Troy:
We can surmise that the payload came off around this time as it was
recovered about 300 feet from the launch tower and on the ‘new’ azimuth.
The attach system isn’t given to a partial failure since the four pins are
held in place by pressure. When the payload came off, all four pins had to
be pulled inward; thus a pressure failure is indicated.
Because loss of pressure was high on the list of failure modes, all leak
paths had two orings. It was also extensively tested, it was not, however,
tested for a 20 degree turn in 1/4 second at 450-ish ft/sec and 11-ish g’s
acceleration.
I’ll be carefully pulling the pneumatic system apart over the next few days
to see if there is any evidence for a breech.
Bill
On Wed, Oct 20, 2021 at 3:26 PM Troy Prideaux <troy@xxxxxxxxxxxxxxxxxxxxx>
wrote:
Bill,
Looking at one of Ed’s frame grabs, it looks like the airframe is not
entirely straight at that moment (of the turn). That could be an optical
illusion of the different colour sections though as the bend seems to occur
where the shades transition?
Troy
*From:* arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx]
*On Behalf Of *William Claybaugh
*Sent:* Thursday, 21 October 2021 8:04 AM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Re: Test Launch
Looking at two videos I see the turn starting around 100-120 feet (based
on the known 24 foot length of the launch tower). I counted 14 frames to
complete the turn. Given the trajectory, this implies the video was shot at
60 frames/second and the turn took place in 0.25 seconds. (At Mach 0.38....)
The vehicle is flying straight and true up to the start of the turn, which
makes a stuck belly band questionable: why didn't it turn as soon as it
left the launcher if a belly band was adding drag to one side? Conversely,
why did it stop turning if not because a stuck belly band coming off?
Similarly, if the sudden turn was due to an internal failure leading to an
off-axis mass asymmetry, why did it straighten out and fly true on the new
heading?
And then there is the telemetry LOS occurring at about the same altitude
as the turn and the subsequent finding that the antenna had snapped off at
the base. For now, I am tentatively assuming that was an effect of the
sudden very sharp turn but I'm open to other suggestions.
All thoughts are welcome....
Bill
On Tue, Oct 19, 2021 at 6:13 AM William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
Troy:
Antenna was mounted vertically and internally.
Bill
On Mon, Oct 18, 2021 at 8:03 PM Troy Prideaux <troy@xxxxxxxxxxxxxxxxxxxxx>
wrote:
Yeah, you’re most likely correct Ken. We mount all our antennas
internally, so it that didn’t occur to me, but Bill might be constrained to
mount his externally with a metal airframe or surrounding structure.
Troy
*From:* arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx]
*On Behalf Of *roxanna Mason
*Sent:* Tuesday, 19 October 2021 12:31 PM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Re: Test Launch
Sounds like damage from the launcher,
Ken
On Mon, Oct 18, 2021 at 6:15 PM Troy Prideaux <troy@xxxxxxxxxxxxxxxxxxxxx>
wrote:
Bill,
Any ideas why the antenna snapped off? Was it in the same area at the
chute and shock cords? Any photos to share?
Troy
*From:* arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx]
*On Behalf Of *William Claybaugh
*Sent:* Tuesday, 19 October 2021 11:32 AM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Test Launch
Launched a 6” rocket at the MTA this weekend.
The rocket part worked fine: clean ignition, full 8 second burn.
Bellybands worked and separated as planned.
The payload had multiple failures: telemetry stopped at 119 feet and 425
ft/ sec when the antenna snapped off at the base. About the same time the
payload separated from the rocket. (The two may well be related.) Payload
was recovered and I will download the data for review when I get home.
The bellybands were pretty chewed up by the ride up the rail. The fins
clearly tore into the bottom band on ignition (bands were 0.020” 2024-T3).
A redesign with stronger bands appears a good idea.
Bill