spraybar

Hi Guys,
I am new to building these V-Tail pylon racers, can any body help me with the following answers to these questions.
I have built a Q500 racer, I have glassed & painted it & it looks really awesome I test flew it the other day fly's really good, but it was climbing so
I had to feed in about three trim clicks of down Elevator, now what I want to know is if somebody can tell me, if I sand the back trailing edge of the wing saddle
Would that square up the elevators to the tail plane, & then the elevators would be neutral to the tail plane. I don't want to cut the tail plane out of the fuse just
To move either the trialing edge or the leading of the v-tail up or down cause its all been painted so nice ah! so could i just sand the back of the wing saddle & would that correct the neutral position of the v-tail by doing this or would I have to sand the front of the wing saddle to correct this problem can some give me some advice please.

BobHH

My Feedback: (18)

To fix your problem you would need the front of the wing saddle sanded to lower the leading edge thus decreasing the lift. Before I would do that I recommend putting a small shim under the rear trailing edge say 1/32 plywood and test fly it. Keep adding these shims until you get your desired results. If it only requires a shim or two then my suggestion is to pot the wing in with the shims in place thus eliminating the need to sand the wing saddle.I never pot a wing in until I test fly the model to see if it needs any final trimming.

Bob Harris

fizzwater2

My Feedback: (61)

high wing or low wing?

spraybar

Its a high wing same as a viper.

fizzwater2

My Feedback: (61)

Bob's correct then, for a high wing - you need to raise the trailing edge of the wing a tad, not lower it. For only 3 clicks of down trim, I wouldn't expect you'll have to raise it much - start small.. 1/32" or so, shim till you have it where you want it.

Or sand the LE, but shims are easy, and you can try a little at a time, find out how much you'll need to shift it.

BobHH

My Feedback: (18)

Good catch Fizz. I forgot to ask whether high wing or low. I thought I was the only one flying low wings!!!!

Bob Harris

fizzwater2

My Feedback: (61)

We see some every once in a while at a 424 race - old scat cats, doddgers, etc. Not very often, mostly vipers & scratch builts, but once in a while someone will dust off an oldie and come play with us at a 424 race.

spraybar

Hi Guys,
Just want to thank all you guys for your information, & what I will do is first put light shims either side of the trailing edge of the wing saddle & fly it once I do that & it brings
The V-Tail back to neutral on the tail plane, I will know then to lightly sand the leading edge of the wing saddle, this all sound correct to you guys.

fizzwater2

My Feedback: (61)

sounds good. I'd be tempted to make the shims permanent after you get the plane flying the way you want, and "pot" the wing to the fuse with the shims in place. Potting the wing is a good idea anyway, it helps stop air leakage in the wing/fuse joint, which only creates drag..

spraybar

Ok
Thanks fizzwater2