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Viv wrote:I never thought it had steering let alone steering by feet it would be interesting to know if it ever ran

Viv

It must have. Craig was too much into pressure jets and too much of a hands-on guy to build something like that and then not to run it.

loco wrote:was that a Hind following you?
Love those choppers...

Yes. I admire it in a detached kind of way, but won't ever really like it. How can you get to like a machine that has tried to kill you?

Hello Simon, [snip] ...perhaps best not to go poking at sores with a sharp stick, if you catch my drift. Yes, you are right. I edited my post (above). FWIW, the wanker in question is not the innocent he pretends to be. Cheers! M. I have now edited my own. Maybe I shouldn't have, given the language ...

Pater Bruno, What is this "we" business? As if you will be designing, much less building a pulsejet for this or any other competition. As far back as 2003 (yes, records do exist), you have consistently opposed or subtly throttled any possibility of Forum members conducting a "pulsejet challenge". A...

I think that fuel flow as a limit is untenable, even if everyone had a perfect orifice, pressure is just flat out going to be different time to time, temp to temp, early in the run, late in the run. The only way to make that work is fuel mass flow, which is the single most difficult thing to do acc...

The only restriction that really makes sense is the one on the maximum fuel flow rate. That's by far the simplest and easiest way available to measure engine efficiency. Given the same fuel flow rate, whoever achieves highest thrust has the most efficient engine. He has extracted the greatest amount...

One more thing -- his engine probably develops between 15 and 20 HP. Cannot be more than that. Try flying a fixed-wing aircraft that can carry a man with suxh a small engine! And fixed-wing aircraft need rather less power to fly than helicopters do... An amazing feat of engineering.

This , no, Bruno? Yes, that's Mr. Schoeffman's little jewel. The clip only shows him doing ground hops, but there's much more to the machine than that. I have talked to a guy who has seen Schoeffmann do normal flights with it, in order to demonstrate that the thing actually works. The problem, howe...

It is not a successful project. Flies rarely and badly. It's been around for years. Mechanical overkill -- 4 separate engines each with its own clutch etc... Better efforts at a personal helicopter have been made. There's an old guy by the name of Schoffman in Germany (or Austria) who flies nicely w...

I have developed a mantra:

"Do not respond to 'comprex'. Ignore."

If I repeat it fifteen times, it works. I never respond to mention of 'comprex' anywhere anymore.

It should work, but it's almost certainly useless for anything but fogging. The diaphragm valve is slow, with great inertia and cannot follow the pressure swings in the engine quickly enough to be very effective. Good for what it is, but not good as an engine, I'm afraid.

Seems we've all got whirly-gigs on the brain. I made a spreadsheet for that centrifugal compression. Gotta find that. I remember being surprised at how little compression was realized. I thought it would be a lot more. Remember this one? Damn, Mike, why do you have to intrude with rude reality? It ...

Interesting. Looks simple enough. Should be tried, I guess. One thing I have been thinking about is a rotating combustor. Wouldn't centrifugal force provide high pressure and thus higher compression than in a stationary combustor can? Feed the air from the compressor axially into a rotating combusto...

Damn, I hate change...

But, if it had to change, at least it was done well. Looks pretty good. Even I can navigate through it without quite getting lost... Not bad.

Hi Ghrey - have you tried an exhaust manufacture shop? Over here they have toridal donut thingys that they use in exhaust pipes etc.I was thinking about a toridal CC a few months back incorparating the vortex trap...but the exhaust toridal donuts are too expensive for me.Some were even cut in half ...