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by jackssmirkingrevenge
Sat May 30, 2020 4:20 am
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Re: QEV blowback mod?

On a small scale it's not worth having a piloted exhaust valve, the hammer can open your main valve directly:

Image

by jackssmirkingrevenge
Mon Aug 21, 2017 8:01 pm
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Re: Small semi automatic hybrid project

An ambitious project but having seen what you're made so far, I believe you can pull it off :)

Seems a bit wasteful of propane though, I don't think you want to be firing this thing in an enclosed space...
by jackssmirkingrevenge
Sun Jun 07, 2020 6:46 am
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Modern cellphone cameras and recording ballistic tests

Technology has come some way since the "lazor" era of my Nokia Prism over a decade ago. I had a play with the Slow Motion and Super Slow-Mo modes on my Galaxy S9: https://youtu.be/Z_6Tnh5XUq8 The projectile was a 0.25g airsoft BB at high subsonic velocity. The Super Slow-Mo is particularly interesti...
by jackssmirkingrevenge
Mon Jun 08, 2020 5:33 am
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Re: Modern cellphone cameras and recording ballistic tests

squib wrote:
Sun Jun 07, 2020 7:03 pm
Look out Taofledermaus :D
Jeff is already familiar with my work ;)
by jackssmirkingrevenge
Wed Nov 09, 2011 1:00 pm
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machined APFSDS projectiles

I've been having a play with milled collars to turn small masonry nails into stable darts without any modification of the nail itself. In 6mm calibre, a simple airsoft BB serves as a sabot. Some test firing at 15 metres shows that the projectile is stable and even fired from a low powered small 300 ...
by jackssmirkingrevenge
Tue Jun 09, 2020 6:41 am
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Re: New to this all

Welcome to spudfiles! what is the purpose of a fan in the combustion chamber When the fuel and air are properly mixed, this will boost performance and consistency. That being said, adding a fan is not going to double your power. what is hgdt I have seen it quite a lot in older stuff from like 2010 a...
by jackssmirkingrevenge
Fri Jun 12, 2020 3:39 am
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Re: HA-VI

Re-hosted the image so it appears animated in the thread:

Image

A simple idea but at the same time complex in its execution... it looks like it should work!
by jackssmirkingrevenge
Fri Jun 12, 2020 3:35 am
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Re: Port size vs performance

I think your reasoning is spot on.

Port size and opening time are what determine the rate at which pressure rises behind the projectile.

That rate of pressure increase is not linear vis a vis the port size so it reaches a point where the advantage of making it any bigger is minimal.
by jackssmirkingrevenge
Wed Jun 10, 2020 7:01 am
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Re: Short question topic

Any one could tell me whats these holes on the baffle are for? Like why isn't the hole/cut mirrored? Wouldn't' it cause non uniform turbulence? My understanding is that the turbulence increases the effect. These ports are commonly known as "mouse holes" and introduce what is essentially an angled j...
by jackssmirkingrevenge
Fri Jun 12, 2020 5:45 am
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Re: Browning Airstar 200

I have often wondered why the electric airsoft guns didn't use a sear. It would give the trigger a more realistic feel, completing the firing cycle rather than starting it, and would allow better reduction through the gears so a weaker motor could be used. It would add more complexity to an already...
by jackssmirkingrevenge
Fri Jun 12, 2020 5:49 am
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Re: Hgdt and comp programs

Replied to your other thread but here it is again for reference: download/file.php?id=28593
by jackssmirkingrevenge
Sat Jun 13, 2020 5:22 pm
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Re: Short question topic

I feel that such losses are probably not that significant. Pistons typically have a large surface so they do not require a high pressure to move. Added to that, their travel is usually very limited so the increase in chamber volume relative to the total is minimal.
by jackssmirkingrevenge
Fri Jun 19, 2020 6:30 pm
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Re: Pull Trigger, loads, then releases chamber?

Here is one working:



Looks like it is basically the same concept as a NBB airsoft gun.

A double action trigger seals the chamber and then knocks open a valve poppet.