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Posted: Sat May 19, 2012 12:23 pm
by jackssmirkingrevenge
Labtecpower wrote:And about the rich mixture, what kind of performance increase is to be expected if you put a slighly richer (I have no idea about concentrations) mix in a butane-air hybrid?
I doubt you would see an increase...

Posted: Sat May 19, 2012 12:38 pm
by DYI
what velocity and energy figures are you expecting?

And about the rich mixture, what kind of performance increase is to be expected if you put a slighly richer (I have no idea about concentrations) mix in a butane-air hybrid?

seems a bit like a piece-of-string question to me, hope this is clear

I have tried gaseq, but I can't get it to work right
This build is similar to HyGaC20, but only capable of 12000psi or so and with a smaller bore. The aim is to explore whether the theoretical advantages of the rich mixes play out in practice.

A slightly rich mix will perform slightly better for butane/air, as is the case for any hydrocarbon fuel I'm aware of, but as Jack mentioned, you're unlikely to notice a difference because of the very large percentage of nitrogen present (which, as you're probably aware, is an AWFUL buffer gas in terms of SOS, pressure generation, and barrel life).

However, there's still a tangible advantage to running slightly "rich"; you'll be aiming closer to the center of the flammable range, and thus less prone to failures to ignite or running lean mixes (which are useful for nothing except for incinerating your sealing faces...).

Posted: Sat May 19, 2012 3:05 pm
by Labtecpower
only capable of 12000psi or so
:roll:

any rough guess on how much it would improve performance in your case?
A slightly rich mix will perform slightly better for butane/air, as is the case for any hydrocarbon fuel I'm aware of, but as Jack mentioned, you're unlikely to notice a difference because of the very large percentage of nitrogen present (which, as you're probably aware, is an AWFUL buffer gas in terms of SOS, pressure generation, and barrel life).
but the reaction products will have a less water vapour and carbon dioxide, and more carbon monoxide and hydrogen in them,( as you stated) so there will still be a slight win, and if it doesn't increase the performance, it won't hurt I think :D

which are useful for nothing except for incinerating your sealing faces...
no problem for me, I don't have any sealing faces exposed to the deflagration :P

Posted: Sun Jun 17, 2012 3:43 am
by jackssmirkingrevenge

Posted: Sun Jul 08, 2012 1:37 am
by Solar
Image

I recently acquired a Fastec Troubleshooter HR. This was taken at 4000 frames per second. The rigid fin/foam nose projectile is traveling at 250 fps. The camera outputs avi files between 1280x1024 down to 1280x32 at 16000 frames per second. This shot is 1280x128.

If anyone can recommend a good video codec to use with resolutions like this I will upload some to youtube/here. I think I need to use a 4x3 letterbox format to save something that can be uploaded easily with a decent quality.

We will be doing extensive testing with a number of different rounds this week. I will post what I can here.

Posted: Mon Jul 09, 2012 8:21 pm
by ramses
I like xvid as a codec, but it is apparently obsolete. You could probably upload the avi right from the camera, unless its uncompressed.

I think you mean you need editing software. I think youtube will letterbox if for you. Windows movie maker for win xp will not deal with weird aspect ratios.

Posted: Mon Jul 09, 2012 11:34 pm
by Solar
I have Newtek's SpeedEdit so I have options for sure. I will get something to work soon. Tomorrow we are starting to record some various ammos with the camera and a chrono. I find it interesting that instead of telling the camera to start and stop, it is constantly recording and the trigger just gives a cue as to what segment it will send out to the CF card. At 4000 frames per second we got 40 minutes of video by simply taking two shots back to back and triggering in the traditional way.

Posted: Tue Jul 10, 2012 12:06 am
by jackssmirkingrevenge
Sweet, looking forward to these! Make sure you get some good impact shots :)

Posted: Tue Jul 17, 2012 3:20 pm
by jackssmirkingrevenge
[youtube][/youtube]

Pretty awesome 3D animation and high speed footage side by side...

Posted: Thu Jul 19, 2012 4:54 pm
by Solar
[youtube][/youtube]

Testing the equipment. More recording tonight, but still prepping the range.

Posted: Thu Jul 19, 2012 10:52 pm
by Solar
[youtube][/youtube]


This is framed better. The metal halide light will need to be replaced with something that gives us a more consistent light.

Posted: Fri Jul 20, 2012 1:15 am
by jackssmirkingrevenge
Nice, looking forward to more! What's with the "strobe" effect though, are you using fluorescent lighting?

Posted: Fri Jul 20, 2012 2:19 am
by Solar
[youtube][/youtube]

Posted: Fri Jul 20, 2012 2:22 am
by Solar
We are using a metal halide lamp and the camera picks up the cycle at various speeds. We are still learning how to operate the software and camera. I am using Midas OS for camera control.

Posted: Fri Jul 20, 2012 3:17 am
by Larda
Large halogen light usually works better , but with the drawback that you will need about 4 time the wattage because of the halogen lights lower efficiency. :)
Another way could be to run the from a 3-phase connection, and connect one lamp to each phase.
That will give you a much more steady light.

Image