Scorned by many, loved by few........

The series .21 the "Brick" for short were the last of Mccoy engines. Too heavy for any kind of aerobatic use for the power it produces. A fellow did some major rework of the .40 and was able to reduce the weight considerably. All said and done it was neat, it didn't do much for the power. As mentioned, flying any kind of bipe which isn't balanced correctly results in a plane essentially rekitted. Aside from that they run pretty good. These engines though can also be hit or miss due to the Dyke's ring not properly being fit. Dyke's ringed engines can sometimes be problematic to start anyhow. They utilize compression to expand the ring. If the end gap clearance on the ring was too wide the end result was an engine that needed a starter to start. Frank Bowman AKA Bowman Ring's can provide a superior ring over the stock Mccoy ring. Taking these apart are highly discouraged. The rings are cast which can break just looking at them. Fitting the rings can be a test of patience and a test of metal due to putting it on and taking it off without breaking the ring. The series .21 piston and ring can be swapped directly into the Mccoy Red heads that have the GATED cylinders. This is obvious looking through the exhaust stack and seeing the serration on the liner. Ken

Hi Rusty, Yes, Series 21. They were offered in .19, 29, 35, and .40 sizes. I'm still looking for a .40. Last engines to bear the McCoy name.

This is probably the best info out there, concerns the .19 mostly but touches on the others.

http://sceptreflight.net/Model%20Engine%20Tests/Testor%20McCoy%2019%20Series%2021.html

I'd never buy one.

I think it has a look only a mother could love and they are weighty. However, they are built better than the old McCoy .35 and provide useful parts to make those engines better.

That said, I applaud those who like them and use them. To each his own.

Ron

RknRusty wrote:That is a pretty stocky looking engine. I've heard a lot of love/hate talk about the McCoy 35, deficient metallurgy and inconsistency, and short life from the detractors. But I suppose this predates them. Is that right? Is this one usually called "McCoy 21" for short?
Rusty

Rusty these engines were made later than than the McCoy .35 red head types.

They were built using better materials, but are pretty heavy for stunt use.

You might want to check that the rings are not stuck and that the conrod upper ends are not stuck to the wrist pins.

Make sure you give them a proper break-in. Remember they have a Dykes ring, not ABC.

I have two CL .19's...one has been run and the other is NIB. Someday I'll get them on a plane.

George

There is one Series 21 in my inventory, the Testors McCoy .40 Black Head CL/FF engine. It weighs 9.6 oz. The McCoy .40 Stunt weighs 7.4 oz. (same as .35 Red Head). Thus, the Series 21 is 2.2 oz. heavier. However, comparatively speaking, the K&B .20 Sportster Schneurle weighs 10 oz. Some swear by it as being a good drop in replacement for your legacy plain bearing .35 cross scavenge baffle piston engines.

I've bench ran the .40 Series 21, seems to be a very user friendly engine that breaks in relatively quick, is easy starting, turns some decent sized props. Even tried it with an APC 11x3 plastic prop. and a wood 12x4. Seems to have no trouble turning these. (I only use a 1 oz. (30 cc) tank for shorter runs, so I don't potentially ruin a breaking in engine.)

After discussing with various CL fliers, I'm under the impression that these heavier engines work best in planes with greater wing area than the 42" span 400 square inch Ringmaster, where the heavier weight will be well handled by the ample wing area, like a Sig Banshee or Sig Twister with the nose shortened for balancing.

I'll know more when I graduate up to something with 50 - 55 inch wingspan and 500 - 550 inches wing area. I don't think the heavier engines are a detriment if properly matched to the airframe. It's just that it may narrow down the number of planes one can put them in.

Being heavy is a bonus on many biplanes as the nose is pretty short due to the very heavy engine most had.

Phil

There are positive reviews of these engines in Sceptre Flight:

Sceptre Flight: Model Engine Tests/McCoy 19 Series 21

Sceptre Flight: Model Engine Tests/McCoy 35 Series 21

Sceptre Flight: Model Engine Tests/McCoy 40 Series 21

Of interest, one of the articles mentioned they had an engine failure due to the breakage of the Dykes ring.

