Let's talk flaperon rigging

[C5Engineer 1170]

I installed my F7A's per the manual on my plane but other than that I didn't mess with any of the controls during the restoration of my plane. I leveled my plane and set them using my warp drive protractor but I've NEVER been happy with my rigging since day one I just got sick of messing with it and been flying it ever since. It rolls to the left but what's weird is if I pull on just a little bit of flap it isn't nearly as bad. I think I rigged them with about 5 degrees reflex. I need all the nose up I can get due to a forward CG. What really has me perplexed is it's not just a roll it's almost more of a yaw which leads me to believe to I'm getting differential flaperon when I put my flaps full up. Because it's not just a straight roll I don't want to monkey too much with my left rod end till I'm confident my flaperons are good.

 

I was around another guys plane today and he had a nice detent type feeling when the flaps were full up. Mine doesn't do that I have to keep the flap bolt really tight to keep them from creeping on.

 

How have you guys done your rigging? I have a nice digital angle finder now and I want to start over from scratch and totally redo them.

 

1. How did you lock the stick in place so your not fighting them moving back and forth?

 

2. Angle finder on the bottom of the flaperons since it's flat? How to attach it so it's accurate?

 

3. How far out from the inboard edge of the wing did you take your measurements?

 

4. The flaps linkage has two adjustable rods. From what I can tell it looks like all that really does it adjust where your flap handle travel limits are. I'm wondering why right at the end of my travel with flaps up I get that yaw.

 

I've attached some pics of my mixer and my flap handle position. If you see anything that looks different from your set up PLEASE let me know. I want to make sure everything is good before I start over.

 

Mixer...

 

 

Flap Handle position with flaps full up

 

 

Rod end on the end of the flap handle. Notice how it doesn't really line up. Looks like it's been tweaked to me. The paint missing is from the last set of bungees I had it was rubbing on the metal piece that holds the bungee loop.

 

 

Thoughts??

[1avidflyer 1983]

I had a lengthy discussion with Steve Winder about this subject one time, and his suggestion was strap a straight stick tightly to the bottom of each flaperon pointing back perpendicular to the flaperons.  Close to the fuselage, equal distance from the plane.  Sticks should reach back 18" to 24" behind the flaperon.  Put a mark on each stick same distance back of flaperon.   With plane level, and if floor was flat, and if the flaperons were adjusted properly, when you put the joystick all the way to the left and all the way to the right, you should have the same dimentions up and down from the marks on the sticks to the floor.  That would tell you that each flaperon was going up and down the same amount.   The main reason to put the sticks on the flaperons, is it will give larger differences to measure to than if you measured off the back of the flaperons themselves.  If your measurements are different, then you have to adjust till they are as close a possible.   My Avids had a tendency to be left wing heavy also that was helped by pulling in a bit of flaps.  Hope my explanation made sense.  To hold the joysticks in place, I cut a 1X2 that wedged tight between tubes on bottom of door openings and clamped or wired the joystick to the 1X2  Jim Chuk

[saskavid 47]

So how did the plane behave before you installed the modified bell cranks or did you not fly it with the old f7's?Knowing would be a helpfull reference to know what/where to start checking.

[C5Engineer 1170]

Never flew it stock

[SuberAvid 617]

I like the method that Jim describes.  I spent a lot of time working to set my flaperons but FIRST set the wing adjustment.  I adjusted the joint so the wing angle was the same on both wings at the lift strut attach points.  The wings were not perfect at the tips but the attach point seemed to be the best point to make them the same on average

 

I used a cheap weighted angle finder to set the adjustments of my flaperons and probably should have tried clamping the sticks vertical (plumb) to save a lot of checking and rechecking.  Then set the flaperons at the same reflex angle with stick plumb, no flaps, measuring the flat bottom at the same point about midway on both flaperons, then with full flaps at 26 degrees, and then to balance the deflection at full throw of the stick right and left (but could not get this closer than a few degrees).  I probably worked on this 3 or 4 days (at least) so I like the method Jim describes; it looks faster and more accurate with a lot less checking and rechecking.  I think it was worth it though, mine flies hands off with only rudder input.  Probably should put a small tab on the rudder to fly "feet off" .

[saskavid 47]

Joey:

beyond the typical steps to setup and adjust the rigging I'd check 3 thing:

 That your inboard and outboard flap attach brackets are at the exact 50 deg. as specified in the manual.

 That your f7a's are exact mirror images of each other.I bolted mine together at the main pivot piont and found they weren't.

 That the bell cranks on the ends of each flap are at the same angle when the flaps are at the same angle.

 

Been a while since I did this to my plane but the most critical part is to get the plane all leveled out and then to get the teeter tottter that the f7's bolt to absolutely level and keep it level.Always use a level in the same direction don't flip it end for end between checks or uses.

