Tim Wiltse-RCU

This picture if of some cool rear intake Cox engines, all reedies. The big one in the back is a Sportsman .15. The one in the middle is another Space Hopper .049, the red/blue in the front is a Olympic .15, same as a Sportsman but with ball bearings.

Tim Wiltse-RCU

This is one that I posted on a different thread. It has a ground/balanced crankshaft, .093 venturi, multi color Splash anodized tank, clear anodized crankcase to increase durability of main bearing surface and a chrome cyliinder! It's a bad picture though.

That's all for now. I hope everyone enjoys looking at my weird stuff!

Later,
Tim

William Robison

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Tim:

I think the Space Hoppers you show in your pictures are composites. As near as I remember Cox never sold a SH with that barrel on it - they were all the small diameter cylinders. What I called the "B1/P1 double port" in my post here:

http://www.rcuniverse.com/showthread...75&forumid=161

I don't think Cox even made the larger diameter barrels until the SH was long out of production.

The rarest of all Space Hopper versions wasn't done by Roy Cox, but it did have his approval. Selected fit pistons and barrels were turned down, removing all fins but the one directly above the exhaust ports. The glow heads were cut to match. This was to decrease the frontal area to the minimum, for control line speed flying. This is the one I still have.

Did you ever see the ball bearing version of the Space Hopper?

And thanks for the pictures.

Bill..

Tim Wiltse-RCU

Bill,

Oh sure the cylinders I have mixed and matched to fit my needs. When I received one of the Space Hoppers it came with shaved head/cylinder. I'm sure it had been run in a speed plane at one time or another. No I can't say I have every seen a SH with bearings in it. Never heard of anyone trying either. Not alot of extra meat to bore out to install them in.

Later,
Tim

William Robison

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Tim:

The SH BB used a different crankcase to allow room for the bearings.

And I doubt your Space hopper ever sat in a speed plane, as almost without exception those that did had the mounting lugs narrowed also.

So, if you still have the shaved barrel and head that came with it you might have one of the specially prepped engines intended for c/l speed in almost brand new condition.

The Space Hopper was king in 1/2A speed only a short time, all of 1959 and early 1960 - when the TeeDee hit the SH's day ended abruptly. As did its production. Just 1959, and maybe a little way into 1960. But that was the end. And the few SH BBs were inside that same time frame.

Bill.

Tim Wiltse-RCU

Bill so this different Space Hopper style was an aftermarket piece?
The cylinder that I have is a early style thin walled 7 fin cylinder with it's fins turned off most of the way and with TD #4, 3 flute per bypass porting.

Later,
Tim

William Robison

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Tim:

The special ones were the early seven fin barrels, and the bypass ports were hand ground three flute equivalent, but they didn't have the two ridges, they were all ground out as large as they would go. And all I saw, including mine, were ground out to the point that some of the base thread was also cut away.

I've never seen a factory 3-fluted bypass on anything but the latest style B3 and B3A barrels, but I'm sure many could have been made that I didn't know about. Perhaps they were special for the TeeDee engines, coming after I got out of the speed business.

An easy way to tell - if the metal is blued inside the port, it's almost definitely factory, as the bluing has to be done before the bore is finished.

And something we did the opposite of what seems popular now, was to position the bypass ports front and rear, having a special vent to blow air up on the exhaust ports at each side. This blew the exhaust gases away from the ports, ensuring that the air sucked in under the piston was fresh, and not stale exhaust. With the bypass ports on the sides we couldn't keep the rear exhaust port blown clear.

These mods were good for about ten mph over everybody else, until everybody learned the tricks. Then we just had to figure new ones.

When I left Texas my speed flying just ground to a halt, where I was on the east coast it was all sport flying, almost no competition except rat racing. So I got into that for a while, then became just a sport flier like almost everyone else out there.

Bill.

Tim Wiltse-RCU

Bill,

The bypass(s) on my cylinder are blued!

Later,
Tim

vauxhall

Meanwhile,back at the ranch,my 051 reed now sports a 1 1/2 " neoprene tube slid onto the plastic backplate and the r/c carb off my old TD 051. The tube runs through the firewall,so the engine just mounts as usual. I thought the long inlet tract might interfere with the mixture velocity,but in practice theres no difference. Thus the carb would be back past the fuel tank and in the battery area,if it was in a plane ! This opens up all sorts of possibilities. If the tube was longer, the carb could be mounted anywhere. Under the engine,or, next to the throttle servo. Throttle response was OK,considering the crude old thing it is, never worked too well on the TD, but it seems happier on the reed. Idles down to a steady 8000 or so.No tacho, but, I reckon that'd be close. Tomorrow I'll look for something a bit more "state of the art". All in all I'm pretty happy with Frankenstein ,and can't wait to get it in the air.

