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Joined: 2/3/2003 From: PENTWATER,
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I was just given a new never mounted 1957 Super Tigre G21 .35 size C/L engine-Can anyone tell me anything about this engine and what is the fitting on bottom of crank front housing used for-I assume it`s for pressure but ,Ive never seen one located here- Appreciate some info on this Italian stallion--
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Joined: 11/9/2002 From: Rochester, MN, USA Status: offline
Yes, it's a pressure fitting. From that, I expect this is the combat version of the 35. Look into the exhaust. If the piston has a flat top, it's the combat version. If it has a baffle, it is the stunt model. The combat model would be fun in an older design combat model for some nostalgia, but not very good for stunt flying.
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Joined: 2/3/2003 From: PENTWATER,
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It has the baffled piston--Therefore I presume it`s a fairly good stunt engine.I`m I correct in saying that??-- One more ?---Is the tank hooked up with feedline and pressure line only--much like exhaust presurerized RC setups???
Wulfman, Yes you do hook the engine up just like muffler pressure. However it does not operate quite like muffler pressure. Crankcase pressure will pressurize the tank whenever you turn the engine over. Muffler pressure bleeds off through the muffler when the engine is not running, and indeed when you run at low throttle. When starting the engine with crankcase pressure you should squeeze the fuel delivery line closed to prevent flooding. Release the line as soon as the engine starts running. Normally it is necessary to prime the engine to get it to start. The pressure fitting on the bottom of the case gives timed crankcase pressure that is higher than the pressure obtained with a fitting in the backplate. The port in the crankshaft aligns with the fitting when the piston is at bottom dead center and the pressure in the crankcase is at its maximum. Note too that if the pressure line in the tank is below the fuel surface fuel will be forced back into the crankcase through the pressure line. BTW I still run my old ST 35C's and G21-35's on tank pressure; I never made the switch to bladders. Chuck
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Joined: 10/24/2002 From: Port Ewen,
NY, USA Status: offline
Around that time Super Tigre switched models. My G21 .35 has a separate crankshaft assembly and crankcase. It came with several intakes. The large one needs the pressure fitting, the others will run on suction. I also have the G20 .15 that has the same setup except it has two ball bearings where my .35 has a BB in the rear and a sleeve bearing in the front. I think I remember reading that my version broke crankshafts easily. Not sure about the other versions.
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Joined: 11/9/2002 From: Rochester, MN, USA Status: offline
I think I remember reading that my version broke crankshafts easily. Not sure about the other versions. George [/quote]
That's why they didn't make it in combat-under high nitro/highrevs, they broke a lot of cranks. But on mild fuel for sport/stunt, I don't know of any failures.
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Joined: 11/10/2002 From: Mary Esther, Florida, FL, USA Status: offline
I ran a ST G21 5.0cc (0.29 cid) in proto speed, nd a G20 (later G21) 2.5cc ia A speed. Never broke a crank, nor did I ever hear of anyone else breaking a crank in one of them.
Bill.
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Real Airplanes have Two Engines AMA 25139 - More than 40 years.
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Joined: 10/24/2002 From: Port Ewen,
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Bill, I guess I was a little vague in my statement. It was/is my understanding that the early G21-.35 did not make a good combat engine because of crankshaft breakage. I never had a newer version. My first G20-.15 was the version with the removable front housing. I have later versions of the G20/15 (1960, I think) in glow and diesel. Never had a crank problem with any of them. The G15 and X-.15's I have are still new so I can't speak for those.
Here are the .15 and .35 I was referring to with the removable front end.
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Joined: 11/10/2002 From: Mary Esther, Florida, FL, USA Status: offline
George:
I'm not certain on the "G" numbers, my first 15 did not, as I recall, have a removable front cover, but otherwise both it and the 29 looked like your picture. The later 15 was physically larger, and the intake was angled to the front.
Bill.
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Real Airplanes have Two Engines AMA 25139 - More than 40 years.
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Joined: 10/24/2002 From: Port Ewen,
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quote:
ORIGINAL: William Robison George: I'm not certain on the "G" numbers, my first 15 did not, as I recall, have a removable front cover, but otherwise both it and the 29 looked like your picture. The later 15 was physically larger, and the intake was angled to the front. Bill.
Between my first one and the 1960 version came one called the "Jubilee", I think. I do not have a Jubilee, but here is the 1960 version:
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Joined: 11/10/2002 From: Mary Esther, Florida, FL, USA Status: offline
George:
If that engine has an unfinned head it will be the one, so far as I remember. I did get the factory supplied spinner with mine, the factory spinners were no more expensive than the Froom, and they were a lot stronger.
Bill.
< Message edited by William Robison -- 11/7/2004 10:17:44 PM >
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Real Airplanes have Two Engines AMA 25139 - More than 40 years.
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1957 Super Tigre G21 .35 - 
