Search found 571 matches

by Graham C. Williams
Tue Nov 04, 2008 5:07 pm
Forum: Valved pulsejet forum
Topic: External valve grid
Replies: 45
Views: 1672852

Re: External valve grid

OK. Using Forrest's Form we have: dfr = f/fn : dfr = Driving Frequency Ratio f = Pipe (driving) Frequency fn = valve frequency We have: Tharratt: dfr = 0.8 P. Schmidt: dfr = 0.33' or dfr = 0.2 Alright, this asks the question "is fn the free reed frequency"? This isn't the place for this discussion. ...
by Graham C. Williams
Mon Nov 03, 2008 7:35 pm
Forum: Valved pulsejet forum
Topic: External valve grid
Replies: 45
Views: 1672852

Re: External valve grid

H Grim. Here is an interesting difference of opinion! I found these some time ago. They are recommended set-ups for valved motors Nf = Pipe Operating Frequency Nr = Reed Frequency Tharratt: Nf/Nr = 0.8 P. Schmidt: Nf/Nr = 0.33' or Nf/Nr = 0.2 Graham. P.S. I've lost the source of this information so ...
by Graham C. Williams
Sun Nov 02, 2008 8:46 pm
Forum: Valveless pulsejet forum
Topic: Need Help With First Jet Engine
Replies: 7
Views: 1559

Re: Need Help With First Jet Engine

I want to maintain some level of dignity and for a few minutes appear I know what I'm talking about. Hi. Ha, Forget the Dignity. The mechanical simplicity of these motors hides a horrible complexity. They all have a habit of doing the unexpected when you don't want them to. We all have stories but ...
by Graham C. Williams
Sun Nov 02, 2008 8:24 pm
Forum: Valved pulsejet forum
Topic: External valve grid
Replies: 45
Views: 1672852

Re: External valve grid

Hi Grim. Will your motor run, without forced air, on Propane? If it will then the pipe and valves are probably OK and you can be sure that it's the pressure drop across the fuel system that's the problem. If the motor runs on Propane, try sleeving down the induction cone. This will increase the air ...
by Graham C. Williams
Thu Oct 23, 2008 6:24 pm
Forum: Tools and Construction
Topic: NUDiS
Replies: 50
Views: 43816

Re: NUDiS

Hi Charles. Yes, it is a bit of a macro Fest! Start by reading everything here. I have posted some instructions. Be sure to update the major programmes with the Public Release 2. It's a whole lot better. I have a much faster version here with lots of good bits but get this running first. Open the Co...
by Graham C. Williams
Thu Oct 23, 2008 11:20 am
Forum: Valveless pulsejet forum
Topic: Messerschmitt design?
Replies: 11
Views: 3177

Re: Messerschmitt design?

Hi As part of the NUDiS download package in the Tools section I have modelled a Type 06 motor with 100mm dia combustion chamber. The Type 06 model starts up easily and in the real world should run well statically. The Thrust is not spectacular but will improve with forward speed. The Induction plug ...
by Graham C. Williams
Thu Oct 23, 2008 10:27 am
Forum: Valveless pulsejet forum
Topic: Ozpulse, Symmetry series.
Replies: 11
Views: 1973

Re: Ozpulse, Symmetry series.

Hi. When it's running, you could try feeding some fuel, via a Rosscoinjector, into that exhaust pipe, just to see what happens? My one concern is the amount of cold air drawn into the exhaust pipe. In ordinary designs it's this mass of air that provides the majority of the thrust. With this design y...
by Graham C. Williams
Sat Oct 18, 2008 4:02 pm
Forum: Valveless pulsejet forum
Topic: Mike's Build Log
Replies: 379
Views: 105877

Re: Mike's Build Log

Where are the Dims?
Sorry mate.

Graham.
by Graham C. Williams
Sat Oct 18, 2008 10:40 am
Forum: Valveless pulsejet forum
Topic: Mike's Build Log
Replies: 379
Views: 105877

Re: Mike's Build Log

Dear Mike. I have a feeling that your exhaust cone should be a little shorter but should first run this motor through NUDiS. If your happy would you send me the as constructed dims and I'll model it. I'm a little perplexed that it should run for ten seconds then stop. it's not going out of tune as i...
by Graham C. Williams
Thu Oct 16, 2008 10:05 am
Forum: Valveless pulsejet forum
Topic: Question?
Replies: 7
Views: 1532

Re: Question?

Mr Jim Bamford (http://www.onthewire.co.uk/bamford.htm) developed a boiler for his flash steam hydroplane. From the Book Experimental Flash Steam, J.H. Benson and A.A. Raymond. Tee Publishing. I Quote "The 'Bamford' venturi-type boiler is undoubtedly the most efficient steam generator yet devised fo...
by Graham C. Williams
Tue Oct 14, 2008 6:31 pm
Forum: Valveless pulsejet forum
Topic: Mike's Build Log
Replies: 379
Views: 105877

Re: Mike's Build Log

Hi Bill and Joe.
Take a look at the Snecma - AS1. For That matter it's not too far from the TYPE06 either. They are probably doing much the same thing.

Very nice bit of work Mike.

Graham
by Graham C. Williams
Tue Oct 14, 2008 9:52 am
Forum: Valveless pulsejet forum
Topic: *UPDATE* It Lives!!Need Help! Noob built focus wave motor
Replies: 14
Views: 1934

Re: *UPDATE* It Lives!!Need Help! Noob built focus wave motor

Good work! Glad to hear you got it going. Intake and Exhaust internal diameter is as important as the length of these pipes. Perhaps it's better to say that the internal diameter and length of the pipes are related. If your happy that the lengths of the pipes are correct look to the diameter of the ...
by Graham C. Williams
Tue Oct 14, 2008 9:11 am
Forum: Valveless pulsejet forum
Topic: Multiple inlets
Replies: 18
Views: 3342

Re: Multiple inlets

Good Morning.
'Kentfield' et al, did some work and made some comments concerning multiple intakes. Later 'Bill' duplicated this work, I think his results are on the forum somewhere?

Graham.
by Graham C. Williams
Mon Oct 13, 2008 8:48 pm
Forum: Valveless pulsejet forum
Topic: *UPDATE* It Lives!!Need Help! Noob built focus wave motor
Replies: 14
Views: 1934

Re: Need Help! Noob built focus wave motor won't self sustain

Please see this Topic. http://www.pulse-jets.com/phpbb3/viewtopic.php?f=3&t=2021&start=0&st=0&sk=t&sd=a Here you see the FWE as made by James D. He is using spark ignition ! To quote James D "The FWE is built to the dimensions given by Larry in his jetzilla article, 1.25" tailpipe and 26" total leng...
by Graham C. Williams
Thu Oct 09, 2008 8:15 am
Forum: Valveless pulsejet forum
Topic: Mike's Build Log
Replies: 379
Views: 105877

Re: Mike's Build Log

Thanks, Graham! ---- and try some tail expansion. The acoustic length, intake length and throat location are in the same places. Dear Mike. A good place to start. going from straight exhaust to expanded tail does not seem to be quite linear; you may have to move a little either side of this length!...