This was our Iowa Amateur Rocketry Group Fall launch on November 14 and 15, 2009.
My first launch was the Cosmo 2 rocket on 2.1 pounds of KNSU. Recovery was a single chute at apogee via a Missile Works RRC2X. I used 2 charges, one connected to apogee channel and a second as a Hail Mary charge on the mail channel set to 1,000'.
Here's the Cosmo 2 coming off the rail
Here's the Cosmo 2 at motor burn out, another great boost and flight...
But the Cosmo 2 didn't deploy at apogee. On the way down the main "Hail Mary" charge went off and deployed the chute.
Unfortunately you can see the nose cone coming down under a slightly damaged chute, but there's no rocket under the chute.
Being in the launch trailer and running the launch controller made it difficult for me to know what was going on. When I saw only the chute and nose coming coming down, I had suspected I forgot to connect the chute to the shock cord. That wasn't the case, after we recovered the nose cone it was clear the shock cord had been cut. Next I wondered if I had left the mach delay set too long from a previous flight, but after I recovered the main body I saw the altimeter was set fine, the apogee charge was also intact. So this was a simple case of a failed e-match, or in this case I used a Christmas bulb to set off the charge and it had failed.
Now a little of my thinking on matters such as this. I usually fly dual altimeters using dual apogee charges, dual batteries, everything backed up. But in these smaller, older rockets that I don't lose sleep over if I lose them, I've been going with a single altimeter, my own HLA altimeter that is programmed to deploy one channel at apogee and the second channel one second later. That gives me a fair bit of redundancy, but on this given day I didn't have an extra one of my HLA altimeters available, I sold one too many it seems... So I used the Missile Works altimeter, but since you can't program it to do both charges at apogee, I had to settle for the second charge going off at 1,000'. It did help, the nose cone deployed and at least the nose cone and tracking transmitter came in undamaged, and I'm sure it slowed the rocket down some too. The upper body tube is toast, but the altimeter survived and the lower body tube is repairable if I decide to do so.
This is the first time I've had a Christmas tree bulb fail, so I won't give up on them, but I will make sure to have plenty of my HLA altimeters on hand in the future so I can at least have some redundancy. I've decide to start a new rocket design so I have some smallish rockets to fly just for fun. This new design will called the Impulse and will be modular in design, using all interchangeable parts. Look for a web page on the design soon.
My second launch was the A2MD on a more or less full load of KNER propellant. Steve Mason and I co-launched the
A2MD with Steve casting the propellant while I loaded the motor and prepped the rocket. The density of the propellant
was a bit on the low side, so this propellant load was just about exactly one pound less than the A2MD's first
flight on a full propellant load some years earlier. Flight simulations put apogee at about 18,600'. I've flown
the A2MD a couple of times on lower propellant loads this year and had used a single chute at apogee for recovery.
This worked well with a tracking transmitter in the nose cone coupled with a descent rate in the 65 fps range.
While that's a bit fast for most rockets, the soft soil and aluminum construction has led to no damage landings
in past flights.
Here's the A2MD coming off the rail.
Almost a cool picture as the A2MD flies by the sun.
The A2MD had a nominal flight to 17,960' and good recovery using one of my HLA2.0 altimeters in redundant apogee deployment mode. John and I did spend a bit more time trying to locate the rocket than we should have. We had a good signal on the homing beacon, but when we got close the signal was so strong we were getting some signal bounce off a small hill that sent us several times back and forth. In the end we walked right past the rocket laying in a grass waterway just 50' or so from us. I really need to get a signal attenuator for the receiver...
There were numerous other flights during the two days of the launch, but I didn't get much for data on those flights and these were my only 2 flights. The video link below has most of Saturdays flights.
Click Here for the video of Saturdays flights. It's unedited other than compressed to a smaller file format.
