91zulu

My Feedback: (2)

From the initial post it did not seem like he was flying slow. That would be an obvious stall situation. I sounds like the plane was flying along above stall speed but wanted to roll left. That from my experience means something is off. Balance, control surface, or wing problem. P factor kick in from the time the throttle is open on take off run and even more when the plane leave the ground. He said the take off was good but as the plane flew he had to continually correct right . I bet if he changes prop to 13x8 the same thing will happen. I flew some pattern planes back in the 90s and it was normal to use larger diameter props for the up lines. None of them rolled left because of the larger prop. Another clue was trims were not helping. Also he need to check aileron and rudder servos to be sure one is not bad.

ram3500-RCU

My Feedback: (221)

One correction, Torque and wing warp do require aileron trim, as well as a heavy LEFT wing. But NOT weighting the right wing. That is the beauty if it. The engine cancels the weight the on the RIGHT wing. If you have the correct weight, absolutely no aileron trim will be needed. If you do need a little left aileron trim (with a neutral rudder), you need a little LESS weight. If you still need a little right rudder trim, you need a little MORE weight. It works, and for war birds, I find it especially beneficial.

BTW, you would think when landing, this would cause a noticeable right wing drop, but not so. It is hardly noticeable because at landing speed, you are holding all the sticks anyway.

ram3500-RCU

My Feedback: (221)

I understood his post the same way 91zulu. Flying around at stall or just above stall would be an obvious problem with an engine at full or near full throttle, and he made no mention of that.

Didn't get the impression it was the lumbering box of balsa P-40 driver describes.

LDM

My Feedback: (15)

Let me be clear on one point of discussion and perhaps why flying with larger props was not an issue for me for so long . At no time flying my VQP40 on a saito 91 , or Top Flight on a Saito 120 or CMP on a Saitio 180 all with now perceived larger props was I ever lacking of power in any way .
As a matter of fact , I would and could easily fly a mid throttle .
The 4 strokes on wood props seem to haul as,,,, easily , its this VQ P40 that had me puzzeled .

91zulu

My Feedback: (2)

A wing drop caused by torque will happen when the wheels leave the ground. I don`t think a 91 4 stroke will produce that much torque with a 15x6 during flight to cause a constant wing drop unless the plane is flying very slow. If that was the case there would be a very good chance he would have crash. As stated by ram3500 the weight of the wing counter act that factor. Now if the plane only weigh 5 pounds then that is a different story. Torque will surly be a big problem.
Something is off. He has to find out what it is. Its not the 15 inch prop.

91zulu

My Feedback: (2)

LDM you can forget the prop and torque . That is not your problem for sure.

rcflyer4fun

Lou check your radio programming. Make sure there is no unwanted programming causing your problem.

LDM

My Feedback: (15)

Radio is great , did that check and have used it on 2 other planes ect .
Ok if this was a CSI team its getting more puzzeling ,
"A wing drop caused by torque will happen when the wheels leave the ground"it does happen , i correct it immediatly with rudder and alerons , obviuosly there is not enought speed to fix just with the alerons so rudder is was my main rescue tool .

One thing I did not do , the version #2 VQ release was supposed to have wing washout added because version one virtually has no washout . I can easily fix this with some up trip on both alerons , just wondering if the desire to snap left could be caused by the lack of washout but .... remember when flying a good speed with 100% rudder /airleron correction the entire flight , (in other words ) fighting a left wing snap the entire time the plane will fly with left rudder and slight left aleron .

Experten109/40

My Feedback: (-1)

was it doing that since day one or is this a more recent thing?

LDM

My Feedback: (15)

One maiden flight now its grounded until I can decide what the problem is

P-40 DRIVER

Hey LDM, did you build this plane, how much does it wiegh. are the flaps fully retracted and even.

P-40 DRIVER

Another thought, that plane has a huge amount of roll coupling on the rudder so the rudder can cause alot of roll issues if it is not in trim.

SIMCO

My Feedback: (33)

Borrow some one's angle of incidence meter and see if you have wing warp. Every one else has played out your airplane with good suggestions. Or put it on the floor and measure with a ruler from floor to leading edge in several areas from side to side. If it'd warped you will see it. Apply heat gun to warped side and hold while cooling to take out the warp..

G-Pete

Seems to me the geometry of the airplane is off.

What I'm suggesting is, the wing sits not perpendicular to the airframe center in the saddle.

A little off thrust angle on the engine mount makes not that much difference.


And for the guys with the theory about too big of a prop - well, I just give you an example a 25 inch solo 4 blade prop (weight 2.5 pounds) swinging on front of an 30 pound 85 inch airplane. The motor has 10 hp. Engine is 1.5 right and 1 degree down. She is NOT torque rolling..and if, this would be compensated with a few clicks aileron trim.

Airplanes who are not build straight are fish tailing. Simple as that, just sad is - 95 out of 100 are build not straight.