 

 My best guesses for success...

 Mike

[C5Engineer 1170]

Thanks everyone this was the type of info I was after. I did a pretty hasty job when I rigged them the first time after reading how you guys did it. Looks like I have another big project to do. I talked to Dean Wilson today about this and he didn't have much to add other then to make sure the flaperons were good before tweaking the rod ends.

[C5Engineer 1170]

I just spent quite a while re-reading the flight control and rigging sections of my manual. For those interested

 

Elevator 30 up and 17 down

Rudder 25 left and right

Flaperons 15 degrees flap as at 20 reversal MAY occur

 

How are you guys leveling? Middle rib or the door frame? I need to level my right wing and then adjust my left wing rod end as I've screwed with it. That will be step 1.

 

I've also noticed that I get more travel of my stick one way than the other. Is this normal? I think I have enough data to confidently re-rig this thing from scratch. I'm also going to double check my elevator as I've never seen how much travel it actually has. The manual has you grind away the elevator horn to get more travel.

 

Joey

[herman pahls 9]

Joey

When I installed the 20 pound heavier Jabiru several years ago I used the flapperons to trim out the nose down instead of adding tail weight or a trim since the CG was still in range, just further forward and I did not want to add weight.

The airplane flew terrible in comparison to with the 532 and it took almost 2 years until a Kitfox flyer in Idaho told me on a forum that the flapperons were probably reflexed too much.

Sure enough he was very correct.

The bad symptoms that too much reflex caused on my Kitfox was higher stall speed since I did not use flaps at the time, less elevator authority, very heavy aileron stick forces and heavy right wing probably due to unequal flapperon reflex.

Plus I did not enjoy flying it anymore.

I am not sure how much this applies to your wanting more elevator but seeing reflex on your post brought back mistake in the past.

Herman

[C5Engineer 1170]

Herman due to having two radiators in series and an E gearbox with the starter hanging off the nose, my airplane is nose heavy and I do have a lot of reflex. To alleviate the roll heaviness I crack on a little bit of flap when I want to maneuver. As far as the elevator I cannot get my wing to stall.  Basically it just mushes and starts losing altitude. The early models were made with a heavy fwd CG and small tail to make them basically stall proof. In the early days of light flying alot of people were killing themselves from stall spin accidents....I was told all of this from Dean Wilson btw. Alot of folks upgraded to the larger tail feathers later on. John Miller riveted bigger aluminum strips to his to make it bigger and said it was a very significant difference. In addition to having more authority I think having the electric trim tab will be a very worthwhile upgrade. My next big mod is to ditch the side radiator and just run my belly radiator. If it works I'm going to invest in a Murle Williams aluminum one. That will shave a significant amount of weight off my nose and hopefully alleviate some of my heavy nose issues. I've been flying my plane pretty much as is for the past 4 years. It works really well but I'm ready to do some tweaking on it to try and make it even better.

 

I tossed around the idea of selling it for something bigger but like you after looking at the numbers and my mission I just can't justify it right now.

[C5Engineer 1170]

Last check to see if anyone has any other techniques that worked well for them. We are forecasted crappy weather this weekend so I am going to try and knock out the flaperon re rig. The only thing I don't have a solid plan for is locking the stick in place. I think the right sized bungee stretched across the cabin should work okay.

[1avidflyer 1983]

I cut a 1" X 2" board that fit tight between the sides of the plane and then clamped the joy stick to the board.  Jim Chuk

[C5Engineer 1170]

Thanks Jim not sure why that made more sense the second time I read it

[1avidflyer 1983]

I did hit the keys harder this time! LOL  Just remember on the flaperons, same amount of up and down movement on both sides.  That's what you want to have when you are done.   Have fun!  JIm

[BryceKat 125]

Hey Joey,

My bird would fly right wing low. My rigging was perfect. Then someone on the yahoo site mentioned to check trailing edges for trueness. Sure enough, my left wing t e towards the root bowed down considerably. It was noticeable from the side And also the front. So I unbolted the flaperon hanger plugged the hole and redrilled so the flaperon pushed up on the hangar. That was 2 years ago and lots of level flying since😄. Bryce

[lostman 198]

That brings up a good question, should the flaperon have any bow to it or should it be perfectly straight? I notice today flying that mine are both bowed up in flight. Meaning they might be straight on the ground but when the wing flexes so do they. Just curious if anyone else has noticed this?

[Av8r3400 1179]

On my plane the wings and flapperons flex quite a bit at the tip.

In level flight, I would not say they have a bow to them, though.

