Introduction:
After getting back into rocketry via 3x18mm and 3x24mm Estes-que scratch-built rockets, I figured it was time to move on up and try composite motors. Econojets were the best bet for the short-term, since I wasn't ready to invest in a reload casing, and they have a decent burn time and a rather unique louder-than-normal sound. The original goal was to aim for a design that would sneak under the 16 ounce FAA notification limit, but I haven't strolled into the local supermarket yet with the rocket under my arm. Doesn't matter that much if it is over, since my limited club experience has been enjoyable so I don't plan on launching at the local field any time soon.

Nose Cone:
Made from a $.99 foam cone at the local fabric store. Haven't bothered with a drill lathe system yet. Results were 'good enough' for this proof-of-concept rocket. Covered it with three layers of tissue paper/wood glue, with a final layer of wood glue to seal it. Sanded, primed and sanded again. Depressions were then filled with some leftover whitewall mud and sealed with glue. Resulted in a heavy yet fairly smooth and strong nose cone 5.25" long, with 1.25" of it being the shoulder.

 Recovery System:
1/2 inch sewn flat nylon elastic cord from the local fabric store, 4 feet of it. Yes, I know the cord is supposed to be longer, but smaller versions of the same material worked fine on my clusters, so I trusted my instinct on this one. Mounted to the body via two wooden dowels that are glued through the body tube. The idea was to have them 90 degrees from each other, but in my haste to build, things got a little out of alignment. Tied a loop in the cord, then placed the dowels through loop inside of the rocket. Parachute is composed of two plastic layers from a garbage bag, 23 inches in diameter. Eight shroud lines composed of a waxy version of kite string, which keeps tangles down, attach to the parachute via duct tape. The 'chute is attached to the shock cord through a grommet in a folded over section, which was then layered with wood glue and tissue paper as well as CA. I was going to use swivels to attach the parachute, but decided against it. Just didn't trust the ones I had on hand. Nose cone is attached at the end of the shock cord via tissue paper and wood glue, about 2.5 inches from the parachute grommet.

Body Tube:
Grabbed the parallel-wound tube at the fabric store, the clerk gave me a rather odd look when I asked if I could have it. 39.5" long, 2.23" across and .125" thick. It was longer, but for some reason I chopped off 8.5" of it. Covered it in a layer of watered down wood glue. Fin slots were started with a drill, then finished slowly with a keyhole saw and then 40 grit sandpaper until desired width was obtained.

 Motor Mount Tube:
Had to make my own. Took a garden tool handle, coated it with some oil, and used a few grocery bags cut into 1" strips. Once the glue was tacky, added another layer of paper wound diagonal to the first. Removed the tube before it became attached to handle.

 Fins:
I've got a huge amount of balsa stock leftover from friends at school who were in the architecture program. Decided to go simple by gluing two 1/8 pieces together, and going with three fins with a rectangular shape. Gave them an aerodynamic edge, and covered them with 20 pound white paper and -you guessed it- watered down wood glue. They are 3.5" by 3", not including the the amount that extends to the motor mount tube.
 

Fin Can Mounting:
Centering rings were made from 1/8 balsa stock soaked in wood glue. Was going to double them up, but they were a pain to make, and they seemed strong enough. Fin edges attach to both of them. Since I figured a strong bond to the centering rings was more important than internal fillets on the fin body tube joint, I glued the rear ring in place before sliding it into the body tube. Used some more 20 pound paper to form some external fin mounts once the fin can was glued into the body tube.

 Launch Lugs:
I wanted to use a ¼ rod for this bird, so I grabbed two eyelets from the workshop. One is within a few inches from the bottom, and the other is a few inches above the CG. Screwing them into the body tube then soaking the area around them with CA seemed to work well.

 Painting:
I've never been a really big fan of beautifully painting rockets since you never get to see them up close while they are launching. As long as they have a decent gleam in the sun, I'm happy. I primed the rocket and covered it with royal purple. I then tried a clearcoat which started to strip off the paint. That's when I discovered the whole problem of mixing enamel with lacquer paints, tehehe. Never did get it perfect again, still have some cracking on some of the fins. A coat of auto wax later and Econoexpress was ready to fly!

First Flight:
I finally got the chance to launch EconoExpress at CMASS's last sport launch of the year. I loaded her up with an Econojet F20-4 at home, with plenty of tape as an external thrust ring as well as motor retention. Two pieces of Estes recovery wadding were installed, as well as one piece around the bottom of the parachute. I was somewhat worried about the over stability of the design, which at 3.6 calibers with a F20 loaded, would make it fairly susceptible to weather cocking, especially at the windy CMASS launch site. The weather turned out to be decent however, with moderate temperatures and light winds.

 Got the copperhead installed, and absentmindedly flipped the rocket back over before putting on the rubber band. The field then ate it. I was placed out on a high power pad, since this was the first launch of the rocket and I needed a 1/4 rod.

 Ignition was within a second of the button being pushed, and the flight was nice and straight, with very little if any weather cocking. The Econojet didn't disappoint, plenty of noise for an F! Ejection was a bit early, about 1200-1400 feet up, and then the fun started. Rocket did 5 to 6 revolutions around the now-opened parachute before finally settling down. Everything held together though, and I recovered it a bit downrange in perfect condition.

 Conclusion:
I'm happy with the results, 2 bucks (for the foam and shock cord material) isn't all that bad for a rocket of this size that can fly on Econojets. Going to try out a F20-7 next time around, and then step up to a G35-7. Hopefully I won't stress the recovery system as much with these delays, or so the sims tell me. Heck, maybe I'll get somebody to stick in a H125W!

As of 01/12/00, EconoExpress has flown a total of 3 flights. F20-7 is a little long but works fine, and a G35-7 really pushes it up there!