Enough Motor for Double Fat Boy?
 

It's time to send this up,I bought some B6-0 boosters for it and it weighs 6 ounces without engines or recovery and I might use two 'chutes. I should be able to find some A size boosters too,would these be too small?

Judging from what I have read, a C motor just barely gets a stock Fat Boy up into the air, so I can't imagine why you would want to try to hoist a two-staged version of it up on a B booster :eek: (and with an A booster, it probably wouldn't even make it all the way up the launch rod, if it even budged at all). Change that motor mount to 24mm, and put a D12-0 in the booster!

MarkII

Well,unless I find some B14's the impulse will be the same,I'm trying to get it to go low not high,yet still be stable. I think the old A's were A10-0's were they not? It does seem like a bit of a pig though,so I'll start with the B's and see what happens with a B6-0/B6-2 combo. Of course I'll have some C6-0's on hand just in case...I'll video my next launch so I guess we'll know!

Well, I suppose that it might be possible to get an OK boost of your Fat Boy on a C6; I don't know. I'm very skeptical about the chances of a successful boost with the B6-0, though, and I definitely wouldn't try it with A10's unless you clustered, say, five of them (or more). The thing about the FB isn't so much the weight but the frontal area of the BT-80. A motor that can easily launch a BT-60 based rocket that is the same length and overall weight of a stock Fat Boy will have to do a lot more work to get an actual FB going, even though it is exactly the same weight, because the much wider body adds significant drag. For that reason, putting a D12-0 in the booster and having it stage to say a B6-4 would probably not result in that high of a flight because the rocket is so draggy. A booster motor doesn't just have to loft a certain amount of weight off the pad; it also has to push the stack through the air.

MarkII

I can't wait for this video! Please, try to get a few cameras filming from different angles. This could turn out to be the video of the year. :D

Why not play it safe and sister up 2 small tubes and cones and put a couple of A10's in side assists boosters on that lower stage? Just thinking out loud.

Look up the maximum liftoff weight for the motor to avoid a crash and fire.

http://www.esteseducator.com/Pdf_fi...t%20pg%2030.pdf
http://www.esteseducator.com/Pdf_fi...s%20PG%2031.pdf

If you're at 6 oz dry weight, I think that's firmly in the D12 catagory for the booster. D12-0 to B4-4... maybe. That'll keep the upper stage low.

B6-0 has plenty of power. I've launched a 5 oz (dry weight) rocket on an A8-0 just fine. So a B6-0 should handle a 6 oz rocket easily.

Please read the first post in this thread. The rocket weighs 6 ounces without motors. it will be very overweight with the motors.

And, a B6-0 is different than an A8-0. The thrust curve is different and there is an opportunity for the rocket to 'fall out of the sky' during the sustaining phase of the B6-0 burn. of course, the modern A8-0 is very different from the A8-0 of 20 years ago. it also has a sustaining phase with low thrust. The older version acted like a short core-burner. Not anymore...

C6-0 to B6-4

or

C6-0 to C6-5

That's what I would do. It should stay low enough on those combos. I don't think it needs a D12-0, even though it might be the best choice. The Estes C6 is a workhorse of a motor and should get 'er going and make for a low and slow staging event(might be cool to see). I would definitely stay away from any A or B booster....no way, no how.