50+AirYears

I had one well broken in Fox.45 with that particular throttle. Flew it 3 seasons. Could set on the ground at idle at just under 1900 rpm for almost 20 minutes, and still goose the throttle without bogging the engine. Top end on an APC 10-6 was around 14,400-14,600 depending on temperature. I generally only reset the high end 4 or 5 times a year, only when there was an extreme temperature change. After a bit of dumb thumb, I rebuilt the plane from a standard sport low wing box fuse (Royal 40L ARF) to a more streamlined plane with cowled engine and turtle deck. Also increased the control area. At the time I usually flew until the engine got quiet, and the little plastic meat slicer up front was no longer turning. The plane was now so clean, I had trouble landing it on a 450 foot runway. Just went by me fast with a very shallow glide. After that, I tried to land with the prop at that idle, which seemed to act like an air break. Much easier, slowed the plane down significantly, and made the approach just a bit steeper. Flew it that way for about 5 months, then one day, the rudder horn broke, and jammed the elevator. Plane targeted a large boulder in the field margin. Plane, receiver, fuel tank, and a couple servos were destroyed. Engine needed a new prop and two new needles. Foxes can take a lot of beatings.

GallopingGhostler

It seems that Foxes are durable, 50+AirYears. The legacy CL's might be a different matter. I've seen photos of CL engines with broken crankcases, particularly the 1950's design Fox .35 stunt engine. I've straightened the crankshaft on a Testor McCoy .35 Red Head and Enya .19-VI TV; that told a story of its former life. (BTW, straightening worked after some judicious pounding.) Those without spring handle needle valves, I'm thinking of going remote NVA to spare needle breakage on CL's.

50+AirYears

I had a situation with a couple older Fox .25s, the old cross scavenged engine. Both cracked the cranks just behind the port while in flight. First one, I l called Fox, told them what I needed and why. Got a new crank and an invoice against my credit card about 3 or 4 days later. When it happened to the second engine about 3 months later, I again called Fox, explained what had happened, that this was the second engine. About 4 days later, I again got a new crankshaft- no charge. They may have liked my comment about having over 50 Foxes.
They are durable but not indestructible. I was flying a little Italian kit built CL combat job with an old .15X I'd done a little hop-up work on when I was stationed at Wheelus AFB. Hot, dry day, edge of the Sahara desert. Flying with 52' steel lines. Started feeling a tingling in my hand at the top of loops. Did a wingover, got zapped by static electricity. Plane went straight up trailing the handle. I guesstimate the handle was about 20 feet in the air when the plane started down. The only salvagable part was the cylinder head, and that was severely scratched up.

Hobbsy

My Feedback: (102)

I sort of regret talking about these engine in a thread like this one, the front left is a PeeWee .020, next is an OK Cub .024, then as Spitfire .049, then a Thimble Drome .049. Not sure of the center row two engine, I took a separate picture of the center right one. The rear left is a McCoy .35 I got for Christmas in 1956 when I was 14 and dumber than a "mine mule" but the engines survived. The rear center is a McCoy .36 I bought myself the following year, those two still have excellent compression. The right rear engine is another McCoy .36 but has a slightly larger crankcase and is taller than the the center .36, it has very little compression.

Note spring on the Thimble Drome is for starting CW viewing from the front. The engine pictured alone is unknown to me.

GallopingGhostler

I'm definitely no engine expert. Sounds like, Hobbsy that as a teen you took reasonable care of the two McCoy's for them to still have decent compression. About the only thing I have from my high school years are two.049 Cox 290 engines with the Goldberg nylon engine mount. (These engines were donor engines from my crashed Cox RTF's, had no mounting lugs.)

Regarding the low compression .36, I've also heard that Testor had QC issues with their engines, don't know if it was the metallurgy or poor lapped fit, but some engines wore out quickly out of the box.

In one case, I received a Testor McCoy .35 Red Head as a parts engine that have very little compression. Disassembly revealed serious rubbing of the upper piston exposing bright, bare iron. I gathered that it had been run very lean, overheated and scuffed off the iron surface. I ran the piston / cylinder set in another engine, probably could build up the piston seal with high all Castor oil content fuel (25% - 29%) if I found a crankcase back and prop drive washer. So far, the engines I've got seem reasonable and haven't lost compression yet.

That particular .049 is a Series 8000 Testor engine from one of their later model RTF's. Some have called it the Pipe Bomb Engine. They made a version of it with integral tank mount, whose bolt pattern matched the Cox .049's, so one could use it in a CL kit plane. Peter Chin provides a report of it in:

http://sceptreflight.net/Model%20Eng...rs%208000.html

According to him, it is a powerful .049 engine, in spite of its humble looks and it is a reed valve at that. Interesting to note it uses a fiberglass impregnated plastic engine block.

