Wing strut not same

[N2782C]

I have a '54 C-170B and noticed the other day that parked in my hangar the left wing at the aileron was 2" lower than the right aileron measured from the hangar floor up. The 180 gear legs are the same distance apart from the center of the aircraft, the gear entry point on the fuselage is exactly the same distance from the hangar floor but the left wing strut is 90.25 inches long measured from the fuselage to the bottom of the wing and the right wing strut is 91 inches measured in the same way.

The left wing strut has 5 bolts external near the fuselage and 4 near the wing while the right wing strut has the same 5 near the fuselage and 4 near the wing but are flush mounted....no nuts visible. Aircraft seems to fly OK and at one point in it's history I believe one of the wings was replaced with a C-172 wing.....does any of this make sense to anybody.

I hate to touch anything that is working but the plane is a bit lopsided, at least in looks and measurements.

Thanks,

[N1277D]

You have two different models of the strut on the same aircraft. The one with nuts on the outside is from the earlier model 170's, The 170A had the external nuts on the strut near the fuselage

[Bruce Fenstermacher]

You can find B model struts with both visible and not visible nuts. They are interchangeable and not a problem unless you don't like it.

You need to take a better measurement of both struts from a known point of one end to the other that you can match identify on the other strut and compare the measurements. Just to the wing or were it enters the fuselage is probably not good enough.

It is possible somewhere along the line an A model strut was installed on your aircraft. It would be the shorter of the two.

The 172 wing most likely wouldn't be the problem.

[lowNslow]

Your wings may be find and you might just need to shim the landing gear. Here is a note from the Service Manual.

Shims (or AN960-616 washers on some models)
are installed under the inboard end of the spring
as required to level the wings within a total
tolerance of three inches. If it was necessary
to install any during manufacture, the number
originally installed is stamped on the extreme
end of the spring. However, more may be
added whenever the wings exceed this tolerance
during service.

If you are off only 2 inches you are within tolerance.

[GAHorn]

If I understand your original post, I believe Bruce is on-track here.
A-model struts are shorter than B-model struts. (The B-model increased dihedral by using longer struts.) You may have a mixed pair.

The actual fasteners used to attach the internal castings/extrusions within the ends of both versions of the hollow struts can be any of three different types. The first type was hi-lok rivets (with large heads), the second type was an intermediary short-term use of ordinary AN bolts/nuts, and the final type was use of ordinary AN 420 rivets (flush). Any of these types may be replaced by AN hardware as an approved repair. (But when replacing rivets with AN hardware the most technically correct method is to ream the holes prior to installation of AN hardware so that the hardware shares the load equally.)

As for actual height above the hangar floor... the wings may be out-of-level as much as 3" difference when measured at the wingtip. This condition is adjusted by the use of the shims (ordinary AN960 washers) mentioned by lowNslow.

[Bruce Fenstermacher]

Another thought. Measure from the same point under your elevator out at the tip and see how that corrolates to the wings. If they are more or less equal on each side then it's more than likely a wing issue. If they are unequal on each side the same at the wing then it's probably in the gear.

If you suspect the gear, besides gear shims, unequal tire pressure or two different tire profiles would do the same thing.

Do you have a level floor?

[N2782C]

Thanks for all the info. Airplane flies just fine...landings are a real treat sometimes but then, It's probably the operator. Will be up at OSH for the duration (my lovely wife is the head of the medical unit there...just below the tower...EMS....stop in)

Does the TIC170A have a booth up there or do they do any forums at all?

Thanks. When I get back I'll try out some other ideas on this...but I'm probably just chasing rainbows....leave well enough alone?

[johneeb]

Contact me when you have time after OshKosh, I am just down river in St. Charles and we can compare measurements between your 54 and my 53 B model. My E-mail address is in my profile.

[n3833v]

Yes we have a TYPE booth and Joe Scoles usually has a topic session. Check the schedules.

