Fuel without nitro
 

Hello. Do any of you have experience with nitromethane-free fuel? Today we saw a partner who used acetone instead of nitromethane. A .46 engine worked just like he had nitro. 13500 rpm and at a temperature of 113 degrees Celsius. Will this have negative effects on engine life? The mixture was 4% acetone, 16% beaver oil and 80% methanol. Thank you for your answers

Never heard of it and would be very careful of using it. I was told that the purpose of the nitro was to act as a catalyst with the glow wire. I don't think acetone will do the same thing. In fact it may even eat your seals.

I've used zero-percent(0% also known as FAI) nitro fuel, which is straight methanol(alcohol or alky in the kart world)...mixed with about 17% castor/synthetic oil which is used in high compression glow engines,

My guess is your partners engine would run without any acetone additive just fine as well.. and yes even though the engine runs, it would be interesting to note the long term affects. How long will a glow plug last?.. How long will seals or even rings last in a ringed engine?... Could the acetone attack any plating within the bore/engine? etc.. many questions as to long term affects.

I guess I have no desire to experiment with acetone, but your question was about experience with nitromethane-free fuel..and yes I've used it in a few of my high compression engines that don't require nitro.

I'd have to say there's probably many chemicals that can be an additive. Come back and report on how that engine runs in a year... that will be your real test. We all have glow engines that have lasted 30yrs and more and still run like new with conventional glow fuels. Therein will be the test on acetone though.

Just a question, what is Beaver oil? Where can you get it? 2% acetone is common, it improves the transition on throttled RC motors much like nitro does. I would not be concerned with that percentage. It will not give the same performance as nitro but the motor will run better than with no nitro with no modification to the motor. Sometimes no nitro fuel requires a bit higher compression than fuel with nitro, especially to get a reliable idle. Usually just removing a shim under the head is enough. I doubt that most people would notice the performance drop with 0% nitro to 5 or 10%. Might just get mad if it cuts on idle. That is the main reason for the acetone. I don't think acetone is any harder on an engine than nitro. Nitro is also a strong solvent with similar properties to acetone, and is used at much more than 2%. I found anything over 15% nitro to be corrosive on motors and they need after run oil very quickly after a day of flying. In Europe 0% fuel is more common than North America.. I used it for fuel in the FAI class with no problems in control line flying. I think when done flying that any acetone would evaporate quickly enough to not damage the insides of a motor. I will admit to not using acetone....yet.

Fuel without nitro
 

Hello. Beaver oil or ricino oil is extracted from the seeds of the ricino plant . It is widely used in Mexico as medicinal plant, is very cheap and is easily purchased in many commercial buildings where they sell chemical or solvent products. When I got nitromethane, I make my fuel with this oil as a lubricant, at 17%. Now it's very difficult to get the nitro in Mexico, so we're seeing options for a nitro-free fuel.

I have tried 5% acetone, 18% castor oil and the rest with domestic ethanol, with bad results, but I've heard some engine are made for low nitro % ( as some webra ), some other engine for high nitro %.

But in case of crisis, at least I will be happy to bench run my engines with that fuel...

I have read that ethanol has trouble keeping lit without constant battery on the plug, methanol is the way to go. There is no problem getting it in this country although it is $12 for 4 litres.

I have managed to get a plane flying with ethanol, but with idling a 5000rpm at least ;)

On my island methanol is hard to find and for example we have to order a year of glow fuel consumption as we don't have hobby shop here and the shippment is really expensive if your order 5L by 5L....

I get my methanol from the paint thinner aisle at the hardware store. Fuel at the hobby shops here is pretty expensive too mostly because of shipping. I am not on an island though.

It is methanol, not nitromethane, that supports the catalytic reaction. I run 80% methanol, 20% oil in some of my engines. It runs just fine. Nitromethane is not necessary, although it produces a bit more power and improves the idle on some engines. I use a mixture of castor oil and synthetic (PAG) oil. Note that methanol is not the same as ethanol. Our glow plugs are intended to work with methanol.

Thank you for your Info.

Just rereading this. The Ricin bean is the Castor bean, so that is fine. As mentioned you would be fine with the acetone for ignition improver.

Thanks again, I'll treat mixture methanol and castor oil for my MDS. I'll coment you the results.

The acetone is a good additive but remember to use a good fuel proof paint topcoat and be careful with raw fuel getting on the finish, wipe off quickly.

Best, DennisT

I know this is an old thread, but I am looking for good sources for methanol in the U.S. I have a Saito 180 I plan to mix 0 nitro blend for. Will probably go to 18% oil. I have an ignition conversion on this engine so it has a spark 1/4 32 plug. Runs very reliably, but I want to mix my own fuel to get the cost down. As my previous 180 was very thirsty! I am hoping going to the timed spark will help in this area as well.

No nitro fuel
 

Since you are running spark why not just use regular gasoline with 18% oil (you can use any SAE 40 wt oil, mineral or synthetic is the same viscosity as castor). Other option is to use denatured alcohol (any Home Depot or Lowe's in paint department). If want to go with methanol google local speed shops or Walmart say they have it ( methanol - Walmart.com)

It's an option, but it will cause a bit of powerloss (about 20%) and quite a bit of carburation issues.

