Search found 128 matches

by Dave_G
Thu Oct 19, 2006 3:50 am
Forum: Off topic forum
Topic: dave's corner
Replies: 19
Views: 7872

dave's corner

My previous, immature comments have been redacted by request of our most wise and munificent moderators. Mike, you've denied that these jibes have been aimed at Bill or myself. There's your admission of guilt right there, in that it was made subsequent to Bill's post, which you've already deleted, ...
by Dave_G
Wed Oct 18, 2006 12:41 am
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

Re: re: Spherical Combustion Chamber

[quote="Mark Seems like the side port should tolerate a little curvature to throw the air in the same direction as the main exhaust. [/quote] Good point, Mark. I would think it (a bent or curved inlet) would work as well on this engine as it does on the Chinese. A Chinese with a spherical combustor?...
by Dave_G
Tue Oct 17, 2006 7:30 pm
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

Re: re: Spherical Combustion Chamber

Too short, but I'll have to remember that one for other things. I want to map the entire length of the motor from up the tail, so need more than a metre. I'm thinking multi-walls and water or air cooling, but want to keep it small diameter. Hmmm, not super easy, to be sure. Mike, Sorry. I assumed y...
by Dave_G
Tue Oct 17, 2006 6:49 pm
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

Re: re: Spherical Combustion Chamber

Yeah. I've been designing a cooled probe stinger for my future data acquisition rig. Thinking of running it in and out with a linear stage so I can plot avg pressure vs. position pretty accurately. Mike, That's a great idea! Use a ceramic tube like this one: http://www.mcmaster.com/itm/find.ASP?tab...
by Dave_G
Tue Oct 17, 2006 5:29 pm
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

Re: re: Spherical Combustion Chamber

That is absolutely wild. Can't wait to hear it! I have to wonder if the center of the sphere becomes acoustically significant. I would expect so. Yeah Mike, it would be interesting to put a pressure tap directly in the center, wouldn't it? Or even map the pressure field across the entire section.
by Dave_G
Tue Oct 17, 2006 5:26 pm
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

re: Spherical Combustion Chamber

Hey Mr. B,

I just found your other thread here:

http://www.pulse-jets.com/phpbb2/viewto ... ght=#35963

So, 320 mm diameter, and not thrust-measured yet?

Maybe that Spezial Kommando has a fondness for doughnuts, or something? ;-)
by Dave_G
Tue Oct 17, 2006 5:10 pm
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

re: Spherical Combustion Chamber

Beautiful work, Mr. B!

Am I correct that on the Big Chamber version you built the Combustion chamber is about 250mm diameter?

Yes, please do post a sound (or better yet, video) file, I'd love to hear it running!

How much thrust do you get out of the large version?

Best regards,

Dave
by Dave_G
Tue Oct 17, 2006 3:53 am
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

re: Spherical Combustion Chamber

Here's a better view of the profile.
by Dave_G
Tue Oct 17, 2006 3:37 am
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

Re: re: Spherical Combustion Chamber

Was it a bong in a past life..... Ha Ha, I don't know...it's certainly a strange looking critter, though! As long as the tailpipe is, I find it odd that they didn't give it a slight curve so that the thrust vectors from both inlet and exhaust were parallel. The longitudinal axis of the inlet is ang...
by Dave_G
Tue Oct 17, 2006 1:23 am
Forum: Valveless pulsejet forum
Topic: Spherical Combustion Chamber
Replies: 23
Views: 8538

Spherical Combustion Chamber

Here's a cute little motor that was recently given to me. It's never been run. It's very nicely constructed and the welds are beautiful. Quite an interesting little motor, and very simple construction.
by Dave_G
Thu Sep 28, 2006 3:40 am
Forum: Valveless pulsejet forum
Topic: help i need help
Replies: 9
Views: 4411

re: help i need help

Hi Again, Lucky, I just watched your video again and the most valuable advice I can give you, bar none, is WEAR GLOVES when you do that!! Seriously, never let any exposed skin to be in front of the intake or exhaust, or even close enough to the engine that an enveloping fireball can contact it. You ...
by Dave_G
Thu Sep 28, 2006 3:10 am
Forum: Valveless pulsejet forum
Topic: New APC Motor #1
Replies: 11
Views: 6037

re: New APC Motor #1

Bill, Very nice test report! It's nice to read such a concise yet detailed account of a motor test. Also, very nice execution of the motor itself. I especially like your use of reinforcing rings to help form and support the tapered sections. The motor itself looks very well built. Congratulations on...
by Dave_G
Thu Sep 28, 2006 2:57 am
Forum: Valveless pulsejet forum
Topic: help i need help
Replies: 9
Views: 4411

re: help i need help

Hi Lucky (Got a real name?): Definitely not enough fuel, and not injected with high enough pressure. For your very first experiments try a single injection orifice about 0.5mm diameter. Use a pressure gage on your fuel line and make sure you can get 20 to 100 psi forepressure to your injector. This ...
by Dave_G
Fri Sep 15, 2006 7:19 am
Forum: Valveless pulsejet forum
Topic: APC news 13 August '06
Replies: 17
Views: 7313

re: APC news 13 August '06

Very nice work, Bill. 12 lbs of thrust in a motor of this size is not to be taken lightly -- it's quite good. It's approximately 86% of theoretical, or so I'm told. By way of comparison, the 'fully-optimized' Mini-Kenny only put out 36% of its theoretical potential. I also applaud your honesty. You'...
by Dave_G
Tue Sep 12, 2006 5:04 am
Forum: Valveless pulsejet forum
Topic: Uflow assisted PJ design
Replies: 13
Views: 5588

re: Uflow assisted PJ design

Thanks Bill!

I'll experiment with a few changes and see what I can do to improve it.