Stated in the articles by the engine experts, finned crankcases were for cooling. However, IMO, as in the case of a number of engines to include the sport Schneurle K&B Sportster, Cox .074 Queen Bee, and Testors Series 21, being a heavy weight is of no advantage unless marked by being extremely powerful. These modestly powerful engines being heavy (and in the case of the Sportster an engine requiring legacy oil fuels) were easily bypassed by modelers.

Had Testors retained the traditional Red Head lightning bolt crankcases and sleeves upgraded with the Dykes ring, they might have had a slight ghost of a chance. With the advent of the then new and superior Schneurle porting making a quantum leap in horsepower output, these engines were too little and too late.

I think this is why the following with the OS Max .25LA-S as a replacement for the legacy .35 stunt engines. It is able to handle the modern fuels, is reasonably light weight with muffler and handles the .35 stunt planes well.

I sometimes wonder why Cox didn't come out with a Tee Dee .074 or enlarged exhaust throttle sleeved Black Widow .074. Being lighter than the Queen Bee, they may have garnered better sales.

Heavy weight sport engines have never been popular among the modeling community.

Who'd of thought the crankcase needed cooling

daddyo wrote:Who'd of thought the crankcase needed cooling

The following is from Sceptre Flight: Testor McCoy 40 Series 21 (2nd article):

Peter Chinn, Jan-1972 M.A.N. wrote:Externally, there is not much to connect the .40 Series 21 with previous McCoy 40's. The engine's most distinctive feature is its finned rectangular shaped crankcase. This is not just a gimmick: at the cost of some increase in weight, it results in a very sturdy front end and the fins have a practical purpose in helping to dissipate heat from the crankcase. A cooler crankcase means less pre-heating of the incoming fuel/air mixture and so contributes toward a denser charge eventually reaching the combustion chamber.

There was a supposed logical reason toward the madness, although personally I haven't seen if it really means anything, as all other make of engine did not have cooling fins on their crankcases and they work just fine. Somehow my impressions are that they employed a fashion designer to make for them a killer engine. Problem is, the modeling community overall rejected them and they became a sales clearance item at many a modeling store.

I used one of these in a practice model I was gifted a Bob Whitely owned example in the 80's when I was beween models. The McCoy Series 21 .40 ran like a train, on the Tom Warden Trophy Trainer, and it was a real good engine for stunt.

When people speak of the power to weight of this engine, unless they are a Top 10 flyer in competitiion aerobatics and accomplished builder and trimmer of Stunt models, you can be assured they are repeating what they read or heard. The reason I say this is that 2 to 4 oz (the difference between the Series 21 and other .40's) in a model's total weight is of minor consequence compared to the huge variations on the building table of the typical Beginner to Advanced Stunt flyer's model. When reading these comments I wonder about the Stunt models built and flown by the commenters. Are they really speaking of known balance and total weight problems on their own models? If so, one must ask why?

This engine is a viable engine as much as a Lightning Bolt Red Head McCoy 35 or 40, a Fox 35 Stunt, or an OS 35 S Stunt. In fact, for a muffler equipped engine it's superior because of it's tolerence for the muffler mounting and heating variable; ie, no warpage of the cylinder, no overheating from it's carraige and heat sinking. I use all castor 24% to 29% fuel in my bushed, slug piston engines depending on which engine used, OS less, McCoy Red Head, more. Fox, the most. Why? Japanese engine had the best metal, McCoy and Fox, less so. The Series 21 is very stable, big case. No slug piston, it has a ring. If it's bad, change for a new one. Nowadays we have Frank Bowman for our rings, better than ever in every way compared to the days when they were new.

When using the series 21 in a Stunter, the engine's extra weight should be factored in to the plan as would a lighter engine. As well one would do when building an older kit, like a Nobler, where a Fox 35 is shown and has no muffler, and one is to use a modern engine with a muffler. Especially a ball bearing engine. In this case the Nobler's nose would be looked at for best use of engine placement compared to room for the fuel tank. With a short little Fox, the engine was used with a Fox or Veco crankshaft extension, with the Series 21 it wouldn't be necessary or beneficial. case is longer than the Fox, more metal up front would mean additional weight penalty. Moving the engine back, to the point needed for the tank dimension would be most prudent, the smallest and lightest spinner, a wood prop, smallest cowling design. The nose might be a bit shorter than the kit sides once the rearmost placement is found, in fact if you were able to get there, you would be seeing the fruits of your labor.

