Yes, three 4-40 nylon at 120s
Jimmy F.
Tripoli Rocketry Association
Member 12524
Level 3
[Image result for gif of rocket]
From: tccrockets-bounce@xxxxxxxxxxxxx [mailto:tccrockets-bounce@xxxxxxxxxxxxx] ;
On Behalf Of kevinkal@xxxxxxxxxxx
Sent: Sunday, July 16, 2017 3:47 PM
To: tccrockets@xxxxxxxxxxxxx
Subject: [tccrockets] Re: Analysis opinions
What was your shear pin configuration for the nosecone? Three 4-40's?
-----Original Message-----
From: JAMES FRANCO <ALDOCYBER3@xxxxxxx<mailto:ALDOCYBER3@xxxxxxx>>
To: tccrockets <tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>>
Sent: Sun, Jul 16, 2017 3:40 pm
Subject: [tccrockets] Re: Analysis opinions
All the added weight in the nose is just electronics stuff and associated.
The nose cone alone weighs just over 31 oz.
Jimmy F.
Tripoli Rocketry Association
Member 12524
Level 3
[Image result for gif of rocket]
From: srkendal@xxxxxxxxxxx<mailto:srkendal@xxxxxxxxxxx>
[mailto:srkendal@xxxxxxxxxxx<mailto:srkendal@xxxxxxxxxxx?>]
Sent: Sunday, July 16, 2017 3:17 PM
To: tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>;
ALDOCYBER3@xxxxxxx<mailto:ALDOCYBER3@xxxxxxx>
Subject: Re: [tccrockets] Re: Analysis opinions
Cool. Still a bummer, but I think the changes you've outlined are a good choice.
Your N/C does sound a little heavy, but not unusually so. It's under 3 lbs. Do
you have electronics/batteries in there or just ballast weight?
Good luck with the shortening (been there done that!). Remember to polish down
that cut tube's inside edge!
Steve Kendall
TRA 10478L3
Sent from XFINITY Connect Mobile App
-----Original Message-----
From: ALDOCYBER3@xxxxxxx<mailto:ALDOCYBER3@xxxxxxx>
To: tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>
Cc:
Sent: 2017-07-16 3:08:32 PM
Subject: [tccrockets] Re: Analysis opinions
So after looking at the data from the Ravens, not only did they operate
normally, they did exactly what they were programed to do. So no early
deployment. The data from the RFS GPS-1 supports this flight profile. So my
theory of early deployment is incorrect. I have to believe now there was still
inertial deployment of the main, but the main shock cord was abraded (CUT) by
the body tube at apogee or right after. So lesson learned… use appropriate
shock cord for heavier birds. So the rebuild will include Kevlar cords and new
ground testing with additional shear pins??. One thing also noteworthy is the
nose cone is abnormally heavy for a 4” size. It weighs in at just over 46 oz.,
this seems to add support to the inertial deployment theory. This is the
twelfth flight of this rocket and the first time with inertial deployment. The
main thing I do not understand now, and did not originally is what is the
zipper resulted from? Maybe when the main inflated it caused direction change
which resulted in the zipper. Thanks for your input guys.
The good news is the Dominator will fly again, she will just be 5-1/2” shorter.
Jimmy F.
Tripoli Rocketry Association
Member 12524
Level 3
From: tccrockets-bounce@xxxxxxxxxxxxx<mailto:tccrockets-bounce@xxxxxxxxxxxxx>
[mailto:tccrockets-bounce@xxxxxxxxxxxxx] On Behalf Of ;
srkendal@xxxxxxxxxxx<mailto:srkendal@xxxxxxxxxxx>
Sent: Saturday, July 15, 2017 11:11 PM
To: tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>;
ALDOCYBER3@xxxxxxx<mailto:ALDOCYBER3@xxxxxxx>
Subject: [tccrockets] Re: Analysis opinions
Hmmm, does the data support that? Did you (or anyone else) actually see it go
early?
I see James said it was a Raven. Hmmm. I've had issues with two of them, but no
early's. Shear pin failure? Sounds like it was pretty heavy, could it have been
some sort of drag separation thing that sheared the pins? Need to see the data
plots... Timing will be everything I think.
