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Post  jmendoza Sun Sep 26, 2021 2:32 pm

When I was at Cox in 1980, they brought over several parts bins full of TD .049 cylinders for us to use in customer service. They were thick wall with #4 stamped on the vertical edge of the exhaust ports. In looking them over, we noticed that when the side flutes had been cut on the Cox-O-Matic, somehow it was off and one flute was a little wider and taller than the other. We called Dale over to take a look at them and he said that they were OK to use, but had been rejected because the worn tool fixture was cutting them with this offset.

Dale suggested we should build up a few engines and try them out, so we did. The results were interesting in that these cylinders consistently ran faster than a regular #4, adding about 1000 rpm . Dale hypothesized it must be due to the swirl created by having the higher side flute open first which he said improved scavenging and volumetric efficiency.

Leisure at this time was not concerned, and was more focused on using everything we made if it would work. So much so that they never bothered to correct the problem on the Cox-O-Matic that was causing the side flutes to be non-symmetrical.

A few months later we noticed that the fixture was so bad that by now, the one side flute was much bigger, and the other one was almost non-existent. This condition went unchecked and was typical of the "If in doubt, ship it out!" mentality Leisure had right before they closed the Santa Ana facility. At any rate, these rejected cylinders were not tossed out but used instead and ultimately found their was into the Killer Bee and Venom versions of the engines. This is classic example of what we called a "happy mistake". There were slit versions of them made using the TD porting fixture, based on the testing we had done with the afore mentioned TD cylinders. Leisure was not interested in spending much money on R&D at that time, but Dale would come over to customer service in the Helms building and we would test engines with him when we had extra time. In this way, out of sight of the "bean counters" as Dale called them, research continued.

Dale used to say that in spite of all the issues we had, sometimes Leisure would screw up and make a good engine. It is testimony to the solid design of Cox engines.

I still miss "Mr. Ambroid", he was a great modeler and a walking encyclopedia on everything Cox.
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Post  gkamysz Sun Sep 26, 2021 4:18 pm

Now that is an interesting story. I did wonder how the single booster came to be.
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