The X2 design is scalable, which makes possible its use in several different types of missions. These include combat search and rescue, armed aerial scout, medical evacuation, attack, special operations, and the transport of VIPs and offshore oil. In addition to speed, Sikorsky expects that the design will give its RAIDER aircraft dramatic improvements over conventional helicopters in maneuverability, range, endurance, altitude, and hover efficiency. These should be attractive to the US Army, which is expected to replace its OH-58D Kiowa Warrior helicopter with a new light-armed reconnaissance helicopter design for its Armed Aerial Scout program.
Hexcel is a major supplier of carbon-fiber-reinforced composites to the Boeing 787 Dreamliner and the Airbus A350 XWB commercial aircraft. It is also the supplier of all the Airbus A350 XWB's primary structure prepreg, which includes Hexcel carbon fiber.
Sikorsky is investing about 75 percent of the expected cost of the S-97 RAIDER program, and members of the supplier team will invest about 25 percent. The program is currently in the advanced design stage. Demonstration of the helicopters' flight and aerodynamic performance in a simulated military environment is slated to begin in 2014.
Jerry, thanks for all the detailed info. It's interesting to hear about composite use for awhile in small aircraft, since the other "root" of their use has been in military aircraft going back several decades.
Re delam, Boeing is having ongoing problems with this, although they claim it's minor and won't slow production this time:
Composites have already taken over the small plane and kitplane industry. Now just eating it's way up the size chain.
A really good thing about most composites is they can be made from renewable or extremely common materials like sand and various biomass from fat to celulose with RE.
CF was and maybe still is made from carbonized Rayon thread which is made from celulose IIRC. Most if not all plastics, resins can be made from biomass.
With it's other advantages like lightweight, easy start up costs, doesn't oxidize and flexibility means it will be the future of transport and many things now done with metals which will become increasingly costly.
For instance starting up a Car production line in steel is about $1B vs one in Composites $10M. Sadly if 4wheels the legal is $15M so I'll build 2 and 3wh EV subcars legally motorcycles with almost no legal costs.
This is a really a great move. With the advancements in the field of SHM ( Structural Health Monitoring) systems it is possible to explore the possiblilties hitherto a bit cumbersome. Aircraft manufacturers are incorporating more and more composite materials into their new aircraft structures. Airbus' giant A380 is made of 25 percent composite materials, while about 50 percent of the weight of the Boeing 787 Dreamliner is composite, a dramatic increase over the approximate 12 percent used for B777.
It's mostly a QC problem as Boeing had with the Italian 787 parts they just couldn't build so they had to move the factory IIRC
You can make very good part with CF but you need people with experience and constant QC or your reject pile becomes very costly.
When I'm sailing new waters I always sek out local knowledge can make the difference in a pleasent cruise or losing the boat on some uncharted rocks. Same really in most fields, real life intrudes, things one would never expect, on carefully laid plans. This is especially true with CF where experience counts.
Sadly too many armchair quarterbacks and few who actually make things.
Jerry, thanks for the detailed reply. It sounds like you're saying it's tough to avoid delam during the CF composite manufacturing process--or perhaps during the process of making components out of the composites?--compared to FG. It's interesting that something as simple as the presence of absence of a color change can make such a big difference! It also sounds like the specific process method for making composites can make a big difference.
CF is shiny black with a very high surface tension means it really doesn't like to wet out throughly and because of the color, can't tell when it is completely wet out. With FG it is white and turns clear when fully wet out.
Even one area like this can down a helicopter/plane or in my case million $ racing sailboats in the FasnetForce10 race in the UK losing their pricy CF rudders .
Which really come down to do CF corectly one needs pressure resin feed very well designed or better, pultrusion forcing an much higher CF/resin ratio be squeezing it.
Or prepreg is great or very labor intensive of many thin layers I normally do.
And 1 small slipup and the 10% advantage CF gives disappears leaving one with a 10-20x's cost underspec piece.
For spars/wings, blades pultrused CF rods should take 90+% of the forces with the rest for shape, stiffness and hold the CF in columm is the lowest cost, weight, is the winning app.
And I just finishing details on a contract to build Composite 2kw wind generator blades of 16' dia which in many areas will power an eff home at costs well under coal for a customer and do my own design as well. Cost complete is about $3k/kw installed and they should work 50 yrs.
Customers blade like normal ones and mine is a variable pitch one without moving parts be tayloring the fibers, area, etc to make it twist as, when I want it too. This alone increases eff 25% while being lighter, easier to build.
Jerry, could you expand a bit on your comments regarding CF composite delam: "Delam is mostly a process/QC problem which extremely hard with CF." What's hard--having the problem in the first place? Catching it?
Finally a place where CF can earn it's keep! The skin and core of a helicopter rotor have little bearing on it as everything almost is in the capspar or whatever they call it. Most are made up of CF pultruded rods to take the forces.
Heli and windgen blades have very different roles and not much in common other than materials. WG blades and aircraft wings, bodies is another story with much in common.
Windgen and heli blade speeds are similar as both are limited by the speed of sound/drag. Also why they turn so slow rpm to keep the tips from getting close to mach1. Otherwise higher rpm would be much cheaper to work with.
And about time they went to twin rotors which is about 15-20% more eff/ payload plus the added speed plus more stable.
Delam is mostly a process/QC problem which extremely hard with CF. Prepreg and pultrusion are best way to make CF work. If you screw up just 10% then your advantage over FG is gone.
When you think of the DARPA Robotics Challenge, you may imagine complex humanoid contraptions made of metal and wires that move like a Terminator Series T-90. But what actually happened at the much-vaunted event was something just a bit different.
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