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Apr 21, 2008, 02:28 PM
WrongRudderR/C
FlattyFlier's Avatar
No, it will be slimy unless cleaned with alcohol, but it will not hurt styro or EPP foam.
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Apr 21, 2008, 09:12 PM
Registered User
Keemos's Avatar
Quote:
Originally Posted by jpilkinton
Will the fuel hurt the foam? I don't care about the color changing. I just don't want to be flying and the engine fall off in mid flight due to melted foam from the fuel.
I agree with Jake... glow fuel will not hurt the foam. I used to have a CUB power by .15 glow engine way back in the 80's.
Apr 21, 2008, 10:39 PM
WrongRudderR/C
FlattyFlier's Avatar
I use a $1 store mini spray bottle filled with 50-90% rubbing alcohol that spray the plane down with and wipe it clean with a paper or terry towl. Cleans right up, as the thin alcohol gets into the little bumps and crevises and gets the oil out.

Cox used to make RTF .049 2-3ch. airplanes way backwhen I first started. They came out with the first Lazy Bee design in a .049 powered 2ch. RTF package with an all styro airframe, as well as a couple others!
Apr 21, 2008, 11:54 PM
Registered User
Cool, thanks for the heads up guys.
Apr 22, 2008, 09:31 AM
WrongRudderR/C
FlattyFlier's Avatar
One more hint, dont run dark colored fuels, they will turn the plane that color! Pinks and blues will discolor the least, but you cant escape it completely, unless you get some clear (or any color) Ultracote or low temp covering to cover the area most prone to get greased!
Apr 23, 2008, 02:26 AM
Registered User
OK. The fuel that I just bought has a blue color. Man I didn't realise how expensive model fuel is. I bought a gallon and it was $26(at a local hobby shop). It's been like 30 years since I bought glow fuel.
Too bad I can't run unleaded with an oil mix!
$4 a gallon sounds better than $26 a gallon.
Apr 23, 2008, 07:05 AM
Registered User
Make sure it has a sufficient percentage of oil, with the oil content being at least 60 to 80% castor.

At around 8 to 9 minutes an ounce, you have enough fuel for 17 to 18 hours of flying. That works out to about $1.50 an hour -- where else can you have that much fun for a buck and a half?
Apr 23, 2008, 09:23 AM
Registered User
Quote:
Originally Posted by jpilkinton
... Man I didn't realise how expensive model fuel is. I bought a gallon and it was $26(at a local hobby shop)....

Some more calculations:

18 hours -> 1080 minutes

I bought my 1300 mAh Hextronik LiPo's at HobbyCity (aka UnitedHobbies) for about the same price (when shipping added).
Flight time per cycle is roughly 8 minutes.

1080 / 8 = 135 cycles

They all puffed after 20-30 cycles or latest 3 months of use. Whatever comes first.
So reaching 135 cycles would be pure theory. 135 cycles without drop of performance and capacity - science fiction.

Be happy!
Apr 24, 2008, 01:25 AM
Registered User
Quote:
Originally Posted by Andrew0820
Make sure it has a sufficient percentage of oil, with the oil content being at least 60 to 80% castor.

At around 8 to 9 minutes an ounce, you have enough fuel for 17 to 18 hours of flying. That works out to about $1.50 an hour -- where else can you have that much fun for a buck and a half?
Yeah that's true. My wife was there when I bought it. Her jaw dropped quick when he said the price. But like I told her, that will last me a while. And now we have more stink'n rain and too high of winds, I think this gallon will last me a year or more.
I am currently working on a cylindrical fuel cell about 6-8 inches in length that will(or should) give me plenty of flying time at one shot. I don't know for sure, since I have not ran my engine yet. I plan on testing this weekend.
Apr 24, 2008, 01:41 AM
Registered User
OK, I think I seen this somewhere about using diesel in these cox engines.
Has anyone tried using pump diesel with these cox engines before? Both engines have the same theory. I know the compression is far lower on the cox, but I am curious about it. I have seen head kits for using diesel that don't use glow elements to aid in combustion, but I'm thinking the glow element would help the cox ignite the fuel better than no glow plug at all.
Curious minds want to know...........
Apr 24, 2008, 07:02 AM
Registered User
Quote:
Originally Posted by jpilkinton
OK, I think I seen this somewhere about using diesel in these cox engines.
Has anyone tried using pump diesel with these cox engines before? Both engines have the same theory. I know the compression is far lower on the cox, but I am curious about it. I have seen head kits for using diesel that don't use glow elements to aid in combustion, but I'm thinking the glow element would help the cox ignite the fuel better than no glow plug at all.
Curious minds want to know...........
You'll need the diesel conversion head, which I think are pretty easily available. A glow plug is based on a chemical reaction between the glow element, (dunno what it actually is made of) and methanol, thus diesel fuel won't work. OS Engines made a bioethanol engine a while ago, the OS .55 AX BE, which needs a special glow plug. Ever wonder why?
Apr 24, 2008, 07:23 AM
Registered User
JP --

You cannot get enough compression using the standard COX head to run diesel. There are conversion heads available, but to expect any longevity from your engine, the crank will also need to be replaced with an aftermarket version. The OEM crank is not beefy enough to withstand higher compression required by diesel fuel. The typical point of failure is in the web just below the crankpin.

COX glowheads are becoming difficult to locate and can be quite pricey -- the Sure Start at $6.99 from COX Models can really be thought of as an inexpensive head with a free engine attached. A good replacement head is the Galbreath head/NELSON plug combination available from Larry Driskill at Kitting It Together. It is one of the few aftermarkets that will work as well or better than the original head. If you order an aftermarket head, it may be a good idea to pick up a pack or two of head shims (gaskets) -- some of the Sure Starts I have purchased recently have been notorius for leaking around the head. Additionally, the copper gaskets are easily damaged and may need replacement.

If you intend to use anything over a 6x3, you may want to reduce the compression even more and an extra shim will give you this option. I agree with Jupeli -- 6x3 is about max for most runs. Texaco competitors have used 7" props, but with reduced compression.

andrew

Out of curiosity, what brand and mix of fuel did you buy?
Apr 24, 2008, 07:30 AM
piro-maniac........
GunnyGlow's Avatar
It's a catalytic reaction between the methanol in the fuel and the platinum in the glow plug.........
Apr 26, 2008, 11:54 PM
Registered User
Quote:
Originally Posted by Andrew0820
JP --

Out of curiosity, what brand and mix of fuel did you buy?

It is Traxxas Top Fuel 20% nitro. I did get it to start with the large prop but before it could get up to speed, it dies. So I used a smaller prop from a GWS slow stick electric. Now it starts and gets up to speed rather quickly, but then dies quickly. I am having a fuel delivery problem. So I decided to tear the engine down and clean it completely and make sure there were no shavings from the factory and make sure everything is square.


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