Gotta watch out for those photobombers!
Mike
On Monday, June 15, 2015 4:35 PM, Kurt Gugisberg <kurtgug@xxxxxxxxx> wrote:
I don't know about that white rocket but the yellow and black on the pad sure
looks good. ;-)
Kurt
On Mon, Jun 15, 2015 at 4:24 PM, Adrian P. Bailey <adrian@xxxxxxxxxxxxxxx>
wrote:
We weren’t in the drag race but here’s a pic of Max’s Mirage launching, if it
helps. The rail buttons were at the bottom and just below the unloaded CG. The
rail was angled into the W. From: roc-chat-bounce@xxxxxxxxxxxxx
[mailto:roc-chat-bounce@xxxxxxxxxxxxx] On Behalf Of R Dierking
Sent: Monday, June 15, 2015 2:07 PM
To: roc-chat@xxxxxxxxxxxxx
Subject: [roc-chat] Re: Launch Pads and Interest Posting for Construction of
Large Launch Pad So, were the buttons on everyone's Punishers installed at the
same locations?
Sent from my iPhone
On Jun 15, 2015, at 1:49 PM, "Kurt Gugisberg" <kurtgug@xxxxxxxxx> wrote:
I was wondering about the button placement too. My top button is well below
the cg by 6" or so and the bottom button is screwed into the bottom centering
ring. So the rocket under thrust is probably trying to rotate around its cg.
So as perhaps as EJ said, one at the cg and one ahead would be the best
location.Kurt On Mon, Jun 15, 2015 at 12:41 PM, E J <ejackson1075@xxxxxxxxx>
wrote:
I was just skimming and this reminded me of a tip I got many moons ago, but
never really tested. It was off the ancient news boards
(rec.rockets.something), but the tip was to put one guide/button at the center
of gravity and the other a couple calibers above it. The idea was to keep the
contact points from being somewhere that would exert more force on the rocket
than needed to keep it from falling off. On Mon, Jun 15, 2015 at 11:35 AM,
Kurt Gugisberg <kurtgug@xxxxxxxxx> wrote:
Richard, I'm not sure if stiffer rail is really the answer. Last year at
XPRS, there was a pad out there that had a triangulated super structure that
kept the long rail straight and it was on a huge base anchored to the ground
and I think it even had guy wires. I watch for four days as rockets came off
of it and kicked out at an angle just like on our loosey goosey pads.
Asymmetric thrust might be one reason but this pad had a long rail that should
have helped. I'm beginning to think it might have something to do with the
spacing or location of the rail buttons. The fact that one button is off the
rail prior to the second one may allow it to torque sideways. I wonder if one
continues rail guide would solve that. Kurt On Mon, Jun 15, 2015 at 9:55 AM, R
Dierking <applerocketry@xxxxxxxxxxx> wrote:
First, I’m wondering how much stiffer a 1515 is than a 1010 rail? Cross
section is 50% more, so approximately double? One of my last fights over a year
ago now (way too long ago) was a K1275R off one of the back pads using a 1010
rail. The rocket went noticeably West immediately after leaving the rail and
it wasn’t the wind. Luckily, the rocket landed close to the pad because of the
wind during descent. One time the wind really helped. There’s always a lot of
discussion about rocket stability, but think about how important a reliable
launch pad is. Of course, what engine in what rocket is very important to how
massive/stable the pad must be and how long the guiding structure should be.
Regardless of size, I think there is some occasional thrust vectoring with AP
engines that takes place moments after ignition that seems to stabilize. What
would be the reason that some rockets left the rail in the Punisher drag race
at an angle? I’m curious if other people believe momentary thrust vectoring
occurs? If you are going over say 10K’ in a location like Lucerne Dry Lake,
you need to be reasonably sure that the rocket is stable (of course), and that
it’s going to fly in the direction you choose. I’ve been considering launch
pad designs for several years, and checked out all the custom pads at the last
two BALLS launches I’ve gone to. Some are really cool with elaborate pad leg
designs and lifting mechanisms but the ones with a sturdy/stiff launch rail
adequately supported along its entire length seem the best to me. This is my
opinion, and I might be a little jealous of the money some spend on their
launch pads. I’m considering purchasing a 12’ x 5” utility trailer for the
base of a launch pad that would also be a platform for a test stand. The pad
would use the triangular aluminum tower material that seems to be popular for
many large launch pads. A link follows that shows a base for an antenna tower.
I would like to know if anyone else is interested in participating in the
construction of a large launch pad/test stand. It would serve as our launch
pad/test stand at ROC and FAR launches and be very useful for XPRS/BALLS.
http://www.dipolnet.com/footing_for_aluminum_antenna_tower_E9151.htm Richard
Dierking
