black powder competition

[Algenco]

I put together a short version of Dan's test chronograph using the angle iron and triggered it to time a 12" burn via a stopwatch. I'm not sure anymore which thread it's in but somewhere here in the APC forums there are videos of some burn tests.

 

I want one

[Bobosan]

That's one of the first projects once I get the new workbench squared away. Still haven't got test equipment installed or rest of the parts bins situated but it's getting close.

Edited February 18, 2013 by Bobosan

[shouldnoteatindat]

is it two late for me to enter this competition?

[bob]

is it two late for me to enter this competition?

There currently is not any black powder competition. However if you want to know how your bp compares with other people's just post a video of it burning and we will be happy to say if it's good, bad, or ugly.

bob

[Bobosan]

<bump>

 

After months of procrastination and just other more important stuff to do, I finally finished and tested version 3 of my BP/Fuse burn speed chronograph. The black timer box will eventually be replaced with a sports stopwatch as used in version 1 shown in above post. Operation is identical to the vids in this thread http://www.amateurpyro.com/forums/topic/9064-charcoal-charcoal-charcoal/ but instead of mechanical start/stop trips, version 3 uses flame sensors looking through Pyrex windows and is much easier to prep for repeated testing.

 

Edited August 24, 2014 by Bobosan

[Peret]

This is ok - sort of - for comparison tests, but it doesn't really tell you what you need to know. BP burns differently at atmospheric pressure and when confined, at different speeds and with different reaction products. If you need to know if it's good lift, the best way to do it is by, you know, lifting something. Golf balls are traditional, so are baseballs in a 3 inch mortar.

 

There were a few traditional ways to test BP. One was the "eprouvette", which looked a bit like a small flint lock pistol. The end of the barrel was covered by a small plate that rotated out of the way on a spring loaded ratchet. You loaded up with powder but no ball, moved the plate to cover the barrel and fired. The force of the escaping gas pushed the plate round on the ratchet against the spring, and you estimated the power by how far it moved. Another tester used a gun barrel hung horizontally from the end of a pendulum. The recoil swung the pendulum back and again, how far it went depended on the powder quality. For a direct reading of projectile speed, they would fire a test projectile so that it hit and broke thin copper wires various distances in front of the barrel, the time difference giving the speed. That last method strikes me as do-able by an amateur, for example firing a golf ball from a horizontal fiberglass mortar into a nest of sandbags. The time delay between breaking wires (say) 1 foot apart would be easily measurable with simple electronics. Given the speed, and knowing the weight of the ball, you could calculate back to the chamber pressure and get a really good idea of how the powder would perform under a shell.

[Bobosan]

Peret,

 

Agreed and as you pointed out, for simple comparative tests of BP and fuse. It won't replace or substitute for the methods described in your post above. Ultimately, it will have a processor and sensors to record and store environmental information such as temp and humidity. Baseball, golfball and PVC shuttle are prone to human timing error. If you really want to do lift height testing, you get an altitude sensor/recorder and fire a dummy shell with the sensor contained within. The rocketry folks use such a sensor to record altitude.