Teach me about RC fuel?

Cadillac STS said:
The smell of castor oil fuel always brings me good memories. But I would avoid using much of it because of the burnt oil mess it can make.

One idea is find your local R/C flying field and start hanging out there. Talk to the guys there and ask them questions about fuel.

Then when you know who is who at the field maybe you can find someone to put your engine on a plane and fly it!

Maybe if the interest grows learn to fly yourself.

The season is almost here!
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I'm already flying. But I flew in December. And January. And February. : o
 

They will mix fuel to your requirements. Just call and tell them what you want. Their fuel is good - I have been using it in my model engines for over 20 years.

You can mix your own, but it is hardly worth the troulbe unless you intend to use many gallons each year. Methanol can be found a race tracks for around $4 per gallon. Nitromethane can be purchased online, but the cost is around $100 per gallon with the hazardous shipment fee. Castor and synthetic oil are available online, castor for around $25 per gallon and synthetic for around $40.

I run typically 5% nitromethane. More than that is just not necessary for most engines. In fact, most engines will run OK without nitro. I run 16% oil (blend of castor and synthetic) in my ball bearing engines and 22% in my bushed engines. Percentages are by volume.
 
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Just another thought @JRaut because its crossed my mind on my own methanol radial. There is a gasoline / spark ignition solution that doesn't require a substantial rebuild meaning distributer etc. Just a timing magnet on the drive washer & relatively small battery. I haven't fully researched the company/product myself, but on first pass seems to be a longstanding product/service & the video runs look good. There is an off the shelf 5-cylinder ignition system available.

Coincidentally I called them today to explore what might be involved for a future project. Apparently the 9-cyl module can be modified to run a V8 for example. But custom cylinder count modules are also possible. I thought an existing methanol compression ratio might be an issue on a switch to gasoline, but he said its not actually not that big a deal on commercial glow retrofits. Some decompress a bit with head shims, some run higher octane Avgas (I think). So food for thought. I've read of too many nice homeshop engine builds that were mechanically sound butteh builder struggled with ignition systems. I'm familiar with glow so taht dictated my decision. But I se the benefits of gasoline.

5 CYLINDERS CDI Archives - CH-ignitions

5 Cylinder CH CDI Ignition For Radial Engines , Saito Engines 325 5-Cylinder, OS FR5-300 Sirius 5, ASP FS400AR , MAGNUM XL400, Various Spark Plug Cap Options
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Gasoline also runs hotter than methanol. The engine may need additional cooling area. You may also need to switch to a more heat resistant valve material.
 
Good points. I need to do some conversion lurking on RC forums to absorb some of their experiences. Aside from gaskets, tubing, O-rings etc. most of the gasoline (shop built) engines I've looked at don't seem appreciably different that what was called for on my engine materials wise. But I haven't looked at it super deep. The Ageless engines would be a good proxy. I followed those builds on other forums & have the BOM for 9-cyl. 6061 heads, SS valves etc.
 
Well I'm blown away by the amount of cross-knowledge folks have on this forum. Thanks everyone so much for the input!

You've all certainly convinced me to go with a store-bought fuel rather than mixing up my own brew. I'll either go with S-W Fuels or FHS Oils. The aim will be to find something with about 5% Nitro. If I can find one with a hair less oil in the mix, I'll probably go with it, but I'm not going to go too far out of my way to pare back on oil.


Dhal22 said:
Love the smell, love it.
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I guess I'm in for a treat! One of my other hobbies is working on old 50cc 2-stroke mopeds --- quite a pleasant fragrance out of those too!

petertha said:
This excerpt is from OS Sirius 5-cylinder radial instructions, a pretty similar engine to the Edwards with the exception of Edwards separate lubrication system. OS say's pretty much the same in their other multi-cylinder engine manuals.
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I've been referencing the OS manuals as well. There's some good info buried in those.

petertha said:
Another thing I will pass on is 4-sroke plugs are getting harder to come buy, at least in my neck of the glacier. I found this place that sells OS plugs (and many other Japan engine goodies). The were expedient shippers & great to deal with.
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Good to know, I did notice they were not easy to find. I found some surplus plugs on eBay but will look these guys up next time.

What's the difference between 2- and 4-stroke plugs? Mostly just the heat range?

Cadillac STS said:
One idea is find your local R/C flying field and start hanging out there. Talk to the guys there and ask them questions about fuel.

Then when you know who is who at the field maybe you can find someone to put your engine on a plane and fly it!
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This will be on my summer activity list. Hopefully I'll have the build finished in time to bring it to one of the meet-ups.
 
JRaut said:
Well I'm blown away by the amount of cross-knowledge folks have on this forum. Thanks everyone so much for the input!


What's the difference between 2- and 4-stroke plugs? Mostly just the heat range?


This will be on my summer activity list. Hopefully I'll have the build finished in time to bring it to one of the meet-ups.
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There are many of us with extremely varied other interests.

4 Stroke plugs have a much heavier element to help retain heat during the non fire stroke. 4 stroke also turn slower RPM so it is even longer between power strokes.

Be careful RC flying can be yet another very deep rabbit hole.........
 
Flyinfool said:
There are many of us with extremely varied other interests.

4 Stroke plugs have a much heavier element to help retain heat during the non fire stroke. 4 stroke also turn slower RPM so it is even longer between power strokes.

Be careful RC flying can be yet another very deep rabbit hole.........
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Transmitters, 5?, engines, 50?, planes, 25? Kits/arfs in box 20?, very deep rabbit hole.
 
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