www.pulse-jets.com

Hi Jerry. Glad to see you back.

I'd just like to point out that it's not necessarily the case that TSFC for a valveless will be higher than for an equivalent sized valved engine (although that's often the case, and, in the case of the Thermojet, certainly is). There have been a number of valveless designs shown here in recent years that (at least claimed) to have a better TSFC than equivalent "valvers". That said, there's been more work done here on valveless motors than valved ones, those being "good enough" in most cases.

Simon

Hi, Simon,
Thanks for the update. To my mind, the chief advantage of valveless pjs is their longevity, a result of their having no moving parts. Because my initiation into p-js was use of (and working on,) the Dyna-Jet/Dyna-Fog, I've been most involved with similar engines. I'm still fascinated by all sorts of miniature engines, piston-type as well as pjs, and have a collection of both. However, I think John Swartzwelder owns more of all kinds than the next 3 collectors, combined.
Jerry