Synchronous Injection

[John Hasler]

I see now that Miller's paper has been mentioned in another thread, but the link there did not work for me. Sorry for the duplication, I still think it is interesting work, though.

[metiz]

How large is medium? I'd like to keep it under 2m or so for ease of transport.

It wouldn't come near 2 metres, more like 850 - 1000mm Thrust would be in the 15-25 pound range. With linear I mean that the intake is welded on the endcap, pointed the opposite direction of the tailpipe (this will affect thrust but that's not the goal of your setup)

[John Hasler]

mwriz writes:

It wouldn't come near 2 metres, more like 850 - 1000mm Thrust would be in the 15-25 pound range.

I've got a copious supply of 35mm pipe plus a long piece of 70mm with a plate already welded on one end. Should go a long way toward approximating Miller's setup [1]. Don't have any 30mm pipe, though. Can I get away with using 35mm for the inlet and compensating by lengthening it? I calculate that 3.44 diameters rather than 2.67 would give me the same Helmholtz frequency. I note that Miller used an adjustable inlet that appears to be of the same diameter as his tailpipe.

With linear I mean that the intake is welded on the endcap, pointed the opposite direction of the tailpipe

That's what I meant by axisymmetric.

[1] According to the paper they used a 75mm diameter combustion chamber and that the overall length was 1250mm, which doesn't jibe with Pyrojoe's rules. Does anyone have detailed dimensions for Miller's motor?