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February 08, 2012, 06:03:23 AM *
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Read August 07, 2008, 06:49:43 PM #0
Hen

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Dobby's Ejection Test
I am sure you fellows can tell me a lot of things about rocket fuselages. One thing is for sure, we here in Douglas know how to build them strong. Our home designed and build rocket named “Dobby” survived this recovery system ejection test. But for the shock cord that was ripped clean of the bulkhead retaining it Dobby sustained no damage at all. If one looks very carefully the Nose, Parachute and piston/payload-bay can be seen returning from orbit just before the end of the video clip! The second test ended much better.
(Note: For those of you that take your language very seriously, please excuse my English, The people around here would start oiling there Mausers if one talk to them in another language. So I don’t get a lot of practice.)     
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Read August 07, 2008, 06:53:15 PM #1
Hen

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Re: Dobby's Ejection Test "Sukses"
This is what we actually wanted the first time around! Cheesy
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Read August 07, 2008, 08:09:52 PM #2
Ryno

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Re: Dobby's Ejection Test
 Shocked . If you put the rocket upside down you can fire it into space!!

I also under estimated the power of a ejection charge in a closed area or chamber.The explosive or burning velocity increases dramatically!

What did you use as a ejection charge?

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Read August 08, 2008, 03:48:35 AM #3
Hen

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Re: Dobby's Ejection Test
Firstly we tried some home made BP, carefully measured out, powdered and after we mixed it the lot was wetted and left to dry. Then we made the bits a little smaller. This power burnt fine but not like the real Mc Coy. It just made a puff but would not kick the parachute out. So what next, we tried some of the Martini Hendry’s black stuff, Shocked quickly realizing that we used an overdose. Rockets are great fun!!  Grin   (Unlike the missus, Dobby didn’t even get stretch marks after labor! )   
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Read August 08, 2008, 04:03:35 AM #4
Ryno

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Re: Dobby's Ejection Test
It's very difficult to make BP correctly! Smokeless shotgun powder also works but you can easily overdose and blow the rocket to pieces.

Is Dobby made of cardboard?The fuselage mainly?

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Read August 08, 2008, 10:18:10 AM #5
Thruster

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Re: Dobby's Ejection Test
Good Ejection Wink

The first time i test mine vertical the AFT fuselage cracked.

Then i put it horisontal on a stand and it worked.

(Ryno i want to send my vidio clip but i cant,?Huh  )
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Read August 08, 2008, 05:15:55 PM #6
Hen

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Re: Dobby's Ejection Test
Dobby was made out of a sheet of paper and wood
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Read August 12, 2008, 02:12:25 PM #7
Ryno

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Re: Dobby's Ejection Test
 Cheesy Paper Power! I prefer paper cardboard. Other materials like carbon fibre etc are to expensive and they shatter.

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