Saturday, September 30, 2017

We have a new TARC Geezer!

Vince's Geezer TARC entry sets on the pad awaiting launch (Click to enlarge).
Well, today was THE day - the annual Geezer TARC fly off. This year's contestants - myself, Duane, Marc, and Vince - gathered at Pegasus field at 10 AM for the showdown. As is the norm with Geezer TARC, there were sighs of relief and expressions of dismay, with things never going as expected. And when the smoke cleared, we had a new champion - one who threw together a model without doing a single sim and flew it on a motor he hoped would work. Those of us who spent many hours with Open Rocket and building finely tuned birds of glory could only shake our heads in astonishment and wonder if we had neglected some sacrifice to the rocket gods.

Vince's improvised V-2 TARC was first to fly. I must confess I was tempted to disqualify him at the outset, for the model was literally a V-2 with a BT-70 payload section taped to the top. However, it was creative, reminding me somewhat of the old White Sands Bumper program (WAC rocket on top of V-2), so I decided to let it go. It took Vince a while to get the bird into the air, as he had 3 ignitor misfires before it left the rail on the 4th attempt. It was a fantastic flight - altitude of 829 feet and a perfect duration of just over 41 seconds. The rest of us were showing grim faces as we stared at Vince's 29 score.

"Fat Chance" and "Best Chance" - Duane's Geezer
TARC entries (Click to enlarge).
Eggsploder clears the rail under the thrust of 4 Estes
BP motors (Click to enlarge).
Duane was up next with his "Fat Chance" entry. Just shy of the weight limit at 636 grams, this thing was a pig. Nonetheless, it achieved 813 feet on an Aerotech F32, the closest of any flight to the 800 foot target. Unfortunately for Duane, Fat Chance's elastic shock cord couldn't handle the load and snapped, causing the sustainer to fall to the ground. The payload section made a gentle landing under parachute after a total flight time of 44 seconds, but that did not save Duane's flight from being disqualified. A shame - he just might have won the day.

The third TARC rocket to fly was Marc Loertscher's "Geezer Cheater." Tipping the scale at a whopping 750 grams (100 grams over the limit), it was disqualified at the outset, but Marc flew it anyway, just to see what it could do. He had developed a novel automated parachute reefing system for this model (which is why it was overweight), and you could actually see the chute being reefed and let out as the model descended from its peak altitude of 694 feet. Marc had programmed the thing to adjust the rocket descent rate so that it touched down in 42 seconds; it landed in 43, which our master engineer attributed to the programmed turn off of the chute control in the last 50 feet before ground contact. I was most impressed - and worried about facing this guy next year.

My turn had now come. It had taken me some time to prep the Eggsploder - stuffing the two eggs into the payload section and wiring up the 4 Quest ignitors in the 2 D12's and 2 C6's had taken more time than I normally spend getting TARC birds ready. But now she was set to go, and I hoped that the C6's would provide enough additional power to loft my 529 gram beauty to altitude (taken together, the 4 motors provided 63% of the impulse of a full F). I was also nervous after the cluster failure with my Deuces Wild a couple of weeks ago, so you can bet I checked those ignitors and the connections very thoroughly.

Turns out, I didn't need to worry...

Eggsploder's altitude profile showing the variable descent rate (Click to enlarge)
Eggsploder shot off the rail with all 4 motors burning bright, reaching 839 feet before popping the 18" parachute just past apogee. All my sims had indicated that this size parasheet would produce the perfect descent rate of 23 feet per second, but sims do not account of the upwelling of warm air from the ground (the launch occurred well past noon). I could tell that the rocket was catching air, and it stayed aloft a full minute - 17 seconds past the mark. A successful flight, but my 108 score looked pretty pathetic next to Vince's 29. I took a look at the altimeter profile after returning to my apartment, and found a very variable rate of descent - 14 feet per second near apogee, shallowing to 13 feet per second for a bit, then increasing to 17 feet per second and finally 20 feet per second near the ground. Weird, and none of the rates were close to the predicted 23 feet per second. Oh well, even if my time had been perfect, Vince was still 10 feet closer to the altitude mark than me.

The last Geezer TARC flight was that of Duane's "Best Chance". Flying on an Aerotech F39 reload, it achieved an altitude of 629 feet - puzzling, as Best Chance's weight of 543 grams was a good deal lighter than that of Fat Chance, which had performed very well. Unfortunately, Best Chance was under the same "Curse of Recovery" as his predecessor; the parachute sheared away, causing the entire model to plummet into a tree at the edge of the road. The model was recovered, but Duane's second flight was also a DQ. He took some solace in the fact that the eggs had survived the fall undamaged - the Mayer egg protection system is almost fool proof.

2018 Geezer TARC results (Click to enlarge).
And so, around 1 PM today, Vince Huegele was presented the 2018 Geezer TARC trophy and proclaimed this year's TARC Geezer. Duane, by virtue of being the most cursed contestant, received the 2018 Flying Pig award. I noted, with some irony, that he had been emphasizing to his teams the need for beefy shock cords and strong attach points - the very things that failed today.

Congrats Vince!

The victor, holding his rocket and trophy
(click to enlarge).
Duane with the Flying Pig award (Click to enlarge).
And wait till next year. It's gonna be my year - I can feel it in my bones...

(My apologies for the lack of pics - I was busy timing and writing notes during the Geezer TARC flights)

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