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  #1  
Old 01-11-2017, 12:35 PM
Rex R Rex R is offline
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Default Bbig Bertha project

something I am working on...note there is a scarlet fish in the photos . I started with a baby bertha kit, I've made a few changes.
Rex
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  #2  
Old 01-11-2017, 04:15 PM
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Overeasy123 Overeasy123 is offline
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Default Sacred Fishes.

Scarlet Fishes? I'm not trying to be Fish-sheshus here, but I hope the Red Herrings are not the 2 Spoons in the fist photo. Please, tell me these are not Heroin Spoons that will lead to the ultimate derailment of your Big Bertha build.

Seriously though, perhaps the Red Herring is the Engine Tube? Are you building a rear-ejection model, or a tw0-stager?
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Old 01-11-2017, 06:48 PM
Rex R Rex R is offline
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the nose cone is the herring...it doesn't come into play for another 18" of bt60 . guess one could call this a 'kit mingle'. now to build the sustainer/big bertha .
Rex
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Old 02-01-2017, 02:23 PM
Rex R Rex R is offline
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and it is almost done.
Rex
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Old 02-01-2017, 05:02 PM
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Quote:
Originally Posted by Rex R
and it is almost done.
Rex
Looks like a fun rocket. Did you upgrade the motor tubes? Or are you planning to fly it on 18mm motors?

Keep in mind, the booster section, with the fins well aft, will surely come in ballistic - it won't tumble. So you will want it to land on soft ground - as soft as you can find. I'm thinking some thick weeds (ie, wild fescue) but that has the downside of making it hard to find.

Anyway, after you fly it, be sure and give us a launch report.

Doug

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Old 02-01-2017, 05:31 PM
Rex R Rex R is offline
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18mm motors for both stages, thinking a pair of B's for the 1st flight, should stage around 35' - 40' altitude. I did try to design the booster to be unstable...guess I'll find out soon enough .
Rex
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Old 02-01-2017, 06:21 PM
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The Bertha is so stable that you can chad stage a D12 under it. Just an option if you want to fly it twice at the next launch.
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Old 02-01-2017, 07:40 PM
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Quote:
Originally Posted by Rex R
I did try to design the booster to be unstable...guess I'll find out soon enough .
If it has some weight on the fin tips, that would help destabilize it, to make it tumble. But it also adds weight to an already burdened booster motor to lift. And it increases the landing mass, which ain't good for tumble recovery parts

Anyway, like you said, you'll find out. And repairing, or rebuilding a booster isn't too difficult. It pretty much goes hand in hand with flying staged rockets

Doug

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Old 02-01-2017, 09:32 PM
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Quote:
Originally Posted by Rex R
and it is almost done.
Rex


That is COOL!!
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Old 02-19-2017, 04:58 PM
Rex R Rex R is offline
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had beautiful weather(who would've thunk that we would get over 60F and no wind, in February, in Wisconsin), so the B-Big got its' maiden flight on a pair of B6 motors. not a blink and miss it launch. it were a slow deliberate launch to about 30' then staged, sustainer got up to approximately 300'. about as close to textbook as it gets. as for booster stability after staging...unknown, by the time anyone looked it had landed(undamaged). beauty shot of it sitting on the pad.
Rex
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