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  #11  
Old 06-06-2005, 12:39 AM
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A Fish Named Wallyum A Fish Named Wallyum is offline
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Sounds like a Goony waiting to happen.
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  #12  
Old 06-06-2005, 12:40 AM
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Exclamation New Plan -- Kick A Pig

Blame Jay for this one!

Fat, short, odd-looking, belongs in the water and not in the air...

It's yellow, too...

Custom nose cone and cored transition (BMS), and the airframe is from PML (PT-3.9).

Estes BT-50 motor tube. Composite F39 with a 3-second delay is the only recommended motor.

Enjoy!
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  #13  
Old 06-06-2005, 12:44 AM
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Better idea. Call it "Squeal Like A Pig" and just put a picture of Ned Beatty on a Fat Boy.
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  #14  
Old 06-06-2005, 12:49 AM
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Kick A Pig should have been posted in the other thread, but it's here for Jay...

My other first thoughts were to make it look like a football, with laces and everything. I might come up with a Flying Pigskin a little later...

...I've got to get that one to spin off the rod, though...

...Maybe a two- or three-motor cluster, with tilted mount tubes, and have the rod going right through the center...

See what you've made me do, Jay!!???

This "thinking" stuff really is dangerous!

Craig
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  #15  
Old 06-06-2005, 01:27 AM
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Quote:
Originally Posted by CPMcGraw
In the simulation drawing, I used a 6" motor mount, but installed the motor block at 3.5" from the rear of the tube.

The E15-7 is one of the motors I used in the list. The simulator hit 1518', and reached speed at 36.25". Still needs the 48" rod.

Best altitude was with the F24-7, with 1719'. Speed was reached at 27.2", meaning you can squeak by with a 36" rod here. I'd still use the 48" rod for the additional speed before free-flight.

Craig McGraw

Hmm.. I noticed on a couple of my D12 flights that my previous 'Roc seemed to "hang" momentarily just off the rod. I wonder if rockets like this and the Mean Machine may actually have such long moments on their CG that they have a bit of "inertial stability" that resists changing direction even if they haven't quite reached aerodynamic stablility off the rod. Not that I wouldn't use a 48" rod just to be safe, but wonder what your thoughts are on this.

The reason I started considering this idea in the first place is because the Thunder Roc would be easy to see at higher altitudes, with a better chance of recovery. Still, a calm day is a must if it's going to 1500'. I went with dual 18" chutes on the last one and never broke a fin, though I DID walk a quarter mile to recover one day with 10 MPH winds. (Where's the emoticon for "exhausted"?)
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  #16  
Old 06-06-2005, 06:25 AM
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Default The WINNER, and still CHAMPEEN!!!

Grip It And Rip It!!!
http://www.rocketreviews.com/review...hunder_roc.html
Imagine my surprise. Here I was looking forward to my first Thunder Roc flight with an Estes E9 and it turns out that I ALREADY DID IT!
Then again, it did do that hangin' thingy just as it cleared the rod. Now I just want to try one that's built without basswood fins and epoxy fillets.
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  #17  
Old 06-06-2005, 11:06 AM
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Quote:
Originally Posted by A Fish Named Wallyum
Grip It And Rip It!!!
http://www.rocketreviews.com/review...hunder_roc.html
Imagine my surprise. Here I was looking forward to my first Thunder Roc flight with an Estes E9 and it turns out that I ALREADY DID IT!
Then again, it did do that hangin' thingy just as it cleared the rod. Now I just want to try one that's built without basswood fins and epoxy fillets.

I thought I saw an E launch in that review's launch reports. (They say the memory is the first thing to go.)

To Craig,
I've been playing with the rocksim demo, and modified the design for the standard configuration, just like I built before (sans baffle). It seems to do just fine on the aerotech E15 now.
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Last edited by Tweener : 06-06-2005 at 03:19 PM.
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  #18  
Old 06-06-2005, 12:21 PM
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Quote:
Originally Posted by Tweener
Hmm.. I noticed on a couple of my D12 flights that my previous 'Roc seemed to "hang" momentarily just off the rod. I wonder if rockets like this and the Mean Machine may actually have such long moments on their CG that they have a bit of "inertial stability" that resists changing direction even if they haven't quite reached aerodynamic stablility off the rod.


Nah, it's just that there so much distance between the two launch lugs that when the upper lug clears the rod, any slight change in direction will cause the second one to bind. Rod whip can cause it. That's why you need such a large kick to get these long birds started. It reduces the lag time between the lugs exiting the rod.

Craig McGraw
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  #19  
Old 06-06-2005, 12:55 PM
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Quote:
Originally Posted by CPMcGraw
Nah, it's just that there so much distance between the two launch lugs that when the upper lug clears the rod, any slight change in direction will cause the second one to bind. Rod whip can cause it. That's why you need such a large kick to get these long birds started. It reduces the lag time between the lugs exiting the rod.

I noticed that, too. I always check my 2 lug birds by putting a finger on the nozzle and lifting up rapidly to check for bind. I used steel wool on the rod then wiped it down with a silicone lubricant to lessen the effect.
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  #20  
Old 06-07-2005, 01:10 PM
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Craig,

I noticed that the "E" ThunderRoc Clone rocksim launch guide data says "User specified minimum velocity for stable flight: 43.9993 ft/sec". Is this something you input or does the program somehow arrive at that figure? If it was input, how was it arrived at? Just wondering because the sim says my 'D' launches shouldn't have been stable for a little over 4" past the 36" rod that I was using.

Bill,

What length rod did you use on your 'E' flight?

Excuse me if I seem a little slow, but after all this IS rocket science!
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