CAN ETHANOL BE USED IN MODEL ENGINES (Full Version)

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SON OF PALEFACE -> CAN ETHANOL BE USED IN MODEL ENGINES (1/19/2008 3:46:29 AM)

With the price of model fuel (methanol) going up ...can someone answer this without getting technical , that is , can you just swap ethanol for methanol successfully in our model engines????



togatoga -> RE: CAN ETHANOL BE USED IN MODEL ENGINES (1/19/2008 7:39:30 AM)

OS released a 55ax recently that runs on ethanol. they decided to go all green so the engine runs on zero nitro. The cylinder head,carb and glow plug is totally new and supposedly burns 40% less fuel. Power is less at .95ps.They will be releasing more ethanol based engines.
Ethanol has a higher calorific value than methanol but also a higher fuel to air mix ratio. I suppose thats the reason why you need a new carb,head and glow plug ( different thread to avoid compatibility issues)design to keep the glow burning.



downunder -> RE: CAN ETHANOL BE USED IN MODEL ENGINES (1/19/2008 3:21:18 PM)

A few people have been trying it lately and seem to be having success but the best we can do for ethanol is buying tins of methylated spirits from somewhere like Bunnings but it's a lot more expensive than methanol. Last I heard, Scotcher's were selling methanol for $1.20 a litre and John Mod has Castrol M for $8 a litre.



pe reivers -> RE: CAN ETHANOL BE USED IN MODEL ENGINES (1/19/2008 6:37:44 PM)

Back in the 70-ties when I needed to fly my glow CL planes, I bought 80% pure ethanol in the chemist store.
It worked then,why wouldn't it work now?



togatoga -> RE: CAN ETHANOL BE USED IN MODEL ENGINES (1/19/2008 6:58:53 PM)

You need reliable throttling for RC without additives?



KMR1 -> RE: CAN ETHANOL BE USED IN MODEL ENGINES (1/19/2008 7:50:03 PM)

I'll burn the ethanol.. my model engine can stick to methanol [:D] What a waste!



balsaeater -> RE: CAN ETHANOL BE USED IN MODEL ENGINES (1/20/2008 10:32:24 AM)

Real world stuff
Methanol is made from natural gas passed over hot catalyst so saving complex energy intensive distillation methods in the past
in bulk a large barge several thousand tonnes the stuff cost ~$0.80c per usa gallon or ~$1 per imp. gal

methanol tends to detonate at high temperatures and later in the down stroke meaning more powerful push and less violent knock to motor
methanol has more oxygen on the molecule and as such needs more fuel to enter motor but fuel is already supercharged from extra oxygen and more fuel means more cooling and therefore less cooling fins and less weight

compression ratios of up to 14 to 1 are possible so high compression more power but higher compression more tricky to start and tune up

Enter lower compression motor less power then add Nitromethane which has even more oxygen on the molecule and all benefits increases compression increases cooling due to even much more fuel demands (often double on 15% nitro )and you have less tuning to do( wide band ) as most oxygen comes from fuel but fuel tank needs to double in size or weight or flight time is halved on old fuel tank

Enter gasoline petrol fuel has no oxygen on the molecule so less fuel consumption and all oxygen from the atmosphere
problem is gasoline detonates at low temperatures and early in the down stroke meaning more violent knock and shorter power pulse
Also maximum compression ratio of 10 to one and 8 to 1 is the norm
Lower compression less power and easier to tune (wider band) but less fuel entering engine less cooling more cooling fins bigger motor

ethanol only made from distalation cost double to produce than methanol but due to complex government tax strucure and volume etc arrive on the street at cheaper prices than methanlol

Resembles methanol in most features except less oxygen so slightly less power slightly less compression ratios slightly less combustion temperatures

Mixing fuels can give you features you desire
in early control line fuel mixes to get what you wanted were the norm


mixing 75% methanol and 25% petrol or 25% ethanol and 75% petrol can give you more power over gasoline but increase fuel consumption

vise versa mixing 75% with 25% methanol or ethanol or tri mix will also change things to be more powerful than gasoline but increase fuel consumption but on model glow the heat is too much for motors

Glow plugs apparently work for all fuels but cant confirm that

way to reduce cost exist without changing fuels from methanol


Example reduce from 20% nitro to no nitro fuel will reduce fuel consumtion from 30% to 100% depending example WOT all the flight will be closer to 100%

Lost power can be recovered with tuned pipe or sckimming the head or less gaskets

If that isnt suppling the solutions adding in lother more endurace lesser power fuels like Ethanol or gasoline in 5% of 10% or even to 20% might get the required saving but thats at your risk
( you need to change fuel tubing to gasoline resistant types if you opt for gasoline solutions )

basically to get more power get a lager glow motor and tuned pipe and use straight non nitro fuel and that often works out a lot cheaper and lighter or similar weights than switching to ethanol solution

For real cheap go to gasoline and carry a two ton low power brick around

For under 25cc methanol is probably still the better solution


for above 100cc gasoline is probably the only affordable solution


ethanol probably can help fill the gap from 50cc to 100cc

balsa eater



downunder -> RE: CAN ETHANOL BE USED IN MODEL ENGINES (1/20/2008 2:51:53 PM)

quote:

ORIGINAL: balsaeater
methanol....compression ratios of up to 14 to 1 are possible so high compression more power but higher compression more tricky to start and tune up

Real World Stuff :)
I run my Enya 60X at 13.5:1 on straight methanol. Starting is still one easy flick although you can certainly feel the extra compression. Tuning was just as easy but the main difference I found was that the idle mix had to be leaned out considerably, presumably because the extra compression at idle made it far more efficient at burning the fuel. HP (from rev rise) went up by 22%.



Jezmo -> RE: CAN ETHANOL BE USED IN MODEL ENGINES (1/20/2008 5:36:16 PM)

quote:

ORIGINAL: downunder

quote:

ORIGINAL: balsaeater
methanol....compression ratios of up to 14 to 1 are possible so high compression more power but higher compression more tricky to start and tune up

Real World Stuff :)
I run my Enya 60X at 13.5:1 on straight methanol. Starting is still one easy flick although you can certainly feel the extra compression. Tuning was just as easy but the main difference I found was that the idle mix had to be leaned out considerably, presumably because the extra compression at idle made it far more efficient at burning the fuel. HP (from rev rise) went up by 22%.

That's great information Brian. I had never measured the amount of increase but knew it was significant. In my race cars I have run compression ratios as high as 15:1 on methanol with absolutely no problems. That particular engine was fed methanol through a Hilborn injection system and was running in an Outlaw sprinter. Most of my carbureted alky engines were around 14.1:1. There was a piston made at that time that allowed for 14.1 without any mods to anything so it's what I ran. The Outlaw motor had the heads angle milled some and that is what brought the CR up to just over 15:1. Like you said I can't see any reason the glow engines would become more difficult to tune because of CR. Going to straight methanol over 10 or 15% nitro makes needling a little more sensitive but not by much IMHO. Have a good one man.



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