Bruno Ogorelec wrote:I was wondering; why 'Reynstodyne'? To me it does not look like owing a particular debt to F. H. Reynst's designs. To my historian's eye, it looks like belonging to the family of 'sidewinders', together with the Logan, the NRL, the Thermojet etc.
Mike Everman wrote:I agree, the Reynst is a two hole breather, but no exhaust comes out the intake. I think that should be the criteria for something with Reynst heritage... Though it's the source of great pleasure when Larry adds 'odyne and TM to his developments. LOL
I plead guilty only to the usage being confusing -- I have never meant the Reynstodyne name to imply that the derivation is from the Reynst Pot per se. [Of course, I have never read Reynst -- just seen the copy that Ben Brockert got and had it in my hands a few minutes.]
For the name, I appeal to something more fundamental than the refined geometry of a specific device. To me, the significance of Reynst is the realization that breathing and valving could be done behind
the expansion zone, rather than out in front of it. That, for me, was a revolutionary concept to consider. It's really quite profound when you think about it -- it takes you out of the realm of trying to block outward flow with an inefficient rectifier of some kind [the "original" Pulsodyne(TM) idea that I had, back before I knew that valveless pulsejets had already been thought of!] and into a design that gets the entire reaction energy developed against a hard wall at the front. That is different from any rectifier design, different from Schubert, and even from the Logan [though theoretically, if you bent back the Logan intake pipe, you would have that part of it]. The other aspect, as Mike said, is to develop separation between mass and wave ejection, at least as much as possible at the intake. That way, you get all of the explosion mass momentum transferred into moving the cold piston mass you've taken in behind.
The Reynst Pot is simply that principle taken to a high degree of optimization; it is not the only possible geometry to exploit the priciple.
So, to me, any engine that breathes from the rear, reflects all wave energy to the rear to optimise the reaction force in the thrust direction and tries to keep the explosion mass flow concentrated on moving the cold air piston sum up to what I have previously termed a 'Reynst pattern engine', and my 'trade name' for that will always be 'Reynstodyne', regardless of the specifics of the geometry.
Not 'derived from the Reynst Pot' but 'working from the Reynst pattern' is the key definition. It is perhaps not as clear in the Focused Wave Engine as in some other designs because here there is no distinction between the chamber and the exhaust nozzle. You can be sure, though, that the 'constant volume expansion' all takes place forward of the intake, so the breathing of the device is still typical of 'Reynst pattern' operation.