William Robison

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Tim:

Put that barrel back on your Space Hopper and preserve it for posterity. You have one of the rarest.

Bill.

William Robison

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vauxhall:

Sounds like you're getting into the "Experimenter" class also.

I would have thought you'd get a lot on fuel condensation with a long intake runner, 'specially at idle. Glad it's working.

Bill.

Tim Wiltse-RCU

Bill,

So I get messing with some stuff tonight. Start looking for the head that was on the shaved cylinder. I stick a piston in to it and realize this thing is a .051 cylinder not a .049. I don't have a .051 piston on hand right now but you can just see light past the piston and it just falls through the bore. It makes no compression with a head on it at all! I really doubt it was the right cylinder for my SH, .051's came out on the TD's right? SO who made these different Space Hopper cases? Any pic's by any chance?

Later,
Tim

William Robison

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Tim:

The 0.051s obviously were never modified for 1/2A speed.

In the "Old Days" AMA actually had one person named "National Champion" at the Nats. The more classes you entered, the greater chance of getting enough points to win the title.

And the way the rules were written, you could take one free flight plane, for example, and fly it with an 0.049 and get points in 1/2A. Switch the engine and hang an 0.051 on it, now you're flying class "A" free flight. Two classes, one plane. Never heard of any such in c/l speed, though. An 0.051 FF had a good chance of placing well, but an 0.051 plane in class A speed was a guaranteed last place. No points.

The Holland Hornet, and possibly the Atwood, were also available in 0.049 and 0.051 versions. Ohlsson & Rice, K&B, and Forster also supplied engines on both sides of the A/B class break, all supplied 0.19 engines, the high side engines were 0.21 or 0.23 depending on which brand you chose.

And while I've never looked at any of the seven-fin 0.051 barrels, it's entirely possible that all of them, from the very first, had the three-flute bypass to compensate for the port area lost in increasing the bore, they were the same in all other dimensions.

As stated in other posts, I've never seen an 0.049 with the three-flute ports, although 0.049s with two flute ports aren't uincommon.

Whether it's for easy identification or the added lubrication was necessary, every 0.051 piston I've seen has an oil groove about 1/16" up from the bottom of the skirt. Easily seen through the exhaust port. I really think this groove was for easy ID, to cut down on possible cheating in competition. But none of would do that, would we?

Finally, on that subject at least, I can't see why anyone would cut the fins off an 0.051, as free flight had power loading limitations, and the 0.051 planes had to weight more than the 0.049 powered ones.

If the different cases you ask about are the ball bearinged Space Hoppers, they came straight from Roy Cox - a factory made version of the engine.

If, however, you are asking about the SH engines specially modded for speed, I've been trying to remember his name. I'm trying to say John Thigpen, but I don't think he was the one. But I do remember we had to pay through the nose to get one, they were about $35. And you had to be fairly well established as a speed flier also. Doesn't sound like much now, but a brand new McCoy Red Head only cost $25 then, a Dooling 29 was about the same price. And a Baby Bee was $2.95.

No, I don't have any pictures but I can make some. I still have not only the engine, but I also have the plane I flew it in. It will take a day or three, a I'm still using film cameras, haven't gotten a digital camera. i'll post them when I get them processed.

Bill.

Tim Wiltse-RCU

Bill,

Sounds cool, can't wait to see a picture of the beasties!

Later,
Tim

DICKEYBIRD

Hi Bill, all TD .049's I have owned have what (I think) you're describing as 3 flute ports. Later on (late 80's, early 90's??) Cox dropped one of the additional smaller milled grooves for a total of 2 machining operations per each of the 2 transfers.

I assume your 3 flute port description refers to the 2 standard deeper transfer ports opposite each other on the cylinder plus another small additional port milled on each side of the them; total of 3 separate machining operation for each port.

Here's a pic - hard to describe but easy to see. This is a stock TD .049 cyl.

DICKEYBIRD

Here's a (what I call) "late" TD .049 cylinder. Only 2 millings per each transfer port.

DICKEYBIRD

....and a Black Widow, Babe Bee, product engine, yada, yada ad nauseum cylinder, 1 milling per transfer.

William Robison

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D'Bird:

You got it. In the order of your posted pictures they are what I referred to as P3, P2, and P1 port types.

