Wonder Plug

[Robert Zambelli]

Found these at a flea market.
They have a "W" shaped element.
Anyone ever use one or know anything about them?

Bob Z.

[Dave Hull]

It was introduced with their .049 Sky Fury, I think.

A review in the 1954 Model Airplane News:

"An interesting glow plug is supplied. It has a very large Volume recess and an element in the form of a "W" pointing downward. During the test, conventional plugs were substituted and it was found that few gave such good results at any speed and none at very low speed, where a point could be found at which no other would sustain running unless the battery was connected."

"Test: Allyn Sky Fury .049

Plug: 1/4 x 32, Short reach as supplied, 1-1/2 volts to start; Fuel: O & R AA; Running Time Prior to Test: 2 hours; Bore: .390 in.; Stroke: .400 in.; Weight: 1-3/4 oz.

            Power Prop                    RPM
                   6 x 5                      10,000
                   6 x 4                      11,000
                   6 x 3                      12,900
                5 1/4 x 5                   12,200
                5 1/4 x 4                   13,200
                5 1/4 x 3                   14,300
                Top Flite                      RPM
                   6 x 5                        9,500
                   6 x 4                      10,700
                   6 x 3                      12,000
    Sky Fury prop supplied         12,400


Ref.:   http://www.airplanesandrockets.com/motors/allyn-049-sky-fury-engine-review-may-1954-man.htm


Cox also had a glowhead for a while with a W-shaped element, as I recall.

Dave

[Dane Martin]

I have a couple of the W shaped element heads. I think K&B also tried it? Not really sure on that. They worked pretty good. Like the flat coil nelson where it gets as much surface area to the combustion event as possible.
I've only done rpm measurements on the flat coil vs a standard nelson coil. Not the w shape vs a coil.

[Dave Hull]

K&B merged with Allyn, who seemed to be mostly making model boat engines? I think K&B did most of the manufacturing. So it would seem logical that K&B could just adopt the plug design into all the other stuff they were making.

I am curious whether the Cox W-glowhead had better performance than the coil, or why/how one was picked over the other. Not sure which would be easier to make, or cheaper, which might have been the discriminator. The W-element may have been flat stock, whereas the coil is obviously round wire.

Maybe one of the engine collector gurus will come help us out.

Dave

[Brett Buck]

K&B merged with Allyn, who seemed to be mostly making model boat engines? I think K&B did most of the manufacturing. So it would seem logical that K&B could just adopt the plug design into all the other stuff they were making.

I am curious whether the Cox W-glowhead had better performance than the coil, or why/how one was picked over the other. Not sure which would be easier to make, or cheaper, which might have been the discriminator. The W-element may have been flat stock, whereas the coil is obviously round wire.

   The "w" was A LOT stiffer, maybe it was less prone to fatigue.

     Brett

[dale gleason]

The K&B Allyn twin cylinder was a good boat engine, driving a brass flywheel.

[Mark Mc]

Funny thing, I was just looking at a Cox glow head with the "W" filament the day before yesterday.  I've always wondered how it'd do in tests compared to the filament also.  But being as old as it is, I don't think a fair comparison could be done.  Besides, I only have one, so I keep it as a curiosity instead of running it.  Just looking at it, I can see how it'd be more expensive to manufacture than a coiled filament plug.

Mark

[bob whitney]

the origanal W plug came on the K&B Sky Fury .049 and .074 as a complete head like the cox .tapping it out for a standard 1/4 32 was much slower, the head was perfectly flat ,I never saw a 1/4 32 plug with the W element they held up well with 40 % nitro. did 89 mph in 1/2 A speed` as a JR with one

[Larry Renger]

Cox did have a W plug, but discomtinued it after losing a patent battle.

[Robert Zambelli]

Great and helpful replies - THANKS!
I did inspect the box and nowhere did I see "K&B", only Allyn.

Bob Z.

[Dave Hull]

Here is an interesting thread by Isky from another forum that talks about plugs and patents. Didn't find the patent for the "W" element--but I didn't go thru all the materials yet.

http://www.rcuniverse.com/forum/glow-engines/10626380-glow-plug-patents-design-print.html

Dave