blast deflectors

Pottery.

Shapes.

Abrasive cutting disks

Would those be aluminum? How thick?

Bill the Geek

Last year I found some blank, uncoated hard drive disks at a surplus store. I've been using them as blast deflectors and they work quite well up to about K motor. The only drawback is that they're a bit small.

I'm not sure what they are. The surplus store said they were nickle-steel, but someone else said they were aluminum. They drill pretty easy so I'm guessing they may be a high grade aluminum. They're about a 1/16th inch thick.

Bill

I don't have a direct answer for you, although I am pretty sure Doc of

Promise us you won't try Magnesium ;-)

And now with one of my patented brain flashes...

Hmm, hadn't thought of magnesium. That could be fun... once.

I've heard of people using things like this (right-angle chimney flue material, I believe). It worked great for the smaller stuff, but I guess someone tried to use it with a K motor and the high-speed gasses actually caused the tube to suck it's walls into itself.

Bill the Geek

For my model pads I found galvanized round plates for electrical box covers at the hardware store. 69 cents each. About the same size as the Estes pad. If the rocket is a little large the deflector can be repositioned to use a screw hole already in the plate but off to the side rather than the hole I drilled in the center.

For my LMR pad I have a fairly large $3 Stainless steel bowl turned upside down. I drilled a hole in the center for the rod.

For my rails I have another SS Bowl that I dremel cut a section of the bowl so that it wraps around the rail.

Layne Rossi

I used that on all my pads up until 2-3 years ago. Works great on motor under J size. Since they're just thin sheet metal, the bigger motors really do a number on 'em.

Wok.

Joel. phx

I'll put any test results up on the website. I'm always looking for data.

That could be cool too. ;-)

Currently I use the face or front cover from our old furnace. For the rail, I just got some high speed doohickeys from a friend at a copier repair company. They are heavy 1/8 inch thick disks that are 10 inches in dia.

John Hornsby

Pepsi can 1/8 full of BP?

"Recreational purpose"

Email me for a link :-(((

So what are you using on your bigger suff? A water filled flame trench?

Nope, just a hard drive disk to protect the pad, and rocks on and around the pad which do double duty as stabilizing ballast/blast deflectors. :)

I wonder what kind of a 'steam plume' a water filled trench would generate. Anyone tried this before? I'm guessing a big 'ol WL cluster sitting there for a few seconds before liftoff would be very cool.

Patrick

Large. You can improve it by spraying water over the blast area as well. Self-pressurized sprayers are trivial and can be activated at ignition.

Big dumb rockets rule.

Pardon the tech post!

pie pans are nice and cheap