And the barrels you've shown are all what I called the B3, having the constant outside diameter from just above the exhaust port down, with no added flange at the seat end. And the same shape, with the "Four slit" exhaust ports is what I called the B3A.

And the B3 barrels are the latest shape. The B1 and B2 were the earlier ones.

What Tim has would seem to be a B1 barrel, seven fins, with the P3 porting. and his, being the larger 0.051 bore, agrees with what I've found. P3 porting on the 0.051s only. Yours with the 0.049 bore has to be a true "Rare" bird in hand.

Have you measured yours, to be sure it's the 0.406" bore of the 0.049? And not the 0.410" bore of the 0.051? There's only four thousandths inch difference, can't tell by eyeball. It has to be measured with a small hole gauge, or by trying known 0.049/0.051 pistons in it. You might have some mixed up in your stock, and find your first picture to be the larger bore cylinder.

Bill.

DICKEYBIRD

Not really, they were the standard TD .049 cylinder for a LONG time. I have at least 20 - 25 of these cylinders either on running TD .049's, in my 'stash' or swapped onto reed .049's for the u/c sport racing we did here locally and the 2 channel/reed valve mall foamy 'figure 8' races we held some years ago. Some of them don't have the reduced dia. lower O.D., some do....most are stamped #4 if memory serves. A good one with it's matching taper ground 2.9 gram piston and a good "fit" is worth it's weight in gold if'n ya gotta go FAST!

And yes, I'm sure they are the correct .049 bore; I keep my small snap gauge carefully adjusted to check cyl's for wear, taper and roundness as I pick them up here & there. Gotta stay vigilant in the quest to procure more good Cox stuff before I die! They can be ornery 'lil critters but they do respond to careful measuring and selective fitting of parts.

ps: A really rare cylinder would be the TD 05 R/C cylinder with what I assume is TD .051 bore yet doesn't have sub-piston induction. This was done since that particular engine has a muffler and would be hurt badly by mixture contamination if it had S.P.I.

William Robison

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D'Bird:

I'll have to plead that I paid no attention to the Coxes for many years, those 3-flute early 0.049 barrels just got past me.

And the next time I do any teardown on my two 05 RC engines I'll check for SPI. They both have the throttled carb, one with just the "Spout" out of the ring, and no air bleed adjustment, the other has the barrel muffler attached to the ring, and it has the adjustment screw for the air bleed.

The later one runs and idles well, it's been so long since I've run the older I really don't remember how it did, except that its original installation on a Cox "Foamie" Cessna gave me a lot of deadsticks.

But my throttle on the Cessna was either idle or full bore, it slammed from one to the other. About half the time it would not accellerate from idle and died instead. With propo it might do very well.

Bill.

vauxhall

William Robinson , thanks for telling me something I didn't know! The 051 piston I'm using on Frankenstein has that oil groove you mentioned , but , I never realised it was meant to be there .and spent a few minutes looking for the burr on the cylinder that was causing the damage ! By the way, I finally have an engine that starts as well inverted as right way up. The carb tube is angled down a couple of degrees,so any excess fuel runs back out the carb,instead of flooding the engine. Only atomised fuel gets to the reed valve. Come on guys, one of you give this carb tube thing a try and let me know how it works on your engines. Sure makes putting a carb on a Cox reed pretty easy!

William Robison

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vauxhall:

Glad to have been of service.

Dickeybird and Tim Wiltse:

Has anyone ever done a comprehensive recapitulation of all the Cox barrels?

Somebody surely should.

Bill.

William Robison

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Dickeybird, Vauxhall, and Tim Wiltse:

Apologies to all.

Just checking Cox barrels again, and I find I have TWO 0.406" bore barrels (0.049) with the 3 flute double bypass ports. They are both the "B2" external shape, one is marked "4" and the other has no number.

The others in this batch included two other B2 barrel types, B2/P1 double port marked "1" and a B2/P1 single port marked "2." Now we get the real odd ball. It's also marked "2" with a single bypass port, but the barrel shape is B1. So in that one batch there is found B1/P1 and B2/P1 with the same number "2" stamped.

What gives? Anybody can answer?

Bill.

Tim Wiltse-RCU

Bill,

Have you had the chance to get a picture of your BB Space Hopper? I'm dying to se it!

Later,
Tim

William Robison

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tim:

Sorry, somehow the right information became wrong in the transfer. I haven't had the BB Space Hopper for years.

What I still have is the "Special" version of the plain bearing engine, still mounted in the 40+ year old airplane.

But no, I've not shot the film yet, planning a "Big" photo session, to include the SH and many others.

Bill.