Beware the most common mistakes
"Gyros have things to be aware of too. Pilot Induced Oscillation, or "porpoising" as it is sometimes called, is one of them. It is caused by delays in the pilots reaction time and the over controlling of the aircraft. It can be likened to an automobile that has lost traction at the rear wheels in a cornering situation. First, the back end swings one way and then the other. As the driver attempts to fight the skid he unwittingly contributes to the severity of each successive skid because his responses are "out of sync" with the vehicles movements. Rather than correct the "fish-tailing" the actions of the driver actually help the car into a spin. In a gyro, the movement is up and down not side to side, and that is why it gets referred to as "porpoising". But the result is the same, except instead of a spin, he causes the aircraft to flip over. The pilot thinks he's making the proper corrective control inputs, but he's late and too exaggerated with his movements. At this point he actually helps the aircrafts oscillation increase until it rolls forward, or the rotor blades make contact with the propeller or tail and cause the aircraft to break apart. A gyro pilot will learn all about PIO and how to keep it from happening during training. And just like the stall of a fixed wing aircraft, it's just a characteristic of the aircraft to be mindful of". http://www.gyrosaway.com/ppo_and_pio.htm
"Power Push Over, or sometimes referred to as a Buntover, is a characteristic of pusher type gyros that have a thrust line above the centerline of drag of the fuselage. PPO occurs to gyros when the lifting force and the drag of the rotors is no longer sufficient to keep the thrust of the propeller from pushing the top of gyro into a forward roll. When designing a pusher gyro, one of the problems is how to apply thrust from the propeller to the center of the mass (and drag) that hangs below the rotor. The propeller has to be up high enough to clear the ground and the pilot usually sits low. So most designs started out with the center of thrust above the center of mass (and above the center of drag of the fuselage). This is no big deal most of the time because the lifting force of the rotor disc is angled forward and combined with the drag of the rotor itself, the top of the gyro is held back in normal flight. The times it does cause a problem though, is when the rotor blades are unloaded and their lift and drag is greatly reduced and the engine thrust is at a high setting. This can happen when you are making a steep climb under high thrust. The pushing force on the back of the gyro is high and the lift and drag of those big rotor blades keep everything balanced during the accent. Now, if the pilot quickly pushes the stick forward before he throttles back the engine, he can unload the rotors and the thrust of that hard pushing propeller can tumble him forward. This is considered an unrecoverable situation. As written above, PIO can unload the rotors too, and so can wind shear. Any thing or action that causes the rotors to unload can cause PPO. With proper training a pilot can avoid making the maneuvers that can cause the power push over and be ready to react to turbulence. In addition to training the pilot to avoid these problems, designers are helping too. Early gyros did not have a horizontal stabilizer, but many people now agree that having a horizontal stabilizer greatly reduces the risk of these problems due to the engine thrust moving over the stabilizer, and have now incorporated them into their designs. Also, most Gyro manufacturers are now producing "Centerline Thrust" models. And some even sell upgrade kits to raise the pilots seating position on older designs so that the thrust line is even with or lower than the center of drag of the fuselage". A “Bunt-Over” is not necessarily a Power Push-Over. Without adequate gyroplane configuration design, a bunt-over can be initiated by wind gust, pilot over-reaction, or sudden power changes. http://www.magnigyro.com/features/GyroTerms.pdf http://www.gyrosaway.com/ppo_and_pio.htm
A situation whereby the torque on the airframe by the engine causes an uncontrollable Roll-Over upon loss or rotor thrust and control at low g or zero g load on the rotor. Ref:http://www.rotaryforum.com/faq/GyroTerms.pdf
Tip by SkY (Ariel Devulsky)
Flight outside the certified flight envelope
No fuel, Running out of fuel, Fuel line blockage, Brittle fuel sight tube becoming detached in flight
Over unfriendly terrain, Not trained by a qualified flight instructor for power off landing, Not trained (in theory) about how to land over trees or water, Don`t know the best aircraft Glide Ratio., Failure to consider, evaluate and identify emergency landing areas
Flight behind drag curve
Flaring too soon
To land on the uneven terrain, a beach that looked like hard sand but was actually soft sand
FW disregard for right of way during landing, Ignore radio calls, Distraction
Try to impress someone (audience, friends...)
Take-off, Poor rotor management in take-off run / spin up, Take-off with high speed pre-rotator engaged
Poor weather decisions
No preflight inspections or checklist
Ignore MTOW (Maximum Take-Off Weight)
Improper use of your own skeleton for the purpose of testing when you have cheaper alternatives, Wind tunnel testing, Computer calculation and simulation, Radio controlled gyro-copter, A brave pilot, a parachute for himself and another for gyrocopter.
Wire strike, Power lines you Cannott see, Distraction and low flight
The belt helmet(s) not fasten or properly fasten
The blades, Tools left on the engine going throught the propellers, Hit objects on taxiing, takeoff or landing, Hit Trees, Hit souls who walk into spinning propellers, Bird strikes, Hail
Flying fast down wind refering to ground speed not airspeed
Flying in wind conditions above pilot's level of experience
Heavy head winds suddenly shifting to 90º cross winds during attempted landing
Heavy winds rolling off tree tops can create rolling horizontal "tubes", creating localized micro bursts of quickly alternating up and down drafts, or shears, which may disappear as quickly as they form - like horizontal dirt devils.
Manoeuvring at low level with a low margin of terrain clearance.
High confidence and little knowledge
Poorly trained pilot
Pushing ahead too fast on training
Flying task requirements exceed pilot capabilities
Medical issues, Stress: Am I under psychological pressure from the job? Worried about financial matters, health problems, or family discord?, Medication: Have i been taking prescription or over-the-counter drugs?, Illness: Do I have any symptoms?
Incorrect Eating, Am I adequately nourished?
Flying whilst intoxicated, Alcohol: Have I been drinking within 8 hours? Within 24 hours?
Too tired to fly, Fatigue: Am I tired and not adequately rested?
Do not take seriously Stress Management, First in Life, Second in Cockpit
Risky Attitudes, Anti-Authority, Trap: "Don`t tell me what to do.", Escape: Taking chances is foolish, Impulsivity, Trap: "Don`t think. Do it quickly", Escape: Follow the rules. They are statistically right, Invulnerability, Trap: "I can do it. I`ll show them"", Escape: Don`t try to impress anyone. It could happen to you., Resignation, Trap: "Shit happens", Escape: I'm not helpless. I can make a difference.
Numerous studies indicate that many accidents have occurred when the pilot has been distracted during critical phases of flight.
Bad design or modification
No horizontal estabilizers
HTL leading to PIO
Rudder too small
Non castering nose wheels
Cabin door opening in flight
Other non-technical modification by non-aeronautical engineer
References (in construction) Rotorcraft Flying Handbook (FAA-H-8083-21) http://www.gyrosaway.com/ppo_and_pio.php http://www.faa.gov/training_testing/testing/airmen/test_standards/pilot/media/faa-s-8081-29.pdf http://www.magnigyro.com/features/GyroTerms.pdf And again, all PRA forum members. Ground resonance Report. http://www.ntsb.gov/aviationquery/brief2.aspx?ev_id=20010810X01651&ntsbno=NYC01LA196&akey=1
All PRA forum members
First version: 02-13-2013