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Great Piston Article, Chan

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Gus

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I just read Chan Stevens' article about Piston Launchers in the March/April Sport Rocketry. Great article, Chan. Really well written and informative!

I've had good luck with zero-volume pistons and, even though I fly with Pete and Bob Alway, I never really investigated their floating head models. Your article let me really understand the difference and it's such a small change from what I'm doing now I'm going to give it a try. Thanks.

Now, as for guilty admissions, I've never piston launched a MMX, but I DID once piston launch a Big Bertha in a fun contest. I was trying to beat Art Upton so I pulled out every stop, but to no avail. :eek: He still beat me. What was cool, though, was that there were very few folks there who had ever seen a piston launch so it was kind of a demo flight as well.

For those of you who have never launched a rocket from a piston, get a copy of Chan's article and give it a try. It's very cool.

PistonBertha.jpg
 
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cjl

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I agree - it was an excellent article, and I have been meaning to try piston launchers for some time now.
 

chanstevens

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Jon Stenberg was playing around with his new camera this weekend and caught an absolutely stunning shot of one of my egglofter models (actually the ASP kit in this case) leaving the piston. The Picasa link is to a somewhat watered down resolution, but still shows some incredible detail, like:

  • The igniter is flying above the fins, so there must have been a heck of a lot of back pressure when the rocket busted loose
  • The leads were pulled up at least 25" as the piston tube climbed, meaning I had them on too tight and risked tip-off
  • The piston tube is also just flying off the support rod/dowel. That's absolutely perfect performance.

That was a full 34" long piston tube. Not sure which flight it was, but first one was good for 8:34 on a C motor, two eggs, but I cracked one (the wire lug in the capsule put too much pressure on the side during boost), second flight was much more conservative since I needed a return in higher winds, with woods/pond about 1:30 away, so I went with a poopy plastic chute for about 0:45 and second place. Both flights had outstanding boosts off that piston.
 
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