Maybe this would be enough weight savings to qualify maintaining the puny 14 inch tail moment of the Nobler, but adding an inch or so to 15 inches might be a better way to go as this increase in moment arm would help the puny tail volume (area) on the Nobler move any more concentrated weight in the nose. Especially carrying a muffler.

Also the modern plastic and foam wheels, R/C plastic clunk tanks (my favorite), lightweight spinners, can help reduce the concentrated weight in the nose of a Series 21 powered Nobler. Or a modern ball bearing engine.

If these things are considered and properly instituted in this "typical kit" 35 sized Stunter, one wouldn't see any detriment using the McCoy Series 21 .40, and it would have the benefit of having a potential of more "usable" power by carrying a muffler without run problems, and a larger propeller diameter for better thrust.

Using a good fuel with the proper amount of oil content, as well as a good break-in would make the old Seies 21 a great Stunt engine for someone looking to fly a Stunter for competition or general practice and progression. I flew the gifted model about 3 months and 300 flights, friend Dave Eyskens had given it to me after some months of flying it, then I gave it back and he used it for a couple more months. The Trophy Trainer is a big profile, and this one was straight and trimmed, but solid and no lightweight, so the power myth seems untrue in my mind. Evidence of first hand operating knowledge indicates a great Stunt engine with usable power for flying the pattern well.

Chris...

Thanks for the inputs Chris. Yes, one has to wonder about some of the comments made regarding engines. I heard one modeler tell of his experiences helping another with an older Fox cross scavenged RC engine with earlier carb. On that the trick was to adjust the low speed needle first, then the high speed would track.

He tuned the engine for this low time flier. However this flier had a habit of not being able to leave adjustments alone, always tinkering, and next time at the flying field needed help again. Other modelers were telling him that the Foxes were no good, get himself an OS, which would solve his problem. Sure enough after this experienced modeler helped this flier a couple times sort out his engine problem, he showed up with a new OS on his model.

What you state makes sense. The trick is matching the airframe to the engine, making what ever changes needed before building or selecting a model that has the right moments in place. My comments regarding the weight of the engine has more to do with the average sport builder back in 1970's who needed a general engine that would fit without much adjustment to the then available kits. In general heavier engines have always not had a good following with the modeling community, except for perhaps the 4 strokes.

There are a few experienced CL fliers using 4 stroke engines on their planes. Being heavier, I gather they knew what they were doing setting up weights and moments correctly.

I must admit there have been a few digs by some who for some reason or another had problems with the McCoys. With some parts of history discounted for workmanship issues, were probably exasperated by low oil content Testors '39' fuel, high nitro, lean running, use in speed or combat competition instead of sport or stunt, etc.

A few have insisted the McCoys overall are no good, expecially the Red Heads. I'm wasting my time, get an OS Schneurle and be done with it. Those who use the McCoys regularly have told me their tricks in getting a good life expectancy out of them. Those tricks included having a lower nitro fuel with proper oil content and significant Castor in it, running it rich, and propping it properly.

So, I gather that similar to RC, there are those who follow CL pop culture. Perhaps for them, an OS is a problem solver.

For sure the OS is an easy engine with the best carbs. And have been for years as I use 35 year old FSR's in my Classic Pattern ships today!
Funny, My brother is using a McCoy 40 in his Super Ringmaster for VSC, and Im finishing my Gieseke Nobler with an L&J Fox 35 for VSC too. We've been rounding up fuel and plugs, props and the like so we can get good runs and because it's a contest we'd like to acytually be competitive in are looking for the edge too. I'm going 15% nitro, 28% castor for the Fox. The McCoy is going 10% nitro and 28% castor just because the differences in collective knowledge told us that is about as far as we should go and have both performance and reliability.
So I'm trying to not be the Fox fiddler (which i've never been because of my experience with dad in the old days), and work the old stuff well, but then again i love a good running R/C engine.
Chris...

stuntflyr, your bring up a good point in that in the hands of a master flier, they know how to make best use of whatever engine they want want to give a shot at, and that the Testors engines can be competitive set up right.

