Differential ailerons on XL

[Poorman2]

Joe, the part# is 05-03451 bellcrank bearing from Aircraft Spruce. I just built mine last week.

[joecnc2006]

Joe, the part# is 05-03451 bellcrank bearing from Aircraft Spruce. I just built mine last week.

Thanks, Like to see some pictures of yours also. I image they are mirrored.

[CHARLES DEBOER]

Has anyone tried using differential ailerons on their XL?

A LE builder /flyer used the DE differential bellcrank and liked the control balance...

[font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]What is the advantage of using differential ailerons? ([/font][/b][font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]more up than down)?  [/font][font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]Is there a better role rate?[/font][/u][font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]  Lighter stick feel?[/font]

[stevejahr]

Has anyone tried using differential ailerons on their XL?

A LE builder /flyer used the DE differential bellcrank and liked the control balance...

[font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]What is the advantage of using differential ailerons? ([/font][/b][font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]more up than down)?  [/font][font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]Is there a better role rate?[/font][/u][font='Segoe UI', 'Helvetica Neue', 'Liberation Sans', 'Nimbus Sans L', Arial, sans-serif]  Lighter stick feel?[/font]

Differential ailerons attempt to reduce the adverse yaw effect when using ailerons to bank the wing.  In general the aileron moving down creates more drag than the one going up, which pulls the airplane out of the turn if not corrected with coordinated rudder.  With differential the down movement is reduced while the up movement is increased to get a similar roll rate but without as much drag and adverse yaw.  In theory if you get the differential just right you would not need to add rudder correction when rolling.

[Tom XL-7]

On  high-performance aircraft, It may be fair to say  they need differential ailerons. On the slow and low XL I feel it's a mixed bag.  The offending drag is  then corrected with yet more drag from the rudder. Drag reduction is a reasonable goal as is an easier to control aircraft. But I am giving up some roll rate I may need at slow speeds and landing. Perhaps I should just learn to use the rudder. It is normal practice in stick and rudder piloting.
 I don't think it is a big deal one way or the other. The beautiful thing with these aircraft is how freakishly exposed everything is. Don't like it - change it out.

Tom XL-7

[dennysleen]

i am pleased with how my ailerons function with differential throw on a legal eagle. my plane flys great without  much thought of rudder. bearings were purchased at airventure from one of the hardware booths. my arms were riveted one hole off of 90 degrees so they could be put back to factory spec if needed.

[joecnc2006]

Like the picture above, does anyone see any problem with making the pivot point of the bellcrank inline with the cable attachment points?

[Tom H]

We put the pivot point in line with the cable attach holes on the LEU and DE bellcranks.  Only made sense to me.  Less variation of resulting cable length changes (stretching/loosening) that way.  Worked fine.

We also put the differential type bellcranks on the LEU, where the plans showed the square T design, if I remember.  Worked fine.

The DE has the differential type per design, works fine.

[CHARLES DEBOER]

Like the picture above, does anyone see any problem with making the pivot point of the bellcrank inline with the cable attachment points?

I used the Sam (LEXL A58) design.  See photos.  Haven't flown yet.  Shooting for this summer.  This arrangement can easily be modified later on if I want differential ailerons by drilling out the rivets and shifting around one rivet hole.

[Bob Wood]

I just wanted to add something on this subject after I had flown my XL more. I wanted Diff aileron bell cranks and just used the plans for the double eagle. I pressed a simple bearing sleeve into the bellcrank and it flies great, and minimal weight.

I can do a nice turn with minimal rudder, and have no problem keeping the ball centered with this set up.

It is not like you are going to wear these bearings out. You move the stick very little!!

I just have a hand full of flights now and really am having fun.

My 2000 hours are in my Tripacer and other trikes. I have 2 hours of tailwheel time i did 10 years ago and had no trouble landing or taking off this little bird.

My tripacer is very high drag high sink..I feel right at home in this XL.

Leonard congrats!!  A great little airplane.

[Bob S.]

Like the picture above, does anyone see any problem with making the pivot point of the bellcrank inline with the cable attachment points?

That's where the pivot point is supposed to be! In between and inline with the cable attach points.

[John Reinking]

Passing question here:    Was curious why the aileron cables weren't run within the wing like on the Champs?   Building my DE per Leonard's designs but curious just the same.   Any thoughts?

[Dan_]

Passing question here:    Was curious why the aileron cables weren't run within the wing like on the Champs?   Building my DE per Leonard's designs but curious just the same.   Any thoughts?

Years ago Leonard said he "saw this on an English ultralight and liked it."...  I think that was in one of his videos.

It does make it easy to inspect and maintain.

I think cubs have similar, but with the balance cable returning in the wing.

You see that below.  Also why you should expect the unexpected when hand propping...