I have a S3250 that I acquired it with the idea of installing it in a Nosen Mr. Mulligan that was given to me. The Mulligan was in pretty bad shape so it is now a display item at my place of work.

So to my question.... What kind of fuel useage should I expect from this engine? I've considered taking it up to the auction in the Twin Cities in a couple of weeks. "Might" keep it if the fuel economy is reasonable for another big plane project yet to be determined. The engine is in great shape, the reason I bought it, but I have mixed emotions about keeping it.

Ken

If you fly it on a airplane that doesn't need full throttle all the time, then the fuel consumption is quite good. I only use a 16 ounce fuel tank with my 30cc 1.80 glow engine on my big 3D stunt plane. 10 minute to 15 minute flights then. But at full throttle you are looking at something like 2.5 ounces a minute or more. The trick is to fly something that doesn't have to fly full throttle except for bursts, like climbing back up or going vertical for a bit.

Thinking out loud here..... I wonder how it would respond to a spark conversion?? Still run glow fuel

Ken

Spark ignition does seem to improve the idling and it seems to make the top end better too. With better ignition you do get a little better fuel consumption too. It isn't as hit and miss with spark ignition. Hard to say how much improvement as it varies depending on the engine.

Fuel economy isn't that bad on this engine like stated above
I wouldn't waste money on an ignition system
But you must use fuel mixed specifically for the big ST
Regular glow fuel has too much oil content
The engine will run very ruff and have a very erratic idle not to mention a real mess from all of the oil
The big ST,s only need 12 percent oil content
When ST blended fuel got hard to find I would have the hobby shop get me a gallon of pure methanol from the same glow fuel manufacturer and mix it into a gallon of regular glow fuel either 10 or 15 percent nitro to thin the mix down to 12 percent use 20 percent as the factor of regular glow fuel oil content
If not interested in mixing your fuel you might want to sell it

Yup, knew about the fuel thing. Another reason I may not keep it.

Ken

Car fuel might work. I think its 12% oil but the big cats don't like more than 10% nitro. Most cars use 20% or more.

After considering all the variables I think I'll take it to the auction. Unless someone here wants it. It has a Bison Pitts style muffler an a "heavy" hub. I have some props I'll throw in on the deal also.

Ken

Tell me more about the engine, please!

Big ST engines can be run on 10-12% oil if it's all castor; that's according to Hobby Services and it might even say in some of the old manuals too. Nitro should be kept to a minimum - 5-10% max with 0-5% being better. Fuel consumption is probably gonna be average at 2-3oz/minute at WOT using nitro. Using straight fuel; slightly less possibly.

Here is most of the skinny on it. It's actually in stock. Note HP rpm, ST's are work horses. Pictured, real close to ideal LS needle setting.

Propeller
Muffler
Fuel (at least 16% lubricants for break-in, after break-in, you can
go down to 14%. 100% Synthetic or Synthetic/Castor will work.)




SPECIFICATIONS

Bore: 36mm (1.417")
Stroke: 32mm (1.128")
Displacement: 32.61cc (1.989 cu in)
Power output: 3.2BHP @ 7,700
RPM range: 2,000-9,000
Weight w/o muffler: 1219 (43oz)
Width between centers of mounting holes: 64mm (2.52")
Length between centers of mounting holes: 23mm (.91")
Width of crankcase excluding mounting flanges: 54mm (2.13")
Length from backplate to front of drive washer: 142mm (5.59")
Height from bottom of crankcase to top of head: 137mm (5.39")
Crankshaft size: 10mm-1.25
Suggested prop size: 20x8, 18x8
Carb Settings: H-2-turns out from closed position.
L- Take carb off, rotate and look at bottom side.
Turn trottle until wide open, set tip of low end
needle half-way across cat eye.

The SuperTigre 3250 manual can be obtained here at their website:
http://www.supertigre.com/engines/supg0268.html
The manual for it is here http://manuals.hobbico.com/sup/sup-2...-up-manual.pdf

Originally Posted by boothg-3

Fuel economy isn't that bad on this engine like stated above
I wouldn't waste money on an ignition system

If there is an engine in which ignition is NOT a waste of money, it is a BIG glow engine: you will earn back the investment in no time....

It'll typically save about 20% on fuel, more if you omit Nitro....

Originally Posted by Brutus1967

If there is an engine in which ignition is NOT a waste of money, it is a BIG glow engine: you will earn back the investment in no time....

It'll typically save about 20% on fuel, more if you omit Nitro....

My intention WAS to make this engine a sparky. I think it would be a really sweet and well mannered engine on spark. My comment in post three was to confirm my suspicion.

Ken

If you have a plane for it, that would be (IMHO) the way to go.