Thorp Air Command - T18.net

I was wondering what the weight penalty there is for jumping up to the O-360.

Is it worth going up to the O-360 if If a person was going to remain with a fixed pitch propopeller?

On the used market how much difference is there in price between the two in general? I realize condition matters but I'm wondering about two relatively equivilent "run out" engines that a homebuilder can overhaul?

flyingfool,

Easy questions to answer with a search of documents and sources on the net. The answers will be common to any of the panes that can use both engines.

Jim

Engine HP Wt
O-320-A2C 150 271
O-320-B2C 160 277
O-320-D2A 160 277
O-320-E2A 160 277
IO-320-B1A 160 285
IO-320-C1A 160 294
IO-320-E2A 150 280
O-360-A1D 180 284
O-360-A3A 180 285
IO-360-A1A 200 320
IO-360-B1B 180 295
IMO-360-B1B 225 274

At least a 12.5% improvement in HP with a 360 vs a 320. Food for thought and whatever blows your skirt up.

You can recoup that weight if you go after the new O-360 with a machete.
1) VANs sells a light weight alternator mount,
2) to that you mount a light weight alternator.
3) You get a lightweight starter.
4) You eliminate the vacuum pump, plumbing & regulator, go with EFIS and save weight.
For example, a Dynon D-10a offers more features for about the same price of a 'six pack' gauge group, but weighs about the same as the Attitude Indicator alone.
5) get a lighter battery, maybe even a LiFePO4 unit, mount it on the firewall and get rid of a couple of pounds of primary battery cable while you are at it.
I've been doing those changes to my RV-8. I'm trying out a 4 pound permanent magnet alternator, which is a huge reduction from the 50 amp GENERATOR the engine had when I bought it.
I've done some of it to my T-18. It has a light weight starter.
I've pulled the Attitude Indicator and installed a D-10a.
I haven't pulled the Vacuum pump, regulator, tubing and Directional gyro yet...maybe this week during the condition inspection...
I have an O-290G so keeping the weight down is how I keep the performance 'up',... and I've upgraded one mag to a 'P-mag' for better high altitude and low manifold pressure performance.
Conical mount narrow deck engines weigh less than newer engines, and the engine mount weighs less too. You have to get a little bit obsessive, but weight removed is like power gained.

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE