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Old Nov 15, 2012, 09:23 AM
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Originally Posted by Brutus1967 View Post
Unfortunately, Cox states their engines only require a short break in (one or two tankfulls) but that is due to the residue forming: it doesn't break in any further as the residue arrests that process. On a synthetic oil, they just need the same break in period as any other engine, which can be up to two hours of running slobbering rich.
Er, no, I've broke in my Coxes with several tanks of fuel. In the first 2 tankfuls, one will notice silver flakes of eroded metal, then after that very little. Glenn Cox developed very fine machining and honing techniques down to the millionths of an inch, so they did not require an extensive break in to achieve seating the piston.

OTOH, older tech engines were not as finely machined, and required a more lengthy break in process. The fit was not as precise. This is similar to your automobiles. The break in process is less rigorous with the newer vehicles, because the machining is more precise and finer. The older automobiles of 30 years ago or more used courser hones. Those had a longer break in period and limited speeds during break in.

I remember breaking in a Testors McCoy .19 CL engine. Ran a half dozen tankfuls through. It was not capable of breaking into a solid 2 cycle peak run yet. I flew it 4 cycling using flying time for break in. The Coxes OTOH come up to peak power in a relative short amount of run time.

One poster referred to washing the congealed Castor oil film on the engine, which ruined the seal on an E-Bay purchase. I surmise that the engine was already well worn, and the build up of Castor helped keep the compression seal.

He's got a couple options: 1) run the engine on Castor oil based fuel to rebuild the seal; 2) have the cylinder chrome or nickel plated to reduce the clearances restoring compression; 3) clean up the engine, mount on the shelf for display and install something more solid running.
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Old Nov 15, 2012, 10:10 AM
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Originally Posted by PyroMan View Post
I

Quick question, somewhat off topic but I'm sure you guys will know the answer. Are companies still making engines this small today? If so who? Where does somebody buy a brand new .049 engine or smaller?

Thanks,
Nicholas
As noted, there are two sources for COX engines -- these are mainly old stock engines or engines that have been built up from old stock parts. However, these two on-line retailers have enough combined buying power to have some new parts manufactured at reasonable prices.

COX International

EX Model Engines

NORVEL engines are now available here.

If you're looking for fuel, you can get car and plane fuel from Purchase Area Hobbies, located on old 80 between Mayfield and Hardin. A lot of Paducah flyers use this hobby shop. Ed still had some COX Black Widows available for sale, but you will have to ask for one; they're not out for display.

andrew
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Old Nov 15, 2012, 12:18 PM
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As noted, there are two sources for COX engines -- these are mainly old stock engines or engines that have been built up from old stock parts. However, these two on-line retailers have enough combined buying power to have some new parts manufactured at reasonable prices.

COX International

EX Model Engines

NORVEL engines are now available here.

If you're looking for fuel, you can get car and plane fuel from Purchase Area Hobbies, located on old 80 between Mayfield and Hardin. A lot of Paducah flyers use this hobby shop. Ed still had some COX Black Widows available for sale, but you will have to ask for one; they're not out for display.

andrew
Hey, it sounds like you're from my neck of the woods! Yeah I've been to Jackson purchase hobbies a few times. Last time I was there I brought my engine in and asked Ed if he had fuel for it. He said they did t carry the special 1/2a fuel but I could find it online. I'm hoping I can talk my parents into brining me out there Monday to see if he has something that would work, if he doesn't I'll just order online.

Thanks to the links to the engines. I may have to put one of those engines with the adjustable throttle on my Christmas list if my current engine doesn't work out.
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Old Nov 15, 2012, 12:54 PM
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Originally Posted by Brutus1967 View Post
Second: if an engine is "broken in" and operated on castor oil, it CAN fail when using synthetic.... that is also a very possible outcome if you take the wrong approach....

