Jeff's Rocketry Postal Contest Entry

November 2010 -- NAR 1/4A Flex-Wing Duration

Pre-launch shot of a piston-launched 1/4A FW Dur model and the contestant/photographer/blogger (or at least his shadow)

Background

A postal modeling contest is a contest where you fly your model and submit the results to the contest organizer, originally by postal mail, thus the name. Terrill Willard has started a series of postal rocket contests. You can find more information on his contest at the Rocketry_Postal_Contests Yahoo Group. Postal contests are all about you and your model (and a stopwatch), just like the photo above.

Back when I started flying model rockets and joined the NAR in the mid-'70s, you would frequently read about local rocket contests and see contest model plans in the NAR's Model Rocketeer magazine. If you were interested in design, engineering, and optimizing model rockets (in other words, if you were a budding rocket scientist), contest rocketry was the thing to do! (Ironically, the casual Sport Rocketry reader today probably thinks there is only one contest, NARAM, held each year.)

The problem with contests is that many rocketeers don't have a local NAR section (club) hosting contests in their area. I spent my first three years as a NAR member reading about, designing, and building contest rockets on my own before I flew my first contest ("only" 125 miles away.) I would have loved to have been able to fly a postal meet back then, and I imagine there are others today who will jump at the chance to do so.

November 2010 -- NAR 1/4A Flex-Wing Duration

The first event chosen for these postal contests was NAR 1/4A Flex-Wing Duration. Powered by a 1/4A motor (the smallest motor Estes makes), these models boost vertically like a rocket, then at apogee eject a collapsible glider (think of a miniature hang glider) that glides down to earth. The flight time is recorded from launch to touchdown. The event score is the total of two flights and at least one flight must be returned. I've included photos and more details about the models and my flights below.

My section (ASTRE NAR Section #471) had flown the same event just two months ago, so I had models built and tested for this event (actually, the boosters and one of the gliders date back to the Wallace and Gromit Go To NARAM Team that Chuck Weiss and I flew at our last NARAM in 1998!)

Another problem this time of year in upstate New York is the weather. It just isn't as much fun flying rockets when the temperatures drop below 50 degrees F, so we usually suspend organized flying from November to March. The beauty of a postal contest, though, is that you can fly any day of the month that you yourself are free, not a pre-scheduled weekend when your section gathers for an organized launch. We had some nice indian summer weather in mid-November, with a temperature in the low 60s (normal is 48 F), bright sunshine, and (best of all) almost no wind.

Lacking any further excuses :), I went to a nearby field and made my postal contest flights around noon on Saturday, November 13, 2010. Flight one was timed for 51 seconds and was easily returned, lazily drifting only about a hundred feet from the launcher. It re-developed a tear in the plastic material (it had been damaged and repaired before) which may have reduced flight time a bit. Flight two used a different glider that I hadn't flown before and, most importantly, a piston launcher to increase boost altitude. This model seemed to boost significantly higher, but was stalling during glide, so the descent rate was probably similar to the first model. The flight time was 93 seconds and it was also easily returned. Neither flight found any thermal activity, which would have helped the times a lot (flexies have a slow descent rate, so the slightest lift sends them up, up, and away.)

Future postal contests include:

See Rocketry_Postal_Contests Yahoo Group for more details.

Photo Gallery

(click on an image to view a larger version)
Overall view of the slide-pod B RC R/G

Jeff Vincent posing with glider 1.

The contest venue is the local high school athletic field, about a mile from my home. The weather was sunny, calm, and about 15 degrees F above normal for November.

Glider 1 and booster 1.

The glider consists of three 3/32" x 3/32" x 10.75" basswood/spruce spars, connected by a 0.025" music wire spring (90 degree design.) Glider mass is 4.5 grams.

The booster is 16" of BT-5 (0.54" diameter) with three 1/16" balsa fins. No recovery device (gliding recovery.) Empty booster mass is 7.1 grams.

Glider 2 and booster 2.

The glider consists of three 3/32" x 3/32" x 11.5" basswood/spruce spars, connected by a 0.015" music wire spring (110 degree design.) (I think this was a QCR kit we built at an ASTRE club building session.) Glider mass is 4.0 grams.

The booster is 16" of BT-5 (0.54" diameter) with three 1/16" balsa fins. No recovery device (gliding recovery.) Empty booster mass is 6.8 grams.

Flight 1 (glider 1/booster 1) ready for launch off my trusty Estes Porta Pad with Centuri blast deflector.

The motor was an Estes 1/4A3-3T and the flight time was 51 seconds (returned.)

Flight 2 (glider 2/booster 2), launched from a 13mm floating-head piston launcher.

The motor was an Estes 1/4A3-3T and the flight time was 93 seconds (returned.)

My other flying vice - my Parkzone Ember2. Lately I've been trying maximize my flying time -- longest flight from a ROG takeoff. This day I made a 26:50 flight with a 120 maH battery.

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Last modified December 04, 2010
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