Search found 95 matches

by Bruce
Fri Jul 23, 2004 9:23 am
Forum: Valveless pulsejet forum
Topic: Another jet kart
Replies: 35
Views: 14937

AAAAAAAAAAAAAAHHHHHHHHHHHHH!!!!!!!! as you can see the kart is powered by two IDENTICAL lockwoods. The first one worked perfectly when I tested it so I decided to make another one for additional power on the kart. Unfortunately my seccond engine WILL. NOT. SUSTAIN. It pulsates (barely) when startin...
by Bruce
Tue Dec 09, 2003 9:24 am
Forum: Valveless pulsejet forum
Topic: Worlds simplest valveless?
Replies: 145
Views: 75846

I don't see how they avoid massive polution of the incoming air charge (especially at low speeds) with this set-up.

I'm sure it will have worked, but whether it offered any real benefit over a single engine is something I wouldn't bet on.
by Bruce
Tue Dec 09, 2003 3:04 am
Forum: Pressure jet forum
Topic: Gluhareff 130R power failure issue still open ... Any Idear?
Replies: 583
Views: 225693

Here's an interesting mental exercise for those reading. In the setup described -- using the heat of the flame to vaporize the propane, will the pressure of the gas exiting the copper tube exceed the pressure inside the tank and, if so, will that pressure be appreciably higher, and if so, will it be...
by Bruce
Tue Dec 09, 2003 3:00 am
Forum: Valveless pulsejet forum
Topic: To Bruce Simpson
Replies: 2
Views: 2465

I checked my email log and my reply to you with the book details appears to have bounced. Can you send a message through the contact form on my website at http://aardvark.co.nz/contact just so that I'm sure I've got the address dead right?
by Bruce
Mon Dec 08, 2003 11:11 pm
Forum: Pressure jet forum
Topic: Gluhareff 130R power failure issue still open ... Any Idear?
Replies: 583
Views: 225693

Firstly you say: >As for using a Pulse jet, I would > say on that, that our first > engine was a pulsejet. The > problem is that our machine is > design to word under very cold > temperature. And what happen to > gas propane in at very cold > temperature? That it, no more > evaporation and pressure....
by Bruce
Mon Dec 08, 2003 11:00 pm
Forum: Valveless pulsejet forum
Topic: Worlds simplest valveless?
Replies: 145
Views: 75846

For those who have trouble seeing how an apparently non-sinsoidal waveform can indeed contain a sinsodial component, this page is excellent: http://www.clubi.ie/amhiggins/fourier1.html Note how a sawtooth waveform is built from a fundemental (sine wave) plus harmonics. What an FFT does is calculate ...
by Bruce
Mon Dec 08, 2003 4:35 am
Forum: Valved pulsejet forum
Topic: V-1 Video
Replies: 64
Views: 31411

Yes, but the O-Rays are useless on their own as they tend to cancel each other out. It was for this reason that the Germans also came up with the highly impenitrable partition (HIP for short. However, a single HIP was insufficnet and would soon be broken down by the O-Rays. Eventually they found tha...
by Bruce
Sun Dec 07, 2003 10:16 pm
Forum: Valveless pulsejet forum
Topic: Worlds simplest valveless?
Replies: 145
Views: 75846

Mike said: > I was excited there for a minute, > Bill. I'm not sure a straight > pipe will get you a sine output. > I'm looking at the Schmidt > paper's pressure trace and it's > ugly, and I believe it was a > straight pipe. However, it is a > valve type Someone who's got more time than me could alw...
by Bruce
Sun Dec 07, 2003 9:48 pm
Forum: Valveless pulsejet forum
Topic: Worlds simplest valveless?
Replies: 145
Views: 75846

> People somehow imagine that
> increased frequency will increase
> power. THIS IS NOT TRUE

Correct -- I believe that one of Tharrat's papers explains this also.
by Bruce
Sun Dec 07, 2003 12:08 pm
Forum: Valveless pulsejet forum
Topic: Worlds simplest valveless?
Replies: 145
Views: 75846

I seem to recall that Lockwood himself used linked combustors to secure a phase relationship between the multiple engines he used in his "lift packs" that consisted of multiple engines with augmentors.
by Bruce
Sun Dec 07, 2003 12:04 pm
Forum: Valved pulsejet forum
Topic: Luftwaffe strikes again
Replies: 6
Views: 3875

Don't forget that if the airframe is vibrating, those vibrations will create their own pressure waves inside the structure and cockpit. Pressure-waves create vibration, vibraiton creates pressure waves. The difference between a vibration and a pressure wave could (loosely) be simply a matter of whet...
by Bruce
Sun Dec 07, 2003 6:15 am
Forum: Valveless pulsejet forum
Topic: Worlds simplest valveless?
Replies: 145
Views: 75846

Hey, anyone who knows what a fourier transformation is will understand what you're saying and agree with it.

Those that don't ought to go do some reading -- in theory it's pretty simple, although the math can be challenging if you're a bit rusty.
by Bruce
Sun Dec 07, 2003 6:11 am
Forum: Valved pulsejet forum
Topic: V-1 Video
Replies: 64
Views: 31411

They may not vibrate sinsoudally, but they do vibrate. just do the math: Take an engine like the V1 with a 20-inch tailpipe. That's a cross-sectional area of 314 square inches. Now assume that we have peak combustion pressures (as you quote) of 23psi and minimum pressures (as you quote) of 9psi. Let...
by Bruce
Sun Dec 07, 2003 1:22 am
Forum: Valveless pulsejet forum
Topic: Worlds simplest valveless?
Replies: 145
Views: 75846

The noise issue is a vexing one, and one which I'm presently looking very closely at. However, what most people forget is that aircraft, no matter what form of propulsion they use, are very noisy devices. You can hear a Huey coming from miles away because of the slap of its rotors. Something as anci...
by Bruce
Sun Dec 07, 2003 1:08 am
Forum: Valved pulsejet forum
Topic: V-1 Video
Replies: 64
Views: 31411

Mike said: > You guys are arguing semantics in > my opinion, there is no acoustics > without vibrations and > vice-versa! The poor empenage on > this plane must have shaken right > off from the vibration excited by > the pressure waves. It does not > matter how well you shock mount > the engine to t...