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Re: Piston Ejection System/Baffle

I'd recommend a baffle over a piston. The flight-proven baffle system that I developed goes something like this:

  1. Epoxy a chunk of steel or aluminum screen in the top of the motor tube. For a 29MM tube for example, use a fired Estes 24MM casing to shove the screen in the top of the motor tube a 1/2" or so. Then epoxy or CA the screen in the tube. 1" aluminum screen patches work great for 29MM.

  1. Stuff some steel wool (not packed tight) up the other end of the motor tube. You can use whatever grade of steel wool you want, or stainless or copper scouring pad. I use #0000 steel wool with no problems.

This is my variation on the Aerotech type baffle. I use a long hook to yank out the steel wool and change it out after a couple of flights. I like this baffle better than others which involve drilling a series of holes in the motor tube and top centering ring. Reason being that you don't have to listen to crap rattling around inside the baffles of your rocket after firing.

-- Joe Michel NAR 82797 L1

All, > > I'm looking for some advice on piston ejection systems/baffles as a > replacement for chute wadding. I'm just getting back into the sport and I > would like to use something other than wadding on my new Public Enemy 3" V2. > Any advice is appreciated... > > Lou > >
Reply to
J.A. Michel
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Bad idea. Regular window screen rarely survives one flight. Even for 18mm motors.

REALLY BAD IDEA!!! Steel wool, especially as fine as 0000 is extremely flammable! It makes great tinder for flint and steel or other matchless campfire starters. Use only stainless scouring pads if you are going to do this type of baffle.

For a better baffle design, see my .sig

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

Maybe you missed the part where I said it was FLIGHT PROVEN.

-- Joe Michel NAR 82797 L1

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Reply to
J.A. Michel

Yup, steel wool is really bad. A lot of steel wool has a oil like substance on it.

You can take a 9 volt battery and touch it's contacts with the steel wool and you have a very good fire starter.

I even have *tried* to use steel wool as a filement for a low current cluster ignitor for small composites. No joy as it's damn near impossible to wrap steel wool.

Ted Novak TRA#5512

Reply to
the notorious t-e-d

Many venders (like Giant Leap, etc.) carry nomex and/or kevlar chute protectors. I'd go that route instead of a piston. Simple, inexpensive, and works fine.

If you really want a baffle and you have the room, check out Bob Kaplow's. I recently used his design on a crayon rocket and it works great.

Reply to
Bill Wehner

More like lucky...

As a Scout Master, we use steel wool to start a camp fire. In other words, it doesn't take much to get it smoldering. I wouldn't say that it is as effective as smoked cotton scraps or magnesium shavings, but it is a viable alternate for fire building.

DEFINITELY do not use steel wool. Use stainless scouring pads as Bob suggests, or some other heavier guage style baffle. Many common metals are flammable in the form of fine mesh or shavings.

~Duane Phillips.

Reply to
Duane Phillips

Agreed. Or he's just never looked at what happens at the critical time...

I've heard it works even better when damp! I guess it starts the oxidation reaction ahead of time...

If the material will oxidize, very fine shavings / powder will burn. Or even explode. Steel. Magnesium. Flour. Balsa. BATF paperwork.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

One more time: Coarse (pot scrubbing) stainless steel wool os OK for baffle material. Fine steel wool (even the stuff labeled coarse is fine) designed for paint finishing is NOT, and in fact is quite flammable. DO NOT USE IT IN ROCKETS AS WADDING OR AS A BAFFLE. It makes excellent tinder for starting campfires.

Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!

Reply to
Bob Kaplow

I think you're overstating the blazing baffles a bit. The fine steel wool will burn when you open it up and spread it out, but shoving some up a motor tube where it is compressed is another matter. Have you ever flown a rocket with this type of baffle? Probably not because yours is better. Why don't you try it once before you 'flame' my idea? Tell you what, next time you need to start a campfire, try using nothing more than a C-6-5 and a steel wool baffle system complete with motor tube. I think you'd be in for a cold night of camping.

-- Joe Michel NAR 82797 L1

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Reply to
J.A. Michel

Bob, relax, that's what I meant: night launch, get it!?? smiles for the :^) impaired.

Reply to
Cliff Sojourner

I've used a medium-fine grade of steel wool with great results, but I wouldn't wanna try it with the really soft/fine stuff.

Reply to
rocket

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