor keeps fan blades from wobbling and reduces vibration and noise.

Says Hall, "The key to the success of this project really is the communication between MagneTek and Ore Ida during the entire design process."


Add-on software for Excel enables data acquisition

Cleveland--Rather than acquiring data with one software package and then transferring it to spreadsheet software such as Microsoft's Excel(TM) to analyze it, wouldn't it be better to combine the two functions into one program? Now that's possible with IOtech's DaqViewXL, a data-acquisition and display application that seamlessly integrates into Excel.

DaqViewXL lets users set up data-acquisition applications from within Excel without programming. It also provides graphical access to all the functions of IOtech's parallel-port-based DaqBook, plug-in DaqBoard, and Daq PCMCIA data-acquisition hardware. The software allows hardware configuration via a graphical user interface by adding a new toolbar to Excel, and provides a strip-chart, recorder-like display that users can open within Excel to view acquired data in real time.

In turn, Excel lets users manipulate data and retrieve previously acquired data in a spreadsheet format. Excel also offers an array of graph and charting functions for presenting data in a graphical format, and mathematical and analysis functions, including frequency domain functions such as FFTs.

DaqViewXL is the first in IOtech's new series of "software components," which users can launch and operate from inside a "home" application such as Excel. Under this software-components concept, software developers divide their products into pieces that users can add on or embed into other applications. To access or attach these components, the developer must use an inter-application communication standard that all the components support. Dynamic Data Exchange (DDE) and Object Linking and Embedding (OLE) are examples of such standards.

By combining software components, users can customize general-purpose software such as Microsoft's Word(TM) or Excel into a specialized application without having to write a single line of code or glue together icons.

Compatible with Windows 3.1 and Windows95, Daq-ViewXL retails for $195. Demo disks are available free from IOtech.


Cyrix challenges Intel for desktop CPU performance

Richardson, TX--Computer designers and buyers looking for an alternative to Intel's advanced CPUs now have a real contender. Cyrix's new 6x86 microprocessor is faster than Intel's Pentium at the same clock speed, and the two chips are cost-competitive.

Preliminary performance figures show that a 100-MHz 6x86 scored 164 on the Winstone 95 benchmark, compared to the 159 scored by a 133-MHz Pentium running in the same system. Based on Intel's published benchmarks, Cyrix's chip is 30% faster than a 133-MHz P6 when both run under Windows for Workgroups 3.1.

"There's nothing on Intel's roadmap that's going to be dramatically faster than this chip," said Martin Reynolds, director of technology assessment at the San Jose-based market-research firm Data-quest. "It doesn't really matter whether it's the fastest processor--it's right up there with the fastest Intel has and that's not going to change."

The 6x86 sports two superpipelined integer units and a floating-point unit. All three use register renaming, out-of-order execution, data forwarding, branch prediction, and speculative execution to speed instruction throughput. In addition to Windows variants, the 6x86 runs DOS, UNIX, OS/2, and Solaris.

Reynolds believes the chip is more advanced than the Pentium--due to speculative execution, out-of-order instruction execution, and its ability to almost always be executing two instructions concurrently--but not as advanced as the P6. "But the Cyrix part performs a lot better in desktop applications than the P6," he notes, "which does not do very well with Windows code."

Production quantities are available now for $450 from Cyrix, IBM Microelectronics, and SGS Thomson Microelectronics. PCs based on the 6x86 are also available now from Epson, AST Research, and Peacock (Germany).

--Julie Anne Schofield, Associate Editor


Software helps design muscle exerciser

Midvale, UT--At least eight million older American women suffer from urinary incontinence. Recently, Utah Medical Inc. developed the Liberty(TM) "pelvic floor muscle exerciser" to address the problem. The battery-operated unit uses a low current to stimulate and strengthen pelvic floor muscles. To speed the unit's development, the company used solid modeling and rapid-prototyping techniques.

When designing the Liberty, Utah Medical created a compact battery enclosure to give mobility to users of the device. Fifty urethane prototypes of the enclosure and battery door latch were developed for testing against theoretical form, fit, and function criteria. They were also put through failure analysis, bicompatibility tests, and clinical validations of safety and efficiency.

The company used I-DEAS Master Series(TM) software from SDRC to prepare the device for clinic trials. "I-DEAS enabled us to cut the time for soft molding (silicon rubber molds of urethane parts) from 12 weeks to three," says Tod Cook, project leader for Liberty development.

Utah Medical's I-DEAS solid model files were converted to STL format to generate stereolithography models and patterns, silicon-rubber molds, and urethane parts. Utah Medical says the prototyping cost was money well spent since no changes were needed in the production tooling.

