Anyone know anything about Spezio tu holers, and/or Lycoming O-290G4's
Thanks Gary

To my limited knowledge, the Spezio Tuholer is considered a reasonably good design. Nothing that special any one way or another... basically a flat bottom wing on a low-wing fuselage with open cockpits and pretty "normal" proportions. It is not a "hard acro" airplane by any means, but going out to do an aileron roll is no big deal. Although I have never flown one, just looking at the design I would fully expect it to have fairly normal handling. There are certainly no significant "watch out for that one!" legends and stories circulating in the experimental world regarding the Spezio. Just don't expect it to handle like an RV.

The Lycoming G series engines were originally built for use as water pump and electric generator power units, and obviously based mostly on the earlier Lycoming airplane engines. But they had a large flange cast into the crankcase for mounting, instead of the "ears" for mounting to an airplane engine mount. I think this crankcase also had only one magneto pad.

During WW2, Lycoming sold a modified version of this engine (cut off the large flange, etc.) to the British Taylorcraft company for use on the license built Auster liaison airplane under lend-lease. This was the first "conversion" or use of a ground power Lycoming for aircraft use. It was designated Lycoming O-290-3, using dash number instead of a dash letter like the airplane engines. It worked perfectly well, although I'm sure there were some differences between the internal parts of the ground engines and Lycoming's flagship airplane engines.

After the war, homebuilders learned that the internals of the ground engines were "close enough" to the airplane engines, and the ground engines were available cheap. So they developed a procedure to modify them back to being usable on an airplane. This was well-documented, but Lycoming never approved it because it would interfere with new engine sales.

The technical services people at EAA will have all kinds of information on the specific technical differences, what makes a G4 different than a D2, etc. I think I remember hearing about solid lifters on some of the ground engines to save money versus hydraulic lifters?

But the bottom line for your use is that if converted properly (hydraulic lifters, airplane valves, airplane accessory case for dual mags, and such) it is a perfectly reliable and usable engine that can be operated the same way as the O-290 in an early Tri-Pacer.

The real experts on the ground power unit conversion are the old-timers and archivists in the Thorp T-18 community. I believe the largest number of ground engine conversions were put on T-18's, because that airplane came out when cheap was surplus G engines were growing on trees..

Thanks Bill
I have wondered about these on and off for years. They looked like fun. Used to have a friend in Az,that flew a Fly-baby to Sedona every morning and afternoon for coffee. Short take off, cheap to fly. The spezio looks like it has suspension, and room for another, so I was hoping maybe put some bigger tires on it and have some cheap flying for awhile while I am waiting for m y 180 to show up.

The Spezio had an option for folding wings if I recall correctly. So assuming that it is built well and the wing fold mechanism is welded and adjusted right, then it could be a big plus to conserve storage space.

The cool thing is that the stock Spezio looks quite a bit like the old 1930's Brown B-2 racer, so with racing numbers and a 1930's paint job and maybe a couple of really minor cosmetic tweaks you could have a lot of fun along those lines. Not that it would go any faster than a Spezio is supposed to go...

From dim distant faded memory I think it was designed with a Clark Y or 4412 wing. If that is correct, then both of those wings would respond reasonably well to VG's for improved slow speed characteristics. I can't remember if the Spezio has flaps or not.

I did some welding repairs to a Spezio in the past. It is a good airplane in it's time but a little outdated now. It's heavy, the cockpit is narrow and short. The rear seat pilot's legs do not straddle the front seat pax like in most tandem airplanes so it is for height challenged people. The folding wing arrangement was possible due to a heavy welded center section with the wings hinging outboard about 2 ft. from the fuselage. As far as GPU engines I have never built one but I have owned an airplane with a converted GPU and it was a strong runner. I have a friend that built one into a hot rod engine with surplus O-435 cylinders and a mix match of O-290 and O-320 parts. There is a yahoo group on the Spezio with Tony Spezio available for questions. I'm not a member of it so can't tell you how active it is.

Thanks Kevin
I'll probly just wait for a good 180 to show up. I can see this turning into a money pit for me, then not havin the money to buy the plane I want when it becomes available.
Gary

FWIW, I'm sure it's absolutely true that nobody ever regrets buying a 180. I suffer from Skywagon Envy like a lot of other people do.

But make a personal, honest, and accurate analysis of what your flight mission really is, and what you want to spend your money on. Solve this equation from several different perspectives, including expressing your budget for dollars per hour flown, dollars per mile, your desire for number of hours flown every month. And then the obvious stuff like how much cargo, range, etc. you need, airport elevation, carrying a Jet-Ski in the airplane, etc.

This will be very helpful in the age of $6-7 / gallon fuel, $80,000 airframes, $2000 insurance, $20,000 overhauls, $5000 propeller AD's. If your realistic mission and your budget point to a 180, or a Caravan, or a Maule, or a 100HP Tayorcraft, have the patience to listen to those numbers. There are a lot of very high performance and high utility airplanes that are sitting there not being flown as often as they should. Gotta ask why.

I like em all. I'd like an experimental super cub, a Pponked early 180, a hot rod RV8. My thought on the spezio was that I might have some cheap fun while waiting for the 180. I'm just impatient, and miss flying.
But, I know me, and as soon as I got the spezio, I'd be rippin into it, tires/engine etc, to make it fit my needs better, and in the end that would probly be a bad$$$$$ idea.
I fly quite abit for a guy not getting paid to do it, and I'll try to jus be patient