Here's a recap of the launch that I had posted to the forum:
First up for launch was John's shiny new Anicetus Rocket. We originally planned on flying
this rocket on a 5 grain 75 mm APCP load. But the AP we got from the vendor was damp and much finer in particle
size than I was used to. I tried drying the AP, but it just made a hard skin on the surface. In the end I cast
the APCP but I had very low density and the propellant was almost spongy, so I decided we better fly on KNSU. The
day before the launch John was lamenting not being able to use the APCP, so we decided to try 4 grains of KNSU
and one grain of APCP. John's rocket cato'd on the pad with the nozzle blowing out and the motor pushing up into
the electronics bay. The rocket didn't suffer as much damage as you'd have thought, and is pretty easily repaired.
Both altimeters were pretty badly damaged, but aside from that and a bulkhead, it'll fly again.
Next up was my Cosmo 2 rocket. I flew it on 2.1 pounds of KNSU in the MB1 motor. Nice boost but the apogee charge
went off late resulting in the shock cord getting broken. The rocket came in ballistic and the nose cone drifted
off under the chute. We recovered both the nose cone (transmitter helped) and the main body. The only real damage
to the rocket was the upper body tube. I have an extra body tube that diameter so I think the Cosmo 2 will fly
again pretty quickly. The cause of the late deploy was just a mental mistake on my part. I replaced my HLA altimeter
with my Missile Works altimeter in the Cosmo 2 just the day before the launch because I had sold one and it was
the last new one I had. In the process I forgot to reset the mach delay, I had too much delay for this flight,
thus the late deploy.
Next up was Scott Fraser's carbon, minimum diameter, 5 grain 75mm APCP rocket. Scott had a great boost and flight.
We tracked the rocket for some time and assumed a good recovery, but after many hours of searching for the homing
beacon signal, we gave up shortly after sunset. The next morning Scott went out early searching again, later in
the morning John and I went out using Craig Shore's antenna and receiver. After searching the expected landing
areas pretty well, I decided to extend the search radius and we picked up the homing beacon signal. I called Scott
Fraser and we met to finalize the search area in a corn field. It didn't take us too long and we located the rocket
in the corn field, only problem was, we only found the upper half of the rocket. It seems the motor unscrewed from
the retaining bolt, which held the rocket together. Joel thought he'd seen something shiny falling from the rocket
right after launch, most likely it was the motor. At some later point the booster/fin can probably fell away from
the upper section. So we recovered a lot of the expensive parts, the nose cone with the locating beacon and the
upper body tube with the altimeter in it. Apogee was 14,600'.
The next rocket to fly was the A2MD with 17.2 pounds of KNER. The A2MD had a nice boost and apogee event. It came
in a little fast as the shroud lines twisted up a bit, but we found the rocket that afternoon with the help of
the locating beacon in a grass waterway. Apogee was via a HLA altimeter reporting apogee of 17,960'.
Those were all of the bigger flights. Craig flew several mid power rockets, one of which went unstable right off
the rail and went into cruise missile mode, it impacted in an open field impressively, luckily the rocket wasn't
damaged at all. It was cool to see one of those in person, but I'm sure glad it didn't fly towards us! The rest
of Craig's flights went off perfectly.
Steve mason launched several mid power rockets as well, he had one non deploy but the only damage was one broken
fin.
Scott Fraser finished up on Sunday with a couple of mid power launches, his first of the day went great, but had
another first for use out there as it landed in a tree. We borrowed a ladder from Joel and had it down in short
order. Scott's last flight was another failed deployment, the built in motor charge went off but failed to blow
the nose cone. The rocket landed in Joel's grove of trees, actually hitting a tree with a loud "crack".
Surprisingly there wasn't much damage, only one fin broke and a little body damage.
It was a nice weekend in respect to weather, mostly clear skies, mild temperatures and not a lot of wind. We did
have more failures than we usually have, but it's all still fun and educational. John want's to rebuild his Anicetus
rocket and build another smaller rocket. I'll have the Cosmo 2 ready for the next launch and might just try the
A2MD on an even larger load of KNER next time.