Tight outsides, insides not as tight.

[Paul Taylor]

Got some good weather today to do my first trim flight on my new ride.

I have a few minor issues to fix. Try a few different props to locate the magic prop. Need to make a uni-flow clunk tank.

But here is my question I need a little help with.

When flying outside loops the plane will turn great. When doing insides the plane will turn but it is not as "fast" to turn. Question. Can I adjust my line spacing on the up line to get more turn?

I got some expert help setting up the controls and we got them dialed in and it is as good as it is going to get on the plane. CG is correct, so I don't think balance is the problem.
This is on a Nobler, FP 40.

[Jim Thomerson]

Maybe you have a hair of downthrust.  I had that problem and cured it with thrust wedges. 

[Steve Helmick]

That, (what Jim sed) or a bit of positive incidence in the stabalizer. I'd check for downthrust (you should be able to see the nose come up when the engine quits). If everything is right, then lengthening the elev. pushrod is the normal fix. If you can't do that, then you can "tweek" both elevators up, like a flap tweek, but both sides...as a last resort. Kinda brutal, but that's why adjustability should be built in.

Whatever it takes, do it! Having a model that does that will not live a long life, because it throws your timing off. Is this a "NoblARF", by chance? They have some alignment issues if not carefully assembled.  Steve

[phil c]

Rather than just opening the line spacing up, try moving the attachment for the up line out, so it has more overhang.  This will speed up the up response, compared to the down response it bit.  Something like a Tom Morris handle you can have the line attach eyebolt extended out.  Other handles will take some cut and try.  Even as little as 1/4 in. of more overhang can make a difference.

[Garf]

My NoblARF needed a little downthrust. Also done with thrust wedges.

[Don Hutchinson AMA5402]

Fix it at the airplane. It flies as if it has the flaps down a bit, Like Steve says, lengthen the pushrod a few turns and try it again. Fixing a mistrimmed airplane at the handle is not "the cowboy way"! You many think it is OK but the airplane still has the error in it and will not give you it's best performance.
Don

[Trostle]

Besides the ideas already suggested, there are two more things to look at.

1.  First, check to see that your elevators are lined up with each other.  I cannot explain it, but if the elevators are not aligned, the airplane will turn better one way than the other. I do not know when one elevator is higher to cause the model to turn one way better than the other but misaligned elevators will make that happen.


2.  Your flap/elevator trim might not be as exact as you think.  After you have checked to see if there is any down thrust or up thrust, check to see that your wing is at zero degree incidence and check to see if there is any horizontal tail incidence.  Then check to see if you have nuetral elevator at zero flap deflection.  If your measurements check out, then try some slight down elevator trim for zero flap deflection.  If that makes your problem worse, go the other way with the elevator trim.  (This means that you will have to have an adjustable pushrod to the elevator horn, or if you have an elevator horn that can be "tweeked" to move the elevators up or down - might be done with a 3/32" horn wire, a bit more -as in a lot more - difficult with a 1/8" horn wire.)

Keith

[L0U CRANE]

Paul,

No one else has asked so far, so I will...

Does your elevator pushrod flex any? UP input pushes on the length of the pushrod; DOWN pulls on it. Wire, or any other, "slim column" is susceptible to 'bowing' under a compression loading. In tension, as in pulling the elevator horn for DOWN inputs, the wire's tensile strength is loaded so that 'bowing' (flexing) isn't possible.

If you can detect any bowing, it is too much.

Best solutions:

-- a steady-guide* halfway between the forward (usually flap  horn) connection and back (elevator horn) ends of the pushrod;

-- a stiffer pushrod, like the arrow-shaft types,

-- or a heavier pushrod.

* - at the halfway location, the pushrod moves up and down, and side to side, very little over its full travel. The guide should be only large enough to stay clear of the small motions at the mid-point in the travel. It may contact the guise if it bows at all, but the guide keeps that deflection very small.

[Zuriel Armstrong]

Paul,

I believe you told me you bench trimmed the plane with a "touch" of down elevator.  If so, remove it and make the elevator neutral.  Fly and report.

[Paul Taylor]

Carbon Fiber Rods. I can try and tweak on the one clevis in the back maybe a turn or two, but I think we got it real close.

I will make a few of the suggestions above and report back.
Thanks guys!

Stay tuned.....

PS - The temp dropped 10 degees in the past few hours. I hope flying season is not over for us here in the mid-south. 

[Frank Imbriaco]

All the suggestions here are  very much worth looking into. I'm a  recent retread, had a Nobler ARF going this spring and most of the summer until... Anyway, I  flew several Noblers in the 60s and they all flew much, much better.
My Nobler ARF did the same thing. I tried like hell to open the outsides- it just wouldn't. In hindsight, wish I had  researched the incidence specs before I completed it.
Top Flight should supply  that one with the kit.

Oh yeah, I did the usual  eye lineup of the wing/ stab relationship, thrust alignment of engine, set it up with an adjustable rudder, CG & lateral balanceand followed the excellent Garden State Circle Burners Nobler ARFwing/fuse  alignment tips.  The flap/ elev. were in perfect sync.; ditto the elev. halves.Those surfaces were relatively warp-free.
No doubt all  these helped ... but if I had the  original 57 Nobler incidence specs( I've been told the ARF is a "copy"), I would've metered the wing and stab because they had to be wrong . My wing  also had washout on both halves. The wing saddle and stab slot in all likelihood,  needed help. Having adjustable leadouts is another thing I'D DO. Swapping out the stock bellcrank and pushrods as another reader suggested is another excellent idea.

Yours is already built and flying. Get up the nerve  this winter AND TAKE OUT THE KNIFE IF YOU WANT TO KEEP IT FLYING.

[Martin Quartim]

Sealing the hinge line of the elevator and flaps can help  too. I had the same problem with my Pathfinder and I just  sealing hinge lines eliminated the problem.

Martin