Why do glow engines need high oil content(10%-25%) in the fuel? Gas engines run fine at 3% oil or lower. It would be nice to have a glow engine that does'nt spray the plane with a oily mess every time you fly.

Is it because of the properties of methanol? Or the design of the engine?

Is it because of the properties of methanol? Or the design of the engine?

I think it is because of the bearings and the RPM that is produced. I'm sure someone will respond that knows the details. However, there have been glow engines in the past that had needle bearings and used very low oil in thefuels.

Paul

Actually its mostly because gas is not a pure product. It has some heavier hydrocarbons that act as oil. Methanol is dryer and has no oil. If you put you fingers in gas and methanol, the gas is slightly slippery, the methanol is not.

Hi Anybody know the specs for the 15% and 30% fuel. I need to get some but the shipping company needs to know if it is hazzadous and if it is flamable before they put it on the ship. Please if anybody know the spec let me know so i can get my fuel shipped. thanks mike

Yes it is hazardous and flammable. In the US, depending on quantity and shipping method, there is a hazardous materials surcharge added to the regular shipping charges.

"Typical" glow fuel contains
Oil - 16 to 20 percent
Nitromethane - 15 or 30% for your example
Methanol - whatever percentage it takes to make the total equal 100

thats what i think too, the bearings and the high RPM,as well as the properties of the fuel. Paul what past engines are you reffering too?
Could you give the make and models?

I think its posible to make glow engines that will work with low oil, but at the expense of power and higher price tag.
The biger glow engines from SuperTigre need only 10% to run.

The earlier large Supertigres had that recommendation in their manual. With no changes to the engine they changed it to 15 or 16% I think. People have had problems running 10%.

hi guys i actually need the manufactures data safety sheet for the 15% and the 30% heli copter fuel for the shipping company if any of u guys know where i can get such a sheet, it doe not matter the company of the fuel. thanks mike

By law the MSDS sheet must come from the manufacture. Not RCuniverse, and not from another manufacture. So give them a call. Or check their website.

This from the Morgan Fuels website. http://www.morganfuel.com/msds_fuels.htm

There is variation in requried oil content among gas engines - plain bushed conrods require notably more than those with needle bearings for example. I am not 100% sure but I think we could get away with less oil if the connecting rods ran bearings versus bushings - IIRC that is one of if not the highest demand location for lubrication.

Slightly OT but a common mistake with gasoline engines is to run oil:gas at a lower ratio than the engine manufacturer recommends, usually because the oil bottle says "50:1" or something like that. The engine manufacturer knows the requirements of the engine based on metallurgy, bearings or bushings, etc. and makes a recommendation accordingly which should be followed. The ratio on the premix oil bottles refers to the minimum ratio that it can be mixed at and maintain film strength, not the ratio that it should be used at in any engine. An engine calling for 50:1 for example needs an oil rated to mix at up to or beyond that ratio. An engine needing 20:1 can run "50:1" or "100:1" rated oil but it needs to be mixed at 20:1.

MJD