Lycoming in GPU...

Trooper1276 · #1 08-31-2009, 05:51 PM

Was at an aviation junk yard today and they had about seven or eight old airline GPUs (Ground Power Units) lying around two of them had Lycoming 4 cylinder motors and the rest were continental 2 and 4 cylinder types. the old guy running the joint said I could have any one of them for 400.00 bucks. I couldn't get a look at the data plates to tell what versions they were because of the GPU "box" surrounding them. Does anyone know what models they put in these things? Can someone identify it by the pic? I figure it might be worthwhile to pull them and get them overhauled. Any thoughts or clarification would be helpful.

Thanks

Trooper1276 · #2 08-31-2009, 05:57 PM

http://tinypic.com/view.php?pic=ofpkrn&s=3

RV-3Bravo · #3 08-31-2009, 06:00 PM

Might be a O-290??

Lionclaw · #4 08-31-2009, 06:01 PM

It could be a Lycoming O-290. Bill Repucci could probably answer for certain - http://www.repucci.com/bill/engine.html.

mannanj · #5 08-31-2009, 06:19 PM

Quote:

Originally Posted by Trooper1276

Was at an aviation junk yard today and they had about seven or eight old airline GPUs (Ground Power Units) lying around two of them had Lycoming 4 cylinder motors and the rest were continental 2 and 4 cylinder types. the old guy running the joint said I could have any one of them for 400.00 bucks. I couldn't get a look at the data plates to tell what versions they were because of the GPU "box" surrounding them. Does anyone know what models they put in these things? Can someone identify it by the pic? I figure it might be worthwhile to pull them and get them overhauled. Any thoughts or clarification would be helpful.

Thanks

Not trying to discourage the spirit of experimentalism, I offer the following:

The Lycomings are probably O-290-G's They have a very thin crankshaft flange that is not suitable for use in any of Van's RV series aircraft. You would also have to machine off a couple of pounds of aluminum on the nose of the crankcase that was used to bolt the generator portion of the GPU to the engine.

Back in the 60's-70's they were used in some of the early experimentals that flew straight and level. There were some aircraft that were lost due to the crank flange breaking and the propeller departing the aircraft.

With the weak crankshaft flange and all the modifications that you would have to make (not to mention probable extensive corrosion internally from years of sitting in the elements,) RUN---don't walk away from this idea.

The Continentals could either be a four or six cylinder engine with the same problems. The four cylinder engines won't produce enough power and the sixes won't fit.

Oh! I just remembered, the operative word in GPU is; GROUND!!!!!!

N941WR · #6 08-31-2009, 06:33 PM

The Lycoming GPU's were all O-290's.

At one time a number of them were converted to aircraft use by us experimenters but I wouldn't touch one today.

At best they would put out 125 HP, which isn't that bad but to convert them you need to replace the sump, intake tubes, carb, and grind the flange off where the generator mounted.

Also, for our use, you would have to change the accessory case and add the flange strengthener (Aircraft Spruce has them).

The parts for this engine are hard to come by now, especially the carb, crank, cylinders, etc.

If you want an engine, buy an O-320 and overhaul it and stay away from the O-290. The only reason I put one on my plane was I found one for a good price that was 0 SMHO. Now that it is damaged I can't locate the parts to overhaul it so it looks like it is heading to the dumpster.

az_gila · #7 08-31-2009, 07:35 PM

...prototype had a O-290-G engine...

http://www.airventuremuseum.org/virt...ovations/vans/

It was a popular power plant in the 70's, and the Thorp T-18 (a RV-6 predecessor?) was also based on this engine.

http://www.airventuremuseum.org/coll....asp#TopOfPage

...but, 40 years later....

Trooper1276 · #8 08-31-2009, 08:12 PM

Thanks guys. Thought for a moment that this might be a great find, but alas the search continues. As a side note the place I went to was amazing they specialized in DC-3 parts and they had TONS of radials, props, wings, landing gear..etc. Anything you would ever need to complete your project DC-3. I had fun just wondering around for a couple of hours.

dmaib · #9 09-01-2009, 04:17 AM

This is the kind of knowledge and experience that is available on this site that makes it well worth the price of entry!

Geico266 · #10 09-01-2009, 04:56 AM

If memory serves me correctly the 0-290-G has single ignition also, but this can be converted to dual. It uses the same crank shaft as the 0-235 which is 88% as strong as an 0-320 crank. The problems seems to have been caused by changing pistons from 6.5-1 and trying to get more HP out of the engine. Not a bad choice for an engine if you have a tight budget, and if you fly it with respect to it's capabilities. Would not be my first choice.

Several of them flying in older Experimentals around here, they seem to be solid as an aircraft engine.