Experiences with the James Yawn "Snapdragon" DIY plans.

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New Member
Aug 22, 2014
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So my son's scout Pack participates once a year in a public sport rocket launch, conducted by NARHAMS here in Maryland. For the last two years, we used kit rockets (first year was Gnomes, second I think we got the Estes Wizard). Anyhow, this year I decided it would be fun to build from scratch. Why? I don't know. Something in me loves building things from scratch.

Here are the plans we went with: https://www.jamesyawn.net/modelrocket/intro/index.html

We built a total of five rockets. One for me, one for each of my three kids, and one for my wife. Most of the steps were simple enough that I could actually have the kids do them.

I used basswood for the fins and we left them unpainted. For attaching the shock cords, I elected NOT to wrap them around the engine block, and instead did the "paper packet glued to the inside of the tube" method.

The construction yielded a rocket that was extremely solid, but also extremely dense. It weighs something like 2.6oz with the motor installed.

Anyhow, our experiences flying the rockets:

- The NARHAMS guys were a little bit leery of the rockets, due to their weight. They actually thought I'd used PVC tubing, instead of the rolled cardstock that we built them from.

- The launch lugs required some filing to get to fit on the launch poles. This was surprising to me, because I'd tested them with a 1/8" drill bit, which dropped right through. Next time I'll make 'em a little larger.

- The rockets flew quite well. We used B6-4's for most of the flights, and two C6-5's that I had left over from last year. They flew higher than I expected, and I had no misgivings about altitude. Unfortunately, I didn't have an altimeter installed, so I can't comment on actual numbers.

- Most of the flights deployed recovery successfully. We used streamers in all of them, and it was sufficient to provide safe landings. We had one nosecone fail to deploy, giving us a lawn dart that, miraculously, didn't even knock off a fin. We also had a streamer break loose. Altogether, each rocket flew twice, and they were all intact at the end of the day.

All in all, it was a successful outing, and the kids were happy with their homemade rockets. That said, I don't know that I'd use this design again, as I really felt like the rocket was just way too dense. I think a lot of the blame lies with the construction of the body tube and the nose cone, which could probably be lightened significantly.

Would be very interested in any other beginner-level DIY plans that folks might have to recommend!


Well-Known Member
Jan 18, 2009
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Glad you had a good experience with them. Here's a few things to consider for next time. Commercial launch lugs will fit snugly around a 5/32" tube, this gives some leeway for the nominally 1/8" launch rods. The bodies of your rockets are way overbuilt. Having built a good number of cardstock rockets, I can tell you that a double walled laminate will give you a light but strong airframe. Little Joe II.jpeg
The Little Joe II was built in that fashion and is quite sturdy. It is fairly comparable in size the current Estes kit. There are some excellent free downloads for cardstock models out there. Check out Fliskits.com for some cool ones. Also here: https://rocketry.wordpress.com/ultimate-paper-rocket-guide/ for everything simple to complex. Happy building.

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