Question on fuel.......

micro 0951 Wed May 24, 2017 9:03 am

Hello there, i recently got into glow power with cox 049 after 5 years of flying elec***. I ended up getting a gallon of glow from the LHS, the same kind that the company i work for uses. At a glance, the fuel appears cox friendly at:

*BYRON Aero Gen 2*
10% nitro ( low i know )
20% oil

However after doing some research and checking the byron website, it turns out the oil in most of their fuels is actually a 80/20 mix of syn/castor. That leaves the total castor content in the fuel at 4%. Is this fuel considered safe to use in my little noisemaker? Or must the castor content be higher?

Happy flyin,
Micro RC Plane

MauricioB Wed May 24, 2017 11:31 am

Hello, I have tried several formulations of fuels for Cox engines and I have consulted here with the users of these engines to know their experiences.
Personally, I make my own fuel with very good results, even in different ranges of gear and flight radio control.
The fuel I use is 100% beaver and the percentages are as follows:
18% beaver
15% Nitro
Other Methanol
This is for most of the months of the year. In case of very hot summers, I raise the percentage of Castor to 20% and 20% of Nitro, but this only for the hot summer months!
I have also used very good quality fuel such as Byron, which has synthetic and beaver with 10% of Nitro, (very good) ... but I recommend that the fuel for Cox preferably its higher percentage (in case it has synthetics also ) Be Castor.
I hope it is useful.

roddie Wed May 24, 2017 1:12 pm

Take a look at these L.M. Cox Manufacturing fuel-mix/order sheets from 1977.

Sport fuels; 10-15% nitro

Racing fuel; 30% nitro

The "Dow-Lube" (by Klotz) is a synthetic.. and if you notice, there isn't much used in the formula. The high castor content is said to be superior in properly lubricating the piston-rod's ball & socket joint.

Sig Manufacturing's "Champion" 1/2A glow-fuels by comparison use a 1:1 ratio of synthetic-oil (Klotz) to castor-oil. Sig's 25% and 35% nitro fuels run very well in Cox engines. There are also Cox fuels sold by Hobbico/Tower, that went through a comprehensive formula-change with input from this forum a year or so ago. The castor-content had been much too low which can lead to premature engine damage. The Cox fuel now has the proper amount.

Here's the thread.. in case you're interested. It's a good read.

https://www.coxengineforum.com/t7143-cox-super-power-fuel?highlight=cox+fuel

pkrankow Wed May 24, 2017 1:42 pm

Drug store castor oil is good enough to dope up that low oil fuel to be safe to use. (degummed castor is probably better) A little math and you can break percentages into volumes, then add more volume and get percentages back.

I wrote a spreadsheet at one point to aid in this. I don't know if I have it still, but probably do. Quite a few other people did the same.

Phil

micro 0951 Thu May 25, 2017 12:36 am

That thread is indeed a good read, unfortunately for me pretty much every LHS in singapore doesn't carry fuel with a good amount of castor inside for cox engines. The LHS i go to does have SIG 1/2a 25% , but with cox engines a distant memory here, i doubt they would restock once its gone. Crying or Very sad

Back to the oil....what ratio of syn/castor should i be going after? I've done some math for a 50/50 mix, but that bumps up the oil content to 28.6%, which seems like too much oil.

And just asking....what is "beaver"? Some kind of oil?

Micro

Surfer_kris Thu May 25, 2017 2:25 am

micro 0951 wrote:
And just asking....what is "beaver"? Some kind of oil?

I think that is simply a "google translation" for castor....

pkrankow Thu May 25, 2017 7:31 am

More than you may want to know
https://en.wikipedia.org/wiki/Castor_oil

micro 0951 Thu May 25, 2017 8:12 am

I think that is simply a "google translation" for castor.... [/quote]

Yea....google does a good job explaining beaver "castor oil". I roughly get the idea now. Babe Bee .049

+ castor = happy engine. Is 28.6% oil usable? Or would i run into problems in the future?

