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Old Jul 30, 2012, 08:38 PM
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cox engine questions

I was given a fairly large collection of model engines. Three or four being various Babe Bee incarnations. Decided to combine these with my own and have undertaken a reconditioning program of all, hopefully to running/flying(?) condtion.

First question: I've got the prop washer and threaded collar off my favorite TeeDee .049, wishing to replace the plasic carb housing. Is this threaded also or just pressed on. I've simply forgotton since mid 80's! In any event, the old collar is not coming off as easlily as I remember. Any advise?

Second Q: One of the gift engines has a muffler w/spring wraped around to adjust exhuast opening and an exhaust pipe stiking out Rt side. The cylender seems screwed right down on top opf the spring starter. Appears to have two ports in cylinder wall, one infront and one directly behind. finish is all aluminum except for fins and bronze back plate but also has stunt tank like on a GoldenBee. What engine is this?

Third Q: Another gift .o49 engine has a black plastic back plate/mount like the red PT-19 mount. It also came with a reverse pitch black prop of 4-3/8" diam. Tips are thickend, almost to knobs at the tips. The spring starter appears to have a clutch arraingment that automatically grips the prop washer (has a hex section to fit into the black plastic spring collar) when wound backwards for strarting. Also the exhaust ports are a pair of transverse slits front/back of Cylinder.. Is this a helecopter engine from one of those RTF reaction helos Cox had a few years back?

Thanks in advance
charlie
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Old Jul 30, 2012, 09:40 PM
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Removing the plastic carb body requires unscrewing the Anodized ring/collar behind the prop driver..which forces the propdriver off the spline crank end More than a bit Mickey Mouse.
Yes.. it can be tough to get off.
Try not to chew it up too much, as the oem Cox wrenches are poor quality and barely up to the task expected. So be careful.
Also be sure you actually need to remove the plastic bit.

The muffler gizmo sounds like a QRC .. Works OK.. sux some power but tames the Shriek ! .. some.

Motors fitted to the ewww.. plastic barely or non flying Cox in a Box airplanes were basically Junk. Had them, felt truly cheated of my paper route earnings and lived to tell the tale.
Slit exhaust engines are best quickly disposed of on EBAY imo
Having said that some love 'em.
But then there is a customer for every perversion :-)
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Old Aug 02, 2012, 04:00 PM
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The TD crankcase where the venturi holder fits is tapered. Combined with leftover castor oil goo, the holder may take a little persuasion to remove, but it just comes straight off, no mysteries.

And yes, it is Mickey Mouse to use the collet to force the drive plate off the crank. That's why you should use a prop screw or stud and a bench vise as an improvised arbor press to take the plate off.
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Old Aug 07, 2012, 06:35 PM
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Originally Posted by ahrma_581 View Post
The TD crankcase where the venturi holder fits is tapered. Combined with leftover castor oil goo, the holder may take a little persuasion to remove, but it just comes straight off, no mysteries.

And yes, it is Mickey Mouse to use the collet to force the drive plate off the crank. That's why you should use a prop screw or stud and a bench vise as an improvised arbor press to take the plate off.
Use the vise or even a drill press, but put a block of wood behind the crankcase so it does not get marred. Also remove the piston/connecting rod. Don't lose the thin steel thrust washer.

The plastic bit slides off, but like ahrma says, it might be gummed up. Some heat like a hair dryer or heat gun will help- don't melt the plastic!

Q3- sounds like a standard product motor. This was used on a number of the ready to flies, including the helicopter. The thickened tips on the prop was meant to make the prop safer.

I like using product motors, but i toss the spring starter bits. The old style spring starter was OK, but the newer auto grabber just drags on the motor.

- Norm
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Old Aug 09, 2012, 09:15 PM
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Originally Posted by Bare View Post
...Slit exhaust engines are best quickly disposed of on EBAY imo
...
Sorry Bare, but no they're not. That slit exhaust comes with a newer type internal bypass porting that produces more power than the older non-SPI Bees that had open exhaust. Combined with a newer type short piston that allows it to have SPI(sub port induction-can be seen as a gap under the piston at TDC), they out perform the older style open-exhaust cylinders such as the pre-1996 Black Widow.
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Old Aug 10, 2012, 12:25 PM
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OK....Would be a Dull world, if we all thought similarly :-)
Not so sure about that one though.
I have a 'few' BW's from first to last (a couple of slit ex ones too).
Yup.. bought a couple, first season they came out..still have them too.
Then a 'few' more over the years.
Later ones do have a goofy looking but quite workable spring starter though...useable enough so they haven't been removed.
But my very first BW's remain as MY very best performing examples.. still :-).
Small variance in porting gouges or not, I have not seen (noticed?) advantage beyond the starters on my newest ones.
Any 'improvements' seem illusory, to me at least.

In fairness I was referring to those "product' engines.
Clearly there are those that think them worth buying.... ergo; EBay.
I do not .
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Old Aug 10, 2012, 04:11 PM
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Also in fairness I should add, any facts I claim to know about later Cox engines refer to the ones actually made by Leroy Cox's company and not the toy rocket makers. Estes had no quality cares, throwing parts at each other, not test fitting pistons, cylinders and cranks and screwing things together that barely resembled the original engine name. Not being one of the avid collectors, I cannot eyeball an engine and tell you from when and where it originated. Yeah, many of those latest ones were carp. And many were full of metal burrs, requiring dis-assembly and inspection before the first fueling.
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