Search found 613 matches

by pezman
Fri Nov 26, 2004 6:40 am
Forum: Tools and Construction
Topic: Schlieren photography
Replies: 2
Views: 1893

Schlieren photography

This might be a good design tool if coupled with the MAPP pulse generator. I think that you could make test parts out of plexiglas, visualize flows and refine the part. By making subtractive images (i.e. subtract a Schlieren image of a part without flow form a part with flow), you can eliminate the ...
by pezman
Thu Nov 25, 2004 3:40 am
Forum: Valveless pulsejet forum
Topic: High compression demo
Replies: 2
Views: 1927

Re: High compression demo

Sorry, had a problem uploading. Here's a link to the file.

http://home.comcast.net/~mike_hogan/mapp_demo.MOV

The film doesn't come close to demonstrating the kick this thing has.
by pezman
Wed Nov 24, 2004 8:12 pm
Forum: Valveless pulsejet forum
Topic: High compression demo
Replies: 2
Views: 1927

Re: High compression demo

Here's a small film. The device is a 1' section of 1/2" pipe joined to several sections of 1" pipe (12", 10" and 12") joined with elbow fittings. I ran MAPP into the device for about 6 seconds and then set off the ignition spark. At bout the 7 second mark, you can see the device blast a lid from a s...
by pezman
Wed Nov 24, 2004 2:56 am
Forum: Tools and Construction
Topic: Pulse generator for testing flow
Replies: 8
Views: 3258

Re: Pulse generator for testing flow

I did a little playing around with it. If the flame is held a few cm from the pipe, you get a shrill whistle. With the head a few inches into the tube, you can get a pulsing effect, kind of like what you are describing. I was thinking if it as a kind of quick and dirty Gluey. I didn't experiment wit...
by pezman
Wed Nov 24, 2004 2:49 am
Forum: Valveless pulsejet forum
Topic: High compression demo
Replies: 2
Views: 1927

High compression demo

Using the Berz-o-matic pulse generator , I was able to test some geometries for a high-compression prototype. Basically, I ran some propane into some structures of various geometry, pointed the pulse generator into the mouth and pulled the trigger. In a few cases, the resulting concussion was impres...
by pezman
Tue Nov 23, 2004 11:56 pm
Forum: Off topic forum
Topic: Something That Might Sell
Replies: 106
Views: 43657

Re: Something That Might Sell

I think I'd like to buy one, though I didn't notice the price. Also, it would be cool if there was an option for folks ordering the calendar to kick in a few extra bucks for the forum. I I want to support the forum, but I just don't trust PayPal (irrational maybe) and getting an international money ...
by pezman
Tue Nov 23, 2004 4:51 pm
Forum: Tools and Construction
Topic: Pulse generator for testing flow
Replies: 8
Views: 3258

Re: Pulse generator for testing flow

Thanks for the flowers! As far as conditioning the pulses is concerned, the pipe geometry seems to be key. This is just a qualitative judgement based on the sound of the impulse -- maybe not the best way to go based on the fact that hearing is log-normal ;). You can get a manifold pressure sensor at...
by pezman
Tue Nov 23, 2004 1:31 am
Forum: Tools and Construction
Topic: Pulse generator for testing flow
Replies: 8
Views: 3258

Pulse generator for testing flow

I think that Bruce Simpson's DIY Gasflow Modeling Rig is pure genius, but I was interested in coming up with a way to test how parts will respond to a pulse -- things behave differently at hight tempertures, pressures and speeds. I came up with a trick that might be useful. If you take a Bernz-o-mat...
by pezman
Tue Nov 23, 2004 12:56 am
Forum: Tools and Construction
Topic: Cheap "Ready to use" ignition!
Replies: 1
Views: 2354

Re: Cheap "Ready to use" ignition!

Not bad!

I just bought a cheap bug-zapper at Wal-Mart for the same purpose, but I like your solution better.
by pezman
Sun Nov 21, 2004 8:04 am
Forum: Tools and Construction
Topic: Check valve
Replies: 17
Views: 8873

Re: Check valve

Air-amps move about 18 times as much air as they consume, so I think that the adverse effects from scavenging would be negligible. Also, if you use fuel mist instead of air, you can kill two birds with one stone -- plus I think that the fuel mist will be even better then air at inducing flow due to ...
by pezman
Sun Nov 21, 2004 7:13 am
Forum: Tools and Construction
Topic: Check valve
Replies: 17
Views: 8873

Re: Check valve

I bought a small container for handsoap at Walmart yesterday because it was spun stainless with an interesting shape. At any rate, in the process of tearing it apart, I found that it has a small glass ball that was part of a check valve. I'm guessing it was glass, but it could be synthetic sapphire ...
by pezman
Sat Nov 20, 2004 12:24 am
Forum: Valveless pulsejet forum
Topic: Propane, liquid form vs vapor
Replies: 4
Views: 1734

Re: Propane, liquid form vs vapor

Thanks, great tips as usual. I think I'll try the Bernz-o-matic hack first since I'm starting small. I'll post photos once the prototype evolves a little bit. Right now it's hacked together using black pipe etc. Already learned a thing or two about dimensions of components, fuel delivery etc. The pr...
by pezman
Fri Nov 19, 2004 10:57 pm
Forum: Valveless pulsejet forum
Topic: Propane, liquid form vs vapor
Replies: 4
Views: 1734

Propane, liquid form vs vapor

I was experimenting with a high-compression valveless design. Very cranky, but occasionally it will sputter to life with a spectacular series of pops that build until they blow the flame out. At any rate, I was having a hard time determining why it was sometimes anemic and sometimes a tiger. Finally...
by pezman
Mon Nov 08, 2004 10:35 pm
Forum: Valveless pulsejet forum
Topic: Interesting valveless patent
Replies: 6
Views: 2076

Re: Interesting valveless patent

I've spent about a half hour so far reading through it and labeling the figures. It does not seem to be a valveless design -- the things labeled 45 are check-valves and the thing labeled 49 is an "optional bypass check-valve". At this point, I think that I understand pretty well how the thing is put...
by pezman
Sat Oct 23, 2004 4:10 pm
Forum: Tools and Construction
Topic: tapering tubes?
Replies: 11
Views: 4627

Re: tapering tubes?

lol

I'm glad I asked the question - not only got an answer, but the thread has taken such an interesting turn