Comanche helicopter blends CAD models from 14 suppliers

A finished Comanche is a soup of components with 40 main parts coming from 14 suppliers in 21 states.

Huntsville, AL-Boeing-Sikorsky's RAH-66 Comanche helicopter is designed for armed reconnaissance, light attack, and air combat.

Scheduled for production in 2004 and deployment in 2006, the five-bladed rotorcraft reflects the U.S. Army's post-Cold War strategy to deal with conflicts with a small number of people using long-range aircraft based in the continental U.S. And since the military will have fewer soldiers, the helicopter has the added design targets of improved mobility, increased survivability, and reduced operation and support costs.

To achieve these goals, the two-man craft boasts cutting-edge systems like triple-redundant fly-by-wire controls, helmet-mounted displays for the pilot, triple-redundant electrical/hydraulic systems, and self-healing digital mission electronics.

But one of the hardest parts of this job is bringing all the suppliers together. With 40 components coming from 21 states, the joint project between Boeing (Philadelphia, PA) and Sikorsky (Stratford, CT) depends on the cooperation of 14 main suppliers:

  • Boeing Electronics Systems, Seattle, WA

  • General Dynamics, Burlington, VT

  • Hamilton Sundstrand, Windsor Locks, CT and Rockford, IL

  • Harris Corp., Melbourne, FL

  • Kaiser Electronics, San Jose, CA

  • Lear Astronics, Santa Monica, CA

  • LHTEC, Indianapolis, IN and Phoenix, AZ

  • Link Training and Simulation, Arlington, TX

  • Litton, Woodland Hills, CA

  • Lockheed Martin, Orlando, FL

  • Moog, East Aurora, NY

  • Northrop Grumman, Baltimore, MD

  • TRW Military Electronics and Avionics Div., San Diego, CA

  • Williams International, Walled Lake, MI

Mission: Interoperability. One tool that has allowed these diverse suppliers to work together is CAD translation software called Acc-U-Trans(TM) from Translation Technologies Inc. (TTI, Spokane, WA). An engineer sends his file to TTI's central server-protected with 128-bit security-then retrieves it within 48 hours. The new file behaves like a native model, complete with functional history tree.

In the helicopter project, contractor Williams International had used Pro/Engineer (Pro/E) to design a small gas turbine engine, called a Sub-system Propulsion Unit (SPU). This complex, 250-piece assembly would usually require much time and money to translate into the CATIA system that Sikorsky uses for its electronic mock-up (EMU).

But using Acc-U-Trans, Sikorsky saved 75% of the time and 50% of the cost, compared to remodeling the SPU themselves, TTI says. Where it usually takes Sikorsky five months to rework suppliers' designs using STEP or IGES direct translators, TTI returned them within six weeks, says Tom Kopinski, TTI's VP of business development. The typical cost for such translation is $140 per 150-feature file. In the Sikorsky case, the 148-Mbyte assembly was dissembled into its 250 component files, which were translated independently and then reassembled.

Today Acc-U-Trans works with CATIA, Pro/E, Unigraphics, and I-DEAS, and will announce a capability for SolidWorks in the first quarter of 2002. At that time, it also plans to release an enterprise version to run inside a company's firewall, says Lee Taylor, TTI's VP of marketing.

For videos of the Comanche, check out or And see for a geographical breakdown of components from nearly half the states in the country.

For more information about software from TTI: Enter 533


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