In I think Stunt Hangar, may be Stuka Stunt forums, I read that someone recently won stunt with a McCoy, which debunks a good number who have been stating that the McCoys (and oddly Foxes too) are no longer competitive, to go with a modern Schneurle.

An engine properly set up right for consistent and reliable operation and propped for optimal speed, these old engines still perform. I gather it is more to do with the flier's skills for the success in winning.

I think if you did a survey of R/C carbs, you'd find the Fox carbs toward the bottom and O.S. carbs toward the top.
I had a Fox .50 R/C that I ran a for several years, flew it a bunch, never did get that transition lag out of it, it never died on me and i got used to pulling out of a spin or maneuver, hit the throttle, wait a second for the power and there it was...a lot of it!

Not knocking OS, they are good engines, I've got a few and so far no complaints about them. I just find it interesting that some folk have such a dawg of a time with one engine but not another. Part of the learning curve, have found that minor things like particular plug to use, right prop and fuel have a lot to do with success. In some ways it reminds of knowing the rights lures for a particular day to catch fish.

I've found my Enya .09-III TV's are easier hand starting with wood props than heavier inertia plastic props, a couple flips and she's up. Plastic props on the OTOH, start by hand was real fickle with starting needle setting. My OS .10R/C cross scavenge with RC carb and exhaust restrictor didn't like Fox idle bar plugs, but ran fine on Swanson Fireball hot standard stort plugs. Testors .35 Red Head was one of the easiest starting, a couple flips and she lit off no matter the prop. All Cox .049 reed valves started right up with problem at all. Thunder Tiger Magnums are just like OS, very easy starting.

Norvel, took a little more work to start but more powerful than Cox reedies. One thing though I must admit, a Cox reedie never let me down with down time as long as I had a good starting battery. They just run. I'd get over a dozen runs in a day on RC planes with Cox, one right after the other, great way to have a blast on a minimal budget.

I realy dont understand the dissrespect that the McCoy redheads get, especially compared to a Fox35. In my personal experience, out of the box, the redhead is the better engine. Right out of the box the redhead has a great stunt run, is more powerfull, needles better, runs cooler, etc. If you want to read my story let me know.
Phil

Thanks Phil, for you down to eartch comments. Yes, please let us know your story, we'd be willing to hear.

So far with my experiences on the McCoy RH, I concur. What I have heard from others and what I have personally observed are two different things. So far from what I gather, yes, metalurgically they have a softer iron piston, which is easier to erode through lack of adequate lubrication and overheating. If one avoids those, avoids excessive RPMS and lean runs, use a fuel with adequate oil content with a decent bit of Castor, don't run excessive nitro, they will give a decent life.

Perhaps it is just another form of prejudice some folk exercise.

George,

If you like McCoy's then use them. You don't need anybody's opinion to tell you if it's good or not. If you have a good experience then that's all that counts.

Just remember, the folks that say otherwise have had bad experiences or just experience in general. Many have had decades of competitive and/or sport flying experience to draw from.

Certainly any advice given from wisdom and experience is valuable and should be considered.

I had been flying 1/2a planes and one jr. size for many years but nothing bigger. The reson was I didnt have any place to fly longer than 35 foot lines. i had a S!A Ringmaster and a Magician, but were not finished. The Ringmaster was close though. About 5 years ago a place to fly came available that would clear 52 foot lines and I was determined to get a 35 size plane in the air. The Ringmaster went together first with the Fox35's. I had three of the Fox's. I bought new needle valve ass., plugs, gaskets, and stuff for them years before. On the first run the Fox was very hard to start, and if I un-hooked the battery it would quit, also if I touched the needle it would quit. I cut a piece of fuel line to fit tight on the nva. to stop the air leak around the very sloppy threads and then I could adjust it some. I called Fox about the nva's being so loose all three of them were junk. The finally admitted that the two hole nva's werent any good but they refused to replace any of them. Nice guy's. Ok, now on to the battery problem. I figured I needed a better plug so I went through my plug collection and low a behold a r/c plug I found would run with the battery disconnected. Back on the phone with Fox. They finally admitted that the Fox standard plugs they sold me werent good for the 35 but they were cheep so thats what they supplied with them. Again I asked them to replace mine and they refused. In the mean time other people from forums were helping me out as well. The engine would also throw crazy shakeing fits, and I was advised to install a second head gasket. It helped. By this time I was in touch with Randy Smith. I got one of his collet nva's and some thunderbolt r/c plugs. He also told me I might be more satisfied with fuel with a 10% nitro and 26% oil, mostly castor, and not the 5% stuff that was recomended to me by fox. Finally the thing ran good enough to fly. All three engines suffered the same problems and all responded the same to changes.
By this time the Magician with the McCoy readhead was done. I tried it with the 5% fuel, the 10% fuel, several different plugs and it just ran great period. Then I flew it and its just all around better just as McCoy made it.
I am sure that the questions about some of the metalurgy is true, and the pistons may not be the best, but I have two seasons on it and can detect no loss of compression and no visable wear on the piston or anything else.
Phil

