Hi all,
I'm new to this community but an electronics engineer and would offer to help
if that's useful...
Thanks,
Mark
On Jul 25, 2016, at 12:43, James Dougherty <jafrado@xxxxxxxxx> wrote:
Hey Richard
Nice work! Would love to give it a shot with some calibrated altimeters ...
Maybe bring it to Roctober?
Thanks
-James
Sent from my iPhone
On Jul 23, 2016, at 4:27 PM, R Dierking <applerocketry@xxxxxxxxxxx> wrote:
This is a follow-up on an earlier post on creating a vacuum chamber for
testing altimeters and other rocket-related equipment. I’ve attached a
photo of the chamber that measures 3” square and 12” long.
Mike Kramer suggested that I make a smaller test version to work out
potential bugs, and it turned out that cutting the grooves in the 1 ¼”
polycarbonate ends for the o-ring seals was more difficult than imagined.
Also, it took a couple tries to create electrical connections through the
end to connect a switch. Unfortunately, the 2nd stage on the vacuum pump
isn’t getting as low as specification. I’m still working on that, but so
far achieved about 29 ½” of vacuum *. I tested a PerfectFlite SL-100 a
couple times and it recorded about 102,000’. So, I think that’s adequate
for awhile. 😊
The next chamber will be 6” square and about 40” long to accommodate the
upper half of a rocket I’m working on.
This vacuum chamber project has been kind of a distraction to my L-3
project, but I’m still glad for the time spent. Always fun building
something different and learning more about atmospheric pressure for amateur
rocketry.
Richard Dierking
* There are many different ways to denote atmospheric pressure such as PSIA,
Inches Hg, Torr, mbar, and microns. A Torr is 1/760 atmospheric pressure
and there’s about 1 Torr at 150,000’. I have an inexpensive (aka cheap)
vacuum gauge so it’s really only good for low vacuum.
<Test Chamber.JPG>
