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

  • From: "Dave Peterson" <woshugui@xxxxxxxxxxxxx>
  • To: <roc-chat@xxxxxxxxxxxxx>
  • Date: Tue, 16 Jun 2015 01:12:21 -0700

Gene,
Yes! CFC-18, Serial Number #2561 by JE 03/14. It is a favorite and well
travelled. In addition to the Comp 3 at Springfest, you can see it in a
Wildman 4" Jart (0:20 of https://www.youtube.com/watch?v=AwJBIwRz3uc at XPRS
2014, 4:30 of https://www.youtube.com/watch?v=_rBTAYnt-uQ at ROCStock 40)
and a Madcow 4" V2 (0:52 of https://www.youtube.com/watch?v=mT1LGzzduKU ROC
14-Feb-2015).
-Dave

_____

From: roc-chat-bounce@xxxxxxxxxxxxx [mailto:roc-chat-bounce@xxxxxxxxxxxxx]
On Behalf Of Gene Engelgau
Sent: Monday, June 15, 2015 12:36 PM
To: ROC Chat
Subject: [roc-chat] Re: Rocstock 41 Pictures + Punisher Drag Race Video


The Springfest 2015 on board video was awesome. The pilot chute is a custom
color Fruity Chute we made at some point, I can tell by the colors and the
chute bridle.

-Gene

- Regards

Gene Engelgau
Web: http://fruitychutes.com - Professional Aerospace Recovery Systems
Facebook: www.f <http://www.facebook.com/fruitychutes>
acebook.com/fruitychutes

Twitter: @fruitychutes
Cell: 408-499-9050

On Mon, Jun 15, 2015 at 12:28 PM, <kramer@xxxxxxxxxxxx> wrote:



Couple of things all add up against you here, in no particular order they
are,

1) The relative wind is very much NOT in line with the rocket when it comes
off the pad, the wind was coming from one side, the rocket wants to turn
because of the wind, 2 buttons keep that from happening, once one lts go for
a BRIEF instant the lower one acts like a pivot point.

2) stiff rail, not so stiff mount. Ignoring the rail (assume it as
infinitely stiff) all of the rest of the pad adds to the flex at the top.
This gets magnified by the length of the rail (small angle over long 6')
distance.

3) the thrust isn't in line with the button, small difference but anyone who
has slid a button on has felt what a slight off axis angel feels like.

4) If you leave the rail buttons loose so they spin it creates a gyroscopic
effect off axis creating a torque causing the rocket to twist, stationary
buttons would not have this effect. This is total nonsense but I cant help
throwing another thing for the spinning vs stationary rail button debaters
to obsess about.

Mike Kramer


-------- Original Message --------
Subject: [roc-chat] Re: Rocstock 41 Pictures + Punisher Drag Race Video
From: "Dave Peterson" <woshugui@xxxxxxxxxxxxx>
Date: Mon, June 15, 2015 11:51 am
To: <roc-chat@xxxxxxxxxxxxx>


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: ýMondayý, ýJuneý ý15ý, ý2015 ý8ý:ý43ý ýAM
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: ýSundayý, ýJuneý ý14ý, ý2015 ý5ý:ý55ý ýPM
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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