Home brewing!

[skatefreak]

Afternoon all.
Well, there must be some people out there who make their own fuel and I'm curious to know what people use!

I have come across shell Racing M (2 stroke oil soluble in methanol),
however at £14 per litre which would make up 5 litres (+ .50ppl for methanol) we're talking 15% + model shop fuel prices! :|

So methanol aside, what are the options for lubrication?
Castor is 'okay' and good in smaller quantities however I can only for the life of me find it for medicinal use and it is prohibitively expensive as such.

I'm currently working on a blend using straight methanol and methyl Esters (FAMEs) for lubrication.
£0.50 or < per litre of methanol.
£0.10 or < per litre of Methyl Esters.

Interestingly there is little to nothing of using this online that I can find however it seems promising and I have a cheap ASP52 that I will burn a few gallons and see how it holds up/if it survives!

The only real problem with this blend so far is that at lower temperatures the Methyl Esters can precipitate out of the solution which makes it less suitable for lower temperatures :|

On the plus side, if I can get this to work reliably then I'm looking at around 0.60ppl (£2.34 per 4.5 litre gallon)
Addition of acetone is supposed to help so another avenue to investigate. I also have 2EhN (2-Ethylhexyl nitrate) which could be tired as a cetane additive.

However, there is every chance after a few gallons the engine may show signs of blowing bearings/worn pistons etc so what are the other options available?

Any thoughts would be very much appreciated.

Best regards

-Jvr

[dieselcarb]

U may be able to get oils etc direct from model techniks. If you own your own business I might be able to swindle a ripmax account and buy oil at trade. Cheaper by the gal espeacialy edl2.
Dont bother with castor as its needs to be a certain type and super good quality snd to mix it youd be needing a machine so it dont settle lumpy/foamy.

[pgkevet]

I've never tried mixing my own and know very little about it. But when prompted to think on the subject then the usual 20% oil is a huge percent. I understood that engine oils were there more to lubricate than to be burned and petro 2 strokes only use 10-40mls oil per litre instead of 200. It's also noteworthy that local rural rogues use ordinary cooking oil mixed with heating oil to run their deisel cars - and essentially castor is just a veggie oil. the aspects of a lubricating oil will be whether it degenrates at engine temps/pressures and whether it burns at those temps.. presumably those figures are available for both castor and cooking. Or just gamble and mix some chainsaw oil in alone or with a mix.. since you know that that can cope with abuse.

[electricsceadu]

the oil in the fuel is used to cool the engine as well as lubricating it
differing grades/types of oil are used to alter the burn of the fuel
talking to jerry at wildcat fuels a few years ago he said that he uses the oils to alter the timing of the burn, the burn pattern, the rate of burn etc
and the difference between the plank/car/heli fuels is the blending of the oils used

[Grumpy]

Castor is 'okay' and good in smaller quantities however I can only for the life of me find it for medicinal use and it is prohibitively expensive as such.

Just use 'Castrol R' 2 stroke racing oil... Its a castor based lube intended for precisely this purpose. There are other similar Castor based lubes for racing motorbikes.

Great at lubricating but awfully messy.

[Grumpy]

the oil in the fuel is used to cool the engine as well as lubricating it

I'm not sure about the cooling ability of two stroke oil, do you have any explanation or references as to how that's meant to work? i guess it does carry a bit of heat out of the engine as it's spat out of the exhaust but i'd be surprised if that was a significant effect.
Methanol certainly does improve cooling massivly. Methanol has a very high high latent heat of vaporization, meaning that when it vapourises in the carburetor it absorbs lots of heat thus cooling the air going into the engine. This is why methanol burning engines need much less in the way of cooling fins compared to petrol engines and they also run much cooler. you can feel this if you dip your finger in methanol, it will feel really cold as it evaporates off your digit.

Oil effects the burn because oil displaces the flammable components of the fuel. A fuel that has 20% oil only has 80% actual fuel! For performance you want as little oil as possible, but for lubrication you want as much as possible... so it's a compromise.

[dieselcarb]

Oil and lubricating is a science of its own and everybody has tried and tested and has there own opinion. Engine manufacturers will give a safe range of percentage (this is a guidefor warunty assuming a cheep crap oil is used) the engine will probably run and live strong on half that oil if its of good quality. U can use chip fat if you want its oil it lubricates doubt it will do your engine any good may even blow up on first tank.

