Cluster Choice?

snipped-for-privacy@aol.com wrote:


Seems like good advice for kit bashing to me.
What is your concern with the method?
--
Gary Bolles

summum jus, summa injuria est
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THat's not how "The Master" did things
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snipped-for-privacy@aol.com wrote:

OIC. Well, thanks for that technical critique.
Gotta go, have to break out the slide rule and do some more flight sims.
--
Gary Bolles

summum jus, summa injuria est
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wrote:

Just think, if you did an article about THAT these days you would seem like a GOD. Technology indistinguishable from magic to the computer game fixated generation.
The batteries cannot die, the HD cannot crash and it works in bright sunlight. Better!
Jerry
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
Opinion, the whole thing. <mail to: snipped-for-privacy@gte.net>
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wrote:

I wonder what it says about me that, although I write computer software for a living, and carry a Treo 600 PalmOS-based phone with me at pretty much all times, I also keep a Pickett slide rule in my backpack and prefer to write with fountain pens?
To prevent cheating (by storing text in a programmable calculator), my Economics teacher last semester had a policy that any calculators used during his tests had to have less than thirty buttons. He got a funny look on his face when I pulled out a slipstick for the first test....
- Rick "It qualified" Dickinson
--
"The radio business is a cruel and shallow money trench, a long plastic
hallway where thieves and pimps run free, and good men die like dogs.
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wrote:

I'd call that a slapstick slickstick
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You are a quality individual?

It qualifies!

Jerry "old technology is good technology" Irvine
Vacuum tube based amplifiers. Black Powder Free over the air TV etc
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
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So YOU invented zero tolerance!!!

--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
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Hmmm, my PDA has 6 buttons, including the POWER switch...
Even cell phones have calculators that can store text.
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
... One nation under surveillance, divisive, with liberty and justice for none.
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On 14 Jun 2005 20:51:58 -0500, kaplow snipped-for-privacy@encompasserve.org.TRABoD (Bob Kaplow) wrote:

Phones and PDAs were also specifically prohibited during exams. As mine is a Treo 600, it got hit by all three prohibitions. The slide rule just seemed to be the solution that made the most sense, to me. After all, I already had it and knew how to use it, and it *did* have fewer than 30 buttons....
- Rick "Actually, just as fast in most cases" Dickinson
--
Every parliament or congress worldwide should be equipped with a
hundred-pound chunk of sodium in the entrance foyer, such that any
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I think that's EXACTLY how the master did things...
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
... One nation under surveillance, divisive, with liberty and justice for none.
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kaplow snipped-for-privacy@encompasserve.org.TRABoD (Bob Kaplow) wrote:

How do you think he BECAME a rocket god?
--
Jerry Irvine, Box 1242, Claremont, California 91711 USA
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Bob Kaplow wrote:

My experience has been that a C6 engine puts the Fat Boy at the edge of stability, into the neutral zone until it gets some speed. They usually get to 25-40' and then take off straight in whatever direction they happen to be pointed. These are built stock, with yellow glue, so I don't think it is overbuilt in rear end. Does anyone else have similar experience?
Curtis Reynolds
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writes:

Given the erratic flight I had with mine the first time I tried a D13 reload (and then added nose weight) I'd agree. Another solution for C6 flights is a much longer launch rod.
    Bob Kaplow    NAR # 18L    TRA # "Impeach the TRA BoD"         >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:    http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org
Timid men prefer the calm of despotism to the boisterous sea of liberty. -- Thomas Jefferson
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reload
a
I think they should change their name from Fat Boy to Arch Rockets. Launching one is like target shooting with a bent rifle barrel.
Randy http://vernarockets.com /
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Bob Kaplow wrote:

Thanks, Bob, but I'm just a little concerned about the apparent over stability of a stock FB based upon several online flight logs.. I'll check the margin on a stock setup and see wnat it is.
If not one caliber, what would you consider to be "safe" for a stubby?
I decided on an alternating 18/24mm ring cluster in the BT-80 so I can start with 3x18 and work up to a 3x24 + 3x18. I'll hack off the bottom of the NC and epoxy a removable eye bolt forward in the NC so I can change nose weight (washers) based on motors. I can tweak the stabilty margin to whatever is necessary. Just looking for a reasonable, safe starting point.
--
Gary Bolles

summum jus, summa injuria est
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CJC wrote:

