Troubleshooting: Smaller Outside than Inside Loops

[Brendan Eberenz]

I am a novice flyer that is just getting the Beginner Pattern down. I fly a flapped Magician on 60 ft lines with an electric setup. My inside loops are bigger than textbook, but my outsides are super tight and probably smaller than rulebook specifications. It is incredibly noticeable as I do horizontal eights. The plane flies level and there is equal throw in the elevator. I have tried to knowingly ease up on the outside loops to make them bigger, but they are still very tight. Is there something mechanically to explain my issues or is it just psychologically my brain telling my hand to crank down on the outsides? I guess I could have my more experienced son fly it and see if the loops equalize for him, but I thought I would throw it out to the crowd for commentary. Thanks.

[Dan Berry]

Pushrod length is where I would look first
Shortening it is probably the ticket

[Dan McEntee]

   Double check your thrust alignment to the wing first, and then to the stabilizer. I have several airplanes that I adjust the line spacing where the down line is closer to the center of the handle than the up line. You need a handle that allows that. You may let some one else fly the airplane and see how it performs for them to make sure it isn't something you are doing.
  Type at you later,
   Dan McEntee

[Dave_Trible]

It may be best to try some handle adjustment before fiddling with the airplane.  If it is grooving pretty well in level flight both upright and inverted then likely your inputs to the airplane are uneven and that you adjust with handle.  First you'll need to know that when the elevators are locked in neutral your handle is vertical.  If you've gotten used to something different than that try to readjust YOU to get used to a vertical handle.  Now,  hoping that your handle allows vertical adjustment of each line independently you move either line in or out from center to speed up or slow down your input.  From what you describe you should move the bottom or down line "in" towards the center to cut down the throw or inversely the "up" line up or outwards from center to speed that up to match the feel both ways.  It is normal for airplanes to turn a little faster one way than the other in the case where the stab is mounted higher than the wing centerline.  (or lower-anything but all co-planer to the thrust line.)  Your handle adjustments will offset the difference.  Everyone's feel will be a little different than yours so fix it to suit you.  Once you get the handle dialed in try to dedicate the lines and handle to that airplane.  When you switch them to another airplane you are starting with 'nowhere' all over .

Dave

Just a thought to add:  These are most times very small adjustments-a little going a long way.   My handles allow something around 1/8" to 3/16" increments.   One notch either way can be too much or too little.  You may be able to do something similar -inside the airplane if you could get to it.  For me a five minute adjustment at the field then just get on with my life is a lot more simple.

[Ken Culbertson]

I have had several Magicians and what Dave says is true.  The motor thrust line is lower than the typical stunter and the stab higher.  They will tend to naturally turn better outside.  Let's assume you have covered the alignment, and the wing and stab are parallel.  A Magician does not need stab incidence.  Now look at the pushrod, a weak pushrod will do exactly what you are describing.

Ken

[Jim Svitko]

This might be an alignment issue.  I have seen several airplanes that were built such that when the flaps were neutral, the elevator was either a bit up or a bit down.  Another issue could be stabilizer incidence.  Is the stabilizer parallel with the wing chord?

[Steve Helmick]

Could be downthrust, flexi pushrod, possibly just that the bellcrank is not centered when the flaps are at neutral?

I'm not a fan of trying to fix this with handle offsets. I've tried it, but IMO it's better to fix where the problem is, and that's somewhere in the airplane, outboard from the leadout guides.  Steve

EDIT: There's another thread on the same topic over on the "At The Handle" forum, so check that out.

[Howard Rush]

Could be downthrust, flexi pushrod, possibly just that the bellcrank is not centered when the flaps are at neutral?

I'm not a fan of trying to fix this with handle offsets. I've tried it, but IMO it's better to fix where the problem is, and that's somewhere in the airplane, outboard from the leadout guides.  Steve

EDIT: There's another thread on the same topic over on the "At The Handle" forum, so check that out.

yep

[Brendan Eberenz]

Thanks for all the different ideas. That's exactly what I was hoping for. I will probably have my son give it a test flight this weekend to see if he gets similar results with his loops. Beyond that, I have a lot of mechanical components to inspect and consider.

Explanations about the handle were helpful. We have always used handles were you can really only change the wire length. I do have some handles where you can adjust spacing, so it sounds like we should start using those to give us better tweak options  to optimize performance. If we fly this weekend I will provide an update.

[Howard Rush]

Are the flaps taped?  I suppose you could just tape the handle.

[Ken Culbertson]

I listened in on Charle's zoom meeting last night and I have an additional thought or two.  Since you did not build that wing you don't know for sure if the bellcrank is centered.  That came up.  Here is a quick way since you can't see it.  Pull the up line all you can and mark where the down line exits the wing.  Now do the same thing with the other line.  Pull the lines so that the marks line up.  The flaps should be level and if they are, the bellcrank is roughly centered.  If they are not, adjust the pushrod till they are. This may or may not be your problem but it is the first thing that you check out in finding it.  Once you have the bellcrank centered, mark the leadouts and use clamps to keep them from moving as you make other adjustments.   Plan "B" - get a small camera snake and peek in through the exit hole in the wing.

Now, make yourself a tool to lock the flaps level.  I would use a piece of hard foam or soft balsa cutout you could slip over the flap and lock it level.  With the flaps locked level you should not be able to move the elevator more than about 1/4" up or down including slop and it should be level to start.   From this point forward only use the flaps to adjust for roll.  Regardless of what you think, if the CG is correct, the flaps will center themselves in level flight.  Adjust the elevator or maybe the thrust line.  The last thing you do when finished is adjust the handle for level flight.  Asymmetrical line spacing is an absolute last resort.

As you move up in skill the accuracy of the adjustments will need to increase but the end result stays the same.  Your top experts could tell you if the turn rate was off by a foot or less.   

Getting a 60's profile to fly like a modern PA is never going to happen but you can get close - Good Luck - Ken