Propping McCoy engines

I know there are MANY other variables to consider, but I would like to get some basic guidelines.

McCoy .19 RH LB...I used to use a TF nylon 8x6 way back when and the plane(s) flew to darn fast. I was thinking of using an APC 9x4...more thrust/lower speed.

McCoy .35 RH...I used to use a TF nylon 10x6 way back when and the plane(s) flew too darn fast. I was thinking of using an APC 11x4...more thrust/lower speed.

Also, what is/was the castor content of Fox Superfuel? I'm thinking it is around 27-28%.

Thanks for taking the time to read/reply!

Sounds about right on the props, but only flight experince with them will tell. As to the Fox Superfuel, Fox advertised it at 28% castor, 5% nitro. In fact I just read an add for it in a 1957 Model Airplane News last night while looking for an article.

I don't know what prop is appropriate for a McCoy 19, and I'll be just as interested as you in the answer, since I have one I've never run yet and want to. As for the McCoy 35, I've so far run those exclusively, and always with a 10-6. If a 10-6 is too fast, try a 10-5. I get very good lap times - I adjust the needle so that the engine is running in a fast four-cycle on the ground, just on the verge of two-cycle. Does a nice 4-2-4 break in maneuvers, and lap times are around 5.5 seconds on 60' lines with a 10-6. Of course, the prop itself makes a difference, too. An APC prop will behave differently from a Tornado nylon prop, and different still from a wood prop.

I think 11-4 or 11-5 would probably be too much prop for a McCoy to swing.

For the .19, try a 9-4. If more speed is required, an 8-6.

Re the .35 Redhead: If they run at all (and that is a big if, because many have been used and abused on low oil content RC juice), you may be surprised to find that they have a bit more power, on the average, than the Fox. In fact, I have one, and it is not even a Lightning Bolt model (actually, they aren't any more powerful than the preceding models, come to think of it) that happily swings an 11-5. A 10-5 or 10-6 created too much lap speed. But, usually, a 10-5 or -6 works well.

You got me started, so more on McCoy...

Some 4-2-4 quite well, competitive with Fox.

What they don't do as well as Fox is survive as long, even with the proper care. But you can find them all day at swap meets in good condition, at reasonable prices. The monoblock construction of the Fox also offers better sealing integrity vs the McCoy design, with its bolt down cylinder. Not that this is a particular problem on the Redhead. It simply is a '40s legacy design that is largely abandoned today (and, by Fox, much earlier).

The The McCoy Redhead .35: misunderstood, abused, yet a perfectly workable baffle engine for sport/stunt use. The .40s are even better. So treat them to at least 25% oil, majority castor. Run a hot plug, too. Check fasterer tightness now and then.

My Redheads always seem to catch fire. Foomf!
Keep an extinguisher nearby. Otherwise they run pretty well.

Al

I liked APC 9 x 5's on my McCoy 19 redhead. a 9 x 4 was a little slower than I liked. The one 19 I've flown a lot has several hundred flights on it (got it used) with Sig champion 10% nitro 50-50 oil fuel. It starts and runs like new. I put in a ST NVA. By the By, the McCoy 19 NVA is different from the NVA for the 35. I have another bought used 19 that is 2000 rpm faster than the one I'd been flying, very interesting.

I ran 11 x 5 Zinger wides on Fox stunt 35's for a long time. Works well on large heavy airplanes. McCoy 35's are comparable in power, maybe better, maybe not.

You are in the ballpark. It's a matter try and see.

Just my opinion ( I am NOT an expert...) for props on your 19..
20 or so years ago I used an OS MAX25 in various stunters, a twin engine stunter with 2 OS25's, a Jr. Nobler and a Peacemaker.
I tried a few props on them and always ended up using a 9X4 Taipan.
I imagine a 19 will be much the same, it ( they..) sounded to be revving quite high, I did not have a tacho.... but the 9X4 just felt better.
BTW the Jr. Nobler felt really good with the OS25 ( remember, 20 yrs ago...)but the engine mounting was difficult as it was designed for a 15 size engine.

LAST EDITED ON Aug-21-02 AT 06:44 PM (CDT)

>McCoy .35 RH...I used to use
>a TF nylon 10x6 way
>back when and the plane(s)
>flew too darn fast.
>I was thinking of using
>an APC 11x4...more thrust/lower speed.

My only cautions with the APC prop are the weight and the fact that the dimpled thrust washer on the McCoy has a hard time getting a good grip on a plastic prop. The extra mass of a plastic prop will accelerate the wear on the wrist pin and conrod.

You might want to experiment with an 11" wooden prop, properly balanced.

>Also, what is/was the castor content
>of Fox Superfuel? I'm
>thinking it is around 27-28%.
>

Can't go wrong there. I also run mine on Sig with 25%. I haven't doctored it with more castor, and don't seem to have a problem. I tend to run mine a little rich, so that may help as well.

>My Redheads always seem to catch
>fire. Foomf!
>Keep an extinguisher nearby. Otherwise they
>run pretty well.

Circle: You are right. I have had the same problem with one or two of my Redheads (I have a bunch; they accumulate like Babe Bees, whether you want them or not. They also may be propagating, since there are always more around than you thought).

Anyway, engines with iffy piston/sleeve fits sometimes will backfire an ignited exhaust load onto your plane, and also onto the ground. I have a number of McCoy-mounted models with significant singe marks that attest to this.

Here's what I think is going on, and it is only a theory...Model engines in general with significant wear have a heightened possibility of hot backfires. McCoy Redheads have a heightened probability of wear, since most (pre-Lightning Bolt, anyway) are metallurgically challenged. Therefore McCoys tend to burp out more ignited fuel than, say, Enyas, who are solid citizens indeed as far as wear/materials are concerned. So it is not a McCoy problem per see, inherently.

I think. Maybe.

Having a fire extinguisher close to the flight line always is good idea. Especially during drought conditions when launching over grass. You can start major fires this way. Heck, even before model airplanes, they burned the entire Thumb region (grab a map) of Michigan down not once but twice in the 19th Century. Cigarette or something...

Of course, I have a few models that I wish would immolate. Where is that worn Redhead when I really need it?

So
>it is not a McCoy
>problem per see, inherently.

I meant "per se". My HS Latin teacher will not be pleased. But we didn't care for one another anyway. Currell redux

Bob,

Hey, I like the way you are thinking...engine longevity. IYO, what is the best (reasonably priced) wood prop to use?

Thanks for your input!

LAST EDITED ON Aug-21-02 AT 06:43 PM (CDT)

>Bob,
>
>Hey, I like the way you
>are thinking...engine longevity. IYO,
>what is the best (reasonably
>priced) wood prop to use?
>
>
>Thanks for your input!
>
>Gene

I've been working off a stock of used props I pick up at the swap meets every year. Older TopFlight 11-6s normally check out at 11-5. They are soft enough for the dimples on the thrust washer to grab and light enough to keep the stress on the condrod and wristpin minimal (if balanced properly).

New production Zingers and the Brodak Y-Os are about the only other option we have. Master Airscrew also makes a wooden 10-6 that might be worth looking at.

Anyone know of any others?