GrantR
Senior Member
- Joined
- Jul 16, 2007
- Messages
- 1,329
- Location
- Plains, GA
- Aircraft
- Kolb MarkIII and a "Jake" Gyroplane
- Total Flight Time
- About 85 fixed wing 3 gyro
In the rotorcraft flying handbook is states that
A high TL cause a nose down pitching so the rotor has to be tilted back more to overcome this nose down pitch or the gyro will dive. So when the rotor is tilted back that automatically puts the RTV further forward and ahead of the CG thus making it tail heavy. This is how it compensates for this nose down pitching moment. With no horizontal stabilizer tilting the rotor back is the only way to over come this.
So in a high thrust line Gyro the engine thrust is fighting with the rotor thrust. The rotor wants to keep the nose up and the engine wants to put the nose down. When one variable changes whether rotor thrust or engine thrust it causes pitching, nose up or down in the airframe since the change causes an imbalance in the opposing forces. This plus being tail heavy makes the aircraft unstable.
Now I am going out on a limb and say it seems to me a HTL is safe with a large HS that is trimmed and capable of creating enough down force on the tail of the gyro to offset the nose down pitching. It seems if its trimmed just right it could even cause a nose up pitching with increased engine thrust. Now if the gyro sees 0 or negative Gs this is where it gets confusing. I know from reading the H stab mods for one type of HTL enclosed Gyro is not big enough to offset the massive amount of nose down pitching the HTL causes.
Using an effective H stab at full power, is there a bunt possibility since the H stab is trimmed to create enough down thrust to offset the nose down pitching? Or At full power is there a bunt possibility since the H stab is trimmed to create enough down thrust to offset the nose down pitching in normal flight with a loaded rotor?
if you have a gyroplane where the CG is below the propeller thrust line, the propeller thrust gives your aircraft a nose down pitching moment when power is applied. To compensate for this pitching moment, the CG on this type of gyroplane is usually located behind the rotor force line. This location produces a nose up pitching moment.
Then it goes on to say fuselage drag, pitch inertia and the addition of a Horizontal Stab can alter when the CG is placed.
A high TL cause a nose down pitching so the rotor has to be tilted back more to overcome this nose down pitch or the gyro will dive. So when the rotor is tilted back that automatically puts the RTV further forward and ahead of the CG thus making it tail heavy. This is how it compensates for this nose down pitching moment. With no horizontal stabilizer tilting the rotor back is the only way to over come this.
So in a high thrust line Gyro the engine thrust is fighting with the rotor thrust. The rotor wants to keep the nose up and the engine wants to put the nose down. When one variable changes whether rotor thrust or engine thrust it causes pitching, nose up or down in the airframe since the change causes an imbalance in the opposing forces. This plus being tail heavy makes the aircraft unstable.
Now I am going out on a limb and say it seems to me a HTL is safe with a large HS that is trimmed and capable of creating enough down force on the tail of the gyro to offset the nose down pitching. It seems if its trimmed just right it could even cause a nose up pitching with increased engine thrust. Now if the gyro sees 0 or negative Gs this is where it gets confusing. I know from reading the H stab mods for one type of HTL enclosed Gyro is not big enough to offset the massive amount of nose down pitching the HTL causes.
Using an effective H stab at full power, is there a bunt possibility since the H stab is trimmed to create enough down thrust to offset the nose down pitching? Or At full power is there a bunt possibility since the H stab is trimmed to create enough down thrust to offset the nose down pitching in normal flight with a loaded rotor?