separating mean machine in middle?

[tripleup05]

I am about to begin building the Mean Machine, actually the Sunward 6 Footer, but they are practically the same rocket, and would like to know how to split it in the middle. I know I need to go and buy some body tubes to make couplers because the supplied ones are only like 3" and are junk. I assume that atleast where it will split and not be glued it needs a good and long coupler.

Just guessing here: Build engine mount and fins as normal and attach 2nd body tube to lower tube as normal. Attach top and 3'rd body tube as normal with the exception of gluing in the nose cone.

For attaching bottom half to top half: Use a 6" coupler, and glue 3" of it inside bottom half. Mount shock cord to inside of coupler. Glue some sort of solid ring 5" inside of top half for ejection charge to push on. Attach other end of shock cord to inside of top half below ring. Tie parachute in the middle of shock cord.

For flight: Pack wadding into bottom of rocket, and pack 'chute into top. I am thinking that upon ejection, the chute will get shoved up against the ring in the top half, but as the rocket seperates, the chute will get pulled out as the two halves dangle. Ofcourse the 'chute cords will have to be shorter than the distance from where the chut is tied to where it is packed inside body tube. Wow this sounds kinda complicated...any other ideas???

Uh oh I just realized something. The cord cannot be attached to wall of upper body tube as I thought. If i did that, then it wouldnt slide down over the coupler. Maybe have a small hole in the ring and run the cord through it and attach to the other side possibly?

[sandman]

This is how I did my Mean Machine.

Two halves two body tubes each that break in the middle.

All you need is a 4" balsa BT-60 tube coupler. either make it yourself or you can get them from Balsa Machining services.

They are fairly easy to make with a drill, a block of balsa, or just basically carve it by hand. It doesn't have to look pretty. :rolleyes:

Glue the balsa coupler into the upper body.

Attach a large screw eye to the coupler for the shock cord.

Sand a shoulder on the bottom edge of the coupler to glue the paper coupler to it. This will be an "extension" to the coupler.

You will have to peal a layer of paper off of the coupler so that it slides off smoothly.

Glue the standard tri-fold shock cord mount into the lower half.

The coupler should be at least 4.5" to 5" long so the model doesn't bend or flex.

All you need is the balsa coupler and a screw eye.

[tripleup05]

Yea that does sound like a good way to do it. A little less complicated than my way lol. So how do you use a drill to make the coupler? Somehow turn it into a lathe? (I think thats what it is called)

[sandman]

Yea that does sound like a good way to do it. A little less complicated than my way lol. So how do you use a drill to make the coupler? Somehow turn it into a lathe? (I think thats what it is called)


Well, I am the sandman and turning parts on the lathe is what I do. :D

But here's how you can do it.

Get a block of balsa or glue up some balsa to make a block of wood that's bigger than a BT-60 (a BT-60 is 1.634"...make it 2.0" if you can.) It doesn't have to be perfect just bigger than the body tube.

Find a piece of wood dowel that will fit in your hand drill. The thicker the better. Probably 3/8" maximum.

Drill a hole in the center of the block of wood so the wood dowel fin in real tight...but don't split it!

Glue the dowel into the block of wood and make sure it's as centered as you can get it.

When the glue is dry chuck the wood dowel with the block of wood on it into the drill. Now clamp the drill motor so the wood block is hanging over the end of your work bench (or get a friend to hold onto it real tight!

Turn the drill on and with a sanding block sand it round.

Be prepared!! yer gonna make copious amounts of sawdust! :rolleyes:

Keep checking it with a section of BT-60 body tube until it's a nice fit.

Make sure you make a little shoulder (about 3/8" at least) to glue the paper tube coupler on.

You can check it for fit but turn the drill off first! :eek: :rolleyes:

When that's all sanded to a size you're happy with, cut the wood dowel off flush and drill a hole into the center for a screw eye.

Now glue the tube coupler on and attach the shock cord to the screw eye.

That should do it.

I hope I explained that correctly... :o

[sandman]

For more information on "turning' balsa parts try Apogee Components.

They have a video "book" on CD-ROM that shows you how to make nose cones (and balsa couplers! ;) ).

http://www.apogeerockets.com/make_nose_cones.asp

[tripleup05]

cool thanks for the info. I'm definately gonna give that a try

[Tweener]

Well, I am the sandman and turning parts on the lathe is what I do. :D

But here's how you can do it.

Get a block of balsa or glue up some balsa to make a block of wood that's bigger than a BT-60 (a BT-60 is 1.634"...make it 2.0" if you can.) It doesn't have to be perfect just bigger than the body tube.

Find a piece of wood dowel that will fit in your hand drill. The thicker the better. Probably 3/8" maximum.

Drill a hole in the center of the block of wood so the wood dowel fin in real tight...but don't split it!

Glue the dowel into the block of wood and make sure it's as centered as you can get it.

When the glue is dry chuck the wood dowel with the block of wood on it into the drill. Now clamp the drill motor so the wood block is hanging over the end of your work bench (or get a friend to hold onto it real tight!

Turn the drill on and with a sanding block sand it round.

Be prepared!! yer gonna make copious amounts of sawdust! :rolleyes:

Keep checking it with a section of BT-60 body tube until it's a nice fit.

Make sure you make a little shoulder (about 3/8" at least) to glue the paper tube coupler on.

You can check it for fit but turn the drill off first! :eek: :rolleyes:

When that's all sanded to a size you're happy with, cut the wood dowel off flush and drill a hole into the center for a screw eye.

Now glue the tube coupler on and attach the shock cord to the screw eye.

That should do it.

I hope I explained that correctly... :oAnd don't forget to wear eye protection! Heavy work gloves wouldn't hurt either. :D Always do the Safety Dance!

[tripleup05]

You dont gotta tell me about safety. I learned my lesson. I weld and do all kinds of metal work, and the eye doctor told me i have a piece of metal stuck in my eye. He said never get an MRI cause the magnet will suck it outa my eye :eek: So safety glasses from now on

[sandman]

When turning balsa the worst part is the DUST!

It's probably a carsinogen. :eek:

Even with a dust mask.

It really helps to have a helper holding a vacuum cleaner or dust collector hose! :D

Hey! Why do you think I'm the "SANDMAN"?

I didn't make up that name...that's what my wife calls be when I come in from the shop!

I do a LOT of sanding. :o

[Tweener]

You dont gotta tell me about safety. I learned my lesson. I weld and do all kinds of metal work, and the eye doctor told me i have a piece of metal stuck in my eye. He said never get an MRI cause the magnet will suck it outa my eye :eek: So safety glasses from now onOuch! That hurts just reading it. (grimace emoticon)