Raf Yaw Induced By Doors

[AFRICA MIKE]

Greetings. I am from South Africa and am new to this forum. I fly a RAF 2000, 2,5 which was recently built. I am new to Gyros and have minimal Gyro flying experiance. I have flown a total of 110 hours. I need input from experianced RAF pilots relating to the Yaw that I am experiancing with my RAF. The Gyro was flying absolutely fine, I flew at 90 MPH without any problems. I could have pushed the RAF beyonf 90 but chose not to. However, I recently fitted my doors for the first time. Before flying with the doors, I also had a panel beater do some touch up body work in my absence. I also then fitted the doors for the first time. My first flight with the doors on was a 130 mile cross country. However, the aircraft would not fly straight and level. It weather cocked to the side and required extreme rudder pressure to fly her. Initially, I assumed that the rudder tab had been bent by the panel beater ( body shop) Thereafter, I spent many hours adjusting the rudder trim tab, only to find that she would weather **** to the opposite side as if I had over adjusted the tab. I continued with finite adjustments withour success. I eventually arrived at the conclusion that I was failing to achieve the optimum adjustment or that the doors were effecting the aircrafts flight characteristics. I noticed that she also yawed from side to side under certain conditions( cross winds) However, the weather cocking to one side continued. Due to this weather cocking, my speed also reduced considerably and my fuel consumption increased significantly. I could not cruise above 70 to 75 mph max. I have now removed my doors but have not yet re adjusted my trim tab since removing the doors. Has anyone else axperianced similar such ocurrences. Do the doors have an adverse effect on yawing, the controls, weathercocking . speed , fuel consumption, etc. Could it be that the trim tab was inadvertently and erroneously bent by the technitian working in the rudder? Have I failed to correctly re align the trim tab? I will appreciate comment from pilots that have experiance in this area. Many thanks
Mike French

[gyroman]

Hi Mike welcome to the forum,

The yaw instability has been discussed several times on this forum. With doors on the tail surface of the stock RAF is inadequate. The ship will try to swap ends on you.

This is why the Sparrowhawk went with a substantially larger tail.

[StanFoster]

Mike: I flew a RAF200 with doors on from day one and never had any problems whatsover. However....I did have that Parham stab on it that had those winglets. I cant tell you how one flies without the winglets...but it flies great with them.


Stan

[Paul_Zurawski]

A friend of mine years ago had an RAF. I flew in it a few times without the doors, and it flew fine. He put the doors on, it really felt unstable in yaw. It would never track straight. After that, I didnt want to go up in it again.

[Alan_Loughrey]

Mike French,
We have had some success with vortex generators stuck to the doors with double sided tape. They will make the yaw more easily controlled. Ours are made from clear PVC and were placed at a point of maximum beam. Very cheap and easy to make, they will not damage your prop if they fall off.

[AFRICA MIKE]

Guys, Many thanks for the replies. They have been of immense assistance to me and have confirmed my suspisions.
Mike French

[reelmule]

Mike French,
I to am a novice pilot in the RAF although I am fairly high time in general aviation a/c, single and multi as well as conventional and trike gear. I completed my RAF 2.5 in Jan and since it's hard to teach an old dog new tricks I took 48hrs of dual in the RAF with two of the core group of instructors. The bottom line is you have to be very careful when transitioning from no doors to doors. It's recommended that you fly with one door only for a while before putting both on. After 90+hrs and 500+landings I decided to test with both doors and and light fuel load and no ballast. It was frightening! What I encountered was adverse yaw with roll. Cyclic became very heavy and rudders were extremely sinsitive-very easy to over control in either direction. I also have a HS made by Allen Lourey (NZ) and with this stab it makes the doors a non-event Please remember old silplane instrument-the yaw string which I had taped to my wind screen and eventually got my feet working correctly and may have saved my A---! Happy Landings
Reelmule
Walt George

[Gary_in_Orygun]

I also dealt with the "yaw with doors on" until I added the John Snider antiservo tab to the rudder. Now I can fly feet-on-the-floor most days even with the doors on. I don't know if he is still making that little kit.

I like Harry's idea better of getting a horizontal stab that has winglets. But since I already had a horizontal stab (without winglets), the antiservo tab was the next best thing.

[John_wilkinson]

Mike Alans vortex generators do help but one of Alans stabs with the side wings on it will fix your problem