Electrosonic launch 1

stardate: 9th of August, 2009

it took a LONG TIME to get to this stage, not for any particularly good reason though. i chose dad's place certainly not for its centrality. But it was a bit more open, generally, that gav's area [the traditional launch range] and i suspect a bit less windy.

the weather was overcase and still and tentatively drizzly, not soaring weather but safe at least. we unpacked and set up the launch rail [pictured down the page a bit] first, electing not to go into the muddy cow paddock because it looked like there might be a bit of running to and fro involved. as it happened there was.

kiri took these pictures which i think are rather good :)





once the range was set i unsealed the rocket nozzle, which was a bit fiddly because the motor had been prepared about 2 months ago and had been maturing in the kitchen since. the rocket went on the rail without a hitch and with a coating of silicone spray which is insanely slippery, water-repellant and resilient. i charged the battery and connected the ignitor pins beside the nozzle to the ignition leads with little paperclips. this was extremely fiddly and beyond assuring an easy disconnection in the event of liftoff, didnt inspire confidence.

anyway, by this time everyone was ready so the coundown was called... and then it didnt light.

this was fortunate though it annoyed everyone, because i found upon inspecting that although everything seemed to be in order, i'd forgotten to arm the recovery electrics. DUMB DUMB DUMB. so i flicked the switch ON, backed away carefully and recharged the battery for another 10 minutes, this time on the tractor which had a big battery with big solid terminals.

a second countdown was called after allt he water had been jiggled out of the electrical connections...

it rushed off into the clouds and disappeared over our heads, on a slightly angled trajectory towards the back of the farm.

this is the launch rail by the way. its aluminium < __C > rail for cords, or something, and is screwed to an old door architrave [with holes for door bells i presume]. its guyed by 3 lengths of clothesline anchored with tent pegs :)


about 10 seconds later it popped back into sight out over the back paddock, heading straight down fast. i watched it fall out of view behind the garden shed.

what goes up...

i knew there wouldn't be a resuable rocket sticking out of the ground but the damage was surprising. it had partly shattered and partly disintegrated. the mid second between the motor and the nosecone was completely mashed, the nosecone was collapsed and half burried and the air speed flap was bent and twisted. the face had lost an eye and sam found the PVC pipe motor thrust prop a few meters away.

the nozzle was also smashed to a stump, though from the residue on the surfaces it look like it happened well within the burn envelope.


many hands carried the bits back across the paddock, through the electrified, rusty barbed wire fence and into the tomato box from which all rocket projects are born.

then we all went inside with wonky the cat and had soup :)

BAD:
-rocket mashed to bits
-some off axis thrust
-no launch checklist
-battery perhaps getting feeble
-nozzle may have failed
-recovery system didnt fire
-ignition box / wiring affected by water
-paperclips aren't aligator clips

GOOD:
+ignitor was effective
+motor worked flawlessly after long stagnation
+no gas leakage from motor top end
+motor survived [minus nozzle]
+parachute and lines are OK
+air speed electric parts probably salvageable
+performance was impressive, stable
+launch rail system very successful.
+didn't go in the pond
+no-one was hurt
+more room in the kitchen

next time i'll watch it all the way up.


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