Thorp Air Command - T18.net

Trying to decide what size of engine for my t-18. Does anyone have any suggestions besides the economy and power pros/cons?

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Dean Cuke
Visalia, California
N772DM
KVIS

Look under "Thorp Specs" on the main page. It will give the acceptable Lycoming HP range. Then look in your wallet for the correct answer.

RB

Dean,

I have flown T-18s with O-290s up to O-360s. Many O-290s are great performers, if you keep them light. I had the pleasure of blowing away the BD-5 in the old Oshkosh fly-by pattern back in the day with an O-290 powered Thorp. Jim Bede put the BD-5J (jet) up due to the then new T-18's apparent performance.

The O-360 will get you off, up, and down the road, but is a 2 - 2 1/4 hour plane with its appetite for fuel. It is also recommended that several of the skins be increased in thickness when installing the higher HP motors.

An O-320 job will run with the big dogs at eight GPH, if kept light.

JT's personal plane had an O-360.

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Bob Highley
N711SH
SN 835
KLAL

As Bob said, weight is the key, an 800 lb 0-290 powered airplane flies like a dream, as does a 1050 lb 0-360 powered Thorp. A 1000lb 0-290 airplane though ... not much of a performer.

So as was pointd out already, it's a combo of what you've already built and or what you see yourself ending up with. I would not outfit an IFR T-18 and hang an 0-290 out there personally.

I've given this some thought lately (don't ask why [;)])

If one was not interested in flying in the clouds and had a lightweight airframe, I'm thinking a 160 hp 0-320 and an AD prop might be the way to go.

If I were to do it again I think I'd go straight VFR/lightweight try to keep it under 900 lbs and hang the 160 up there.

Reason (s) ...

1.) more than enough 0-320s out there for parts availability (cannot say that for the 0-290)
2.) acquisition cost is about 2/3s of the 0-360

I'm not in any way putting down the 0-360 (both N51863 and N589LW) have 0-360/CS. This is just a hindsight if i had to (or was about to [;)]) do it again I'd give the 0-320 a try.

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Lee Walton
Houston, TX
N51863,N118LW
KEFD

I wouldn't part with my 360, but on the other hand, I built a 320 for someone else that puts out nearly the same HP and weighs quite abit less. To me that may be the best of both worlds. It does burn a bit more fuel than the stock 320 tho!

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Dean Houseman