Eric Hammond wrote:This was enlightening. I was under the impression this channel was supposed to run down the feed tube, turn 90 degrees, run the length of the burn tunnel and then deposit air at the base of the heat riser.
I think that would work very well though, the air would be very hot and unused until it reached the most useful point.
However that method would be best implemented during the build.
I have a video of my P plate in action, it seems to work but to what effect I can’t really say!
I can see flames exiting the riser with the P plate in action but I don’t actually see much rise in my hot plate temperature.
One thing is does allow, is to turn the fire into a gasifier, that seems to keep the heat up and drop wood consumers by half!
When I build my next one I will be putting much more effort into secondary air and its control.
Haveing a lid on the feed tube and adjustable controls over the air flow seems to offer huge benefits to a J tube rocket.