Search found 987 matches

by CpTn_lAw
Fri May 27, 2016 7:34 am
Forum: Combustion Cannons
Topic: Noise cannon for RC planes
Replies: 162
Views: 17790

Re: Noise cannon for RC planes

Really nice work!

I was thinking... couldn't you come up with a geometry that allows preferably air from one side in the chamber?
I'll try to make a small drawing of what i'm thinking about right now. (whem i get back from work)
by CpTn_lAw
Wed May 18, 2016 1:18 pm
Forum: General How-To & Discussion
Topic: Is spudding dead?
Replies: 102
Views: 25498

Re: Is spudding dead?

Hey D_Hall, I tought I was done with spudding... but then I came to my senses again. I very recently built a homemade QEV piloted by industrial QEV air rifle. I machined my own nylon piston, and it is housed in a 3/4" brass tee, with a 18mm piston seat. The flow is outrageous, and there is almost no...
by CpTn_lAw
Sat Apr 30, 2016 12:50 pm
Forum: Pneumatic Cannons
Topic: ebay QEV thread size
Replies: 7
Views: 803

Re: ebay QEV thread size

Long time off the forums, Just to tell you I bought one from amazon, which is the same as those eBay ones. The one I received is a QE-04 rectangular black box type with a brass port for exhaust. I live in France as well, no problems with the thread size. It's the standard 1/2" (15x21mm) for both cha...
by CpTn_lAw
Tue Nov 05, 2013 3:29 pm
Forum: General How-To & Discussion
Topic: Fly-swatter Ignition
Replies: 12
Views: 2519

Re: Fly-swatter Ignition

I have been testing and taking pictures from the ignition system. I have replaced my casio EX-F1 with a Canon EOS 6D. Unfortunately, one of my lenses (a very old 28-70 mm) has broken a few weeks ago, beyond repair. So, there won't be any good quality videos until I buy a new wider angle lens. I'm st...
by CpTn_lAw
Wed Oct 30, 2013 8:16 am
Forum: General How-To & Discussion
Topic: Fly-swatter Ignition
Replies: 12
Views: 2519

Re: Fly-swatter Ignition

Oh yeah... that happens to me all the time... :D You should have seen the face on my intership superiors when I played Muse in a Xenon UV arc lamp :D That was like a very bright blue-ish white arc in a sealed glass bulb, and electric guitar screaming its way out :D (I must say i was getting close to...
by CpTn_lAw
Wed Oct 30, 2013 5:08 am
Forum: General How-To & Discussion
Topic: Fly-swatter Ignition
Replies: 12
Views: 2519

Re: Fly-swatter Ignition

You got a semi? Didn't get that one. I have a few 4007 diodes from the plasma speaker circuit. I could have just built a simple 2n3055 + flyback igniter... but I already knew it worked so I wanted to try something else. I just did a blank fire with a simple alimentary film burst disc. I forgot how l...
by CpTn_lAw
Wed Oct 30, 2013 4:40 am
Forum: General How-To & Discussion
Topic: Fly-swatter Ignition
Replies: 12
Views: 2519

Re: Fly-swatter Ignition

Mark that's exactly how it works. However, i don't have an ignition coil in hand right now, I only have two flyback transformer i used to build a plasma speaker. I tried to hook them up to the flyswatter and well, it works, but i get a 4 inch spark and i get a little shock every time. The electric f...
by CpTn_lAw
Tue Oct 29, 2013 10:53 am
Forum: General How-To & Discussion
Topic: Fly-swatter Ignition
Replies: 12
Views: 2519

Fly-swatter Ignition

Hey there, Been doing some spudgunning these days. So I took the old combustion out, and saw it needed another ignition since the previous one was missing. This topic is about what I did to build this new ignition system . The very simple idea behind this is "2kV from two 10nF capacitors in parallel...
by CpTn_lAw
Fri Dec 14, 2012 3:08 pm
Forum: Hybrid Cannons
Topic: Semi Auto Cartridge Hybrid Build Log (Lotsa pics)
Replies: 30
Views: 5661

Haha :D Nice job here. However, if I may...do some positive criticism :D It's ingenious. But it could be more. ==> It seems like it has too many parts to me. And in general, too many parts = too many failure possibilities. I like the idea of a mechanical/ electrical hybrid. But in my opinion, you co...
by CpTn_lAw
Mon Jul 09, 2012 12:09 pm
Forum: Combustion Cannons
Topic: cd cannon
Replies: 6
Views: 1141

I was thinking about a design... Unless you fire at very low velocities, that looks like it will destroy itself pretty quickly... I wouldn't be too sure about that. Some sort of damping for the piston at the end of its travel down the primary barrel could potentialy reduce wear of the pieces.I'm th...
by CpTn_lAw
Mon Jul 09, 2012 9:50 am
Forum: Combustion Cannons
Topic: cd cannon
Replies: 6
Views: 1141

I was thinking about a design... I don't think anyone made it, and I haven't drawn any design yet, it's in my brains. But let me explain... A pneumatic ram, clamping the disc from both under and above with free rotational motion. One side of the "barrel" would be something rubbery, the other side wo...
by CpTn_lAw
Wed Jun 27, 2012 5:24 am
Forum: Off-Topic Hobbies
Topic: Hybrid Rocket Engine Tests
Replies: 24
Views: 1732

That would be 0.05 bar absolute since I used the formula putting in relation the distance between Mach diamonds (1,7 cm) , nozzle diameter (6 mm), atmospheric pressure (101300 Pa) and the flame pressure, that would be 5820 Pa. These numbers seem correct if I put them in the exhaust velocity equation...
by CpTn_lAw
Tue Jun 26, 2012 7:41 am
Forum: Off-Topic Hobbies
Topic: Hybrid Rocket Engine Tests
Replies: 24
Views: 1732

In fact that's a very good question... The oxygen pressure has to be higher than the combustion chamber pressure. However, using a bigger diameter valve from the oxygen line and a small diameter injector might solve my oscillations problem. Plus, on the regulator i've installed a flash-back arrestor...
by CpTn_lAw
Tue Jun 26, 2012 3:31 am
Forum: Off-Topic Hobbies
Topic: Hybrid Rocket Engine Tests
Replies: 24
Views: 1732

@D_Hall : The outer shell of the nozzle is way bigger than the inner diameter. So it appears as the exhaust is not filling the nozzle, but it is, the inside diameter is close to 9mm at exhaust. @Ramses: My camera (casio exilim EX-F1) is not good in dark areas... It is grainy even at 100 ISO. The fi...
by CpTn_lAw
Sat Jun 23, 2012 4:54 pm
Forum: Off-Topic Hobbies
Topic: Hybrid Rocket Engine Tests
Replies: 24
Views: 1732

News pics from tests...
Enjoy
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EDIT

New pics from today's test:
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