McCoy 35 History

[Colin McRae]

This is more of a curiosity question.

I have seen McCoy 35's where the glow plug is centered in the head, and also where the plug is located off center. Not sure if the centered plug was the original Testors design for the engine, or vice versa.

But in the air, is there a benefit to one design over the other?

Thanks in advance.

[Dave_Trible]

I'll take a crack at answering,  best I can.   The Red Head .35, .29 with the central plug came out of the original design by Dick McCoy circa 1960.  These have been thought to be the best ones made,  likely because of Mr. McCoy's direct involvement with the manufacture.  I have a number of all versions and in general I'd agree,  however SOME of the offset plug engines have surprised me how well they run.  Sometime 1964-65 Testors took over the company from Duromatic Corp.  One of the things they tried for a while was a bar stock piston instead of the cast sintered iron one.  While I'm sure it benefitted over the lapped iron piston on the production line the reviews weren't exciting since the tolerances weren't very good.  They reversed that practice at some point.  I'm not sure the reason why Testors went to the offset plug unless it was necessary to machine the baffle on the bar stock piston and make it clear the piston.  In any case it became easy to figure out the vintage of the engine.  At one point whoever made the pistons also made them for Johnson engines.   IMHO the later ones that came out as "Custom" with the lightning bolts on the side were scrap metal and a waste of time.   Lastly the Series 21 engines with a Dykes ring CAN BE a pretty good stunt engine if not pushed too hard and run with plenty of castor.  They do weigh a little more but that is not necessarily a deal breaker.

Dave

[Peter in Fairfax, VA]

Hard to confirm, but the reference below indicates Testors bought the McCoy manufacturer 1955.  The AMEE (American Model Engine Encyclopedia) indicates the Red Head 35 was a new design in 1957, followed by moving the plug, painting the head Blue, adding a lightning bolt, etc., as the years passed.  Our club runs a McCoy 35 on a trainer; runs well.  A member has a Tutor with a McCoy 35 that flew and ran so well that it did the full pattern first flight.  As far as the lightning bolt, some buyers prefer it.

Peter

https://www.referenceforbusiness.com/history2/77/The-Testor-Corporation.html