Fliegenmong
4th Sep 2006, 06:57
Ok – here it is...
My son and Father and I fly model aircraft – and I fly full size also – collectively we prolly have around 65 odd years worth of experience.
In desperation I have come to the place where the most esteemed aerodynamic minds on the planet live……..
http://rchobbies.com.au/store/product_info.php?products_id=262
I don’t know if above pic works but a simple google. “Electrofun” will get you a pic. Pls follow link to understand the A/c type I am referring to. A simple pod and boom pusher design, three channels, Elevator, rudder (relying on the secondary effect of yaw to produce the roll) and an on or off motor.
Flies great or flew great for several years, until the wear and tear meant I had to replace the wing & horizontal and vertical stab. This last weekend, all replaced and a check to see that all is square and the wing is at the right incidence – equal distance to tail plane tip to wingtip, viewed from the front – behind the side etc etc, all ready to go and the A/C spirals in to the left. I bent some trim in to the rudder for a right hand turn – this time I was able to manage get the a/c to make a shallow right hand turn but upon stopping the motor (And so losing the prop wash) the plane settled back into an unrecoverable left hand turn, even with full right hand rudder deflection (& manually adjusted to give the maximum possible deflection.)
Now I have tried bending in more right trim, and the radio set on full right hand trim, I have moved the wing toward the down going wing, I have added weight to the right hand wing, added balsa shims under the down going wing to try and increase its angle of attack. Finally in desperation I have added a fixed ‘Barn Door” size aileron on the left wing in order to try to pick it up. This makes it very unstable under power but once the motor is cut the application of full right rudder still produces a diving left hand turn. I can simply not think why this is happening, everything else is lined up CG is correct, nothing has changed, there is no glitching of the radio signal. BRAND new wings and tail feathers and this problem is killing me – what the hell is wrong here??? It used to fly perfectly with really beaten up tailplane and wing – and track straight and true on the glide (a little trim under power) – yet now with a fixed aileron in the down position on the left hand wing, the fin top bent to hell to the right, and the maximum deflection right on the rudder and (aghast!) adding weight to the opposite side of the down going wing has produced a very unstable and unpleasnt to fly airplane under power but STILL settling into a left handed dive once power is pulled what am I missing!!!! I am finding this to be very very annoying as I cannot find a remedy to a problem I cannot see:{ :{
Any suggestions as to where to go from here??
Thanking you guys / girls in advance for anything you can think of (I may have already tried it!)
My son and Father and I fly model aircraft – and I fly full size also – collectively we prolly have around 65 odd years worth of experience.
In desperation I have come to the place where the most esteemed aerodynamic minds on the planet live……..
http://rchobbies.com.au/store/product_info.php?products_id=262
I don’t know if above pic works but a simple google. “Electrofun” will get you a pic. Pls follow link to understand the A/c type I am referring to. A simple pod and boom pusher design, three channels, Elevator, rudder (relying on the secondary effect of yaw to produce the roll) and an on or off motor.
Flies great or flew great for several years, until the wear and tear meant I had to replace the wing & horizontal and vertical stab. This last weekend, all replaced and a check to see that all is square and the wing is at the right incidence – equal distance to tail plane tip to wingtip, viewed from the front – behind the side etc etc, all ready to go and the A/C spirals in to the left. I bent some trim in to the rudder for a right hand turn – this time I was able to manage get the a/c to make a shallow right hand turn but upon stopping the motor (And so losing the prop wash) the plane settled back into an unrecoverable left hand turn, even with full right hand rudder deflection (& manually adjusted to give the maximum possible deflection.)
Now I have tried bending in more right trim, and the radio set on full right hand trim, I have moved the wing toward the down going wing, I have added weight to the right hand wing, added balsa shims under the down going wing to try and increase its angle of attack. Finally in desperation I have added a fixed ‘Barn Door” size aileron on the left wing in order to try to pick it up. This makes it very unstable under power but once the motor is cut the application of full right rudder still produces a diving left hand turn. I can simply not think why this is happening, everything else is lined up CG is correct, nothing has changed, there is no glitching of the radio signal. BRAND new wings and tail feathers and this problem is killing me – what the hell is wrong here??? It used to fly perfectly with really beaten up tailplane and wing – and track straight and true on the glide (a little trim under power) – yet now with a fixed aileron in the down position on the left hand wing, the fin top bent to hell to the right, and the maximum deflection right on the rudder and (aghast!) adding weight to the opposite side of the down going wing has produced a very unstable and unpleasnt to fly airplane under power but STILL settling into a left handed dive once power is pulled what am I missing!!!! I am finding this to be very very annoying as I cannot find a remedy to a problem I cannot see:{ :{
Any suggestions as to where to go from here??
Thanking you guys / girls in advance for anything you can think of (I may have already tried it!)