Cessna SID Poll 5
 

Have you modified your airframe?

Larry, are you referring to any modification, ie, avionics, etc, or major alterations, Horton, Robertson?

I am thinking here, specifically, of changes to the wing from standard. So, in that vein, Horton Stol, Robertson Stol, Wing tip Tanks, flint or owen bell, Owen's wingtips.

Things that could affect the structure of the wing I saw a note about modifications on another SID (the 402's)and that's what made me think of it.

One factor in the stresses on the wing structure concerns the O-2A community.
I don't know what kind of stresses have been placed due to firing ordinance from the hard points on the wings? Also pulling G's with the weights on the pylons. Each pylon has a load limit of 350 lbs, thats 700 lbs/wing. If every pylon were loaded to the max (1400 lbs), that would equate to 2800 lbs in a 60degree bank. Higher than that if there were gust loads involved. Inversely, what would happen if the opposite occured, 1400 lbs in a -1.5G loading, pushing up on the wing attach points instead of pulling down on them? I'm sure that Cessna engineering has the calculations somewhere since I assume that they are the ones that determined the load factors.

As far as I know, the USAF didn't track or log the ordinance delivery evolutions on the airplanes.

it's a good point.
I read, someplace, when I was researching the SID's that had already been developed, that mod's to the wing may involve additional inspections. Alternately it may involve further certification from the developer. In the case of the O-2, we certainly aren't going to get further certifications. Nor will there be any from Robertson, who's STOL kit involves quite a bit of modification to the wing.

It's why, after I sent out the survey, that I thought we better ask about wing mods.

I think as part of your survey as well as any comments to Cessna about this program should separate the O-2's from the civilian 337's. Lumping them together will only add inspections to 337's that simply aren't needed.

As in the 400 series Cessna there is a huge difference between an airframe that's been in high use/high cycle commercial operations versus a private owner/operator.

Larry, How about vortex generators? guy paris

not vortex generators, guy. They don't add significant weight to the wing.

The model number for an 0-2 starts with M, while for a civilian model it does not. That separates the 0-2's from the rest.

You better be sure they are being separated. It was the O-2 that cause the wing spar inspection AD but yet they included the civilian models also.

There were also civillian 337's used in low altitude survey, ie, fish spotting, powerline/pipeline patrol, at the time, so the same stresses, and gust loads, were put on those airplane too.

Yes, and that's why one of the polls specifically addresses this point.

Ernie

Wing Load Changes
 

My bird came from Europe with two previous owners. I know they were IFR rated and used it for business a lot. Probably rough weather flying. Always hangered and they put a total of 2400 hours on before I put an additional 400 hours on it. There are no changes to original wings. It does have De-Icing Boots. All interior of wing was zinc chromated as was interior of cabin and booms. That should have cut down on corrosion. My bird has 150 gallon tanks, so that is 900 Lbs. of fuel pulling down on wings. That is a lot more weight than the earlier birds. Dale Campbell