[sugpro] Re: Verifying Motor Performance Through Flight Tests
- From: "Andrej Vrbec" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "andre09091978@xxxxxxxxx" for DMARC)
- To: "sugpro@xxxxxxxxxxxxx" <sugpro@xxxxxxxxxxxxx>
- Date: Tue, 24 Feb 2015 07:53:06 +0000 (UTC)
Air density was routinely measured in 50's and 60's by a falling sphere method.
See here for example:
http://deepblue.lib.umich.edu/bitstream/handle/2027.42/70398/JAPIAU-27-7-706-1.pdf?sequence=2&isAllowed=y
Andrej
From: "shawn.mchatten@xxxxxxxxxxx" <shawn.mchatten@xxxxxxxxxxx>
To: sugpro@xxxxxxxxxxxxx
Sent: Monday, February 23, 2015 11:47 PM
Subject: [sugpro] Re: Verifying Motor Performance Through Flight Tests
Hahaha! I think I got it. Although.... do we really need humidity, temp and
pressure or are they all just variables to give us air density which is what we
really want. And if there was some way to measure air density directly would
that not be more helpful. One way to measure viscosity is to drop an object of
"standard" mass and shape through the substance and measure the rate of
descent. So if we flew a rocket to 500m and pitched a 10cm/500g cube out the
side with a 50cm square chute (or whatever other "standard" object we can make
up) and measure it's descent would that not be all the data we need to measure
air resistance directly. It's just a matter of making an easily repeatable
standard. Maybe a tube or sphere instead of cube and streamer instead of
parachute.
Shawn
On 2015-02-23 16:27, Michael Monteith wrote:> Com on. Keep up. lol It's really
just figuring out what it would> take to determine motor performance> through
actually flight testing. I do like your idea though. Just> measure things like
temperature,> humidity, and pressure on the way down so you can correct for air
density. > > Thanks Shawn> Michael>
--------------------------------------------> On Mon, 2/23/15,
shawn.mchatten@xxxxxxxxxxx <shawn.mchatten@xxxxxxxxxxx> wrote:> > Subject:
[sugpro] Re: Verifying Motor Performance Through Flight Tests> To:
sugpro@xxxxxxxxxxxxx> Date: Monday, February 23, 2015, 3:54 PM> > > Not sure
I'm following all this conversation but> instead of a balloon can you gather
data from a parachute> recovery on the way DOWN instead of on the way up to>
establish air density etc. For that matter are there any> papers that show air
density or viscosity based on a> specific parachute and mass configuration. If
not that would> be a cool standard to create for the community.> > Shawn
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