But the statement that an iron piston in a steel liner MUST be lubricated with castor, is just utter BS.
I have seen brand new Enya engines which where run in with synthetic oil from the start, and they just wear out straight away. There is simply no substitute for castor, a blend might be fine though.
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Old Nov 15, 2012, 01:04 PM
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Originally Posted by PyroMan View Post
Are companies still making engines this small today? If so who? Where does somebody buy a brand new .049 engine or smaller?
There are several options that are a lot more modern designs than the cox engines. They also come with a working throttle, unlike the intake choke version you can get for cox sure start engines. Most also have a muffler to reduce the noise and keep the oil away from the fuselage:

Norvel .049 and .061 with a proper RC carb and muffler
MP Jet .061, available with twin needle RC carb and muffler
Brodak .049 RC (unmuffled)

Slightly larger:
Thunder Tiger .07 RC carb and muffler

For diesel engines you have:
PAW .030, .045, .061 all with ballbearings and RC carbs, plus an optional exhaust collector
MP Jet .061 twin needle RC carb and muffler
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Old Nov 15, 2012, 01:12 PM
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Originally Posted by PyroMan View Post

Hey, it sounds like you're from my neck of the woods!

.........to see if he has something that would work, if he doesn't I'll just order online.
I'm in Murray.

You can run car fuel -- you want a fairly high nitro (25 to 30%) and low oil content fuel to start with. The low oil percentage lets you add castor oil without driving the total oil content too high. Also, starting with a high nitro content keeps you from dropping the nitro percentage too much with the additional castor. I've been using Klotz BeNol for years as my castor additive --- you should be able to find it at one of the auto parts houses or motorcycle shops.

I have written a Windows application that allows you to easily determine how much castor oil to add to your fuel mixture to reach a desired percentage of castor. It also re-calculates the percentages and ounces of nitro, overall oil, castor oil and the syn/cas ratio. If you're interested, PM me with your email addy and I'll send you a copy.

There is also an Excel spreadsheet available on the COX International site, but it doesn't seem to want to download at this time.

http://coxengines.ca/files/FG.pdf

I also wrote that one and can send it if you wish.

andrew
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Old Nov 15, 2012, 03:15 PM
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I've been using Klotz BeNol for years as my castor additive --- you should be able to find it at one of the auto parts houses or motorcycle shops.
Andrew, thanks for the tip. I have motorcycles and not being in competition, didn't realize such a product is available at motorcycle shop and possibly auto parts places. This makes it easy for me. Thanks!
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Old Nov 15, 2012, 10:08 PM
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Glowplugboy Rocket 24

Brand spanking new website: www.gcbmrc.com . Our 1/2A Rocket Power fuel is on the opening page in the featured products.
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Old Nov 16, 2012, 07:33 PM
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I have seen brand new Enya engines which where run in with synthetic oil from the start, and they just wear out straight away. There is simply no substitute for castor, a blend might be fine though.
surfer_kris, I'm just curious what part of the Enya engine wore excessively? Was it the piston / cylinder fit or plain bronze bearing / steel crankshaft fit? Piston pin / con rod slop?

Anyway, I was able to successfully run my Fuji .099S-II R/C engine today on O'Donnell 30% Heli Fuel with a Swanson Associates Fireball Hot Standard plug. Some time back I could not get it to run reliably on standard glow fuel, ended up using an OS Max 15FP that did.

Engine was a little dusty being tucked in a drawer. This engine is an odd ball that I bought 2 for $10 each at Hobby Shack some 25 years ago. It is baffle piston by design, but uses ABC construction with an aluminum baffle piston run in a chrome plated brass sleeve. It's got a rather low compression ratio of 5.5:1, putting out 0.16 horsepower at RPM's of 2,500 - 12,500, recommended props 7x4 (FF) or 7x5 (CL and RC). Weighs 4.3 oz. without muffler, heavy like an Enya. Interesting that they don't recommend the 8x3 or 8x4 props like Enya and older OS Max baffle piston engines do.

