Champ aileron spars

[dlrude]

Hi all,

I am fixing the wings for my champ. One was damaged in the crash when it hit a tree. When uncovered the aileron from it I saw that the aileron spar was cracked near the center hinge. I assumed that it was from the crash.

I started on the other wing that was not damaged and did not expect any aileron issues. However the aileron in the second wing was also cracked at the center hinge.

Is this cracking of the aileron spar at the center hinge a common ailment for these airplanes?

I also noticed that both of the wings has compression cracking in the rear wood spar.

Thanks, Dave.

[james gevay]

I think I remember reading or seeing a photo of cracks in the steel aileron fitting attachment that is riveted to the aileron.

[David Johnson]

Dave, since you have compression failures, maybe the crash did it when the wing was bent. Usually the hinge cracking is the one at the bellcrank, not the middle one. David J., Jasper, Ga.

[bsafran]

My job takes me all over the country and that gives me a wonderful opportunity to meet other Aeronca fans. It also gives me a chance to look at a lot of Aeronca parts. I specifically ask to see uncovered ailerons because I have been concerned for many years about the spar problem you have discovered. Seven out of ten that I have looked at have the same buckle / crack at the center hinge. I talked to Bill Pancake about this and his opinion is that all those ailerons were attached to planes that ground looped or had some other wing incident that smacked the aileron. My theory is different. Unlike the J-3 Cub (or 15AC Sedan) the Aeronca Champ / Chief aileron is not actuated in the center. It is pushed up and down at the inside corner. The first point of resisted movement is at the center hinge. All those years (over 70 now!) of rocking the wings wildly over your girlfriend's house has really beat these spars up. Please go back and look at your damaged ailerons. Is the buckle on the fuselage side instead of outboard? All of the ones I looked at were. The real problem is that this damage is impossible to detect when the control surface is covered. Every Aeronca person I discussed this with argued against any notice being sent out to other 7 / 11AC owners. This was about the time the wing spar AD came out which mandated that everyone cut open their wings to find that only a small handful of airplanes were affected. Nobody wanted to add inspecting ailerons to the list. While I am very confident that there is not a chance in the world these internally damaged ailerons will fail in flight, they are indeed damaged at the spar. I designed a spar repair kit that conformed to the "Accepted Practices, Methods and Techniques" and was having an out of work aviation mechanic make up several dozen sets. He got another job and dropped the project. Now, I can't mind my original drawings. Thanks for bringing up an issue of importance to everyone who has an Aeronca.

[Paul Agaliotis]

Brian,
Univair sells a replacement spar for the aileron, it's pretty cheap and not too hard to install.
Any hinge point outside of the struts moves around quite a bit. Thats why the hinge is designed to float on the two OB hinges. Many I have annualed have the ailerons installed improperly. The clevis bolts at the hinges should be tight. This is so the aileron moves around the bearing and not around the loose bolt. Champ hinges have extended race bearings Citabria don't and rely on spacer washers to secure the hinge attach. I find them loose, bearings frozen and the one in the shop has Citabria hinges. They all work but the installation differs just a bit.
Paul

[dlrude]

Hi,

Thanks for the responses. If I knew how to do it I would post pictures.

The spar cracks are on the inboard side of each aileron center hinge just as you suspected.

The bearings were bad and mostly stuck so it took more than expected torque to move the aileron with tight bolts.

But it is hard to believe that the torque alone did it as the pilot would notice for sure.

Perhaps torque plus flex and vibration do it??

Dave

[dlrude]

ha! Richard Murray explained how to post pictures.