Mike Everman wrote:We found at Burning Grape that the joint where fuel tube met air tube to be excessively leaky, but maybe we were only concerned because compressed air became precious. Some solder there would go a long way.
That's probably true, but when I got the Fo Mi Chin II engine back in my hands, it started up right away (within 3-5 seconds of turning on the propane). Remember, that was the first time I had ever tried to start that engine! (This was with 30 PSIG and small diameter air hose, my "standard" setup for Dynajet starting.)
On the two tube motor: I have great doubts that it will work, there is no restriction aft of the CC. I suspect it will be a torch only, unless you can make a restriction.
I suggested this as a reason why I couldn't get my Black Princess going. In response, Graham stated that he and Nick had gotten perfectly straight pipes to run well. Of course, I think it's harder when the L/D ratio is low, as my recent designs tend to be. I think that makes both the length dimensions and the starting technique a lot more critical.