Seriously I'm looking for a dealer in town selling Klotz BeNOL Racing Castor Oil, will add that to the O'Donnell prior to serious flying.
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Old Nov 17, 2012, 01:16 AM
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It is the piston to cylinder fit that wears and it will not seal. It may well be a combination of the castor being a thicker oil and also being able to build up a varnish that both helps to improve the piston to liner seal on iron/steel constructions.

On engines with excessive crank to case slop, like the AP wasp, the thickness of the oil can also help to seal at the crank, without forming a varnish layer.

I'm not dissing synthetic fuels overall or without trying it, they have their place. I do run all synthetic fuels in ballbearing, ABC engines, and have had no problems with that. But I would never use it for iron/steel constructions, where to me the castor is necessary and was the fuel used when the engines were ones developed.

For obvious reasons I don't test and prove this every weekend. But let me give you an example that certainly has had me convinced. I was visiting a friend and we vent flying at his local field. There was another guy there with an Enya engine that he struggled with. It had no compression at all when turned over by hand, although it would occasionally fire when turned of with an electric starter, it would not stay running. I asked him about the history of the engine, and it had been donated to him from his friend who could never get it too run. He said the engine had been run-in, very carefully, on his regular all synthetic fuel, and the compression was only getting worse and worse. I then convinced him to try regular FAI fuel (80% methanol, 20% castor, 0% nitro). The engine would then run well enough that he could fly and it would also have compression when turned over by hand. The guy thought this was some kind of magic trick, and could not wait to tell his friend about it...
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Old Nov 17, 2012, 05:05 AM
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Originally Posted by surfer_kris View Post
I have seen brand new Enya engines which where run in with synthetic oil from the start, and they just wear out straight away. There is simply no substitute for castor, a blend might be fine though.
And I have broken in and succesfully run in Enya's on Synthetics without any problems.... strange, huh?
Trust me, if you need castor, you're either doing something wrong, or there's something wrong with the type of synthetic you use.

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Originally Posted by surfer_kris View Post
It is the piston to cylinder fit that wears and it will not seal. It may well be a combination of the castor being a thicker oil and also being able to build up a varnish that both helps to improve the piston to liner seal on iron/steel constructions.
That is just plain rubbish: Castor is maybe thicker when cold, but way, WAY thinner at operating temperature, it has a terrible viscosity index compared to synthetic oils.
And it is for a large part viscosity that keeps metal surfaces separated.
What happens is that where metal to metal contact occurs, local flashtemperatures also occur, causing the Castor to form the deposits at these exact spots.
A good synthetic prevents these flashtemperatures all together, by preventing metal to metal contact, if properly run in.

That all being said, I am not contesting the fact, that given the alternatives available to the individual modeller (and possibly their local prices), Castor could be the better choice.
But the statement that Castor is the ONLY alternative, is just plain not true.

Brgds, Bert
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Old Nov 17, 2012, 08:05 AM
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But the statement that Castor is the ONLY alternative, is just plain not true.
That's just semantics, among the readily available fuels, castor is the only alternative. A blend of oils may work, but I cannot see any reason to not use castor in old-school design engines.
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Old Nov 17, 2012, 11:15 AM
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And I have broken in and succesfully run in Enya's on Synthetics without any problems.... strange, huh? Trust me, if you need castor, you're either doing something wrong, or there's something wrong with the type of synthetic you use.
Because this topic has always been a hot one, I decided to do a little informal research from various sources on the 'net. Of course, one can break in engines using a synthetic oil based fuel, particularly the hand lapped steel piston running in a steel liner ones. According to,

http://www.geistware.com/rcmodeling/.../fuelfact2.htm

It states, The metallurgy in today's engines barely resembles that of a generation ago. The end result, as far as model engines are concerned, is that the engines today simply don't require as much lubricant - not nearly as much. I will be quick to add that those running antique engines in Old Timer events should certainly continue to use the old-time formulas - no doubt about it. [...] There a couple of types of engines that do require an all-castor fuel, or at least one with a considerably higher castor content than most others. One would be the Fox ringed iron piston type, and the other would be the small Cox engines, because of their rather unique ball-and-socket connecting rod-to-piston design.

