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Hi Larry, I have had a fiddle with the "far-field conditions" checkboxes. They appear to dimulate continuing the piper forever. The effect is to eliminate any wave reflection at the end of the diagram. So, I now agree with you that the simulations should have these turned off, and most of my previou...

Well, Leisure Suite Larry, I have confusing news. The difference between your simulation and mine is that I run with the "far-field conditions checkboxes checked on the Data tab, and you don't. I'm not sure what that really means. I assumed that it meant allowing for the "free-air" conditions outsid...

My apologies Larry.

Not sure what I did wrong the other day.
Perhaps I did not simulate for long enough.
The negative white instake section does not kick in for a while.

Don

Hi all, I'm usually on the valveless PJ forum, but I guess I must be leaking a bit. Subsonic ramjets don't work well because they can't get the pressure up high enough to work efficiently. I was wondering if it would be practical to bump up the pressure intermittently using high amplitude sound wave...

Hi Larry, I have had a look at your engine UFLOW designs. I notice that you analyse by setting up an initial partial sine wave throughout the engine, and then seeing how well it resonates. I take a different approach (as indicated in the Trainer I have already posted). I assume that the combustion p...

Looks like another variant on the Lockwood (prior to the lockwood?)

Chamber, short intake tube, long exhaust tube, intake produces most of the thrust, exhaust provides the resonance.

Are we doomed to repeat history forever?

Don ;->

If you straighten out a lockwood (for UFLOW simulation, for example), you get a chamber with a short pipe out one side, and a long pipe out the other. If you straighten out the Smooth Lady (?) for simulation, do you get a specially shaped chamber with a short pipe out one side, and a long pipe out t...

Oops...

Larry, that was my previous email. must have been a late night.

please send to don.lawn@bigpond.com.au

I even cheked it four or five times before realising the mistake! Duh.

don

Karry,

certainly doesn't look constipated.

I'm thinking about your tank circuit stuff.
At the moment I can see both sides. Confoosin.

Don

Hi guys, here is a basic version of the sort of jet I have been playing with in UFLOW. (attached) Its purpose is to give a clear example of the basic concepts of valveless pulsejet operation, rather than to focus on any amazing performance etc. Sort of a Trainer. I don't have any significant points ...

hey Larry,
whats italian for "constipated"? :wink:

Yup, a long narrow tube has heaps of inductance, and loses very little energy.
superb for resonance, especially when combined with a nice big chamger which has lots of capacitance. Good low frequency resonance.

Don

And to Hinote, always happy for healthy debate! Thy this with UFLOW. Put in a profile for a straightened Lockwood, or similar, and similate an ignition puls originating in the chamber. Now, reduce the diameter of the intake and/or exhaust pipes. You should find that the resonance of the system impro...

Aw shucks Bruno.... To those who don't know me, and those who wondered why I went away, back then most people based their theories on gas mass movement, whereas I pushed the idea that the pressure front moves through the gas, and so the moves faster than the gas, in accordance with wave theories. I ...

Hi Larry, I had a look at the UFLOW charts you posted for the Smooth Lady on the other thread. I'd be interested to see the original files and run the time simulation, if you'd care to post them to don.lawn@ozemail.com.au As a first impression, I think I can make the following observation. Your engi...

Hey Larry,

Good to see you are still working on this....:-)
Congrats on getting her running.

The big question of course for the Lady will be
wether the Focussed Wave effect improves efficiency over other designs.
I'm dying to find out.

Don Lawn