SARG Launch 11/13/2010

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o1d_dude

'I battle gravity'
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Tube-O-Mania at SARG Launch 11/13/2010

It was with a great deal of concern that I’d gone to bed the night before the scheduled launch. The weather reports had mentioned a National Weather Service alert for high winds in the Central Valley of California yet when I awoke Saturday morning, there was absolutely NO wind. Woohoo!!

I’d worked like a madman getting all my tubefin birds ready for the launch, had loaded everything up the night before, and was on my way to the range by 9:00am. When I arrived there were already approximately 30 cars in the parking area so for the club’s first public launch of the year, the turnout was beyond our expectations.

First bird up was my “FlatBlack” which was designed by Larry Brand a number of years ago as an entry to a contest…possibly sponsored by BRS Hobbies. Of course it’s a tube fin but it was specifically designed to perform well on the Estes E9 motors. I’d found the construction article on EMRR and thought it worth trying. My first launch on a D12-5 had some chute problems. As did the second. And the third. Finally, figured out the problem (my experiment of not using a swivel…pah!) and launched with an E9-4 right around noon. The launch speed was a little bit slower but it just kept on climbing. Now a 15” rocket gets pretty small at a thousand feet and although I lost it, another rocketeer was able to point it out to me at just about 100 feet above the ground. I’d already spent about 45 minutes after the third flight looking for it on the ground so I was relieved to be able to walk right up to it.

After lunch I broke out the Estes “Super Neon XL”, another tubefin. You wouldn’t believe how many people looked at it and told me I’d forgotten the little finlets on the tubes. Yes, Virginia, tubefin rockets are perfectly stable without conventional fins. First flight on a D12 , the SNXL did something I’d never seen a rocket do before. From the reaction of those watching, I don’t think anyone else had either. It bolted straight up into the sky as if on rails. After reaching apogee, it started to slide backwards on those same rails…tail first! Of course once the chute deployed it just drifted normally. After retrieving it, I motored up with an E9-4 which produced a somewhat slower but higher launch that did not recreate the tail slide behavior.

Next up was my Larry Brand “E-Pod”. Again I built this little tubefin from a construction article on EMRR. It has a highly visibility paint scheme of fluorescent pink and green. Everyone thought it was “cute” as it’s only 12” long. In order to get the cg/cp relationship right I had added 22 grams of lead into the nosecone so the all up weight of the airframe was 126 grams. Larry designed this one to fly on Aerotech single use E30’s and his bird required 29 grams but came out a little bit lighter at 117 grams. Needless to say, the D12 was more than up to the task and putting this little dude into low Earth orbit and in a hurry. Straight up. BTW, fluorescent pink is very easy to spot on the ground, even from a distance.

Over all I was very pleased with my launches and am happy that the effort I put into my little tubefin fleet paid off.

Earlier this evening, I applied two bands of reflective tape, commercial product called “Sky Sheen”, around the body tube of “FlatBlack” hoping that it will flash while under the chute canopy. RC glider guys and AMA Free Flight hand launch/catapult glider fans use this stuff for just that reason. When your bird specks out overhead, you can usually still see a flash of the tape as it circles.

Looking forward to next month’s launch. I hope to have ready a BT60 sized tubefin that flies on 29mm F reloads...another Larry Brand design called the "Little Big Rocket".
 

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