Cox 010 glow head filament size?

Filament diameter and I was trying not to break the little stock we have lol. However, we will have to send a sample to vendor. Just wanted the diameter for an email quote to see if this is even a feasible project.

Ah ok, I don't have a tool to measure something that small. However, I can mail you  a head if you want.

Cribbs74 wrote:Ah ok, I don't have a tool to measure something that small. However, I can mail you  a head if you want.

Nah, don't worry but thanks all the same  

Bernie:

Why would the filament size be any different than any other Cox 1.5V glowhead?     

SD

X-Ray image shows about 5 looops. There may be a way to extrapolate the diameter by the pixel width of the filament to a known diameter on the engine.

SuperDave wrote:Bernie:

Why would the filament size be any different than any other Cox 1.5V glowhead?     

SD

Good question ... not sure lol.

Nice Xray  

Jason, the mad scientist of modeling.

Cox International wrote:

SuperDave wrote:Bernie:

Why would the filament size be any different than any other Cox 1.5V glowhead?     

SD

Good question ... not sure lol.

I assume the heat emitted by the glowing filament is proportional to the mass i.e. the size of the filament. Thus the filament size has an impact on the ignition timing. A 010 would probably have too early igmnition with a 049 size filament.

If you consider the fact that standard 1/4-32 threaded plugs can be used with success in many different size glow ignition engines (including Cox .049's; using an adapter) then there couldn't be too much difference in the way that they work. If there were less coils in an .010's glow-head filament... it would theoretically burn-out as soon as battery current was applied. 

The difference is in the heat range... and is determined by the diameter of the filament wire only. A Hot plug's filament will have a slightly less diameter than a cold plug's. Hot plugs are helpful for attaining a low-idle... which is not a concern with the Tee Dee .010. Cold plugs are recommended for high-nitro content. I assume that the Cox Tee Dee .010 performs best on high-nitro fuel... (25%+) so I would think that you'd want to go with a larger diameter wire in the filament.

After looking at "Merlin" plugs for Norvel/Cox applications.. they show their plugs as being color coded "red".. or HOT.. ??   and Mecoa claims to have Cox .010, .09 and .15 heads available soon... (for what that's worth)

Yes seems with a nelson plug a blank could be threaded to fit this cylinder
Also there isnt alot of meat left to work with an aluminum adapter but a helicoil type thread conversion will work with a standard plug.

That's the first .010 with a standard plug I have ever seen. Is it yours?

Just painting a picture Cribbs, sorry no data at this time.

I am not sure how a TD 010 would work with a full-size glow plug. This emits way more heat than the stock glow head of a 010, meaning the ignition timing would be significantly impacted and the engine overheated.

In principle, the higher the average temperature at which the heat is input into any thermal power cycle (like the Carnot cycle taking place in an internal combustion engine like COX etc.)  the higher the efficiency of energy conversion from thermal to mechanical. This means that the efficiency of an engine in principle would be the highest if the ignition of the fuel charge could occur in an infinitely short period of time just when the piston is  at the top dead center. Because the ignition in reality takes time it should start some time before the piston reaches the TDC. This is how stock heads including the filament mass and compression ratio are designed. But if ignition starts too prematurely (e.g. triggered by excessive heat emitted by an oversized glow filament of a full-sized glow plug in a TD010) then too much part of the explosion energy will work against the piston moving towards the TDC and the useful energy is partly lost.

You may experience the same phenomenon when the number of shims under the high compression TD head in a COX 049 is too few thus, due to the excessive compression ratio the self ignition of the fuel charge occurs too prematurely and the engine loses power and overheats.

Sorry for the long theoretical explanation of IC engines that many of you surely know better than I.

I suspect a TD .010 won't have enough punch-volume to cause excessive tempts to happen. With a hot (thin) filament from a standard short plug the coil likely being slightly longer than a stock cox coiled filament could run colder than designed. I would try 10% nitro initially.