Good friend of mine did the 0-470 conversion on his 108-2... Makes a real airplane out of it... The only drawback to the conversion is lack of fuel... It needs an auxiliary tank to extend the range by an hour and it will be perfect..

Since I’m listed on his trust to inherit the airplane I have a vented interest in figuring out getting more fuel... not really interested in the current STC available because of where the tanks are placed.. I want to see if I can get bigger wing tanks approved...

Brian


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Rotsa ruck and I hope you're not in a hurry. It took me forever to get the STC approved.
John

hardtailjohn wrote:Rotsa ruck and I hope you're not in a hurry. It took me forever to get the STC approved.
John

Yah... I know about yours... I may still go that route yet...

Brian

When Mark and I started the search for more fuel for his O-470 Stinson, his goal was one hour, so he could fly from Anchorage and be comfortable with a bit of reserve going pretty much anywhere he wanted. Our first thought was the Serv-Aero tank that was STC'd long ago and goes above the baggage area, but found that wasn't supported anymore. We did manage to get a print, but kept running into dead ends when we talked to the Feds.
Then I suggested we go outboard with the tanks...couldn't take more than one rib bay on each side to gain what we wanted easily, and be where fuel is best kept. That all sounded great and the fact that we weren't going to have to alter the primary fuel system was an added plus as far as I was concerned...then we approached the FAA. The engineering that was going to be required was totally ridiculous!! I was caught off guard by this, as I was used to a 207 with tip tanks that were STC'd, and figured that if you could put that much fuel that far out, then an additional 6 or 7 gallons on the inside of the strut would be a no brainer. I guess not with the FAA. At least with the people I wound up talking to at the Seattle MIDO. There were so many things they brought up that had to be addressed and changed that it was in no way feasible, so we went back to putting it behind the cabin.
At that time, Mark ran across a Fed in Anchorage that had a Stinson with the configuration we finally settled on, that he'd approved for himself. He was a great help and was the main encouragement to get the STC. They seemed happier with that and the added benefit of it lessening the ballast weight required on the tail was an additional plus. At first, I figured we'd have to decrease baggage in accordance with the amount of fuel carried, but the DER I hired had no problem with full baggage and full aux tanks, so that was a pleasant surprise. Even with that, it was an ordeal and cost so much more than I'll ever get back from it, that it's not funny, not to mention that it took almost 5 years. So much for being a rich Stinson modification tycoon!
John

Belly pod fuel an option?

Gary

That would be the other way I'd go, Gary. I would think it'd be easier than the others.
John

When I had my Stinson, I had a letter of some sort in the paperwork from another plane (a -2, I believe) that had had the 25 gallon tanks from a -3 installed. You would THINK that would be pretty easy to get approved.