We finally got a chance to put both Athos and
Porthos back up fully clustered, with as much AP as both could take. We
also found time to put Xavier back up, also in a maximum motor
configuration. We had hoped to get our Aramis Two-Stage project in the air
as well, but with winds on Friday and Saturday, we ran out of time. Athos'
second flight was reminiscent of some of Aramis' earlier flights, and once again
helped us tune our recovery design. Xavier's altimeter switched off
on descent, but she suffered no damage. And Porthos' second flight was
picture perfect, and very impressive. Below is a summary of the various flights. Read on for details.
We arrived at El Dorado dry lake
bed Friday afternoon with the winds gusting 5 to 10 mph. The
winds started to die down around 3:00pm, but none of the big rails
had shown up yet, so we decided to prep Xavier (our glassed PML Sudden
Rush) and throw it up on a K250W. The launch advertised windows to
15,000 ft, and this flight sim'ed to 14,200ft., so we should be in good
shape. We got Xavier ready to fly at 4:05pm, 5 minutes after
the waiver had expired for the day. If the flight wouldn't have
exceeded the standing 7,500ft waiver, maybe we could have flown. But
when you need to call in for the big window, no can do after the waiver
has ended. Well, there was always tomorrow.
Athos,
2nd Flight
The
business end of Athos loaded with
a central M1315W and six J570Ws
E, D, D's
son Evan, & fellow ROC'ers
Brent and Jeff, load Athos on the rail
The winds at El Dorado dry lakebed
were pretty steady through the day Saturday, again blowing at 5 to 10 mph
in gusts, just enough to make you think twice about flying. And just
as they had on Friday, they started to die down around 3:00pm, so we
decided to brave flying Athos. We loaded up Athos with a central
M1315W and 6 outboard J570Ws. The plan was to airstart the J570Ws in
pairs at 8, 11, and 14 seconds, pushing Athos to around 9500
ft. Athos took off perfectly on the M1315W and climbed
straight into the sky. At 8 or 9 seconds, as planned, the first pair
of J570Ws came to life, in sync, and kept her moving. At 11 seconds,
nothing. At 14 seconds, nothing. And not much later Athos
arced over and the drogue popped at a Blacksky reported 3400 ft.
Down Athos came. No main. No main. No main.
Finally at 600 ft. the Blacksky AltAcc2A popped the main. We had
dropped the use of a pilot chute on the deployment bag for the three 14 ft
chutes after our tangle on Porthos at ROCStock, and
unfortunately, from 600 ft. the chutes had no chance to open. Athos
hit hard with all three 14 footers still in the deployment bag,
ouch! Fortunately, Athos landed in the very same mud that our
trailer had gotten stuck in the night before and suffered almost no
damage. The on board video camera, on the other hand, didn't do as
well. It may be a total loss. Unfortunately we had to nearly
disassemble the entire camcorder to retrieve the tape, but it was worth
it. Once again the on-board footage was spectacular. You can
view it in our Movie Theater.
Athos
climbs into the sky on
it's central M1315W
A sad
Athos sits in the mud,
chutes still in the deployment bag
Athos, 2nd Flight Post Mortem
We learn something every time we
airstart. It turns out that a Blacksky Timer2 fires each channel at
it's designated time for one second. If the charge opens, all is
fine and the unit keeps on timing. In our case the igniter wires
didn't completely burn away and were left shorted dangling behind the
rocket. Well, if you short the Blacksky timer while it's firing, it
brings the 9V battery down low enough to reset the unit, and voila, no
second channel event. Lesson learned: with the Blacksky timers don't
try 2 airstarts on the same timer. There is some probability the
second won't occur if the first shorts. We also appear to have lost
the third pair of outboards to a charred igniter wire that left it open,
even with the wires wrapped in Teflon tape. This brings up another
good lesson reinforced: wire those outboard igniters in series. If
one fails, the whole cluster doesn't start. You wouldn't want one or
two motors out of an airstarted 2 or 3 motor cluster not to light.
Can you say "left to Albuquerque"? It also turns out on
the flight, the Olsen FCP-M2 failed completely. It didn't record a
thing. It looks like the battery popped out at take off (why do they
have the battery pointing up in the unit anyway?) We had the right
beeping noises on the pad, but no data afterward. The unit still
said it was in "Record On" mode and the main charge never blew,
it was still intact on the ground. We needed the Olsen to fire the
main at 1200 feet for the chutes to have time to open. Lessons
learned: tie wrap the Olsen battery in and a stock Blacksky AltAcc2A can't
work as a back-up, 600 ft is just too low to pop the main on this kind of
project. We need to get the main out at 1500 feet or above, with the
back-up kicking in well before 1000 feet. We've since talked
to Scott at Blacksky and he's getting us a couple of custom AltAcc2As that
pop the main at 1500 ft. Now we can set the Olsen to either 1800 ft.
to pop high with Blacksky as a back-up at 1500 ft., or we can set the
Olsen to 1200 ft. as a back-up to the Blacksky at 1500 ft.