The firm was ready to begin production six months after Liberty's concept was finalized--half the usual time for a product this new, says Duane Sjoberg, manager of engineering services at Utah Medical. "Prototyping was done so quickly," Sjoberg says, "because iterations in the 3-D solid model can be done in hours and new SLA parts can be made overnight at a low cost."


Integrated countermeasures: alternative to heavier armor?

Newton, MA--The evolution of anti-armor weapons is changing the historical trend in tank design. Ever-more-powerful anti-tank projectiles over the years spurred the development of larger tanks with ever-thicker armor. But simply adding armor to deal with new smart rounds able to probe for a tank's weak spots jeopardizes its ability to fight and travel over tomorrow's battlefields.

Smarter weapons require a smarter response. Taking a cue from military aircraft that face similar threats without the freedom to add extra armored weight, tanks may soon sport active and passive counter-missile defenses in addition to armored defenses.

The Army recently awarded a $24.9 million contract for an advanced-technology demonstrator of an armored-vehicle integrated-defense system (IDS). Contract-team members include United Defense, TRW, and Lockheed Sanders, which represent a wealth of combat vehicle, electronics, software, and electronic-warfare experience.

IDS would scan the electromagnetic spectrum above and around the tank. "It detects when weapons have been launched against the vehicle," explains Tom Winant, IDS program manager. "An artificial-intelligence process then determines the best response and initiates countermeasures."

Sensors include electro-optical devices, laser and IR detectors, and MMIC radars. Countermeasures range from IR and radar jamming to automatic smoke-grenade and anti-missile launchers distributed around the tank's turret.

Reflecting the new realities in defense procurement, IDS includes mostly off-the-shelf equipment and software with a minimum of expensive new-technology development. Getting the components to work effectively together will consume the bulk of the contract costs. Each team member's system-integration laboratory will be electronically linked with that of the Army's Tank-Automotive Command in suburban Detroit to facilitate program development. Such virtual co-location should also keep program costs on track. An IDS technology demonstrator mated to an M1A1 Abrams main battle tank should begin full-up testing in 1997.


Urethane toughens auto glass

San Angelo, TX--With increasing stories of crime and violence on roadways around the world, some people are looking for ways to better protect themselves and their automobiles. One option: bullet-resistant and break-in proof glass from Safe Car Inc.

The company laminates layers of glass and polycarbonate together to achieve additional strength, depending on the safety level desired. Dan Medlin, glass plant manager at Safe Car, explains that the adhesive in these laminations is critical to ensure a strong, durable bond, with no delamination once it is in the field. Visibility is also an issue, since the windows have to be as clear as regular glass.

Safe Car chose an aliphatic Stevens Urethane from JPS Elastomerics Corp., Holyoke, MA, for use as an optical interlayer in its safety automobile glass. The company selected that material for its excellent adhesion properties with both glass and plastic, as well as high levels of optical clarity, light stability, and quality.

"If the adhesive is of poor quality, it will delaminate with daily exposure to UV light, weather variations, and temperature extremes," says Medlin. "The Stevens urethane is impervious to these conditions, and it provides the impact resistance and elasticity needed to stand up to rigorous conditions."

Safe Car's combination of glass, plastic, and urethane can absorb the thermal and mechanical shocks caused by bullets or other projectiles. Safe Car says the lamination does not splinter upon impact, but actually absorbs the incoming force and reflects it back in the opposite direction.


Drive combines servo, vector characteristics

Eden Prairie, MN--One of the most frustrating experiences for a machine designer is to learn, late in the design, that the machine's motion-control system is inadequate. Subsequently upgrading from an induction to a brushless motor can be complex and costly.

With the introduction of a new universal drive, however, those changes may now be far less painful. The BRU-Series Advantage Line, designed by engineers at Electro-Craft, automatically configures itself as an ac brushless servo drive or high-performance vector drive. It can also adapt to input from almost any type of controller, accepting traditional n 10V dc analog, step-and-direction, master encoder, or serial digital commands.

Using the new drive, engineers can easily optimize the motor and control system during the design process. "The advantage of this product is that you have the flexibility to control both types of motors or any type of controller," notes George A. Kaufman, director of engineering and business development for Reliance Motion Control.

Up to now, vendors haven't offered a drive that could be configured for both types of motors. The primary reason was that it wasn't cost effective to integrate the two technologies in hardware. Electro-Craft engineers solved that problem by integrating the logic and control elements in software. Even that, however, awaited the availability of cost-effective computer processing power to make the software work.

The universal drive's flexibility makes it well-suited to the packaging industry, where machinery typically employs brushless, vector, and stepper technology. Electro-Craft engineers say that the drive could also be used in web-converting, bag-making, and material-handling applications.

