I have some commercial 15%/15% nitro/lube glo fuel. I want to add some
synthetic oil to boost the lube up to 20% content by volume. I tried to mix
a small amount of Klotz R/C Model Lube for gas with a small amount of glow
fuel. They appeared to not mix well. My question is what is a good
synthetic oil that I can add to glow fuel?
Why be limited to synthetic lube? Many think the best thing you can do for
an engine is to use some castor oil with your fuel. I'm one who agrees.
Castor oil stands up to high heat better without burning off, and does a
much better job of protecting an engine against rust while stored. Fox
insists that there be castor oil in their fuel.
The only down side is the fact that it leaves the outside of your engine and
plane more of a mess, IMHO. It is worth the tradeoff, if you value the long
life of your engine.
15% oil, assuming it's synthetic, isn't a bad ratio - adding oil will
reduce the performance of your fuel, but if you're concerned about your
engine, more oil never hurts. As you've found, oil designed for gas fuel
isn't miscible in methanol. While it's not synthetic, castor oil is never a
bad choice, but recently I've been running 15% straight synthetic - Klotz
KL200 or Coolpower.
I have moved to mostly four strokes and they do not thrive in a high castor
environment. Many fuel makers still put castor in the fuels even though
they use mostly synthetic, and four stroke users pay the price in carbon
build ups on the exhaust valves. BTDT.
Unless all you fly is 2 stroke, get a bottle of Klotz KL200 at your local
hobby shop if you wish to up the oil percentage. Since I make my own fuel,
I use 20% synthetic and leave it at that. I also use 10% nitro, but it
seems MY way of measurement is different from what the commercial fuel
houses calculate the mixture. Of course I just use straight volumetric
amounts and I am sure they use something else...
"H Davis" wrote
I got mine at a hobby shop, when the fuel that they had did not contain any
castor oil, and I have a Fox. (castor required, according to Fox)
I just add about 4 ounces to the gallon, and it seems to keep all of my
engines happy. I know that it is probably more than is required, but I'm
not racing, or trying to wring every last ounce of speed out of them. I
like the long lasting idea, when it comes to my engines.
Tower has it:
I got some Klotz synthetic at the hobby shop and it mixed well. It has both
SIG and Klotz on the label. there is more than 1 kind of Klotz synthetic.
One mixes with alcohol, the other with gasoline.
| > Somewhere I read that the commercial fuel quoted percentages are by weight
| > rather than by volume. I don't know how big the difference is.
| Volume changes with temperature. Weight does not.
Of course, and I imagine that Marlowe knows that.
It's more likely that alcohol, nitromethane and oil (whatever sort)
have different densities, and a difference would come from that. If
the densities differ signifigantly, then the difference between `20%
by volume' and `20% by weight' WILL become signifigant.
Of course, I can look all this up ...
nitromethane, 1.138 g/cm^3
methane, 0.792 g/cm^3
castor oil, I can't look up, but it's probably less than 1 g/cm^3
So, it looks like it does make a signifigant difference, though when
you're just adding oil to your fuel, you're probably just eyeballing
it anyways and a 20% error probably isn't signifigant.
As for changing with temperature, all of the components of your fuel
are likely to change volumes similarly (not exactly, but similarly)
with temperature, so the percentages by volume probably won't change
signifigantly even with large changes in temperature.