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Robin G
01-22-2009, 06:25 PM
I am sure that one of the disadvantages of purchasing a completed aircraft as opposed to building a kit is a lessened understanding of the machine. And, that would be me. Most of my flying to date has been in the patch, getting used to landing a taildragger. Today I ventured down the Willamette Valley on a beautiful cold afternoon to test out my GPS. I got up to a couple thousand feet and tried to trim thing up for straight and level. I had not noticed prior to this that the slightest left stick is needed to keep the wings level. And, in fact, hands off, ball centered, leads to a rather pronounced roll to the right. I never let it get much passed 60 degrees, but it would have kept going.

Thus, the request for experienced input.

Thanks.

robin g

Skybolt
01-23-2009, 05:24 AM
Hi Robin.

Maybe, not too much help but lets see what comes out with the conversation.

You say "the ball is in the middle but the craft turns to the right" Could this be that the rudder needs a little trim tab? When the rudder was covered and the fabric shrunk a little bit to one side and set a twist in the rudder frame. Could this screw up the rigging of the rudder?

You would probably need to remove the rudder a place on a known flat surface to check for flat alignment.

Be careful new builders! This will probably be the first component you cover and it is easy to shrink too much on one side and cause a twisted warp in the frame. If you do, cut the fabric off, wash the Polytak off with MEK and start again.

Other possibility; rigging the flaperons.
If the builder didn't set up the rigging good enough, this could be the problem.
I know there is an old document out there (by the Kitfox Doctor) which detailed the correct rigging/settings for the flaperon linkage. If you or Kitfox don't have a copy, I can look and maybe copy this document and mail it to you.
But it sounds that something is out of correct rigging.
The rudder removal is the easiest to start with. Have you the builders manual?

Cheers. Eric.

Robin G
01-23-2009, 08:10 AM
Thanks, Eric

I am inclined to think it is a rigging issue as the motion is definately a roll as opposed to a lateral swing of the nose or yaw. It takes very little pressure to hold the wings level. All I have read about the effective contrrol of the huge flaperons leads me to suspect that they may be the source.

robin

Slyfox
01-23-2009, 08:58 AM
I to had the same issue. You may need to adjust the connection of the struts to the wing. They say to adjust the back one, but with mine, I lengthened the front(easier to get to). if it rolls to the right, you want to lengthen the right front. That will make the right wing bite in, raising the right wing. I would do one turn at a time, oh and make sure you have plenty of threads in the struts. If not, go to the left rear and lengthen. If none of your struts can be lengthened, than shorten the right rear.

Slyfox
01-23-2009, 09:02 AM
I just had a thought, the threads are part of the strut, so make sure you have enough threads going into the ends.

gunther
01-23-2009, 10:15 AM
Robin, another possibility is that your elevator halves are not aligned, i.e., left side is at a slightly different angle of attack than the right side.

Gunther

darinh
01-23-2009, 11:19 AM
Robin,

This is a rigging issue. If you center the ball and the airplane still rolls to one side (keeping the ball centered of course) then you have an issue with what is sometimes referred to as a "heavy wing". Not a problem, simply determine to which side the roll takes place (I think you mentioned to the right) then adjust the wing strut rod ends to change the incidence on the outer wings to make them equal. Kitfox wings have built-in washout to help stall characteristic in slow flight and if this washout is not the same in both wings you will get the slow roll to one side.

Example:

If you hold the ball centered in calm air and the airplane rolls to the right, the washout in the right wing is too shallow (or the washout in the left wing is too steep). You can fix this by simply turning the rod end bearing on the left rear strut out a half turn or so, thus increasing the washout in this wing to equal them out. You could also affect the same change by turning the rod bearing on the right strut in to decrease the washout on this wing but I would caution on the side of adding washout instead of removing it. Think of how your flaperons work and the concept is pretty simple.

Speaking of flaperons, they have nothing to do with the roll unless you are intentionally displacing them. By nature they are a "flying" surface and will find neutral automatically (unless they are hanging up on something). Adjusting them will only have an impact on the stick location side to side.

Hope this helps.

DesertFox4
01-23-2009, 05:23 PM
Robin, darinh is right on and adjusting flaperons will just move your stick position left or right of center. I had a slight heavy right wing after test flights and adjusted most of it out with a turn or maybe two of the strut rod ends. I think I adjusted the right front strut end but it's been quite a while now since and can't recall for certain front or back. I had to ask an A&P at our airport at the time. It didn't take much to make a big difference. Make sure when you disconnect the strut from the wing you have someone to help hold the wing up for you or you have a wing stand to take the weight.

Robin G
01-25-2009, 08:05 PM
To all who have helped with their knowledge and experience, I thank you very much.

Randy, this is a great site. Thanx.

robin g

toekh
02-10-2009, 12:21 PM
Hi folks
My model 2 has a slight problem similar to Robins. When I have trimmed out my aircraft at about 65 kt with the flaperons I can easy fly hands off. If I move the flaperon control forward, the aircraft start a light roll to the left. If I move the flaperon control backwards, the aircraft start a light roll to the right. I suggest this must be a flaperon tuning problem. It’s not a big problem, just a little bit irritating. What do you guys think?

darinh
02-11-2009, 08:34 PM
Toekh,

I am not too familiar with the model 2 but with the 7 the mixer for the flaperons will move laterally if not held from doing so causing a slight roll deflection of the surfaces. This doesn't happen in flight as the aerodynamic forces hold the flaperons in neutral position. If your linkages have some binding in them that may be the issue.