L2 TIME

[SCOTT EVANS]

Try using an ejection charge calculator for an initial estimate to ground test with:

http://www.info-central.org/recovery_powder.shtml

I had a 3″ rocket come in hard because there was not enough charge to push the laundry out even though is was the amount included in a standard reload. Turns out the volume of the airframe (sans the laundry) was right on the threshold for what 1.3 gms of powder would pressurize. The nose barely popped out even though it wasn’t in very tight.

Ken.

I wonder if thats the problem with that Arkus I have thats running on that G64. Chutes Popped only 1 out of 4 times. The first 2 failures it came in flat. The last time was balistic.

Scotte

[Tim Thomas]

8) Scott, you should ask Bruce to show you his ground test video 😳 As I recall he shot his nosecone thru a fence, nailed a cat, and ended up in a “82 Honda!! 😯 Or something like that. Truely a great video! 8) GOT YA BRUCE!

[SCOTT EVANS]

8) Scott, you should ask Bruce to show you his ground test video 😳 As I recall he shot his nosecone thru a fence, nailed a cat, and ended up in a “82 Honda!! 😯 Or something like that. Truely a great video! 8) GOT YA BRUCE!

I wanna see that!! 😆

[Doug GerrardParticipant]

Here is a link to a charge test that I did indoors. Nothing like impaling a car but it did scare the crap out of us. It’s a large file, about 11M but it shows a 2.0 gm charge in a 6″ rocket with piston.

http://www.rocketryphotography.com/rockets/FreezeFrame03.avi

Doug

[Bruce R. Schaefer]

Ha! I have it transfered to VHS, but I should still have it on the camera’s tape. I also blew up a PVC rocket stand I made. Just 2 grams. Parts fly everywhere! Only time I ever singed a chute… so far. Still use that chute to ground test. The conversation Tim and I had for the longest time was… me: Tim? Tim: Whatta ya need now? Me: Well, I blew up… He always got me what I needed in time to make repairs and be ready for the next launch. Scott, get your Aeropoxy from Tim next time. He brings it right to you at the launch. 😉 Watch Doug’s video, it is really cool!

[SCOTT EVANS]

Every time I think I have an original idea (like ground testing ejection charges) I find out all you pyros out there have already done it!
Way too much time for some between launches! 🙂

[Jeffrey Joe HintonModerator]

When in doubt, test it out – don’t blow it up to get the laundry out.

[Anonymous]

….get your Aeropoxy from Tim next time. He brings it right to you at the launch.

Tim, do you carry AeroPoxy Light? http://www.ptm-w.com/index.asp?pgid=178 it is a filler… really weird stuff, but I’ll absolutely use it again next time. It is wretched to mix, sort of like mixing melted marshmallows and peanut butter. That said, I lathered on a really thick layer and I wet sanded it away to a *wonderful* finish.

While it was a lot of work to mix and sand, I’d say it was the equivalent of a dozen iterations of Bondo. In the end it saved time. The big bonus is you can lay more glass on top of this stuff..

I used AeroPoxy and AeroPoxy light on my M1939 minimum diameter boost. I did NOT cure in an oven. OK, I guess I did – I left it in my garage (in Colorado) a few days over the summer. It got perhaps 110-120 deg F?

[Tim Thomas]

8) We have the light, Kent is sending over more Aero as I need some for a couple of other guys. It feels weird in the cans, Kent also swears by the stuff. More on our PM 8)

[SCOTT EVANS]

OK

I got this kit for making e matches.(I got them from Skylighter)( I know I know I could have got them from Tim) It said it would do 300 matches. So I bought 500 feet of wire 6 packs of 50 match heads each. I began to solder and solder and solder till I only had 6 heads left cause I ran out of wire. I made some with 12″ leads some with 24″ leads and a few with 36″ leads. Im still waiting for the nitro laquer to turn a few into igniters (I got the black powder of coarse)
Here is the thing. When I first started testing them half would just snap and half would burn. Now they are all good and dry after 2 of 3 weeks hanging in the garage. Now only about 10-20% snap the rest burn nicely.
Will that little tiny snap ignite black powder?
Secondly skylighter recomended this coating (it was red, I suspected it was nail polish though I didnt try it on my nails) I only got 30-40 matches dipped before I spilled the bottle. And Im not sure that was a bad thing!!!
Last night I was testing those coated matches (the ones with the red stuff)
and I only got one out of ten to snap the rest did NOTHING. The best I got was one small snap out of one match. I have not checked continuity on all of them yet, but it hasnt yet historically proved to be a problem with my soldering and these matches. Why did this coating cause all these matches to become inpatent?
I remember loading the matches into the altimeter bay, one had the coating and one did not, I know the main went off because I have a bunch of new spill holes (Conway) in that parachute. The droug chute seemed for the most part untouched. If the droug chute had the coated match and it didnt go off, would the main be able to deploy, with the rocket at terminal velocity???? A whole lot of questions turning in my head! 🙄

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