Alternative to glow fuel

wrote

The only reason to use a 3 bladed prop is to reduce ground clearance.

Every other thing about them is bad. Reduced thrust for the same RPM of a 2 blade prop is the biggest factor.

When you have more blades, each blade is working in more turbulent air, from following the other blade. The most efficient prop is a one blade prop. Yep, I'm not making it up! They are made with a weight opposite the blade to balance the system.

They are usually used on indoors free-flight rubber band models, where the PRM is low, and efficiency is the most important factor in winning.

Control line speed events is where I first saw single bladed props. Also, one sided wing, I.E. the wing was only inboard of the fuselage.

Jim from NC is 100% spot on about the props! I fly "real" planes and some years ago flew a Beechcraft Super 18 with both two bladed props before restoration and with 3 bladed props after. The two bladed props were clearly superior in both climb and cruise. I was really surprised at the difference. More is not always better.

Jarhead wrote:

I'm going to suggest diesel if you like wet fuel or electric if you don't. I've had nothing but praise for my MVVS diesels! The fuel is easy to make and cheap and plenty of formulas are on the web to make your own. If the diesel fuel is a problem, I'm going to suggest gasoline. I've been able to hush them up pretty well! I suppose what you are flying makes a difference as to your power requirements.

Try a diesel. I think you will be happy. Plus, diesel packs far far more BTU than glow fuel or gasoline so you get by with a smaller tank, etc.

snipped-for-privacy@digiverse.net wrote:

I know smaller 3 bladed props are crap for power, but what about noise?

A friend just told me last night that he read about a guy who is flying model diesels using a mixture of automotive diesel fuel and used motor oil. He heats the engine with a heat gun and spins it with an electric starter. Once it gets going, it runs great. Another guy is using olive oil treated with glycerine.

AV8R wrote:

I'm starting to think that pretty much any combustible liquid can be used ...

On 1 Nov 2006 11:35:00 -0800, snipped-for-privacy@digiverse.net wrote in :

The smaller props at the same RPM will have a lower tip speed and hence make less prop noise because of the smaller radius of the circle described by the tip.

Or so they say.

I've never flown a three-bladed prop myself.

Marty

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There is a thread running on the RCU forum "Everything Diesel". The inventor of the fuel mix you mentioned is there and has reported on his success. Frankly, I'm skeptical, but I'm trying to remain open minded and objective.

The olive oil fuel is also mentioned there, as is a mixture of Biodiesel B100 and stoddard solvent.

The goal of the thread is to eliminate ether from the fuel mix as it is becoming more and more difficult to obtain around the world. It just so happens that the type of ether that we use in model Diesel fuel turns out to be an excellent chemical for cooking the drug crystal methamphetamine. Therein lies the problem.

Ed Cregger

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Getting a model Diesel engine to run on alternative fuel mixes at wide open throttle is not that difficult.

Getting a model Diesel engine to idle and then throttle acceptably is turning out to be nearly impossible without some ether in the mix.

Ed Cregger

Methanol isn't hard to make. Some yeast, fruit and a still.

These guys are trying to avoid methanol while making ethanol for drinking, but it forms in small amounts anyway.

I suspect that ethanol/castor oil would be very similar to methanol. I've burned both methanol and ethanol in larger engines (auto size) and the only significant difference is rejetting the carb. Ethanol has more energy in it. Haven't tried ethanol in a glow engine, though.

Someone in the Azores has Everclear (90% ethanol) or a still.

Thanks for the suggestion. I think I've found a source for glow fuel there but I'll also take a clapped out engine to try various stuff with. Looks like petrol/gas and electric will be my power plants there.

I guess there must be something I am missing, sicne the easy solution is just to have a 44 gal drum of methonal sent to you - there must be carriers delivering other fuels so....

David

snipped-for-privacy@digiverse.net wrote:

I don't need 44 gallons of the stuff. The climate there is salty and extremely humid. I don't want to store 44 gallons of hygrophobic toxic explosive liquid that I'll never use in plastic containers. It would be cheaper and easier to go big electric. As it is, there is a large supply of strimmer/weedcutter engines there too. So glow has now slipped to third choice for me.

Gee, I didn't know Methanol had a fear of humidity.

I always thought the proper term was "hygroscopic"

Well, It's more me who has a fear of methanol absorbing humidity.

And you thought right.