Caster the oil of old timers :-P its proven to work and has real good film strength that molecularly alters unlike no other and keeps on going at super hot temperatures. I for one will not use it for so many reasons. No modern engines need it and old engines would be fine on most modern synthetec oils. I personally would prefere a decent fuel and keep a cleen engine af the cost of a rebuild if I cook it. If you like lean burn protection try a model technics fuel containing edl or even better weston fuel. Infact weston is a fantastic fuel and the oil is probably the best in the world for plank flying or a lube in general. But I would use rapicon as I prefere its qualities of its oil package

[electricsceadu]

you've hit the nail on the head the oil takes the heat out to the exhaust as it passed through the engine

and you can't beet the smell of castrol R
if castrol made aftershave it would smell of castrol R coming out of a two stroke

[Grumpy]

you've hit the nail on the head the oil takes the heat out to the exhaust as it passed through the engine

As I mentioned, that effect wont really be very significant.

Bear in mind that all the 'stuff' coming out of the exhaust carries away heat. As the engine takes in six times more air (by mass) than it takes in fuel, when you look at what comes out of the exhaust only about 3% or so (by mass) is oil. So it's pretty easy to see that oil can only be responsible for carrying away a very small proportion of the heat that is expelled from the exhaust.

Then factor in that a lot of engine cooling is done by the fins etc so the overall contribution of the oil in cooling must be tiny.

[pchristy]

Its a long time since I had anything to do with this, but I seem to recall that Castrol make two different varieties of castor: "R" and "M". I believe I'm right in saying that "R" doesn't dissolve well in methanol - that's what "M" is for.

Although castor is a pretty good lubricant, it also has its down sides - and those become more problematic as the engine operating temperature rises. And heli engines tend to run quite a bit hotter than those in planks! In a "hot" running engine, the castor will rapidly start to "varnish" the engine - both inside and out. Inside, this increases frictional losses, as it gums up the works. Outside, it forms a nasty coating on the engine, which is very difficult to remove, and that makes the engine run even hotter. It has also been known to form lumps of "coke" in the silencers, and I've seen at least one silencer almost completely blocked by a solid lump of castor residue.

Synthetics can also have issues. Mostly, a synthetic will only operate over a much narrower temperature range than castor. Most good fuels use a blend of synthetics, so that as one starts to break down (if you have a lean run) a higher temperature one will take over. Certainly Bekra used to contain some stuff for extreme high temperature that used to smell like burning rubber if it came in to play! It was the fuel's way of telling you it was probably a good idea to land PDQ!

For a long time, its been generally accepted that the best oil out there is Klotz, often with a dash of EDL added to improve the temperature range. With a good synthetic, you really shouldn't need more than 15% oil. Bekra only increased to 18% when OS insisted on it for warranty repairs, but all it did was make the models messier.

The oil does have a significant cooling effect, carrying away heat in the exhaust residue. And for those that like their 20% oil, consider this: In Japan, if you run 30% nitro, by law, you cannot use more than 10% oil!!!

[dieselcarb]

Bekra is 50/50 heli klots oil and edl2. I prefere a good runny oil thats around 20-23 % I find that this fires really well timing wise cant back it with anything scientific just personal testing and preference . I used weston fuel prosynth 2000 this is a low oil fuel yet the oil dont burn I belive my heli would run absolutely fine on liquid gold and thats about 6% and the prosynth about 12-15wich is too oily believe it or not. Do not use viper

[Kiwi64]

you've hit the nail on the head the oil takes the heat out to the exhaust as it passed through the engine

and you can't beet the smell of castrol R
if castrol made aftershave it would smell of castrol R coming out of a two stroke

image.jpg
2 Stoke candle

[skatefreak]

Well,
I mixed up some 80% meth and 20% Methyl Esters and gave it a shot however I also diddled the engine some what.
Its an ASP 52 ringed heli engine (the £48 off hobby king).
I opened the ports, turbo thingy'd the con rod end of the crank, opened up the carb side, threw on an OS 50 hyper 60l carb, went to a hot plug and removed a shim for lowering the compression slightly.

As I live in a new build estate I could only hover the heli for a few mins as the neighbours would no double go balmy if I did a full tank however the results are promising so far.

Smokes like a banshe however was running a little hot, oodles more power so cant wait to open up the throttle a little more.

Although going from 15% down to home brew straight the engine seems to be a lot more on the ball, the smoke smells a lot like the older aero fuel I used to smell down the club coming from the plankers.

I will try and get a few gallons through the engine over the next few weeks, strip the engine, crack open the bearings and have a really good look over to see how its fairing.
If all goes well I will think about putting the OS70 in there (if its even needed as I can't out fly a 50 yet) and maybe even put some through the 700 (which I'm yet to fly properly heh).

Thanks for the input, its proving pretty interesting so far

The reference to chip fat - I wouldn't consider putting vegetable oil through the engine for many reasons however fully converted bio diesel is very different. I doubt its going to be nearly as effective as the synthetic oils selected by mainstream brands however i am quietly confident that in reasonable quantities it will do the job

Best regards

-Jvr