Hey guys noticed today one wing tip measures 5 inches lower than the other. Checked tire pressures and fuel levels both are symmetrical. Both Oleos were replaced last year. I haven't had any hard or rough landings that I recall. Do you guys have any suggestions. I was thinking possibly a bent axle but the plane tracks well. It could have been like this for a while. My right tank tends to burn more fuel so I tend to overlook a little droop on the left. The tape measure said otherwise I guess. I just slammed my head into the wingtip and began too look around. Wing roots measure an inch difference. The long span really enhances the droop I guess. Help would be appreciated. Oh 1973 Maule M4220C

The balance of the aircraft would be my guess, if the gear are known to be equal. It will not be a problem with dihedral angle or anything like that.

Also have you tried rolling it back and forth, to get the gear to settle to neutral position? When you park in a turn etc they can be off-centre. Also use a level to check, don't use the ground as level or assume the fuse is square and level - it's not. Measure from the rivet line down the main spar.

Battson, thanks for the speedy reply. My measurement was taken at the trailing edge of the wing where the droop tip meets the wing. Plane was just pulled into hangar with a new concrete floor. I will have to check with a level tomorrow and push it back and forth as well. Thanks again. I may be looking for a reason to buy some extended hd gear unconsciously.

Let us know what you find.
Hopefully it turns out to be a non-issue for you, like a slope in the floor for water run-off or something not related to a bent plane.

Obviously the error is exaggerated at the wing tip, so it would only take a 1" of difference at the wheels to give you 5" of difference at the tips - or 0.5" each side. Unequally worn tires plus a bit of extra weight on one side of the plane could explain everything.

More duct tape.

Have you checked both lateral leveling tubes and the ground you are useing for reference. One tube under seats and other is at top rear of windshield.
If Both these are level, then the wing rigging is off.

This is something I never even considered measuring. I'll take my tape measure next time I head to the hangar. I'd love to find a mechanical problem to blame for how often I bang my head on the wing while moving around the hangar. Good luck figuring out what's going on with your plane.

Hey Jeremy, great talking to you on the phone. My seats are removed so I will check the leveling tubes today. Hopefully it's in my floor and not the plane.

Hey guys I have changed all of my landing gear bolts to the required NAS bolts. Did not find any bent AN but have a better peace of mind now. My issue now is that I have found a bad bearing where the lower oleo connects to the lower gear. I'm worried the gear may be worn or elongated. Should I order a knew bearing and check the fit or is there a proper way to measure the hole and step it up to the next size? Thanks everyone.

FARMAULE wrote:Hey guys I have changed all of my landing gear bolts to the required NAS bolts. Did not find any bent AN but have a better peace of mind now. My issue now is that I have found a bad bearing where the lower oleo connects to the lower gear. I'm worried the gear may be worn or elongated. Should I order a knew bearing and check the fit or is there a proper way to measure the hole and step it up to the next size? Thanks everyone.

Thanks again. I may be looking for a reason to buy some extended hd gear unconsciously.

FARMAULE wrote:Hey guys I have changed all of my landing gear bolts to the required NAS bolts. Did not find any bent AN but have a better peace of mind now. My issue now is that I have found a bad bearing where the lower oleo connects to the lower gear. I'm worried the gear may be worn or elongated. Should I order a knew bearing and check the fit or is there a proper way to measure the hole and step it up to the next size? Thanks everyone.

That whole NAS vs. AN vs. Grade 8 bolts issue is very interesting - especially for gear & wing attachments. But you may have no choice in a certified plane with ADs to comply with. The experienced professional engineers all seem to different opinions. The NAS bolts are only fractionally stronger than Grade 8 for example, but much harder...

To me, the question is - would you rather the bolt bent and deformed in an overload, or sheared-off abruptly? Besides, everyone seems to talk UTS rather than yield strength, which gives interesting info about their failure behaviour.

I can't picture the part you mean, do you mean the aurora bearing?

Hey Battson, I'm not familiar with an aurora bearing. The best way I can describe the bearing is it looks like the inner workings of a traditional rod end used in a heim joint. Part# Sherco sbg-6s if your interested. Should be here tomorrow. I really hope the new bearing needs pressed in, hoping the old one is plum wore out and its not the seat within the gear. Just in case I ordered some loctite bearing retainer. If this doesn't work I guess I'll be making a call to Wup for some new gear legs. When staking a bearing is it sufficient to use a punch and hammer? Also how many stake marks should I use on a bearing less than an inch in diameter? Any recommendations wouldbe great. Just a young guy trying to soak up as much knowledge as possible. Thanks

Battson wrote:To me, the question is - would you rather the bolt bent and deformed in an overload, or sheared-off abruptly? Besides, everyone seems to talk UTS rather than yield strength, which gives interesting info about their failure behaviour.

Absolutely. Elasticity is the material quality I believe is most valuable in AN fasteners. Harder is not necessarily better, but the gradient that yields a max deflection without going past ultimate, is.

Zzz wrote:Absolutely. Elasticity is the material quality I believe is most valuable in AN fasteners. Harder is not necessarily better, but the gradient that yields a max deflection without going past ultimate, is.

Yeah that's what I think too, a nice strong yet ductile bolt with a big gap between the yield strength and ultimate tensile strength, so you can bend it and notice the problem before it breaks. Really high-hardness materials have poor impact resistance and are brittle (less ductility), so tend to have a smaller gap between bending and breaking.

Hey Farmaule - you're talking to another young guy on the learning curve I can't advise you on that exact part. That bearing looks the same as the end off an Aurora Bearing in case you wondered, guess that it goes in the gear oleo strut - so hopefully it's pressed into something stronger (4130 steel) to it's the sacrificial part that's easily changed!

Kinda comes back to the NAS bolt question again too, would you rather the gear legs get wallowed out or have the bolt bend instead AN bolts are roughly as strong as 4130N aircraft grade steel, weaker in shear, but NAS bolts are nearly twice as strong as the steel holding them in place, equal strength in shear. Kinda getting off topic sorry (mech engineer)
4130N:
http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=m4130r
NAS / AN / G8 Bolts:
http://www.mphindy.com/tech/bolt.htm

The gear have been inspected, new hardware, and my bad bearing was replaced. Some bolts were just barely bent. Hard to even see really. Great for a peace of mind but my wing level issue is still apparent. The only thing I haven't checked on the gear are the axles. What is the best way to do this? The tires seem to track straight in ground handling. Driving me nuts really.

Maybe check the tires for diameter, there was 5/8 difference between my 8.50's. When I found that I was less worried about my wingtip droop.

You could remove the covers and put a steel ruler down each axle, and then measure to that ruler to get some idea of the angle of the axle and height off the ground on each side. That would tell you whether the axles are symetrical or not.