RogerN wrote:
"Michael A. Terrell" wrote in message
...
Wes wrote:
Tim Wescott wrote:

_And_ it starts with a ni-starter -- Cox glow heads _demand_ a good dry
cell battery, and just sneer at you if you try to give them 1.2V from a
nicad.
http://www.metalworking.com/dropbox/cox_head.txt
http://www.metalworking.com/dropbox/cox_head-inside.jpg
http://www.metalworking.com/dropbox/...d-on_plane.jpg
http://www.metalworking.com/dropbox/cox_head-plans.jpg
http://www.metalworking.com/dropbox/cox_head-top.jpg

That .3v per cell matters at times.

A fresh carbon zinc is closer to 1.55 volts. 1.2 volts would be a
little over a 40% reduction in power dissipate in the glow plug.


--
Lead free solder is Belgium's version of 'Hold my beer and watch this!'

There seems to be a lot of difference in the internal resistance of the
batteries too. For example, it would be interesting to measure the voltage
at the glow head using a Sub C Nicad versus a C cell carbon zinc, I doubt
there would be a 40% difference, the Nicad might even deliver more voltage
to the glow head. However using a 1.5V lantern battery sized carbon zinc
cell would get the voltage up there. For glow plugs I use either 1.2V
rechargeable or my power panel glow driver, I guess the power panel would be
better for Cox engines but I haven't used them enough in R/C to notice a
difference.

For the Cox engines I was told to use two D size alkaline cells in
parallel. I do that, with good thick wires, and it works like a charm.
I use 3/16" (I think that's the size) copper tube on the batteries,
which is just the right size for banana plugs, good thick not-too-long
wires, and a Sulivan clip. It works like a charm.

For the conversion heads with glow plugs, I use a little bitty
Ni-starter -- whee!

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com