atomic_fungus (atomic_fungus) wrote,
atomic_fungus
atomic_fungus

#1832: Dragonfly

In the 1990s I got back into model rocketry.

I'd liked it as a kid, and in my latter years of high school I'd gotten into the model building part of it. Some of this was due to the fact that my friends and I learned enough patience that we realized you had a much better chance of recovering a rocket on a clear day with little wind.

But of course we got interested in other things and model rocketry fell by the wayside; and in fact I don't remember what rekindled my interest in it around 1993 or so--only that I started buying kits and building rockets, and I built a launcher. I turned out some very nice-looking models and kept a log of all my flights.

One classic Estes kit is the Mosquito. It's essentially a body tube, a nose cone, and three fins, wrapped around an AT-size engine. It weighed next to nothing and it was tiny. The kit cost $1 for many years, and you never put a lot of effort into one because the damn things were impossible to find once launched. Even if you used the least-powerful engine Estes made, the thing went fsst! and transcended time and space as soon as you hit the "go" button. The only way you could possibly make a lighter rocket would be to glue the fins directly to the motor casing.

Anyway, in 1985 Estes came out with a kit--I can't recall the name--which replicated the dimensions of the Mosquito in a larger scale. It was a D-powered rocket--using 24mm engines--and its diameter was significantly larger than the motor cross-section. It gave me an idea for a real D-powered version of the Mosquito, one I called the "D-ragonfly".

I never built it...until 1994.

Like the AT-engined Mosquito, it was basically a body tube big enough to fit the engine, fins, and a nose cone. And it was nowhere near strong enough.

The prototype is the only version of the thing I ever flew. My launcher used two 9-volt batteries in parallel, guaranteeing that the ignitor would always (95% of the time, anyway) set off the engine. So when I put in the safety key and pressed the "go" button, it went.

It got about eight feet into the air before the fins began to oscillate--you could hear the hum--and it might have flown as high as twenty before aerodynamic loading tore them off the fuselage.

The fuselage with a partial fin still attached and part of another fin were recovered. That explained why the rocket didn't go out of control; the partial fin provided enough stability. The asymmetrical drag limited its aphelion, though, which is probably just as well.

I concluded that better materials and construction techniques would be needed, and abandoned the project. Plywood fins epoxied to a phenolic airframe would probably have done it, but it would have made the thing weigh as much as a larger rocket, thus offsetting the benefit of building such a minimalist rocket in the first place. At least I was able to say I'd tried it.

My other rocket science efforts worked better, such as my scale model of B-ko's Akagiyama missiles (from Project A-ko) and the Hot Potato, a rocket made from a Pringles can...but those are stories for another time.
Subscribe

  • #9526: One of these things doesn't quite fit

    "It's almost like somebody wanted him to get caught." The CEO-killer's infiltration of NYC was operationally perfect, as was his exfiltration. The…

  • #9525: How could they tell?

    "Mitch McConnell Falls During Senate Lunch and Injures His Head". Quoth Ace: It's a sign of perfect health for a 70 year old to fall for no reason.…

  • #9524: AS PREDICTABLE AS THE TIDES!

    The left is now 100% okay with deporting hispanics because about half of them voted republican. "That's The Bulwark!" You say. "They're a…

  • Post a new comment

    Error

    default userpic

    Your reply will be screened

    Your IP address will be recorded 

    When you submit the form an invisible reCAPTCHA check will be performed.
    You must follow the Privacy Policy and Google Terms of use.
  • 0 comments