Thanks for sharing Phil,

That's my point exactly, experience usually plays a role in what one feels about engines. My experience with Fox engines was exactly the opposite of yours. The difference is I had someone warn me about the needles, bad fox plugs and vibration issues if not hard mounted before I even flipped my first engine.

When it comes to the McCoy I had read some good, but mostly bad so I didn't even bother with them. The only one that I saw run had needle issues and broke lean every flight. It seemed pretty powerful though. At competition circles I never see a McCoy, but I still see plenty of Fox .35's. It would be neat to see a McCoy do a pattern.

Anyway, I hope your McCoy gives you years of enjoyment and if you want some tips on how to make your Fox engines run flawlessly then shoot me a PM.

Ron

Actually Ron, mine broke lean due to an unereliable aftermarket flex needle assembly someone installed. I've heard them described before, made by various manufacturers, of which one was I believe ACME. One clipped off the flex needle shaft, then soldered this assembly to the stub, installed needle, bent it and mounted the shaft knbo with bracket to the backplate. Idea was to get the needle away from the prop.

I suppose that there were some good examples, but this one was mounted slightly off-center. I tried my best to straighten, bend and adjust, adjust drag by the rachet plate, but no matter it would not hold its setting. The bent spring would cause it to hop.

All it takes is one rachet click to affect running. Without the OEM needle, I tried out this Evo remote NVA and it adjusts just like a factory one, restoring factory like running qualities of the McCoy.

Yes, there appears to be quite a bit of FUD (fear, uncertainty and doubt, a Microsoft propoganda term, LOL) toward these McCoys. They don't take abuse well and wear out quickly if not cared for, but if simple precautions are heeded, will give decent service life and good stunt runs.

Based on inputs from a good number of reliable sources (not just 1 or 2), I'm giving these engines a good shot, using their advice. I've got 5 McCoys, all with good compression, so you can't say I don't have an investment in them.

Ron, regarding your 1950's Fox 35 Stunt, I'm targeting it for the 1960 Berkeley Interceptor build. I think that would be time appropriate and feedback I got is the Interceptor was a decent stunter. Also, there is another experienced CL flier in Clovis, Ken Kron. When ever you get another chance to visit Clovis, we might have another friend to fly with.

Stunt World and National Champion Paul Walker won VSC with a Sterling kit built Skylark and a stock NIB McCoy 35 lightning bolt case engine a couple years back. His scores were astronomical, as were all of the front runners in the 590's. His competition were Bob Hunt (World Champion), Bob Whitely (National Champion), Ted Fancher (National Champion), etc flying hot rod modern engines in plans built models.
Stock stuff can fly great and one can have fun with them. I once helped a guy that had a Sterling Skylark given to him with a Fox 40 in it. I didn't know anything about the engine but helped him clean up the plane and get it flying and I trimmed it for him. Wonderful engine run, super nice flying model.
For most of these old bushed engines the secret is the amount of oil in the fuel, and the plug and needle, which are also concerns in any control line engine because we want and need them to run "just right" when trying to do something like fy a Stunt Pattern.

I fly (for fun) a Veco Redskin with a McCoy 29 red head racing engine with an 8x8 prop and it goes pretty good. Lots of castor. McCoys were popular Racing and Speed engines in the 50's to mid 60's, and guys still run them in tether cars.

Chris...