My choice would definitely be the 24+6 cluster! Way more flight options, which means more variety and less boredom. Plus it's handy if you can't afford to fly it fully loaded everytime, or if certain motors become hard to get for some reason.
@
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CJC wrote:

<snip>
Finally attended a non-school launch today, first time since last August.
Fast Boy (nicknamed Stumpy by my sister) was ready to fly (without finish) after a furious late night build session. Fast Boy is a 6 motor (3x24 + 3x18) bash of a Fat Boy. She has stock dimensions, basswood fins, a glassed body tube, and the NC has an eyebolt epoxied in to allow for fender washer nose weight change. She comes back down on a 24" nylon chute and about 10' of 3/8" elastic and Kevlar. She flew today on a 3xD12-5 cluster in light winds at 450 gms launch weight. With a 5 degree angle, she came off the 1/4" rod with all motors blazing and arced gently into the breeze with a tiny, but noticeable, tail waggle. Some heat damage to tail from being too close to blast deflector, but no flight/recovery damage; a very nice flight to around 1,000 ft.
The inner layer of BT-80 tube paper delaminated up forward where I had soaked it with thin CA and it seemed scorched and brittle. Haven't seen this before and it looks like a heat effect from 3 ejection charges. The tube without CA on it did fine. The nosecone could not be replaced on field because of the delamination, so the 3xE9 flight will have to wait till next time. Looking forward to a full-on 6 motor launch.
In other news, the Lake got two of my favorite rockets today. Reverse Causality caught another thermal on an E9-6 flight and this time never came back. PL-1 went horizontal off the rod on two D-11's and a C-11 core motor. Did a pretty impressive cruise missle demo and ejected at high warp velocity. Chute shredded and the tethered payload-rocket flat spun into the lake. A fisherman pulled it out, but too late; the body tubes delaminated and the swelling engine cases split the outboard mount tubes. Sigh. I could not have aimed the thing more directly at the water. Ironically, one design goal of this rocket was a predictable flight path to keep it OUT of the lake. Ten months is too long between flights. It didn't dawn on me till I was on the way home that PL-1 NEEDS payload weight with motors in the outboards.
--
Gary Bolles

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COOL flight with 'Stumpy' Fast Boy! :-)
It's interesting to here about the delaminating BT. Always thought I was doing good by coating the ends with woodglue or epoxy? Maybe woodglue wouldn't go brittle?
Ejection must be a real BLAST (Pun intended) :-)

Dang it!!! Them Rocket Gods are everywhere. And here I am thinking they were just picking on me...... :-)
Cheers, Clint
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CJC wrote:
<edited for brevity>

<snip>
It was pretty neat. Thanks for the inspiration.
This was a difficult, but interesting build. These short, fat rockets mess with my paradigm of stability and I learned a lot by doing it.
<kit bash warning> For those who read this thread and want to stick more or bigger motors in a kit; you cannot just put more motors in a kit and fly it. You MUST consider stability and weight issues. Changing ANY parameter of a commercial kit that is outside the manufacturer's recommendations may result in a potentially unstable and dangerous rocket. If you are not comfortable with checking and ensuring the stability of a rocket, do not modify a kit. Buy a kit which is made for the motors you want to fly.
If you are interested in learning about kit bashing, read up on rocket stability. Apogee Rockets has a LOT of info on stability and they offer a free, demo version of Rocksim. Ask questions here on r.m.r. Don't be afraid to get into rocket design, its one aspect of rocketry which keeps it fun and exciting. Just take your time and never launch a modified rocket unless you KNOW its Center of Gravity, Center of Pressure, and stability margin and how those three parameters affect the flight of a rocket. If you fly at a club launch, tell the RSO it is a modified kit. He/she will give it a closer look and ask you some questions that you should be able to answer before flying a modified, or scratch, rocket. </kit bash warning>
--
Gary "Keep the pointy end up" Bolles

summum jus, summa injuria est
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