#11
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I wonder about a short, fat rocket for the 3 cluster. BT-80 perhaps, simple swept fins, etc.
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NAR # 115523 Once upon a better day... SAM #0076 My site: http://rocketry.gonnerman.org |
#12
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Quote:
Doug .
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YORF member #11 |
#13
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I've run many sim's trying to adjust the coast time to fit a given motor only to learn that coast time is surprisingly flat over a wide range of mass values. The heavier rocket will burn out at a lower altitude with a lower velocity, but with the added mass, its coast time will be about the same. So if you want a rocket to have a short coast time for use with a cluster of A10-3T's, use draggy construction: large but light body tubes such as the BT-100 or BT-101, unswept fins with no airfoiling, six fins instead of 3 or 4, a ring tail or tube fins. These are the tricks for cutting the coast time. Doug .
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#14
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A variation of the challenge...
BTW, FWIW, I was given a challenge a few years ago to use the A10-3T in an upper stage, without zippering or shredding. Here's what I came up with. It uses BT-55 and it works pretty good. Doug
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YORF member #11 |
#15
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Parts Lists for XFNC Challenge #1, #2, #3, #4
Quote:
Here's the basic #1: BC-1031 Elliptical NC ST-10180 Main Body (2) CR-510 Rings ST-530 Engine Tube TB-5 or TR-5 Thrust Block EH-1 Mini Hook SE-10 Screw Eye SCE-24 Elastic Chord SCK-24 Kevlar Thread CPK-12 12" Parachute LL-122 2" Launch Lug, 1/8" x 2.25" 1/8" Balsa Sheet For both #2 and #3, add: HTC-10 Coupler For only #2, add: ST-10100 Body Tube For only #3, add: ST-1080 Body Tube I didn't use a stuffer tube on #2 or #3, as the ST-10 is small enough that I don't think it would be necessary. For the #4: BC-1344 Ogive NC (2) ST-13180 Body Tubes HTC-13 Coupler (2) ST-5150 Engine Tubes (2) TB-5 or TR-5 Thrust Blocks (2) EH-2 Standard-length Hooks (3) Custom CR-513 Rings for 2-engine clusters (2) LL-110 1" x 1/8" Launch Lugs CPK-16 16" Parachute SCE-24 Elastic Chord SCK-24 Kevlar Thread 1/8" Balsa Sheet This is a deviation from the given design, by using two 15" lengths of ST-5 instead of the short 3" lengths shown in the original design. Add one extra centering ring at the very top of the stuffers for internal support and to close off the volume around the tubes. Use the standard hooks instead of the mini hooks, as the second ring is used to "clamp down" on the hook. Use a touch of epoxy (or JB Weld) to hold the hooks down, and you shouldn't have them come loose. The changes this makes to the design increase the mass to 2.79 oz, drops the altitude to 226', but more importantly, drops the Dv to a mere 2 FPS over the top. All of the simulation runs for this Mk II version show the parachute symbols with no arrows in any run. See the attached files.
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Craig McGraw BARCLONE Rocketry -- http://barclone.rocketshoppe.com BARCLONE Blogsite -- http://barclone.wordpress.com BARCLONE Forum -- BARCLONE Forum BARs helping BARs SAM 0044 AMA 352635 |
#16
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Hey, I like that cluster! Very cool. Thanks for the parts lists, also.
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NAR # 115523 Once upon a better day... SAM #0076 My site: http://rocketry.gonnerman.org |
#17
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Ask Carl really nice, and I bet he could laser-cut those centering rings for you on that cluster, that way they'd be accurate with no thrust vectoring...
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Craig McGraw BARCLONE Rocketry -- http://barclone.rocketshoppe.com BARCLONE Blogsite -- http://barclone.wordpress.com BARCLONE Forum -- BARCLONE Forum BARs helping BARs SAM 0044 AMA 352635 |
#18
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Probably he'd do it. I feel rather guilty asking him... I can't imagine my business is worth the effort he's put into it thus far.
Placed a small order with them last night, just a kit and a couple of couplers, and it had already shipped this morning first thing. DANG they're fast.
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NAR # 115523 Once upon a better day... SAM #0076 My site: http://rocketry.gonnerman.org |
#19
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if you're looking for really inexpensive rockets that fly with A10-3Ts, try the Art Applewhite 13mm paper flying saucer, a 2" diameter mini Sputnik (use bamboo skewers for the 4 legs), or a spool rocket made of a pair of CDs and an interconnecting tube.
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I fought the law, and the law LOST! |
#20
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Actually, I'm not concerned about price (well, not so much anyway). I want rockets that require traditional construction, but that will fly acceptably on the engines we have in abundance. Craig has done an admirable job here.
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NAR # 115523 Once upon a better day... SAM #0076 My site: http://rocketry.gonnerman.org |
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