Xavier,
3rd Flight
E
& daughter Jessica place
Xavier on the rail with D's
brother, Kris, & son Evan's help.
Xavier takes off on
a K250W,
flying to an estimated 14,000 ft.
After recovering from the
emotional distress of crashing Athos and losing one of our camcorders, we
decided to fly Xavier. It was still prepped from the day before, so we
hustled out to the rail right around 4:00pm, less than an hour before the
range was to close. We held our breath as the waiver was called in,
but not to fear, it was a go. Wow, the K250W burned for an entire 10
seconds, and Xavier was gone. We never saw an apogee event, or the
main, but thankfully, we had installed the Walston retrieval
transmitter. We whipped out the tracker and started looking.
And sure enough, we found Xavier about half a mile away toward the
highway. Unfortunately the Missile Works Co-Pilot had switched off
somewhere on the descent. Not only did the main not deploy, we
didn't even get an altitude reading! It turns out that on the ride
down from 14,000ft on the 18" drogue, the two halves on the rocket
collided in such a way as to hit the external on/off switch for the
Co-Pilot, breaking the switch, and turning the altimeter off. Lesson
learned: tape those external on/off switches ON! Or perhaps more
important: don't use external switches. And oh yes, use recording
altimeters so no matter what happens, you can get your data. And one
more thing, the rocket suffered no damage. With enough glass a 7 lb rocket
CAN come down on an 18" drogue.
The
business end of Porthos loaded with
a central N2000W and six K250Ws
D,
E, and fellow ROC'ers Ron, Dave,
Carl, and Kurt lift Porthos into position.
Porthos,
2nd Flight
After two crashes on Saturday, we
retired to the Hacienda to perform our post mortems and plan for the
following day. We decided to fly Porthos on the N2000W because we
couldn't do that in California. Additionally, we decided that
instead of airstarts (which we still needed to work on), we would bang
everything on the ground. This would give us the best altitude, and
besides, we weren't all that crazy about trying to take a 220lb (at lift
off) rocket off the pad on just an N2000W. So we spent hours that
evening and the next morning readying Porthos, and by 11:00am Sunday,
under beautiful blue, windless, and cloudless skies, she was ready to
launch from Ron's McGough's rail (thanks again, Ron, for bringing it, and
for getting the new one ready for Athos, too) Just before
11:30am, Porthos took off on all 7 motors: An N2000W and six K250Ws.
All the motors lit at the same time producing the equivalent of an O3500
with 30,000NS total impulse! You should have heard the noise.
It was your usual big motor noise, plus a low frequency thrumming from
having all seven motors going at the same time. And those motors
must have caused some serious vibrations: all six 54mm outboard motor
retainers vibrated off. They were there at take-off, but gone when
Porthos was recovered. Next time a little Locktite should take care
of that.
Porthos, 2nd
Flight Recovery
Porthos
lifts off on all 7 motors:
an N2000W and six K250Ws.
All 7 motors push
Porthos into the sky
Porthos floats back
to earth
under three 18 ft. chutes.
At an Blacksky reported altitude of
around 9000ft (a 220lb rocket going to 9000ft!), the 12ft drogue
popped. And right on schedule, at 2000ft, the main popped pushing
out the three 18ft recovery chutes. We went back to using
a pilot chute to get the mains out of the bag, and it worked. We
also add a 20ft. section to the recovery harness to get the nosecone away
from the chutes to avoid the tangle we had last time. This also
worked. Two of the 18ft chutes started out wrapped around each
other, but after a few seconds they cleared themselves and we had a
glorious landing under three 18ft chutes. The only bad news is the
on board video didn't record. The same issue we had on the maiden
flight of Athos occurred again. E swears he started the
camcorder, but nothing recorded (D highly suspects pilot error
:-) The main body tube also happened to fall over on the camera
side, and this camcorder got pretty banged up, but hopefully not a total
loss.
Conclusion
All in all, a couple of good
flights. And a great flight. Lots of learning. And lots of
fun. We headed for home to start preparing for the April launch and
the first flights of the X-Rockets. And beyond that, the first
flight of Athos II at Delamar in May. We had lots to do.