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Testors/McCoy .049 smoked...

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Re: Testors/McCoy .049 smoked...

Post  Marleysky on Wed Oct 11, 2017 8:08 pm

roddie wrote:I have absolutely no experience/knowledge with these engines. It seems that both the AMF/Wen-mac and Testors/McCoy .049 engines utilize that heavy fly-wheel on the nose of the crankshaft in the form of a starter-spring assembly.. or otherwise. Was its purpose to keep the engine within it's design-rpm limits? Maybe the extra mass was needed for sustaining rotational-inertia to keep the engine running?

:huh:It's a heavy piece; to be fitted to such an otherwise lightweight engine-design.

I've always wondered why the designers put that heavy flywheel along with that extra heavy bolt and nut! Way back then building balsa models, trying to keep them light, and Testors comes along with this "nut job" airplane engine, tank and mounting conglomerateration!
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Re: Testors/McCoy .049 smoked...

Post  gcb on Wed Oct 11, 2017 10:39 pm

Jason_WI wrote:
Old-timers may remember the term, "slag engine." There were several engines made in the USA in the 1930s-1940s, sold mostly through a big store in New York City, that were junk right out of the box. They seemed to be made of the debris that floats on top of molten metal (slag), thus the name. Thor and Deezil were two of them.

Actually I had both the Thor and the DEEZIL. A slag engine was originally defined as an engine that both the piston and cylinder were made from the same material. In the case of the Thor, it was aluminum...very short-lived. It had space for a ring, but I found out it was for lubrication.
The DEEZIL was not a slag engine. From what I understand, the first ones ran fine. Later one were assembled without the skills needed for good fits so some ran and some didn't...mine didn't. I bought a replica with excellent fits and it is a good-running diesel.

George
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Testors-McCoy/WenMac bench-mount

Post  roddie on Tue Dec 05, 2017 6:26 pm

I made this bench-mount weeks ago.. and posted it somewhere.. (I thought..) Huh... but not in this thread.





What a mess my bench is..  Embarassed

Anyway.. I needed a tank-mount/shelf.. and found a bracket that's been kicking-around my work-table for days.. Rolling Eyes So I decided to put something together. I used my trusty old B & D rotary tool with a cut-off wheel to shorten some screws.. and cut a matching piece of poplar-stock for the tank-shelf.




I'm better-off getting these things out of the way beforehand. I may not test-run the Testors/WenMac engines anytime soon.. but when the day comes.. it's now just a matter of shimming a tank and running a feed-line. The mount is all set to screw-into a post on my deck out back.

I'd like to make bench-mounts for "all" of my engines. Most of them will be beam-mounts. It would be a good Winter-project. I like the idea of "dedicated" mounts.. rather than a universal-mount. I enjoy working with wood.. and making fixtures.  Smile
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Re: Testors/McCoy .049 smoked...

Post  rsv1cox on Wed Dec 06, 2017 8:11 am

I made a similar one with poor results.  

Despite being cinched up tightly in a vice the engine vibrated so badly due to the length of the board to the securing point it foamed the fuel.  I think it happened on a Wen or Testors engine like yours.    At first I blamed the engine (bent crank?)  I finally resorted to commercially available mounts.

I posted about it here a year or two.  Rod, Ron, or somebody recognized the problem and set me straight.

Edit add:

This might have been the culprit.



Of course, yours looks a whole lot better screwed together than my hastily constructed example so it may work fine.

Bob
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Re: Testors/McCoy .049 smoked...

Post  roddie on Wed Dec 06, 2017 12:15 pm

rsv1cox wrote:I made a similar one with poor results.  

Despite being cinched up tightly in a vice the engine vibrated so badly due to the length of the board to the securing point it foamed the fuel.  

Of course, yours looks a whole lot better screwed together than my hastily constructed example so it may work fine.

Bob

In your photo, the mount isn't "centered" in the vise-jaws.. which would amplify the "spring-board" effect. You can see the difference in the jaw-gap on either side. The wood appears rather "thin" as well. A short-arm commercial mount will lessen the effects of vibration.. but if the engine or prop has a bad-enough balance-issue.. it's going to cause problems in a model.

I try to use clear solid-hardwood for a bench-mount if I have it.. and yes; I usually anchor the mount to a deck-post or rail using two long woodscrews.
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Re: Testors/McCoy .049 smoked...

Post  rsv1cox on Wed Dec 06, 2017 1:34 pm

Back when I was running every new to me engine I built many test stands, some famous, most infamous. Maybe 7-8 altogether. Individual custom stands for everything from Cox to Spitzys. That one probably wasn't the one that caused the vibration problem. Most were built per your example on the spot using 1X2 pine without much consideration.

I think this picture shows the villain under the larger stand, built for either a Cox or tank mounted Wen Mac out of thin T1-11 siding. It vibrated like mad. I think yours will probably do just fine. I couldn't find the thread I posted about it, probably fell off the end of the earth.

A couple of months ago I threw all of them away replaced by commercial stands.



Bob
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