On Methanol and spark, due to the significantly leaner needle setting there will be less fuel dilution in the lube oil, so you can run a few percents less, like say, 15% or possibly even less.

I have run a very heavily loaded, spark ignited OS 90 fourstroke on 0% Nitro, 12% oil and the balance methanol for a few years.

It IS a consideration if you want to avoid the carburation issues associated with gas.

I do not want to run gas, that is why I was asking for a good source for methanol. I already have plenty of gas engines.

The carburation is probably the main reason why. I am hoping it will get better fuel economy with the ignition.

Don't worry, you will: The change from glow to spark, if done properly, will save about 20% (volumetric) fuel consumption when comparing on the same fuel composition as you were using on glow.
The change from Nitro to zero Nitro will save about half the percentage of the Nitro you omit.
Then changing from glow to spark, and leaning out to "2 clicks rich off peak" (that part does not change) you will notice another conspicuous thing: the slime will more or less dissapear, instead, you will see oil and water, separated.

The slime previous, was oil mixed with the excess unburnt fuel (that excess fuel is a necessity on glow ignition, in order to control ignition timing). This excess methanol allows ALSO the water formed during combustion to mix with the oil, which is the reason for the "slimey" properties of the residue.
This water and fuel content reduces lubricity of the oil, reason why glowfuels contain so much of that stuff.

On spark, and properly adjusted,this excess fuel is not present, therefore, the oil and water do not mix anymore, and the oil retains its lubricity. You can safely reduce oil content to 12~15% or possibly even less, and this volume can also be subrtacted from the volumetric fuel consumption.

So yeah, depending on your previously used fuel composition, you could possibly see a reduction in fuel consumption of about 25~30%, at the cost of a bit of power if you were running high Nitro numbers, and with a much ieasier to clean plane to boot.

Since fuel linearity of glow carbs is designed for glow, there is a slight possibility of a lean midrange, but that is not a given, and with 3-needle carbs usually not a problem.

Word of warning: it is noticably different to detect rich or lean conditions by ear, since spark ignition has a fixed timing, and the audible signs of lean and rich as you are used to with glow, are caused by retarding and advancing ignition due to mixture strength. Takes a bit of getting used to, but no biggie.

1967 Brutus, Thanks for all the great info. It looks like I made the right decision doing this. It looks like Methanol can be had off of Amazon for around $100 for 5 gal. I may be able to better than that, but not terrible considering free shipping and not having to travel to a race track or another town the get it. Still way cheaper than trying to order it through my LHS.

Am I mistaken, or has the price of Methanol skyrocketed over the last few years?
I thought the stuff was much cheaper on your side of the pond?

I guess that is why I am asking the question. It seems like it should be cheaper. But I have not found it yet. At this price I can mix a gallon for around $30.

Around here in Canada, it is around $17 to 19 for a chintzy US gallon. A couple years ago it was $12. Accounting for the US $ that is maybe a bit less than $14 US. We can get it at any hardware store in the paint thinner aisle. https://www.rona.ca/en/product/solva...3-394-02635112 Rona owns Lowes here. I checked in CO, and it seems that they don't seem to carry it. Maybe it is controlled there for some reason. Then again, if we want to use E 85 ethanol fuel, we can not get it here. I have to cross the border to Detroit for that stuff. It is pretty cheap there though. I could run my Dodge minivan on that stuff in theory.

E85 is not worth it. It may be a bit cheaper, but gas milage goes way down so you have to fill up more often. I have a Flex fuel vehicle and have never bought E85. It was a government ploy to do something with all the corn they pay the farmers to grow.

I think the more I look at it, if I can get a gallon of fuel mixed for $30, that is not so bad. I will just order my alcohol from Amazon. To my do in a couple of days with no shipping fee. Not bad.

The "mileage" is common for every alcohol based fuel, as those fuels simply do not have much caloric value.
For me that was the reason to convert ALL my glow engines to burn gasoline, from the 1970 OS Wankel upwards to my ASP radial, each and every one of them.

A single conversion is not worth it, but converting everyone of them, suddenly running RC planes becomes CHEAP. Even here in Europe, where gas is around 8 U$ per gallon or therabout.
The big saving is in the "mileage": I have a 60" wingspan clubtrainer that gets 60~70 minutes of flight time out of a 6 oz tank.Non stop if necessary, or 4~5 instruction flights without refuelling if it is a busy day.
A gallon of gas mixed with oil costs me the equivalent of about U$ 10, but lasts more than twice as long as a gallon of methanol fuel would. Power is down a bit compared to glowfuel, but that is easily compensated by selecting a slightly larger engine for the same plane. Cooling requires attention, but that is part of the challenge, and so far (9 years in now) I still have to suffer the first fuel related engine damage.
Engines are availlable in abundance on the second hand market, and cheap as dirt nowadays. At least over here they are, especially in the smaller classes, like .50~.90 cu.in.

But if it is only one or two engines, running methanol on spark would be my choice too. In fact, I started out with spark conversions while remaining on glow fuel. Did that for a few years, then just for the fun of it, converted one engine to gas, just to see what would happen. Next thing I knew, I stopped buying methanol. No joke, the savings in the fuel bill have paid for half the planes I bought after that.