Your more recent Enya engines that use ABC technology and ball bearings to support the crankshaft are modern contemporary engines. The older plain bearing, hand lapped steel liner ones are of the older legacy technology. It is those that benefit from Castor oil in the fuel. Thus I surmise the yes, you can use exclusively synth oil fuels in that legacy engine, but will you be able to obtain a couple hundred flights, or will it be worn out by the time you hit the 100th flight?

It goes on to state, SYNTHETIC OIL Advantages Little to no carbon or vanish buildup inside Disadvantages Burns off surfaces at about 100 degrees lower temperatures than castor oil [...] The most frequent comment I hear from lovers of all-synthetic fuels is, "Brand XX leaves a lot less oil on my model." My response to that is, "Doesn't that bother you? If you don't see much oil on your model after flying, that tells you one of two things - or both: Either there wasn't enough oil in there in the first place, or the oil is burning off with the methanol. Neither is good.

So, for these legacy engines, to have the lubricating effect of Castor oil, because all does not burn off in the combustion process to continue to lubricate the lapped steel cylinder walls and the steel ball and socket joint connecting rod to steel piston joint of the Cox engines in a hot piston has merit.

Quote:
That is just plain rubbish: Castor is maybe thicker when cold, but way, WAY thinner at operating temperature, it has a terrible viscosity index compared to synthetic oils. And it is for a large part viscosity that keeps metal surfaces separated. What happens is that where metal to metal contact occurs, local flashtemperatures also occur, causing the Castor to form the deposits at these exact spots. A good synthetic prevents these flashtemperatures all together, by preventing metal to metal contact, if properly run in.
Although it thins at higher temperatures, Castor oil continues to lubricate at 100 degrees higher than the synth, since the synth has burnt off.

Quote:
That all being said, I am not contesting the fact, that given the alternatives available to the individual modeller (and possibly their local prices), Castor could be the better choice. But the statement that Castor is the ONLY alternative, is just plain not true.
Regarding cost effectiveness, there may be an exotic synth out there, but where is it? Castor oil is cheaper than synth and will continue to be in model aviation fuels for some time for this very reason.
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Old Nov 17, 2012, 09:01 PM
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Yesterday, I got the Fuji 099S-II baffle piston ABC engine with low 5.5:1 compression to run through a whole tank of fuel yesterday. This was with the synthetic oil based O'Donnell 30% Nitro Heli Fuel.

It sat in a drawer for the past two decades, because I could not get it to run reliably. I replaced it with an OS Max 15FPS ("S" = CL version) on a Junior Ringmaster, which would run reliably.

Details of this unique and fairly rare engine are in:

http://www.rcgroups.com/forums/showt...955929&page=16 and Message #228,

and http://www.rcuniverse.com/forum/fb.asp?m=11300797

Looks like the trick to get it running was high nitro fuel and a hot plug.
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Old Nov 18, 2012, 02:08 AM
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I remember reading through that article... Good stuff and thanks for the reference. The paragraph that lead me to add castor to buggy fuel for my small engines was:

A few years back, the modeling community was in a "synthetic oil frenzy," and the swing was toward all-synthetic fuels. Happily - at least in this writer's opinion, we've seen a very noticeable swing back toward the center, with the majority seeming to prefer a synthetic/castor blend. We think this makes sense, and many years experience proves it.

Since I ducked out of the hobby for these synthetic leaning years, I still want some castor in my fuel.

Bottom line; it keeps me happy and I've read up enough to feel safe about doing it. Same for the Thunder Tiger .39 in my helicopter... the manual actually says full castor or at least a blend.
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