Thanks good info

I have no ideas on C/R limits for Ethanol

My issues in Europe is typical local model fuel cost in components

methanol neat ~$16.00 gal imp ~$13.00 a USA gal
EDL and Klotz ~$100.00 gal imp ~$ 85.00 a USA gal
Castor Recin ~$ 46.00 gal imp ~$ 40.00 a USA gal
Nitro methane ~$140.00 gal imp ~$ 120.00 a USA gal

automobile E85~$7.00 Gal Imp ~ $6.00 a USA gal
automobile GAS~$7.50 Gal Imp ~ $6.50 a USA gal (5% ethanol)

cost for home brew 10%EDL 5% nitro 85% methanol ~$35 a gal imp ~ $30 a USA gal

I don't like to use any Castor and often using EDL or Kloz and I will use half the the amount of same in Castor so that is similar price and more power results from fuel with lowwer oil content but don't tune lean as that might grill motor



(info below supplied is for those confused why bother with these experiments and modeled in SIMPLEX )

From this the lowest costs for me in expensive Europe is a real no brainer
and is to convert to gas spark ignition if the oil content drops to ~3% and use no nitro


But this drops the power typically ~25% compared to methanol zero nitro mix (often even more as the fins for cooling need to be bigger so weight increase issues kick in )

Also pure gasoline motor will risk to stink out my tiny hatch back Japanese car and so does pure E85
and is a issue for traveling with smelly model plane in commercial flights

So after landing and quickly running engine with pure glow fuel will stop most of these problems

The most powerful and costly will be methanol with high nitro~30% plus with tuned pipes and highest compression ratios and cost can be ~5 times more than gasoline version but maybe exceeding ~50% or even more than 100% more powerful than gasoline versions

Mostly because gasoline is less powerful fuel than Methanol or Ethanol and gasoline uses less compression ratio
(Higher compression ratios often results in increased power)

ball park compression ratios C/R average for model motors

gasoline....6:1 to 9:1 ......average......8:1
methanol...8:1 to 14:1.....average...9.5:1 Example often OS tend to be a good bit lower than European low nitro S/Tiger or MVVS
Ethanol......7:1 to 13:1.....average.....9:1 (estimated from real aircraft using Ethanol)

sample reduced table of fuels might explain thing slightly better

source
http://en.wikipedia.org/wiki/Stoichiometry
http://en.wikipedia.org/wiki/Nitromethane

Fuel .....By weight ... Percent fuel by weight

Gasoline....14.7 : 1 .......................6.8%

Ethanol...........9 : 1.......................11.1% ~1.8 times more than gasoline

Methanol......6.4 : 1.......................15.6% ~2.2 times more than gasoline

Nitro.............1.7:1..(ball park est) 58.8% ~ 9 times more than gasoline


Source
http://en.wikipedia.org/wiki/Gasoline
http://en.wikipedia.org/wiki/Nitromethane

Injecting the above table into MJ/litre we see roughly how much power is available from other fuels in MJ/litre gasoline equivalent

nitro methane ~10.5 MJ/litre
(ratio consumption ~9 times gasoline result in a theoretical result of ~ 90 MJ/litre gasoline equivalent
(~ 3 times more power heat gasoline but this often translates to slightly less than double the power increase over gasoline )

Methanol 17.9 MJ/litre

usually a tad more than double the fuel compared to gasoline is used so real results ~ 70 MJ/litre gasoline equivalent
(~ 2 times more power heat than gasoline but this often translates to slightly less than 30% the power increase over gasoline )

Ethanol 23.5 MJ/litre usually a tad less than double the fuel compared to gasoline is used so real results ~ 60 MJ/litre equivalent
(~ less than times more power heat than gasoline but this often translates to slightly less than 20% the power increase over gasoline )

leaded gas 33.5 MJ/litre (estimate from leaded aviation gasoline and comparing to unleaded 5% Ethanol types of gasolines )

Uses the least fuel but less power and gets all oxygen from the air but also lower compression from knock issues

Adding ~5% Ethanol will aid compared to pure gasoline without lead additives to suppress knock but result in ~10% fuel increase and possible ~5% increase in power


Putting a tuned pipe on can retrieve ~5% extra power form most all types of fuels

Nitro methane Stoichiometric ~2:1 gets used up at ~4.5 times faster than Methanol Stoichiometric ~7:1
and ~9 times faster than gasoline ~ Stoichiometric 15:1

As nitro methane costs typically ~10 times gasoline this makes nitro some ~100 times more expensive to use than gasoline
or 50 times more costly than methanol solutions

so some rough ball park conclusions

This might infer using a zero nitro methanol fuel might be cheaper than using a 10% nitro with E85 fuel and return similar power
assuming same oil content typically 18% (50% synthetic 50% Castor) and is likely to be the case with lower compression motors like OS

Increasing the compression ratio and decreasing the oil content to 10% (100% synthetic ) and using 90% Methanol and 0% nitro and motor like super Tigre & MVVS which can do this will then probably produce more power than equivalent lower compression OS using 10% nitro with Methanol or Ethanol and be cheaper than both as the OS which usually require 15% to 18% oil

However for the novice the lower compression motors tend to be easier to start and tune and less prone to dead sticks especially the higher the nitro contents so its swings and roundabouts

