Hi Chip-
I'm looking at a Pitts S-1S for sale. It has an AEIO-360 with about 335 SMOH. The only non-stock part is a solid crank, which was installed when the engine was majored. My question is this: how long would this engine typically last before its next MOH? I believe the official TBO is 1400 hours, but I hear differing schools of thought on how long it'll actually go, especially if it's flown hard (e.g., running past redline on the back of loops, etc.). Some say that if you change the oil very often (every 15 hours, or when it starts to darken), you need not worry much about needing another overhaul before around 1000 hours. Others say that it could go at any time, and you can't really tell how many more hours you'll get out of it.

I'm trying to figure out how fast to build up the engine fund, so any help here would be appreciated.

Tom P.

• RE: A Question for 'Ask the A&P',Patty_Wagstaff, 01:17z, 09-10-02
  • RE: A Question for 'Ask the A&P',TomParsons, 14:39z, 09-10-02

Hey Tom

Before Chip has a chance to answer, the SOLID crank is a really good thing, but you probably already realize that. TBO depends on your usage. What category will you fly it in?

patty

I plan on starting at the beginning (primary and/or sportsman), and working my way up from there. I think it may be a while before I do lots of gyroscopics or anything. I was actually thinking more along the lines of some people keeping the throttle wide open on the back side of loops and on downlines, revving the engine up to 3100 RPM or more, when I mentioned "hard flying". And I guess I could certainly subject an engine to that kind of hard use, even flying the sportsman sequence.

I was working at the IAC Chapter 52 contest (a.k.a., the Kathy Jaffe Challenge) this past weekend, and I got the chance to chat with Danny Adams from Aviat about this. His opinion was that 1) I should try not to let the engine rev much above 3000 or 3100, and 2) if I change the oil often, I should be able to get 1400 hours out of the engine.

Tom P.

P.S. This was the first contest I'd been to. Even though I didn't fly, I had a great time, learned a lot, and met a bunch of wonderful people. Ann Salcedo came all the way up from Florida to be our VC- after just a few days, I feel like I have a new "adoapted sistah"!