Does anyone in the BCP community know off the top of their head if any of the Aeronca Champ engine STC's also allow for a gross weight increase ?

I don't think so, at least for the 7AC. I could be wrong, but I have looked briefly mainly out of curiosity. If there is I do think I would be more compfortable with a metal spar upgrade.

Pete

There are literally dozens of different designations for the various Champs. And some allow conversion from one designation to another. These are just under Champ TC, I believe.

I’d start by talking to the folks at American Champion, and look for a Champ group on line.

But, I seem to recall at least one of these mods which actually changed the designation to another model, and I think increased GW. But, that mod also required airframe alterations.

Good luck on the research.

MTV

The Champ I had with the Buzz Wagner conversion was raised to 1300. Was an O-235 .

Pretty certain long stroke oleos increase GW 50 lbs.

flyingjack wrote:Pretty certain long stroke oleos increase GW 50 lbs.

If that's the "no-bounce gear", I've heard that bumps up the gross-- right out of the LSA envelope.

WWhunter wrote:The Champ I had with the Buzz Wagner conversion was raised to 1300. Was an O-235 .

Did that increase useful load, or did the weight differnce in the engine cancle it out?

Pete

Empty weight was 891 if I remember correctly. So UL of 409.

Hotrod180- you are correct.

There are some engine conversions accomplished through STC (like Buzz Wagner) and there are some conversions that utilized a change in the type certificate designation.

As an example, a 7AC might be upgraded to a C-85 and use a type certificate change to become a 7BCM which is the civilian designation of the military L-16A that came originally equipped with the C-85. The L-16A also came with “no bounce gear”, a brace between steel tubes near the lower portion of the boot cowl, and the lack of a larger dorsal fin that is typical of most C-85 conversions. The original L-16A military manuals specified a gross weight of 1,350 pounds but that is not what the FAA allowed when converting it to civilian designation (at least not the one I flew who’s paperwork showed 1,220 lbs as the gross).

By contrast I instructed in a 7AC with a C-85 with a large dorsal fin, standard gear, and it had a gross weight of 1,300 lbs.

Unfortunately the devil is in the details of how it was converted to C-85 power which makes the topic as clear as mud.

If you find a definitive breakdown of the STCs, type certificates, engines , and gross weights somewhere, please share as it really would be a tremendous resource.

Bill Pancake had an up gross for them. He is probably the sharpest guy alive when it comes to Aeroncas, and just loves talking Aeroncas.
I did a Chief with his C85-12 stc. It’s well written and gives lots of leeway.

https://generalaviationnews.com/2018/08 ... go-to-guy/

+1 Bill Pancake= the best with Aeroncas. Easy to talk to.