In a WOT (wide open throttle ) given a choice between changing from motor 60 example simplex ~ 1 BHP with zero nitro WOT 1/4onz per minute
to use it with with high nitro like ~30% nitro to get ~1.5bhp 1/2onz per minute
or zero nitro motor like 90 to get same 1.5 BHP at ~onz per minute 1/3
the resulting fuel consumption from the 90 version will probably be ~50% a zero nitro version 60 motor
possibly supply 50% more the power 1.5BHP compared to a 60 high nitro version.
However the 60 high nitro version will probably be double the fuel consumption rate 1/2 onz per minute of the 60 motor using zero nitro 1/4 onz per minute
and will probably supply the same 50% power increase but do so on smaller lighter motor than a 90 solution
but WOT expect fuel costs to be quadruple due to high nitro factoring in multiplier affect on fuel cost

In the same scenario above for flying in acro or 3D the case is more confused
In hover with zero nitro 60 motor might be at ~1/2 gas position could be replaced with ~1/3 gas position for high nitro fuel or larger 90 motor and so fuel consumption wont be so much more excessive than zero nitro fuel when in hover mode and possibly fuel cost only ~50% greater cost with high nitro in hover mode and mayby only ~10% more fuel consumption from 90 zero nitro position

If the majority of the flight can be done at 1/3 gas with higher nitro 60 motor the cost impact is less bad the plane will tend to be lighter (but factor in fuel tank will tend to be 50% bigger to supply same flying time ) and have better punch out from hover and more grunt in the mid regime and more easier to tune (wide band tuning as in tuning will often stay the same all day long )

If cost is more important the zero nitro 90 version will be similar as higher nitro 60 version and have reasonable grunt at 1/3 to 1/2 regime as the motor will be less less stressed but will be a tad heavier than 60 high nitro equivalent but a tad more fiddly to tune (narrow band as in tuning cool early morning can be different to hot midday conditions )
The results will be similar in weight RPM and prop size and power to a medium nitro 4 stoke ~70 to ~75 motor

Heli 3D competition copters will tend to have no real choice except 30% nitro but planes can have extra options as wings can support extra weight better than rotor blades can

Replacing the fuel components with cheaper gasoline or Ethanol will impact slightly on power with gasoline affecting power the most
However the gasoline can allow less oil content as low as 2% and when its a component of fuel help lubricate motor so redducing oil lubrication needs compared to dryer Methanol Ethanol fuels
This can result getting some power back compared to 18% oil in pure glow versions
Also fuel consumption will be less with E85 type fuels so smaller lighter tanks can also assist power to weight ratios
Tuned pipes can also return back power but increase weight slightly and tend to be tuned correctly for one narrow rpm range which can be an issue for 3D
Pure Gasoline and E85 or Ethanol or high ratio mixed into glow fuels also nearly always increase weight with continuous drive glow battery or for pure gasoline a spark ignition solution adds weight also

Factoring in all these multiple of variables for me requiring a quazi four stroke large prop turning more slowly affect I can sorta achieve that with a standard two stroke when I double the size the of 2 stroke engine and run it at lower gas regime
Fuel consumption can also be controlled better with slower regime and bigger props turning prop more slowly in RPM tend to return better efficiency than smaller props at high RPM speeds

Bigger engines with low nitro rates will be more stable in engine regime at low RPM and will be possibly less affected with lower power fuel like E85 mixed into the glow fuel and tuned pipe could help recoup the lost power hopefully at ratios of 60% E85

With this formula my 90 sized biplane Ultimate with a MVVS 160 with tuned pipe costing ~$2.50 a 16 onz tank using 5% nitro 10% EDL and 85% Methanol WOT ~1.3 onz per minute mid regime ~3/4 onz per minute could possibly be replaced with a 60% E85 40% zero nitro glow fuel where elements will hopefully be

..8.00 % gasoline
47.50 % Ethanol
37.50 % Methanol
..6.00 % EDL or Kloz

And hopefully reduce cost of fuel to $1.60 c per 16 onz tank and probably still 3/4 onz per minute to get same power at slightly higher gas setting and recoup the lost 10% power with the tuned pipe and higher gas setting
and hopefully reduce costs per tank to
~60% of pure glow 5% nitro version
and suffer at most a 10% power drop compared to pure nitro version

For towing gliders work changing the glow plug and back to 5% glow fuel will give me max power

Changing to pure gasoline on these smaller motors is probably not worth the power drop and the possible risks of the greater vibrations and when I go on holidays on commercial aircraft simply changing the plane to run on glow fuel before departing can remove the serious strong odour problems with the gasoline and E85 fuels and allow me to more easily package the plane for international flights and simply buy the local glow fuels with 5% nitro preferably synthetic but Castor or mixed would do while on holidays


If the experiments fail well the MVVS 160 motor on glow fuel 5% or zero nitro is still affordable as its mostly on 1/3 gas or less to loop and most acro so its not to expensive each flight certainly with low nitro is probably cheaper than Lipo electric versions and probably a lot cheaper than 90 version on 30% nitro



I am also trying to work on a more complex version of this type of program supplied fre at this site


http://www.taa.org.au/html/home_brew.html

For standard glow mix this program works well and can I gather also supply costs per Gal /Litre /KG/LBS as you go along

I would want to try to more fuels including other families of nitro such as nitro ethanes also acetones and ISO alcohols etc and include Stoichiometric rates costs ratios and MJ/litre and so be better able to project better the cost and power ratio issues

If the program already exists or useful info is there be happy to look it up save me leg work

or if somebody with better programing abilities wants to do similar let me know also

Balsaeater