You are right Chris that it rotates around that bottom button but it really
wants to rotate around the cg. So what would be the best way to space the
buttons to lessen the rotation? I would think the top button at the cg and
two at the bottom spaced about three or four inches apart.
If we do another mass launch, how about sparky motors!
Kurt
On Fri, Jun 19, 2015 at 7:52 AM, Chris J Kobel <Chris.J.Kobel@xxxxxxxx>
wrote:
I recall measuring 11 mph from the WNW at 88 degF at our ~9:50am launch
time. I believe as soon as the top button clears, any rotation would have
to take place about the bottom button.
Chris
From: Kurt Gugisberg <kurtgug@xxxxxxxxx>
To: "roc-chat@xxxxxxxxxxxxx" <roc-chat@xxxxxxxxxxxxx>,
Date: 06/17/2015 05:40 PM
Subject: [roc-chat] Re: Punisher Drag Race and Discussion of
Thrust Misalignment
Sent by: roc-chat-bounce@xxxxxxxxxxxxx
------------------------------
I still am voting for the rail button thing. As soon as the top button
clears it will want to rotate around the cg. Now what is causing the
force that makes it want to rotate? Did we discuss weathercocking on a
barely stable rocket? How hard was the wind blowing at the time?
Kurt
On Wed, Jun 17, 2015 at 4:44 PM, R Dierking <*applerocketry@xxxxxxxxxxx*
<applerocketry@xxxxxxxxxxx>> wrote:
So, what do you think? Malformed nozzles, chamber pressure too high,
exhaust gases thrust vector rocket...
Sent from my iPhone
On Jun 17, 2015, at 4:24 PM, "Kurt Gugisberg" <*kurtgug@xxxxxxxxx*
<kurtgug@xxxxxxxxx>> wrote:
From the video, I could see that my Punisher also veered off after it left
the pad. I had to leave my casing with David because it had a heat bulge
in the end near the forward seal. So it was probably close to catoing
too.
Looks like we have a cast of characters that might lead to to behavior we
saw: misaligned thrust vectoring, rail button placement, low level of
stability with high thrust motor. The only thing it might not be is rail
whip.
Kurt
On Wed, Jun 17, 2015 at 1:02 PM, R Dierking <*applerocketry@xxxxxxxxxxx*
<applerocketry@xxxxxxxxxxx>> wrote:
I’m sure we can come up with things to investigate and even reduce this
misalignment problem.
Who’s interested in a Punisher 2 mass launch? I think we should use the
same K1440 engine and leave it up to each flyer if they are going to modify
the rail buttons, pad, whatever else. We have lots of time to collect
details on each project.
Chris, would it be possible to post some details of the AC stand used to
test for misalignments?
Do you think that creating a way to hold the rocket on the pad until max
thrust is achieved would help?
I’m wondering why David Reese has not joined this discussion because
wouldn’t he be one of the best people to advise on something like this?
Again, I think building a large launch pad/test stand for ROC launches
would be cool and we probably wouldn’t need the contribution of many people
to do it. We could use the pad at Black Rock for XPRS or BALLS. Again,
I’m offering to buy the trailer for the project.
Richard Dierking