Micro

MauricioB Thu May 25, 2017 8:31 am

Hi, castor oil is RICINO.
The seed of the plant where the oil is extracted is called beaver, this is crushed and logically the filtering procedure is done.
It should be noted that the oils can be simple degummed or double degummed, this has to do with the viscosity of the oil itself.
Preferably for fuel is the double degumming, which generates little residue.

MauricioB Thu May 25, 2017 8:37 am

Castor oil (RICINO), you should not use more than 20%, since if you do not have nitro the mixture, it costs to start.
As a child we used castor oil bought at pharmacies in a ratio of 4 to 1 (4 methyl alcohol and 1 castor oil), it works, but it improves very noticeably if applied within the formula nitromethane.
I repeat, according to my experience no more than 20% and not less than 18%, in these parameters you will have no problems.

Surfer_kris Thu May 25, 2017 9:58 am

25% all castor is what i often use for running in engines. In old-school lapped engines one can easily use up 30% of oil. This will not hurt the engine but you will have a higher fuel consumption, as more of the fuel it is not combustable.

If you are simply adding oil to a commercial blend you will also reduce the relative nitro contents at the same time. You could perhaps try adding castor up to around 25% of total oil and see how that works.

pkrankow Thu May 25, 2017 1:26 pm

High castor percentages can do some things to the operation of the engine. It will make the NVA less sensitive. It will also artificially increase the compression ratio of the engine. Both of these effects are simply because the castor oil takes up volume in the fuel and does not really burn.

Phil

Surfer_kris Thu May 25, 2017 1:46 pm

It will also make the engine run cooler, there are lots of benefits. Smile

Paulgibeault Thu May 25, 2017 3:56 pm

Well actually, the lowest known "safe" castor oil content for the ball-socket to live is indeed 4%. I did run 100% synthetic fuel at 20% total oil content,
but it damaged the piston to cylinder fit after 3 (quite fast) flights. So I've learned not to do that anymore. Also, this low of an oil content MAY require the ball-socket joint to need tightening more frequently. You would need to keep an eye on that... Even if you added some extra castor oil to bring the total oil content up to 22-25%, that would be quite helpful. Good luck!

Cheers,

Paul (aka Mr. Mouse)

micro 0951 wrote:Hello there, i recently got into glow power with cox 049 after 5 years of flying elec***. I ended up getting a gallon of glow from the LHS, the same kind that the company i work for uses. At a glance, the fuel appears cox friendly at:

*BYRON Aero Gen 2*
10% nitro ( low i know )
20% oil

However after doing some research and checking the byron website, it turns out the oil in most of their fuels is actually a 80/20 mix of syn/castor. That leaves the total castor content in the fuel at 4%. Is this fuel considered safe to use in my little noisemaker? Or must the castor content be higher? :

balogh Fri May 26, 2017 12:53 am

I have always used 20% castor and never any synthetic oil. Castor not only saves the ball socket joint but deposits into occasionally inflicted micro scratches in the cylinder wall and thus heals compression loss....what a fantastic natural lubricant!!!

MauricioB Fri May 26, 2017 1:27 am

András, I fully share your concept! thumbs up.
I have rescued engines like OS .10 FSR and others, thanks to the castor - ricino .... as you say "fantastic natural lubricant"!

getback Fri May 26, 2017 7:43 am

This is helpful in mixing fuel.. http://www.nitrorc.com/fuelws/oilonly.asp This Site Rocks!

gcb Fri May 26, 2017 9:24 pm

Some considerations about fuel:

Some brands of fuel measure by volume while others measure by weight. Make sure you know which your fuel manufacturer uses when adjusting the mix.

Most fuels are mixed to be used in large BB RC engines that often do not need as much lube as their smaller counterparts.

If you are like most of us and sometimes launch with a too-lean mixture, the higher percentage of castor in the fuel lessens damage and wear to the engine.

Good luck, whatever you use,

George

micro 0951 Sat May 27, 2017 8:00 am

Thanks for all the responses! I'll get a bottle of benol and bump up the castor content. Thanks

Happy flyin,
Micro RC Plane

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