A Cox 290 is in the front row center of the photo. I find this engine stuff fascinating.

Hobbsy

My Feedback: (102)

Thanks Double G, the PeeWee .020, the OK Cub .024 and the Spitfire .049 are not much younger than the McCoys. Here is my first RC engine a SuperTigre .46. When I first got the G-21 .46 it had a butterfly on the exhaust linked to the carb, Later I discovered that a Swing Muffler would bolt right on. The .46 has fierce compression for a ringed engine. It has never had anything but Fox 5% fuel with 20% castor through it. For anyone who doesn't know it Fox makes excellent fuel, I have run their 5% with 20% syn/castor 50/50 blend in my two high compression Saitos, they run the proverbial Swiss watch on it.

RJConnet

Been playing with these toy motors (engines for you picky ones) for 70 years. In that time I've only run across two (out of 50 or so) that I would call bad. A Perky .09 and a Bullet .29, both gasoline motors. All the rest have been fine, some required a little more time to get accustomed to but not bad...........RJ

GallopingGhostler

Speaking of bad engines, this bad boy, an MDS .46 Russian engine arrived a week ago, put it on a test stand and ran it yesterday. Very easy to start and runs strong, I think I'm going to like this engine. Some had supposedly problems with carburetion, but others have had really good luck with it. It came with the original instructions and box. I'll know more when I take my Das Ugly Stik out for a spin with it.

aspeed

I have a couple MDS control line piped motors. They rev up great, but spit out of the front bearing a lot. A bit hard to start. I don't know if it is worth the effort to build a plane for it. I also have an Ucktam which is the same company. The casting looks really bad, and the screws look like the slots were put in with a hacksaw, and they are very soft. All the motors have binding screws because the sand in the casting wore out the taps, and the screws don' like it either. Having said that, the Ucktam is a great runner, much faster than most other .15's and it was only $35.

GallopingGhostler

aspeed, it sounds as though the earlier MDS CL engines had quality control issues. This particular RC one has a really nice fit and finish to the exterior, excellent compression, plus it was very user friendly with the chicken stick, starting on only a couple flicks. For break in, I have a mild APC 11x3 prop on it. I'll know more as I get it mated to the Ugly Stik and give it a go.

earlwb

Actually most all of the older engines used open front bearings that were lubricated and cooled by the oil and fuel that was pushed forward on the downstroke of the engines. So they could spew as much oil and fuel out of the front bearing as the old bushed engines did. But usually the bearings tended to wear out slowly and last for really long times like that. It tended to be unusual with these engines if a bearing went bad. Now then sometimes it was possible to have the crankshaft to crankcase fit a little too large and thus the engine would tend to suck air and lean out on you, sometimes you could choke off the carb with your finger and the engine would keep on idling and running like that. Sometimes the engine would run great until it got hot and in that case as the engine heated up the inside hole diameter of the crankcase would increase whereas the crankshaft being steel didn't expand as much and the gap became large enough for a air leak to occur. Some guys making high performance mods to their engines would hone the crankcase out a little more inside the crankcase there to reduce oil friction drag on the crankshaft. But then like all mods being done one tends to go a little too far and screw it up. So then they toss the crankcase they messed up and start over not going quite that far again.

aspeed

On the other extreme, I have a T Tiger .28 that ran pretty fast, but would heat up no matter how rich, wouldn't throttle and wouldn't restart until totally cooled of. There was no compression at all when run even off the prime. I noticed the crankcase was hot around the carb, and polished the crank a bit everywhere except where the bearings were, and it works well now. The T Tiger .07's are all made too loose as well. Some work good, while others don't.

Bill Adair

My Feedback: (1)

I'm not an engine expert by any stretch of the imagination, but one thing I always do now is "read the instructions first" !!!!

Unfortunately, my first McCoy 35 red head engine failed to mention that high Castor oil content was absolutely essential for proper run-in, so my first one didn't last very long. Does anyone know if McCoy ever printed proper instructions for that engine? Pity, because the one I have on my Skyray 35 runs very well, and hand starts very quickly - on the proper high Castor fuel.

I don't expect it to last as long as other higher priced engines, but it may be worth every bit what I paid for it new. New Skyray 35, with a new McCoy 35 RH engine installed, for $35 total. (A club Xmas fund raiser, and not all that long ago)! <G>

Bill

aspeed

I think a lot of motors are ruined by just running lean. Maybe starting out right, but leaning out at the end of the tank. The old lapped and ringed stuff couldn't handle that very often no matter what oil is used. Castor may be extra insurance, but may only prolong it for a few more runs. Expert? Professionals? Legends? Aren't we all?

earlwb

They have the McCoy .35 Redhead and the .19 engine instructions here:
http://www.airplanesandrockets.com/m...ccoy-35-cl.htm

Yeah the single fine print page was lacking a bit. But if I remember correctly the Testors "39" glow fuel was 18% oil. Some people said it was synthetic and not castor too. The fuel was either pink or blue in color, and not the pale clear yellow color one would expect with castor oil. They could have used nitrobenzine at first instead of nitromethane too. They did appear to have more than 10% nitro in the fuel as well.

