[tccrockets] Re: Rock sim
- From: Karl Baumheckel <karlbaum@xxxxxxxxxxx>
- To: tccrockets@xxxxxxxxxxxxx
- Date: Fri, 10 Feb 2012 13:40:41 +0000 (UTC)
I like to use sliders on chutes larger than 4 foot. Another option I have
tried is using a short piece of 3/4 inch nylon tube as a slider. It's cheap
and it slows down the deceleration rate. I also like to use deployment bags on
larger chutes. Skydivers call the decelleration "opening shock" and it can
bust your balls.
Karl
----- Original Message -----
From: "Gene Engelgau" <gene@xxxxxxxxxxxxxxxxxxxxxxx>
To: tccrockets@xxxxxxxxxxxxx
Sent: Tuesday, February 7, 2012 9:28:04 AM
Subject: [tccrockets] Re: Rock sim
Hey Robert, So I'l stating the obvious and the deceleration is why air frames
get zippered. The Iris chutes in particular open very fast since they are
shallower. I'm working in a slider device to moderate that... more on
that later.
-G
On Tue, Feb 7, 2012 at 9:21 AM, AiRobert < airobert@xxxxxxxxxxxxx > wrote:
I ran into something interesting while doing some Rocksim work for my L3, a ten
inch Thumper.
http://stores.whatsuphobby.com/-strse-10/Polecat-Aerospace-10%22-Thumper/Detail.bok
http://www.rocketreviews.com/file-4841/mod_polecat_thumper.rkt
The max acceleration was showing 900+ f/s/s which is ~30g, yet it wasn’t
clearing the rail at a high enough speed for stability (50f/s.) Normally 10g is
plenty. So I reran the sim with bigger and smaller motors and watched the
details at launch. I couldn’t find any acceleration over 180f/s/s (5g using
M1230)
It turns out that the acceleration of 900 f/s/s was actually the deceleration
when the main chute popped out at 800 feet. Once the drogue chute was resized
the numbers started making sense.
WOW who woulda thunk…
RZ
--
- Regards
Gene Engelgau
KI6IBL, NAR 86770 / TRA 12243 - L3
http://fruitychutes.com - Consumer and Aerospace Recovery Solutions
Like us on Facebook!
Follow us on Twitter!
408-499-9050
Other related posts:
