Converting a 4S glow to gasoline and oil only
 

OK, I'm flyin my E-Raptor conversion and I'm thinking I would love to see this heli running on gasoline with double the flight times. I'm not planning on a acrobatic 3D barn burner by any means but a good performer running on gas.

I start the research and find a few folks have used a G231 in a 90 sized raptor and 1 guy built one 90 size raptor using a BME 90 on gas. Worked well actually from what he claimed and the engine / ignition / batteries weigh in at about 48 oz. Problem is on the 50 sized raptor, the 23 - 31cc gas engines are a bit big and a bit heavy (60 oz minimum for most without the fuel) and the BME is pricey to say the least.

Well, I have a 91FS and a Saito 120 4S and would love to convert them to gas as they are light enough / small enough and should work power wise even with reduction in power using gasoline to replace nitro. There are MANY threads discussing the details of chemistry between mixing this and that to burn special fuels, but the issues I can think of are:

1) Heat in the 120 could be excessive using gasoline / oil
2) May need to install a needle bearing on the conrod and would need to be fit WITH a hardened crankpin
3) Carb would need to be replaced with a Walbro on the intake pipe
4) Gas carb will need a crankcase tap to run the fuel pump diaphram
5) Glow hole will need to be drilled and tapped for a plug
6) CH Ignition system and mag pickup will need to be fit for spark
7) Aftermarket glow exhaust pipe may or may not work with gas due to variences in flow rates

Even with all that, still don't know if the compression is correct for gasoline, whether the valve seals will last under the higher heat or worse yet, what main and pinion gears will be needed for the power out of either of these engines.

QUESTION is, has anyone converted a 4S glow engine to gasoline (just gas/oil, not gas/oil/methane/alcohol/Uncle Joe's secret X) and if so, how was it done and did it work all said and done? I would hate to convert the engine only to find that it melts pitons or valves or it just does not have the power to run it around the sky.

Gotta tinker, but hate to destroy a perfectly good engine in the learning process. [:@]

Help me run gas in my Raptor 50! I have to believe someone has tried this before me.

Thanks.

RE: Converting a 4S glow to gasoline and oil only
 

You can do this, and for a minimum fuss (no messing with the engine, all is reversible) here's what I reccomend:

- Get a Rimfire V2 or similar miniature sparkplug. They are threaded for 1/4x32, the same as glowplugs.
- Use the same oil amount as for nitro. Mix gasoline/oil in 80/20 parts. This way you don't have to machine the crankpin nor mess up with the conrod. Sure, it'll be as messy as with nitro! :D
- Drill a hole on the prop hub for the magnet.
- Instead of using a walrbo, and machining a new intake, just make a new needle valve with the right conical shape, as gasoline and methanol, as you know, have different air/fuel mix ratios.

The engine will run cooler on gas than on methanol, so you shouldn't worry about excessive heating. Also, thumpers don't care much about the exhaust pipe lenght (to a certain point).

Here's a photo of my FS26 (haven't finished the conversion due to sparkplug prices in this side of the pond...)
http://www.rc-airboats.com/gallery/a...7/IMAG0075.jpg

Good luck!

RE: Converting a 4S glow to gasoline and oil only
 

Why not try Gas-Glow?

A lot of people are having great success.

1 part glow fuel 2 parts gas.

Keep the oil content the same because of the bearings.
You may need to add oil to the mix to keep the oil raito at 20%.

It works well on 2 cycle conversion engines using 10/10 glow fuel.

Just a thought.