For the customer, the big advantage of the new system is flexibility, say Electro-Craft engineers. "By standardizing on a single drive, customers cut their inventory, their learning curve, and their maintenance costs," says Connell Smith, product marketing manager for Reliance's servo systems. "For example, if they have a conventional stepper drive and they want to upgrade to a servo, they have to tear it all out and put in a control that accepts an analog signal. But with this new drive, they simply reconfigure it in the software and they have the performance they need."

--Charles J. Murray, Senior Technical Editor


Honda of America finds a better way to bond

Anna, OH--When Honda of America sought to improve the gasketing process used to seal engine block ends (the oil pump and the main oil seal cover), the company looked for a gasketing material that would provide 100-percent adhesion on oily surfaces.

The challenge was to find a "drop-in" material that could be used in production without disrupting the assembly line. The outcome was Ultra-Grey(TM) 5699--an oil-resistant, primerless adhesive from Loctite Corp. that adheres to iron, light alloys, and plastics.

The Honda evaluation team tested Ultra-Grey(TM) 5699 in the laboratory, on the line, and over-the-road. They felt it offered the necessary sealing performance, fluid resistance, and high-torque retention. They also discovered that when the product is applied to oily surfaces, it offers oil resistance at higher temperatures. As a result, Honda specified it as the gasketing material to help seal and protect all of the Honda Civic 1.5 and 1.61, Accord 2.0 and 2.21, and Gold Wing motorcycle engines that are manufactured at the Ohio plant.

According to Honda, the implementation of Loctite Ultra-Grey(TM) 5699 was accomplished with minimal modifications. The sealant was dispensed using the existing equipment with only minor programming changes and air pressure adjustments, thus accomplishing the goal Honda had set forth--increased productivity and a better engine.


Aquaculture gains stability through software

Bainbridge Island, WA--While fish farms inshore have long been commonplace, offshore aquaculture has been more difficult. However, Ocean Spar Technologies (OST) recently was able to design an open-ocean pen system for raising fish.

The company studied the problem of keeping aquaculture pens stable in rough, open ocean waters for years before hitting on the "ocean spar" concept: vertical steel buoys anchored to the sea bottom that serve as floating fence posts for nets, keeping them relatively stable through constantly shifting currents.

Gary Loverich, chief engineer and part owner of OST, used computer simulations to test the stability of his net pen system before deploying an expensive, large-scale prototype in the deep sea.

Heavy currents and waves put a lot of fatigue on the net farming system. The most critical points are loads on the synthetic mooring lines that retain the nets' shape while securing them to the posts, or spars. Loverich used Working Model(R) software to measure these loads.

Once Loverich finds the proper load on the mooring lines, and the acceleration of the spar, he then exports the Working Model data to his COSMOS/M FEA program and tests the system to make sure that the hardware connecting the two components is strong enough.

In the Working Model simulation, a vertical spar or spars float in a coordinate axis system. The wave force is depicted by an arrow, which increases or decreases as the wave passes. Loverich measures the tension on the anchor lines, and the velocity of the spar buoys. Overall, he believes, motion analysis has helped decrease his risk and increase the dependability of his product.


Computer simulation key to mine-clearing system

Indian Head, MD--Thanks to computer-simulation technology, U.S. troops may avoid the dangers of minefields.

The Naval Surface Warfare Center is developing a defensive weapon system called the Distributed Explosive Technology (DET) system. It consists of a large net-like structure of rope woven with explosives. Towed downrange by a pair of rockets launched simultaneously, the net unfurls to cover thousands of square feet. Its array of explosives detonates upon impact, safely triggering detonation of all nearby mines without endangering personnel.

It's a simple concept, but the military's initial 2-D analysis code for simulating array deployment was useless. Engineers say it couldn't represent the three-dimensional nature of the system, especially the aerodynamic forces acting on the array.

ADAMS software from Mechanical Dynamics, Inc. (MDI) helped them predict the deployment characteristics more closely, and enabled them to do more design iterations. "We were able to choose the appropriate flight configuration before our test flights, which was critical because of our budget," says Robert Kaczmarek, program manager of the Mine Countermeasures Division.

Using a lumped-mass approach, they modeled the array by a large mesh of masses connected by elastic representations of the ropes. The result was a closer approximation of the actual trajectory of the DET system. Additionally, MDI devised a special module linked to ADAMS for computing airflows on the array. MDI obtained data for the model from extensive wind-tunnel tests it conducted at the University of Michigan.

To boost computational speed, MDI developed a point-mass element for the lumped-mass array model. Those elements reduce the number of equations to be solved.

--Gary Chamberlain, Senior Editor