Fuel Question

Mostly because Cox recommend it and they knew their stuff.
Also because the ball and socket small end gets very hot and
synthetic will break down, castor won't.
If you want your Cox engines to last, use all castor. John

nitroairplane wrote:

Cox 049. wrote:Why must it be castor oil?

Small engines need castle because it is the best lube for them. It doesn't burn off and without it the ball socket joints wear out and the engines have very soft cylinder and without castor oil they lose compression.

Sorry, didn't get a prompt that you had already posted an answer. John

Will this work? Brodak 10% nitro 11.5% castor oil and 11.5% synthetic oil, it says it s for Brodak engines, will this work with a cox?

Sounds OK to me. At 10% nitro you're going
to be running somewhat tame.
Over 20%, and I'd add a little more castor.
Join the forum and use the search feature.
Welcome either way,
Bob

Would 10% nitro make a big difference in power? I haven't joined the forum cause I heard you get tons of e-mails to say your watching a topic.

Cox 049. wrote:Would 10% nitro make a big difference in power? I haven't joined the forum cause I heard you get tons of e-mails to say your watching a topic.

First, email notification is a feature that may be disabled in your preferences. The only email I receive is when someone has sent a PM.

A good source for 1/2A fuel is GlowPlugBoy fuel. You can get 24% nitro/17% all castor fuel for $10 a quart. Shipping on the first quart is high, but additional quarts ship for $2.00 each. Two or three quarts of fuel will go a long way in 1/2A engines. The higher percentage nitro will improve power, but it also eases starting and tends to broaden the needle, i.e., the needle will be less difficult to set when tuning for peak or near peak RPM. Lower percentage nitro fuels can make the "sweet spot" more difficult to locate and maintain.

http://www.gcbmrc.com/GlowPlugBoy_prices.htm

SIG Manufacturing sells their Champion fuel in a 25/20 nitro/oil mix with a 50/50 synthetic/castor blend for $8.39 a quart..

Another option is to buy a high nitro/low oil content car fuel (I use Morgan's Sidewinder Pro 20/10 and 30/10), then add castor to bring the oil content to your desired level. I enjoy tinkering with fuel mixtures, but for the casual user, buying SIG or GlowPlugBoy fuel is probably the best approach.

andrew

Castor and synthetic oils serve two puposes in our Cox engines:

- they lubricate vital parts

- they assist in carrying away heat that would be destructive to the engine

Poor lubrication destroys engines.

Ditto on the Glowplugboy. It runs better and smoother than anything including Sig in all of my engines. I add 1.3 ounces of dollar store Rexall castor oil to a quart to raise it to 20% oil. Just because I like running high engine speeds. He ships fast too. If you buy 4 quarts he told me he will make any custom mix you ask for.

Okay thanks very much for the replies, I will check those fuels out.

You're welcome, I hope you'll join up with us.

Hi,

I own a Black Widow .049 and I use a fuel of medium nitro rating i.e. about 15% nitromethane,
25% Newton R castor-oil, and 60% methanol.

I hope this helps?

Mr G

My Cox Black Widow's and TD .049's seem to thrive on SIG 25% nitro for general flying or, in the extreme, 35 when maximum erformance is desired. Never tried Glo-boy so can't realistically evaluate it.

Note: I tend to run larger rather tan smaller props depending on the aircraft.