Search found 99 matches

by paul fellows
Thu May 13, 2010 8:45 pm
Forum: Valved pulsejet forum
Topic: relevant wd's
Replies: 65
Views: 2488549

Re: relevant wd's

You seem to have assumed that the second wave, the one that reflected of the end wall / valve plate, will continue to catch up with the first wave after they are reflected from the open end of the tail pipe. :? I suspect that it will in fact start to fall behind. :) Whilst they are travelling toward...
by paul fellows
Tue May 11, 2010 8:53 pm
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Re: pulse jet theory V o.1

im gonig to end this post for now :D :( i'v come across the idea of thermoacoustics, and it looks like it might provide the right answer once in understand it :?: when i first came across it i posted to see if it was of interest. and Metiz replide that it is old news los alamos are giving away free ...
by paul fellows
Tue May 11, 2010 8:35 pm
Forum: Valveless pulsejet forum
Topic: Just a thought
Replies: 4
Views: 1984

Re: Just a thought

this might be usefull for those people with thundercains, that suck to much air. :D
rather than sticing a sock in one of the intakes :lol:
you could restrict the flow of air on both intake equily :)
by paul fellows
Tue May 11, 2010 8:32 pm
Forum: Valveless pulsejet forum
Topic: Big Linear FWE for a Paying Client
Replies: 60
Views: 19707

RE THE DEATH RAY

I have being doing a bit of reading about thermoacoustics the last few days, :P
sound can 'carry' heat as a wave :?
at the front of a very intence sound wave the air is sudenly compressed, and when you compress a gas it gets hot 8)
by paul fellows
Thu May 06, 2010 10:30 pm
Forum: Valveless pulsejet forum
Topic: thermoacoustics?
Replies: 1
Views: 1427

thermoacoustics?

thermoacoustics? :? whilst looking for a better theory of pulse jets i trip over thermoacoustics? an odd combination of :? heat sound and resonators :D :lol: :twisted: :P :lol: :D sound :lol: famillier :D http://en.wikipedia.org/wiki/Thermoacoustics http://en.wikipedia.org/wiki/Thermoacoustic_hot_ai...
by paul fellows
Tue May 04, 2010 9:11 pm
Forum: Off topic forum
Topic: Did you listen? NoooOOOooo ...
Replies: 13
Views: 4378

Re: Did you listen? NoooOOOooo ...

In what way are pulse jet theorists like talking clocks? :? :? :?

If you have one
you can be certain about what time it is, :D
if you have two
you can be certain of nothing. :lol:
by paul fellows
Tue May 04, 2010 9:07 pm
Forum: Valveless pulsejet forum
Topic: origonal ???
Replies: 33
Views: 8467

A big mouthed thrust augmenter ???

A better thrust augmenter can be made by having the tailpipe of the pulse jet stick out just a little bit into a large chamber. This chamber and its associated outlet being a Helmholtz resonator tuned to the same frequency as the pulse jet. :) hr.jpg The area of the mouth of this resonator being bet...
by paul fellows
Sat May 01, 2010 7:51 pm
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Re: pulse jet theory V o.1

Joe what type of engine did you use, paticularly the 'loaded' one. :D number 4 Larry i'v just noticed that the lady Ann dose not have its intake and tailpipe on oposit sides of the of the combustion. i'm trying to pin down a theory for the simpler Lockwood type befor moving on to the more complex ty...
by paul fellows
Thu Apr 29, 2010 6:46 pm
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Re: pulse jet theory V o.1

Hi Joe (IMO?) :? it is an interesting idea, build pressure then release it in a controlled way. what I meant by fleshed out is how is the system controlled? :? It sound like you have built quite a few jets, :D do valveless engines sound higher pitched than a comparable sized valved engine. :?: Re th...
by paul fellows
Thu Apr 29, 2010 2:35 pm
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Re: pulse jet theory V o.1

imo :?

newbi :? :oops:

joe do you have a fleshed version of your theory anywhere?
by paul fellows
Thu Apr 29, 2010 12:11 pm
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Re: pulse jet theory V o.1

Keep in mind that the wavelength in the pulsejet and thje wavelength of the radiated noise will be vastly different, because of the temperature difference between the jet interior and the surrounding air. The frequency will be the same, of course. one posible way to test between th two theories :? ...
by paul fellows
Thu Apr 29, 2010 11:58 am
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Re: pulse jet theory V o.1

Hi Larry I'm afraid I'm not seeing three reversals (positive to negative and back) which of the of the four graphs should I be concentrating on. :( Possibly as you cut to the beat it got lessoned. :? Re the video may I suggest for next time, Norwegian wood is in three four tine. Or better still Souz...
by paul fellows
Wed Apr 28, 2010 7:20 pm
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Re: pulse jet theory V o.1

Hi I'm still looking at the animation. The reason I drew a full wave in the pipe, is that that is what I am talking about. A half wave resonator driven at its second harmonic. Picture this, a one meter long pipe stopped at one end will resonate as follows, first harmonic four meters in wavelength se...
by paul fellows
Mon Apr 26, 2010 10:56 pm
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Re: pulse jet theory V o.1

". Seeing them in this way does not invalidate also seeing the whole thing as a half-wave resonator IF you take into account that the antinode is NOT at the halfway point in the overall length..... This "asymmetry" can be clearly shown." an intreguing idea a half wave resonator, but of two very uneq...
by paul fellows
Mon Apr 26, 2010 9:44 pm
Forum: Valveless pulsejet forum
Topic: pulse jet theory V o.1
Replies: 28
Views: 9720

Compare the sound of a Lockwood to a valved pulse

I am not swearing that I am right but please think about this. :? As a half wave resonator being driven at its second harmonic, when the pressure at one quarter of the length from the intake is high, then the pressure three quarters of the length of the tube will be low. pjt1.jpg The gasses released...