Intrepid175
Heliman
Location: Texas City, TX
| Actually, that one's not as bad a the original design that it's based on.
The autogyro it's based on is the RAF 2000, a Canadian built machine that sits a lot closer to the ground and the engine thrust line is somewhat higher, relative to the cockpit. NOT a good thing. The RAF 2000 also doesn't, or didn't the last time I looked into them, have the horizontal stab that this machine has. Both of these differences means that the gyro is more prone to a VERY unfortunate thing called a PPO or power push-over.
Pusher style autogyros, like the one pictured, can be very safe to fly but it is VERY important that certain design parameters be maintained. For/Aft CG is obviously important as it is in any aircraft. Another parameter that's equally important, especially in the pusher style gyro, is that the thrust line of the engine be as close as possible to the "vertical" CG of the aircraft. Many pusher designs, like the orginal version of the RAF 2000 mentioned above, had an engine thrust line that was several inches "above" the vertical CG of the aircraft. Since the aircraft always flys around it's CG in pitch, roll, and yaw attitudes, that hight thrust line is always trying to rotate the aircraft foward around the vertical CG. As long as the rotor system is producing adaquate lift, it can counter this nose down force. If the pilot unloads the rotor disk enough, the engine thrust will try to rotate the aircraft foward around the vertical CG and you'll get a VERY fast forward flip, or power push-over. There have been many pilots killed by this maneuver through the years until they finally started getting a handle on what was really happening.
If you design the aircraft so that the engine thrust line passes through the vertical CG, then you won't have that forward flipping moment if the rotor system is momentarily unloaded. The design of the aircraft pictured above is that way to minimize this problem. Also, the horizontal stab that's located on the rudder and right in the slip stream of the prop, helps to stabilize the aircraft in this mode. The original RAF's didn't have a horizontal stab.
Another option is to stick with the tractor style gyros. Check out http://www.flygyro.com/littlewing/. The prop is in front and the thrust line is always right in line with the vertical CG of the aircraft. Also, the tail feathers are much farther away from the CG of the aircraft to they have a lot longer moment arm with which to control the aircraft so the design is generally way more stable than a pusher design, especially at higher airspeeds.
Properly designed, and with proper pilot training (as is needed with any aircraft!), a gyroplane is one of the safest flying machines on the planet. They can take off in relatively short distances (especially if they've got a pre-rotator on the main rotor) and can consistantly land in 20 feet or less, 0 feet with a bit of a head wind, and they can't stall or spin like a fixed wing aircraft.
The main thing with gyroplanes is that they ARE NOT helicopters and they ARE NOT airplanes even though they share similaties with both. They have their own Idiosyncracies that have to be learned and respected which is where that all important pilot training comes in!
FWIW!
Fly Safe,
Steve R. |