John

[jrenwick]

I met Joe Scoles two years ago while I was passing through Ottawa on a vacation trip with friends who were visiting from England. Joe was very kind, and took us for a tour of the city. I won't be going to OSH this year, but if any of you attendees happen to speak with Joe and would remember me to him, I'd appreciate it!

Best Regards,

John

[GAHorn]

Another thought. Measure from the same point under your elevator out at the tip and see how that corrolates to the wings. If they are more or less equal on each side then it's more than likely a wing issue. If they are unequal on each side the same at the wing then it's probably in the gear.

If you suspect the gear, besides gear shims, unequal tire pressure or two different tire profiles would do the same thing.

Do you have a level floor?

The "level" floor is a good point. But help me out here, Bruce. How will measuring from the elevator help determine anything about the strut length? The difference between the two would be so infinitesmally-small as to be virtually undetectible within acceptable tolerances. (The best method to determine strut-length is to measure the struts when they are removed, and measure between the outermost mount-holes.)
Of course, that's pretty labor intensive, and I believe you can (have already) determine(d) whether or not they are of equal length with a simple measurement along the lower surface from the center of the lowest rivet/bolt hole to the corresponding mate at the outer end, on both sides.

IMPORTANT NOTE: If both struts are not the same length, then the airplane may be made to fly "straight and level" by the use of opposing adjustments upon the eccentric bushings at the rear spar-attach. In other words, unless you have the correct struts.... you may find the wings have been adjusted to provide level flight by improper use of eccentric bushing adjustment, in all likelihood resulting in unnecessary induced drag/loss of speed.

[Bruce Fenstermacher]

George if you measured and found that the elevators weren't level either and assuming the elevator is high on the same side as the high wing then I'd think the whole fuselage is sitting crooked. I'd then be looking closer at the landing gear as the problem.

I guess I didn't make that point very well.

Of course if you found the elevator was high on the opposite side than the high wing then you might be sorry you measured at all.

[GAHorn]

I do not accept those points as "waterlines". The length of struts should be determined seperate-and-apart from elevator angles. In fact, elevator angles may actually vary from side-to-side on the same airframe without penalty.
To check airframe "true-ness" or being "square"....should not take into account elevators at all. (Too many variables exist within the jigs for elevators and torque-tubes. Many aircraft have elevators that do not exactly match with regard to left/right angles due to torque-tube fitment.) The end-rib locating-hole of the horizontal stabilizer should be equi-distant from the top-side outboard aileron-fastener on both sides, as well as the top-rib of the vert. stab. locating hole.) That way one could determine whether or not the fuselage were square. That measurement should be taken only after the airframe has been determined to have the correct struts.

[Bruce Fenstermacher]

George there s no doubt if they are a miss matched set of struts probably the only way to prove that is to measure the struts.

We're talking sitting around the hanger looking at the plane and thinking its all caddywampus and eye balling the thing with a stick from the floor of questionable levelness to see what we think.

I'm thinking if it's my plane and the tail feathers are as crooked in the same direction as the wing then it probably is the landing gear.

I sure didn't mean to indicate the measurement was a definitive one eliminating the possibility the strut is wrong or the gear is right or there was a rivet for every hole at the precise measure there ought to be.

[flyguy]

oooohh I AM HAVIN WITHDRAWL SIMPTUMS HYEAR AN MY EYES A BAWLING TU. IMA ALL CADDYWAMPUSY FRUM NOT BEIN ABLE TU JUMPON THIS STRAT N LEVEL DISGUSTIN DISCUSSIN WITH BOTH FEETS.

BUT HYEARSE MA ANSER EENY WAY- - U KIN HAVE STRATE OR LEVEL U JES CAN'T HAV EM BOTH AT THE SAME TYME.

PEE ESS: U MYTE A NOTICE MA NEW AVATAR IS CAUSE OF ALL THE SAINT PAULS GURLY BEER GAY HORN DONATED TU MYSELF.