FTmustang65

My Feedback: (6)

Hello all,
I wasnt really sure where to post this question so I will try here first. I built a great planes piper cub 40 size and maidened it the other day. It was a little rushed( sundown not everything perfect) but i got it up and down. The only problem was that it was constantly banking to the left and I mean hard. I trimmed all the way to the right and I was still banking to the left it made it interesting to fly. Anyways after I got it on the ground and went over everything I notices I needed .5oz of lead weight in the right wing to balance the plane horizontaly when I lifted the nose. I did install servos in the wings for the ailerons. could this half ounce of weight really cause the plane to bank that hard or is it something else. I did have to adjust nose weight a little as it was a little bit tail heavy. I adjusted all of my throws in accordance with the manual now and have it zeroed out I am just a little bit nervous about flying it again haha I have been flying a few years so I know a couple things but this was a handful!!
Any ideas as if the weight was the issue would be great thanks
Henry

dignlivn

Henry,


I had the same thing happen with my Astro Hog
last year. Double check your Aileron throws and
the Lateral balance. I taped a quarter to the right
wing tip and it made a big difference. You could
try that as a temporary solution. Also try just
balancing the wing, I bet it's heavy on the left side.


Bob

skylark-flier

Hey Henry! Yeah, you've got a real plane on your hands, no doubt about it.

I've got one (same GP .40 Cub) powered with an OS .46LA and had pretty much the same problems that you relate - PLUS a few others.

The banking problem - if yours is like mine (and YES, I had to add a bit of tip weight to the right wing) you're getting "warp" from the wing support struts. I had a devil of a time eliminating that.

Tail heavy - YUP!!!!! She's got more "butt" than any woman I've ever seen. I added enough weight to the nose to make my pick-up tilt (well, not quite THAT much maybe) and it was just barely enough - she still has a tendency to stall if I let her get the speed down too much on approach.

Everything I've ever heard about Cubs, and mine proved most of them right, is that she's no easy plane to take-off, fly or land. You've got to be on her every second of the time. BUT!!!!!!!! She's one of the most impressively realistic planes I've ever flown - absolutely love to watch her pass over at speeds that make most planes fall out of the sky.

Dave

FTmustang65

My Feedback: (6)

Dave,
I have a saito 80 on mine and I was really thinking that my wing support might be off a little as I measuring an inch difference between the left and right wing from the ground to the wing tip. what did you do to figure the warp problem out?
Thanks and yes it looks beautiful coming over the landing strip.
Henry

Edwin

My Feedback: (2)

Use an incedence meter to check for wing warp. Make sure you check all your incedences. Alignment is important.
Edwin

CastorTroy2150

My Feedback: (10)

Hi Henry,
Maybe you should learn how to fly, then it wouldnt be a problem...., or you could come down here to Ohio, and I could teach you how to fly. Ha Ha.

skylark-flier

Tip height differences COULD possibly be due to landing gear differences, not wing problems - I wouldn't worry a whole lot about that unless you could absolutely PROVE it was the wing.

Had to re-locate the anchor point on one wing front anchor (about 1/8" farther out) and that took care of it for me. Didn't change anything on the support-strut, just where it anchors, which means it gets stretched and the wing gets warped a bit when you're putting it together at the field.

FTmustang65

My Feedback: (6)

Dave,
I bought and incidence meter and went through a few things the stab looks good the wing is showing a half inch difference between the left side and the right side (left side is .5 inch lower then right). Could that be the problem? Also I was looking at my engine thrust and I mounted my saito inverted and I am showing +2 degree thrust so my thrust is up I am no pro here but shouldnt the thrust be down if it already acts as a tail heavy airplane? I still have to measure the side thrust and the leveliness of the wing if thats a word haha. Thank you for the help.

Castroy Troy, remember I know where you live and if you come up to erie I will teach you a thing or two about flying and not electrics

FTmustang65

My Feedback: (6)

Dave also I was wondering what exactly you meant by anchor and support? Support being the dowel rods going into the plane and anchor being where you bolt the wing to the plane with the nylon bolts. I apologize for the question I am just getting confused on this a little. Thanks
Henry

Edwin

My Feedback: (2)

I think you've found your problem.

I start by putting a bubble level on the stab and adjust the plane till its center. Then check your wings at the root, mid point, and out around the tip. It will help you determine if a wing has a warp or dowel alignment issue. The engine issue is obvious.
Edwin

skylark-flier

Hey, sorry 'bout dat!!! I'm just an old country boy and I don't always use the right terms. I was talking about the point where the "V" wing support struts attach to the outer wing. I had to move the attachment point on the front one out just a bit to keep the wings matched to each other.

FTmustang65

My Feedback: (6)

Dave,
Honestly I never installed the wing supports I did install hardwood blocks that are epoxied in the wings and bottom of the fuselage because I wanted to add functional supports. The supports in the plans are just for looks so I figured I can fly it and get it squared away before I add the functional supports. What do you think about this and this should make it easier to adjust the wing now. I was thinking about this last night and the if you look at the picture I have attached if I just raise the hole where the dowel goes into the plane on the left side that should bring my incidence readings to about equal. I would like to hear your thoughts on this guys thanks.

Edwin,
Thanks for the response I am going to call GP today and ask them what the down thrust should be because it says n/a in the specs.

skylark-flier

Yeah, understood!! Actually, 90% of the time that I fly mine - it's without the struts either. It's a "Dave's eyes" kind of thing, but when the struts are on her I get all jumpy for some reason and don't have nearly the fun I have with them off. I simply ended up re-adjusting one of the ailerons to make up for the tiny bit of warp my wing has, and that's pretty much taken care of it for most flying.

I agree with your assessment about the hole - 100%. That'll work just fine.

As far as down-thrust goes, GP says straight, I've found that with the engine straight she does just fine - - with one "advisory". If you come across the field at full power and chop the throttle to idle, she's going to nose-up a bit (a very little bit) until she slows down. That's perfectly logical, and to be expected with a "flat-bottom" wing (and the wing is for all intents and purposes, a flat bottom wing), even though it's not quite really that way. It lists as a semi-symetrical, I believe, and it really is with the Cub .40, but it acts more like a flat-bottom.

I really would at least start with a straight engine. I adjusted mine down 2 degrees and it helped that "balloon" in that one circumstance, but went back to straight shortly after and have kept it that way ever since. I like the way she maneuvers that way a whole lot better.

Dave

Edwin

My Feedback: (2)

Now that I think about it, my busa cubs have 0deg down and about 2deg or so right.
Edwin