It does make sense and evidently some grain configs produce significant
vectoring at lower speeds. So, the rail would have to be about what, 50’ long?
😊
But the 1440’s are Bates grains. I still believe the nozzles (at least some of
them) were malformed. David has some of the spent engines and even one that
wasn’t used in the lot for the mass launch. Hopefully, he will get his
computer fixed and we’ll get more info about the engines.
Seems many people are interested in long burns for a mass launch. BTW, what’s
the maximum burn time for a commercial K? If this happens, rocket stability
and the length of the launch rails are going to be even more important - and
maybe where to locate the rail buttons!
From: Rick Dickinson
Sent: Thursday, June 18, 2015 11:12 PM
To: roc-chat@xxxxxxxxxxxxx
I can attest to this! Every single time I flew my Estes Fat Boy on a J90, it
vectored off the rail at an angle. Switching from a moonburner to the BATES
J275 cured that.
Offset core = offset thrust.
Cheers,
Rick Dickinson
On June 17, 2015 5:54:56 PM PDT, Cliff Sojourner <cls@xxxxxxxxxxxxx> wrote:
And grain configuration. I am certain that moonburners and C slots have offset
thrust, there's only so much the convergent section of the nozzle can do.
On June 17, 2015 4:44:03 PM PDT, R Dierking <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> 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 Dierkin g <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
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
