Can Anyone Identify These Strips?

JGug1 · #1 06-21-16, 12:37 PM

Kim Geyer, you win. The prize is a stay at a Trump Hotel. This airplane has Flint tip tanks and the people at Flint are very helpful. Two years ago, you may recall, that Aviation Enterprises was required to pull their tip tanks. At that time, the Feds required a strengthening of wings of earlier 337's, the ones with the smaller tanks, if they had Flint Tip tanks. The straps are the only way Flint could discover to resolve the problem They were not required to have the tanks but they were required if you put fuel into the tanks. So, that mystery is solved. I don't like the looks of them one bit but now that there is an explanation, I don't feel quite as bad about them as I did.
Thank you all for your help.
JG

Skymaster337B · #2 06-21-16, 02:02 PM

I wonder if this will be a requirement for all 337's in the future, in the form of an AD? Spare strap AD's seem to be the FAA solution to keeping 50+ year old airplanes in the air. Just a thought, since there's no economic solution for new wings.

JGug1 · #3 06-21-16, 03:19 PM

I spoke with the manufacturer of the Flint Tanks. He said that there is a "weak" point in the models made before '74 (?). If tip tanks are put on later models, they are not required. He also said that the '73's do have a "weakness" at that point but that Cessna had not found it problematic and requiring a fix. To clarify, the tip tanks make the wing more vulnerable in the earlier models. Apparently not so in the later models. 337's were found plenty strong in Vietnam.

skymstr02 · #4 07-31-16, 12:23 PM

Quote:

Originally Posted by Skymaster337B

I wonder if this will be a requirement for all 337's in the future, in the form of an AD? Spare strap AD's seem to be the FAA solution to keeping 50+ year old airplanes in the air. Just a thought, since there's no economic solution for new wings.

Typically the spar straps go on the lower surface to be in tension vs. the upper surface (compression).