91zulu

My Feedback: (2)

LDM I think you need to go over your wing with a fine toot comb. Also check your horizontal stab. Make sure no trailing edge is down more than the other. Please check your wing and let us know what you find. Something is out of line. Please note most times you just can`t look at a wing and tell it is warp. There are measurements you need to take or use a dowel on each wing tip, about 24 inches each piece . Lay the dowel about 6 inches from the end across the wing leading edge to trailing edge. Secure it there. Do the other wing tip, then hold the wing trailing edge pointing up to the ceiling parallel to the floor and look at the two dowels . They should line up with each other looking at the wing ,wing tip to wing tip. Let us know what you find.

Experten109/40

My Feedback: (-1)

that sounds like adverse yaw. I do beleive thats when one wing is producing more drag, thereby dipping
that wing. perhaps a landing flap is the culprit.

rcflyer4fun

Sounds like you have a bad servo. I had one go bad this weekend on me my plane did the same thing

LDM

My Feedback: (15)

Ok guys I found the problem and its two causes .
1)The dowel test worked , the left wing has a warp
2)couple this is a slight gap on the wing to fuse that is visable when you get on your knees and look at the plane from the ground up .
part two is easily fixed , more so then the warp .
I cant thank you guys enought , if I am ever missing anything important I am reaching out to you guys .
Your the best and true tribute to what this hobby can be nice people helping total strangers with a problem .
Thanks a ton , I should be able to get both of these fixed and I will still downsize my props a bit , I think I was still overproping my planes

All Day Dan

My Feedback: (5)

Good news. Tell us how your next flight goes. Dan.

P-40 DRIVER

Thats good news, Its pretty hard to make a crooked wing on one of theses planes if you follow the directions. As for fixing the problem, that could be a problem. Good luck and let us know how the next flight goes. You might be able to compensate with flap, but be careful, it might cause more harm then good. I think I kind of assumued you had checked all that when you set up the plane originally. Thats what you get for assuming, I suppose.

91zulu

My Feedback: (2)

Ok that `s great you found the problem. Now to fix that I`ll leave to the experts on here. Me personally I would contact VQ and get a replacement wing . Take a pick of the wing with the dowels and email it to them. That twist most likely occurred during assembly . They should send you a new wing .
Fixing warps is not easy . Especially sheeted glass wings. You have to know what you are doing or you will damage the wing. There is a method using heat and weighting the wing down. You have to go past to point you want to be because when the weight is removed the wing want to go back to where it was. So the trick is how much past to go so when it goes back it stop on point. Get as much info on how to go about fixing the warp before you start. Remember if it get damage then you most likely will have buy a new one. Would n`t hurt to make the call first to VQ. I hope they have good costumer service.

LDM

My Feedback: (15)

Thanks , P40 I did check the wing in the beginnig as stated , I check every angle , actually I am very experienced builder , only been doing the arfs the past 5 years due to work load ect .
I was fooled by a plastic fuse former that made the problem seem miniscule when actually it was measuably off by more then it appeared .
One more thing , the plane also lack washout as speculated ,that I can fix easily
Thanks again

P-40 DRIVER

Now I'm totally confused, I thought we were talking about a top Flite P-40. A VQ is a whole different thing. I retract everything I said except for you need a smaller prop. There is no washout in the wing but it did not seem to be an issue with mine. Easy flying plane, gears a bit flimsy,

Peter_OZ

My Feedback: (1)

Lou,
how you doing mate? Long time no chat, hope all are well and the biz is solid?

Lots of good tips there.

If you back off the power does the left yaw still persist? If it does not then quite possibly a engine thrust angle issue.

If it does persist with power backed off then I would be looking at your fin to ensure it is true to the fore / aft line.

Others have stated lateral balance, good point but would think that affects bank angle not yaw. check it anyway.

I would not think overpropping would cause the effect you mention, on a YS120 maybe but on a OS .91? Hardly a power house. My TF P40 was 9 1/2lbs with a OS 120III Pumper and I had that over propped as well, no dramas. My only problem was CG was wrong! eeek

When CG was spot on it flew beautifully and landing with full flap were a dream.

By the way I have just picked up a P40, 96" span, with 3W-75 and rotating retracts and wheels by Custom retracts here in Oz, kit is glass fuz with foam core wings and build up tail feathers. Will do it in RAF North Africa scheme with shark mouth.

still to build it.

cheers
PEter

RBean

LDM, glad you finally found the problem. I've learned you need two pieces of equipment. An incident meter and c.g. gage. If the fuslage is reasonably straight, the wing and tail straight, the c.g. correct, the airplane will fly. Before I fly any airplane, wether kit built, ARF or aquired used, I always check with the incident meter and c.g. gage. Also good if a warbird has about 2 degrees right thrust. But you know all this, so why did it take you so long to find the problem? I have a VQ P-40 less than two yrs old. Measured for washout with the incident meter. It has none, but it flys ok. Are you going the the Warbird Fly at Andover, NJ on May 15? Not too far so I'm going to try to make it.