[roc-chat] Re: Rocstock 41 Pictures + Punisher Drag Race Video

  • From: "Dave Peterson" <woshugui@xxxxxxxxxxxxx>
  • To: <roc-chat@xxxxxxxxxxxxx>
  • Date: Mon, 15 Jun 2015 11:51:19 -0700

I have had a rocket take a hard turn even out of a tower. (Darkstar Mini at
01:34 on this video <https://www.youtube.com/watch?v=ewsgZf2crAQ>
https://www.youtube.com/watch?v=ewsgZf2crAQ ). Even a tower can twist and
bend, so maybe they are no better or even worse than a rail from that
perspective. At the time I attributed it to wind, but this was a fairly high
thrust:weight flight so I also wondered about thrust vectoring. When a motor
is static tested on a stand are there also YZ gauges to look for off axis
thrust?

I am planning to use a K1440 as the booster for a two stage with a K250W
sustainer at Black Rock in September so I hope we get to the bottom of what
happened befiore then.

My Open Rocket simulation was predicting 15,100' but I was taking that with
a grain of salt since RockSim 9 was saying closer to 12,000' which "seemed"
more realistic. That said, RockSim has a reputation for over-estimating mach
drag, which on my simlation was about 50% higher than it was in OR.

_____

From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx]
On Behalf Of R Dierking
Sent: Monday, June 15, 2015 8:55 AM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: [roc-chat] Re: Rocstock 41 Pictures + Punisher Drag
Race Video


The ground and flight videos are excellent, and I don’t want to get far OT
but I noticed the diversions as well Kurt. Interesting that you have
basically the same rockets, engine, and igniter, on the same pads and rails
with lots of differences in the ignition times and way they exited the rail.

Maybe it would be best to start a new thread on launch pads.

Also, hopefully, there will be an analysis about the engine failures because
the K1440WT seems like it would be a great engine for a 2 stage rocket.
And, why did everyone get a much higher altitude than they expected?

From: Kurt <mailto:kurtgug@xxxxxxxxx> Gugisberg
Sent: ‎Monday‎, ‎June‎ ‎15‎, ‎2015 ‎8‎:‎43‎ ‎AM
To: roc-chat@xxxxxxxxxxxxx

Great Video Dave. It's a little disturbing seeing some of the Punishers
came off the rails at an angle. In the slo-mo you can clearly see a number
of them angling right off the top of the rail. I think that is a common
situation with rails. I think that even thought the rail is so much stiffer
than a rod, they still whip around. Maybe it is slop in the pad but you can
see those rails vibrating back and forth quite a bit in even a moderate
wind.


Kurt


On Mon, Jun 15, 2015 at 12:48 AM, Dave Peterson <woshugui@xxxxxxxxxxxxx>
wrote:



Here is my video... https://www.youtube.com/watch?v=vFF-6Dwud9U
Thanks to everyone for putting this event togather.

_____

From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx]
On Behalf Of R Dierking
Sent: Sunday, June 14, 2015 7:26 PM
To: RocChat
Subject: [roc-chat] Re: [roc-chat] Rocstock 41 Pictures + Punisher Drag Race
Video


Nice!

How many people had on-board cameras?

From: Payton <mailto:Payton@xxxxxxxxxxxxxxx> Kramer
Sent: ‎Sunday‎, ‎June‎ ‎14‎, ‎2015 ‎5‎:‎55‎ ‎PM
To: RocChat <mailto:roc-chat@xxxxxxxxxxxxx>

https://www.flickr.com/photos/130292873@N02/sets/72157654165375170
<https://www.flickr.com/photos/130292873%40N02/sets/72157654165375170>

https://www.youtube.com/watch?v=7k1lceVPdbM


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