GallopingGhostler

Regarding the wet nose engines, earlwb, I got to agree with you there. My Enya's tend to seep a little fuel around the prop washer. Wasn't the Testors "39" glow fuel responsible for ruining these lapped plain bearing engines?

But talk about a bad engine that became a good engine, I had a difficult time getting an simple Enya .09-III TV to run reliably on my 40" Sureflite foam Cessna 180. I finally got it to run on an APC 7x3 prop, but it produced weak thrust because it was not within its power curve. Plastic fiber filled Masters 7x4 had too much inertia. I read Peter Chin's 1966 report on the engine. He ran larger props with it even a wood 10x3.5, which ran fine.

I put an NOS Top Flite 7x6 wood prop on it. The needle was less fickle, I could start it with several flicks of the chicken stick. Plane flew with authority, prop was definitely within its power band.

What was a bad engine became a good engine by resorting to wood props.

50+AirYears

I also have the instruction sheet for an older McCoy Duromatic .19 (available at the time glow or ignition) which calls for 2.5 to 3 parts methanol and 1 part degummed castor oil. I think I only used Testor's 39 once or twice on anything, then used either O. K. glow, Fox Superfuel, or Fox Missle Mist. Except on smaller engines when I'd use Fox Blast or Hi Nitro. I did once try a can of Francisco, I forget which blend, but on a 20 degree F day, it was so thick, I had trouble filling the tank with a fuel bulb. Today, for the older engines, I use either Omega 10%, castor mix, with about 6 ounces of castor added.
I once tried some 18% all synthetic fuel in a McCoy RH .35 and my Fox .59, and they nearly cooked from overheating. I had to squeeze the fuel lines to kill them. They seemed to be in thermal runaway.
The McCoy survived, but with a new black head.

Bill Adair

My Feedback: (1)

Recommending their own totally inappropriate fuel for their RH engines, is about as low as you can get. <G>

I vaguely remember seeing that instruction sheet, but do remember using Testors 39 fuel at one time. That info sheet could very well be the reason I tried Testors fuel.

Bill

earlwb

Yes I agree, I think suggesting that people use their inappropriate fuel was really bad. That likely was what led to everyone thinking that the engines were junk, as the fuel ruined the engines with its poor synthetic oil of that time period. A more experienced modeller probably could use the fuel Ok as they were careful to not let it go lean. But then the lean run at the end of a control line flight likely did not help matters though.

earlwb

I almost forgot that I had a couple of old pictures of a Testors 39 fuel can.

GallopingGhostler

Wow, earlwb, those are some really old photos. The Cox one looks somewhat familiar. I guess they must have used 2 cycle oil of the day with the Testor fuel. Don't know what possessed them to market it, perhaps a marketing person? Perhaps they got a special deal on the 2 cycle versus Castor, that they figure could make sales by selling cheaper? It does make one wonder.

This make surprises me, and kind of reminds me of the Testor 39 fuel:

http://www.coxmodels.com/fuel/index.html

Oil content, especially the Castor oil seems low.

Bill Adair

My Feedback: (1)

Nice pictures Earl.

The only cans I remember seeing, are the Cox, and Testors 39 cans!

I always bought Cox fuel for my small engines, and whatever the LHS recommended for the other engines. (Bad idea, even back then I suppose).

Geo, like many others I'm disappointed that the Cox name is used with that new fuel. The lube contents go against everything I've ever learned about Cox engines, and are nothing like the original Cox fuel. They may have bought the Cox name, but they have no right to mislead model engine enthusiasts with that fuel labeling.

Bill

Hobbsy

My Feedback: (102)

Thanks for the pictures Earl, I remember buying those Testor fuels at Burbick's Hardware in East Liverpool, Ohio as a kid. ELO was the nearest town of any size to where I grew up in western Pa. Those engine I showed back a ways all came from Burbick's.

GallopingGhostler

Bill, back then, I think most hobby store owners were in the best interest of their customers in supporting them. You'd think that a manufacturer, when they market a product would ensure that at least if you used their fuels, it would be safe to use in their engines. I think the mighty dollar won out in this case prematurely, unfortunately, and probably was a contributing factor, along with the failure to modernize and compete with other engine manufacturers using later technologies (Schneurle porting, machining techniques, heavier without additional power to offset) that lead to the failure of the Testor engine line.

Yes, it does make one wonder, as I have considered this distributor marketing it as their product line previously reputable.

earlwb

You are welcome.
Cox had quite a few different fuel cans and blends for the little engines years ago too.