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New question, The new nostalgia rules mention globee type heads or inserts for cox 020’s (legal) so they must be available commercially somewhere. Does anyone know where?
Dean, The only place I’ve found them is E Bay, 3 shorts sold today for $8.45! They aren’t common however. Thermals, Glenn
I think those were the screw-in type, not the flat-coil button type. The screw-in plugs, except the Nelson, all seal at the top of the threads. It evidently makes a difference.
Dean, Sounds like you are looking for .049 heads, some of those show up on ebay from time to time too. In my experience, a Galbreath head and Nelson plugs works better, meaning faster, they are readily available at reasonable price and very sturdy. Problem is, that doesn’t solve the 020 issue. Thermals, Glenn
No, I am looking for the flat coil button type heads. I agree the Galbreath head with the Nelson plug is a better deal. I am using those on my Cox 049/051 engines as well as my Fox FAI .049. Indeed, all my engines except the Cox 020 uses Nelsons.
Much better product all round.
Just wish we could solve the 020 plub problem. The Cox plugs are junk. I went through 4 of them last year at Muncie. They did not survive running out a port prime. If it weren’t for Lee Campbell finding some used ones in the bottom of his van, my grandson would not have been able to get a flight off, and win 1/2A Gas! 🙂 🙂
Made it. Experimental head. We are looking for someone to mass produce. We only have simple machinery, no CNC.
There is no performance gain over the stock heads. It just allows use of a Nelson plug.
The stock heads are quite good, and are only $4.00 each. We don’t anticipate much of a market for our head, just a challenge. Therefore, the folks that only want to talk about numbers in the thousands are not interested in us.
Dean and others, GloBee made flat coil plugs in the conventional shape. Screw in the head. Had the solid glass backing. GloBee also made plugs for Nelson for a number of years.
OK, my friend and I have a Cox 020 head bored out to accept the flat-coil Glo-Bee type plug that Larry Driskill sells at http://www.kittingittogether.com.
It is a simple drill-out through the coil area, and a shim below to clamp the plug and set the head clearance.
Amazed that someone else such as Galbreath or Mattes hasn’t done this before. Works great. A small performance gain, but bullet-proof plugs. Even with 65% nitro!! 🙂 🙂
Dean,
How about some more details about this “shim” below the flat coil plugs in the 020? How thick is it to get in the ball park for head clearance? It has to be shaped on the top side to accept the bottom of the plug, and did you shape the bottom (combustion chamber side) too with a squish band or a simple ‘V’ shape? This sounds like the answer we have been looking for! Not so much for the performance gain but just to have plugs to run the engines. This also sounds like something that should be written up for the Digest.
Thermals, GlennGlenn,
I have no means of measuring. My machinist friend did it by constant fiddling.
Yes, the top had a chamfer to match the bottom of the plug, and the other side is also a simple “V” to complete the combustion chamber. As to thickness, the whole thing when assembled looks like a normal glow head. Only the bottom part is loose, clamped by the remaining threads on the original glow head.
Dean,
Thanks for the info so far, now what I need is the general thickness of the “shim” to start fiddling for myself and perhaps others. A ruler estimate would be helpful, I’m guessing it would be about 3/32 to 1/8 th thick to accomidate the two cambers, the final clearance to be determined using head gaskets. If there is enough of a market to make heads for Holland Hornets there would surely be enough to produce parts for Cox 020’s. Thermals, GlennHey Dean, Glenn and the others,
Does anyone have anything against the “turbo plug” style glow plug. They are the type used in many of the newer RC hi-po cars. They have a 60 degree bevel at the bottom and seal at the bottom like the Nelson plugs. They have a smaller body much like a standard RC glow plug(just use a different thread). I have been making a 1/2a TurboHead for the Cox/Norvel/VA engines for a while and have been working on a TurboHead for the Cox .020’s just haven’t gotten to the point where I was happy with the design yet. As I read the rules there should be no reason a .020 TurboHead would not be legal. It really is a shame what Estes has done with the Cox line of engines/parts. Has anyone else seen the little e-powered FF plane they have/working on that has a plastic TeeDee .020 that the shaft for the electric motor runs through?
LAter,
Tim Wiltse
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