Good forensic exercise. Two weeks after burying an RDAS Mini at Black Rock one
year, I woke up in the middle of the night and ran down to the garage and dug
through the bag of stuff I dug out of the Playa. Sure as morning coffee the
evidence was there: I forgot a jumper.
Bad things happen from time to time. Like they say, it's usually pilot error,
but not always! Check the data. It should help you figure it out.
So, is it repairable? Launch pics? I'm a long way away these days, closest
field is a 5 hour drive each way down to Brothers OR, so kind of jonesing for
rocket news...
Steve
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-----Original Message-----
From: ALDOCYBER3@xxxxxxx<mailto:ALDOCYBER3@xxxxxxx>
To: tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>
Cc:
Sent: 2017-07-15 8:36:03 PM
Subject: [tccrockets] Re: Analysis opinions
Ah but wait… the cord is not cut at the location at the end of the body tube,
but about 20” out of the tube.
I don’t not think abrasion is the culprit.
My prelim theory is the drogue deployed while ascending, causing the zipper,
then inertially deployed the main which snapped the main cord.
Jimmy F.
Tripoli Rocketry Association
Member 12524
Level 3
From: srkendal@xxxxxxxxxxx<mailto:srkendal@xxxxxxxxxxx>
[mailto:srkendal@xxxxxxxxxxx]
Sent: Saturday, July 15, 2017 8:02 PM
To: tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>;
ALDOCYBER3@xxxxxxx<mailto:ALDOCYBER3@xxxxxxx>
Subject: Re: [tccrockets] Re: Analysis opions
OK, then I agree with JD. Further assuming it was F/G tubes, then it was
sheared due to abrasion with the tube edge. That edge will even attack Kevlar
(hasn't won so far, but both list in the competition... but the tube was far
worse for the wear).
I've had tubular nylon get cut through from rubbing on the tube edge. That's
why I switched to Kevlar.
They make Kevlar S/C sleeves. Might try that, or those Nomex ones. Just another
layer of protection.
Steve
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-----Original Message-----
From: ALDOCYBER3@xxxxxxx<mailto:ALDOCYBER3@xxxxxxx>
To: tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>
Cc:
Sent: 2017-07-15 7:55:37 PM
Subject: [tccrockets] Re: Analysis opions
Oh I forgot to mention the details of the shock cords.
Both are ½” tubular
Drogue is 19 ft long
Main is 23 ft long
Jimmy F.
Tripoli Rocketry Association
Member 12524
Level 3
From: srkendal@xxxxxxxxxxx<mailto:srkendal@xxxxxxxxxxx>
[mailto:srkendal@xxxxxxxxxxx]
Sent: Saturday, July 15, 2017 6:19 PM
To: tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>;
aldocyber3@xxxxxxx<mailto:aldocyber3@xxxxxxx>
Subject: Re: [tccrockets] Analysis opions
What was it made of, and how long was it? As an old rocketeer used to say, "it
ain't too much shock cord if it still fits". I use Kevlar shock cords. Never
had one break. But I have had tubular nylon break.
Of course Kevlar will zipper steel tubing of you give it a chance. Sure will
take its toll on fiberglass. But if it's long enough it shouldn't take a lot of
stress (except for late deployments of course). But that's hard on everything.
;-)
So, my guess is... it was nylon cord and was just too short.
Steve
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-----Original Message-----
From: aldocyber3@xxxxxxx<mailto:aldocyber3@xxxxxxx>
To: tccrockets@xxxxxxxxxxxxx<mailto:tccrockets@xxxxxxxxxxxxx>
Cc:
Sent: 2017-07-15 6:09:53 PM
Subject: [tccrockets] Analysis opions
So today I flew and had a deployment mishap.
Recovered the rocket in two parts. The main and nosecone at one landing zone,
and the booster & payload at another landing zone. The interesting thing is the
main shock cord sheared. But the drogue shock cord zippered into the booster.
The main cord is definitely broke from force, not from burnt from ejection
charge. I'm going look at all the data from the electronics later tonight. What
do you think happened?
Jimmy F.
TRA 12524
L3