Estes Bandit K-48 Question

Hi All-
I'm in the process of procuring parts to clone the Bandit and am having trouble locating the BT-51CI tube that's part of the baffle system. I guess
I can cut down a larger tube to make this part, however the more I look at it I really don't see what the purpose of this tube is.
I'm hoping someone here can offer some wisdom on the function of this tube.
Thanks in advance for any replies...
Scott (A 40 something BAR)
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Scott Froese wrote:

Guess: I've sleeved the inside of an airframe for resistance to ducted ejection gases. Maybe it performs a similar function by reinforcing the outer baffle tube.
--
Gary Bolles

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It's a marketing tool. IIRC, the sleeve you're talking about is plastic and has a plastic cross bar assembly inside. Correct? If so, then the only function I can find for it is to provide a connection point for the shock cord that is directly in the path of hot ejection gasses. This ensures that the SC will soon break. This will require the user to buy another rocket. Thus, it's a marketing tool.
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Reece Talley wrote:

The K-48 plans at JimZ show a tri-fold mount. I don't remember a plastic SC mount, for the early kits at least.
In the Bandit baffle, the tube in question would not be in a direct ejection path. It is/was a pretty good baffle system.
I use a less "complicated" baffle (slightly modified Kaplow) with sewing elastic SC and the elastic holds up well to indirect ejection gas.
In my experience, its not the hot gas, its burning/hot particulates which cause most recovery system damage in BP models.
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Gary Bolles

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I was in error and stand corrected. I was thinking about another rocket. If anyone would like a Bandit kit, let me know I may (I'll have to look and will tomorrow if anyone is seriously interested) have a couple and a reasonable offer plus mailing would not be turned down.
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Aha! Perhaps the confusion is the Bandit has been used as the name for at least 2 Estes kits. The original post was about the old classic K-48 kit which was one of the first to use an ejection baffle.
Then there is the recent E2X Bandit (black tube, complex motor mount, slots for 3 black plastic fins, yellow nose cone) that has morphed into several other kits recently. This is the one with the breaks every other flight shock cord mount.
--
Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<<
Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf
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The "new" Bandit like the "new" Renegade should not carry the honorable name. I had both of the original kits and have both of the "new" kits. Quality (now some of this is memory) of the new vs. old is not there and the desings are "not there" except as a profit potential. I am soon going to build both of the "originals" as clones and up scales with a few improvements in recovery harnesses. Now that I know a few new things in this aspect I plan on incorporating them in all kits possible. Aren't new ideas wonderful? mmmmmmm?
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Yup Bob, that's the trouble. I was thinking about the EX2 kit of recent issue.
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I largely agree with that. The one concern I have, and never gets discussed here (or on any other rocketry forum) is the effect of cooling the ejection gas (thru the baffle).
We all know that when a gas is cooled, there is less pressure. The wad of metal in the baffle will absorb lots of heat. Even without the metal, having only the circuitous path thru the baffle, the gases will still get cooled. While both these are good as far as protecting the chute, there will be a resultant pressure drop.
Not sure how much effect it has, but I've always felt better using a big ball of wadding and some dog barf.
Doug
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If you look at the baffle design I use, there is nothing to cool the gasses or drop the pressure. It's nothing but a hot particle trap. Kind of like a darkroom light trap. It absolutely eliminates parachute burn. And it doesn't get clogged like the mesh baffles do.
--
Bob Kaplow NAR # 18L >>> To reply, there's no internet on Mars (yet)! <<<
Kaplow Klips & Baffle: http://nira-rocketry.org/Document/MayJun00.pdf
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Hi, Bob,
If there's any constriction at all - ie, any reduction in cross sectional area - it will act as an expansion valve with a resultant drop in pressure across it. Granted, if there's very little restriction, then there's very little drop in pressure, but a typical baffle must invariably cause some loss.
That said, I must add the disclaimer that thermodynamics was not my best subject :)
Doug
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Doug Sams wrote:

My "mod" to Bob's baffle design is simply a larger number of smaller vent holes. The intent (and I have not tested this at all) is to "encourage" cooling of the hot gas by expanding it across the small orifices. I have not even done any math on this idea, just tried it once and it works as a baffle, at least. Yes, there are several loss mechanisms in any baffle setup, but I have not experienced a failure which I could relate to an excessive pressure drop caused by cooling. Unless you count the cooling caused by the sudden, large volume increase from a kicked motor. ;)
Most of my models (BT-50 and larger) do use pistons, though, which seem to be more efficient than loose wadding. Even a heavily baffled model positively ejects the recovery system with a piston. And I can use elastic on the the motor side of the piston instead of Kevlar, etc. All my baffle experiments were done on BP powered modrocs. I have zero experience with baffles and composite motors. although I am building a replacement L1 rocket right now which has a stuffer tube/baffle and piston recovery sytem.
--
Gary "Never set a fin can where it can be stepped on" Bolles

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