Edited 14 Feb 2014 by Av8r3400

[akflyer 1427]

Mine flex in the air too, they are hard mounted to the wing so when the wing flexes, the flaperons have no choice but to flex.  On the mod 1 and 2 kitfox it is very pronounced, but on my HH with the shorter wing and heavier spars, it does not flex as much, but it still flexes enough to make ya keep an eye on it in heavy turbulence

 

[SuberAvid 617]

Mine flex along with the wing and they are noticeabley stiffer to move in flight than on the ground but I am used to it and don't even think about it.  It might make one a little uneasy if they are not used to the flex in turbulence.

[lostman 198]

The flex doesn't bother me I just wanted to see what other people were seeing with it. Thanks for the input! After punching the numbers I wasn't even up to gross weight on the plane so wondered what others were seeing when heavy.

[C5Engineer 1170]

I thought I would give a quick update from last Saturday's rigging session. I leveled the plane per the manual just inboard of the lift strut along side the 3rd rib. I then leveled it laterally across the door frame. At that point I just took the adjustable rods (F7's) clear out. They were about 1/4" different lengths from each other. I leveled the teeter totter and then clamped the stick down. I made both rods identical and put it all back together. I had also taped the dowels on the bottom of the flaperons as well and I could immediately tell they were not even. With my angle finder I found they were about 5 degrees different from each other. I lengthened one of the rods in the mixer until they were even and I suspect it was just about the same distance as they were originally. I did some measurements of the rods from the F7A's up the the flaperon attach point and they were really close. I'm not sure why the flaperons would be different with everything in the mixer even. 

 

Here's where it got really weird. No matter how many times I walked back and forth and how many times I tested all different places I was getting different degrees almost every time even without changing a thing. It was frustrating. I also discovered that while the dowels worked good to eyeball gross changes it is tough to measure them because just based on where the bottom of the tape hits the floor can alter your measurements by up to 1/2 and it's very hard to be consistent. I screwed around until I was getting very close with the digital angle finder on the same place on the bottom of the flaperon about a foot out as well as the angle on the counterbalance. I set them to approx 6 degrees reflex which is the max for the F7A but until I get my CG back or a trim tab it's going to have to do for now. I just pull on a few degrees flap when I want my roll rate back. 

 

Whenever I pulled on flaps I was getting totally different measurements as well. They were pretty close to the same each time though. I didn't even get to seeing if I was getting the same up and down on each one as I had already eaten up 5 hrs leveling the plane and walking back and forth about 900 times from wing to wing. 

 

Am I working too hard on this or am I missing something? My kitchen pass expired so I didn't get to finish up. I am going out again on Saturday to put the cotter pins back in and button it up so I can go fly. I don't think I accomplished anything though. 

[EDMO 1078]

Joey,

     I haven't checked my Avid book, but was wondering about you leveling fore and aft only on the wings - I believe Kitfox says to level both ways on the floor or door sill -  before going to wings, then set dihedral on front spar and level to rear spar???

Probably don't help you much??

EDMO

Edited 21 Feb 2014 by Ed In Missouri

[1avidflyer 1983]

As far as where the tape hits the floor and getting different measurments, you could put a small X on the floor, and then hit it with the tape every time.  If you want to be real accurate, use a level and plumb down from the mark on the dowel, and make the mark on the floor that way.   Jim Chuk

[C5Engineer 1170]

I went out today before daylight and started my rigging project again. Thanks Jim the first thing I did was level it laterally since I already had my reflex set. I taped the sticks on and made dang sure they were exactly the same on both flaperons. I then hung a plumb bob and taped the floor. I was within an 1/8" on both sides with flaps up and down so I buttoned everything up and went flying. This was also my first flight with the horizontal stab gap seal. I took off and stayed over our 4700ft rwy doing S turns just to make sure everything felt right.

 

It did so I went to 1000 ft and exited the pattern and I was super happy with my results. I lost that weird yaw I had and the making coordinated turns was much easier than it was before. One other thing I did was turn the left aft wing strut rod end in one more turn. BUT... I still have a slight left wing heavy and my rod end is out of out adjustment. It's screwed in as far as it will go. Does anyone have any ideas on how I can lift that wing back up a little bit more. It's really close now but still rolling left slightly.

 

Overall I'm very happy with the results and I'm glad I spent the time doing it.

[lostman 198]

Joey, did you get pictures of what all you sealed up on the horizontal stabilizer? I'm very curious now. I have some gap that could be taped up until I have a chance to make up a fiberglass one. I'm curious if it would help my left turn craziness, like others have commented about in a different thread.

 

Yesterday when I was doing a low pass over the road I intended to land on, I made a left turn and the plane wanted to roll hard to the left, not a fun feeling when I was only about 200" AGL. I did the next pass and turned to the right, with no bad habits...it's strange.