Thorp Air Command - T18.net

I everyone, I am a currently looking to purchase my first airplane and was wondering what everyone was getting in terms of GPH. Also can the 0-290 or 0-320 run on automotive fuel? Sorry for such basic questions but I am trying to learn all I can. Is there a major difference/benefit between the 0-290 ground unit and one that is not.

Thanks

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my side projects..... http://mycorvetterestoration.com/

The O-290 G has a ground power case modified for AC use. The flange end of the case is cut and the engine mount is modified for AC type mounts. If it has standard pistons it is rated for 125 HP. The D is the AC version it has slightly higher compression pistons and is rated at 125/135 HP. Back in the day there were a ton of G units in all the popular AC of the time from Thorps to Pitts specials.

I have an O-360 and run it @2400 RPM and it burns 8 GPH.

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http://www.dixiefriedfabrication.com/

I have a O-320 150HP (lower compresion pistions) and run autogas (no alcohol). I burn 7.3 to 8.0 GPH depending on what I am doing. On XC I figure 8.0 and always have more left than I calculated.

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Matt Smith
Des Moines, IA
55RC

I have an O290-G with D2 pistons and cylinders 140/135 HP. I've been running notin but booz free auto gas for the last 2 years with out any problems. I see 7 gph @ 75% power, about 6 gph @ 65%, your milage may vary.

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Bruce Finney
N18JF T-18C #262
Yelm, WA USA

The 0290 is not a very efficient motor, not much lighter than the 0320. I owned a 125 hp 0290 for a while, I planned on 7-7.5 per hour.

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Lee Walton
Houston, TX
N51863,N118LW
KEFD

More than left is exactly what you want ! ` My 0-360 with the AD prop turning at 2400 RPM and using the fuel flow computer at 8500 ft it shows 7.5-8.0 gph . I like to go fast and get there...fuel cost is not a concern as I pay no hangar rent ! Loud BOOM !

RB

Go go cubic inches!!!

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Lee Walton
Houston, TX
N51863,N118LW
KEFD

Yes Sir ! Trust the man that wears the TEXACO Star ! Fill it up !

RB

O-290G engines, I have 2 of 'em.
the one in 'Feisty" has an O-320 crankshaft, accessory drive case and sump with MA-4 carb.
So basically it's got mostly O-320 parts. It has cylinders from an O-435 six cylinder engine, dimensionally the same, but supposedly better castings. I think it has 7:1 compression, as do the 150 HP O-320 engines. This engine has original O-290G mount ears, and John Thorp's specific motor mount arrangement.
My other O-290 came from a T-18, but suffered from lack of use. It has internal rust damage and a worn cam. All O-290G engines have solid tappets, not hydraulic tappets. This engine has an O-290G crankshaft, which has a thinner flange than an O-320 crank; they have the same stroke. (the flange is where you bolt the propeller, or the spacer and propeller). This is considered weaker, so the O-290G crank I have has been skillfully strengthened with a doubler and propeller drive lugs. This engine's mount ears have been machined to the 'conical' type mount. It has the 6.5:1 pistons. It's a Pile-O-Parts project engine, or educational training tool, depends on what day it is...
My point is that O-290G engines can be pretty crude or exotic.
I run my T-18 with O-290G on 87 octane methanol free Mogas. I buy 100 LL avgas when I am away from home. It runs slightly better on Mogas. I always figure on 8 gallons per hour, but I run it pretty much full throttle, and I don't take very long flights usually, so the previous posters are probably more accurate.

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Scott Emery
EAA Chapter 326
T-18 N18TE

I've been getting approximately zero GPH in my O360, but I expect consumption to increase once I get the engine running.

I plan on 8 gal hr and will usually end up at about 7.5. 2 hr leg at 8,000 ft 2400 rpm 145-150 knts got me 7.750 gal to the hr the last time I checked it and that was on 100LL. It runs a lot better on Mogas and will do slightly better on gph but I still just plan on 8. This will be my 3rd year on alcohol laiden Mogas & MMO, I use the 100LL when IM away from the home field. I have the 0-320E2D 150 HP, wouldn't mind at all having an o-290 had the opertunity to tune a couple of em and they do run very well. Ira and myself flew his bird for 30 min, exactly 30 min. this flight included climbing to 5,500ft, some cruise, some goofing off, decent and so forth. Checking the fuel level before flight and then after we calculated his fuel burn at 5.5 Gal an hr, had a ball, we wernt moving real slow at all, this is awfull cheap intertainment. The logbook for Iras motor was signed by John Thorp, John built Iras 0-290, it is very healthy. This would make for some good conversation at the KVIS flyin, as John did list the parts in the Logbook that he used in the motor...........It has been said that building motors was Johns passion,some of the guys that were fortunate enough to bend metal beside him at the workbench could probably verify the validity of this....but Iras 290 has history, and that history still runs strong today.......Dan

thanks everyone for the quick replies

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my side projects..... http://mycorvetterestoration.com/

I plan 8 gph in my O320E2D 160 hp. It typically burns very close to 7.3gph at altitude. I find the fuel flow goes up significantly in the winter with more dense air. I run 30 to 50 degrees ROP.
Nice Vette. I sold my 69 roadster and am trying to frame off my 66.
Cubes

Ask Jon Levi what his estimated GPH is with his electronic ignition ? I can't recall what unit he has installed , but his numbers were impressive ! OH MY !

RB