I'm a new member, although a relatively longterm lurker, primary interest here is valveless pulsejets in general, and Reynst combustors in general.
As a followup to my post on the eGroups (well, Yahoo!Groups, these days ;-) pulsejets forum here
, some more thoughts and a proposed design. I'd like some feedback as to the validity of this approach.
The attached drawing covers the combustor chamber part of my proposed test rig - this will be a piece of straight steel pipe, honed on the interior to take a piston, and threaded at one end to take varying shapes of combustion chamber 'ends'. These ends will have large holes, the orifices being variable using detachable 'orifice plates'.
Welded to the main chamber will be lengths of threaded rod to hold in place the orifice plates and allow adjustment of piston depth.
After the orifice plate comes a fuel feed system (basically, a 'closed' annular feed of fuel/air mix attached to an air metering system, and then the 'exhaust'. This will be of steel pipe, cut to 'binary' lengths and threaded to fit one into the other, allowing the exhaust length to be adjusted arbitrarily.
The air metering system will be a large, volumetrically indicated, glass belljar, floating in water, feeding from the top and counterbalanced so as to provide air at atmospheric pressure.
I'm thinking liquid fuel, maybe standard unleaded or plain methanol to avoid having to preheat, and I can knock together an atomiser from one of the old (car) carbs I have floating around, or maybe buy a needle jet assembly intended for a large model A/C engine.
Basically, the plan is to have something that can be adjusted (almost) infinitely for a given combustion chamber diameter, to see what effect varying the various parts has. I intend to blag a DV camera that does timecode from somewhere to record test runs and then analyse the results and see if I can come up with something concrete linking variables to results.
I have a bunch of old brake pistons of various sizes lying about (from little tiddly scooter brakes to big truck models) so should be able to vary diameter as well as the other variables, access to steel of useful sizes allowing.