Just another boring HP scratch build

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qquake2k

Captain Low-N-Slow
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I really enjoyed working with the 1/4" plywood for Big Bad Burt's fins and centering rings. So much so, that I decided to do another scratch build using it. This one I'm calling "Ion Disruptor", unless I come up with something I like better. It will be 4" diameter, 50" long, and will have a single 38mm motor mount. It will also be a center break zipperless design.

I really can't stop building rockets. Sometimes I think I like building them more than launching them. Maybe Scotty Dog is right - I am a rocket building machine!

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Using the 4-1/4" hole saw I got off Ebay, I cut out the centering rings and coupler baffle. As usual, I mounted them in my lathe to cut them to the final diameter. Using a 1-5/8" hole saw, I cut out the centers of the centering rings.

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I cut out the discs for the half moon baffles, and sealed the pilot holes with epoxy. I coated the backs with epoxy where the hot gasses will hit, and cut off about a third of each one.

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For the coupler baffle, I printed out a guide to mark the drilling points with. I drilled eight 3/8" holes around the perimeter.

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I put the 1/4" eyebolt in the pilot hole with two fender washers and a lockwasher. I cut off the end, and staked it with a center punch.

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I drilled 3/16" holes for the tee nuts in the aft centering ring, and epoxied them in place. I also epoxied the blocks for the rail buttons onto both centering rings.

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Oooo Ma, Thats too good! I really like this design...like all your others.:wink:
 
Ya, you are TOTALLY boring me to death......
You could at least maybe include a coffee cup or beer can in your pics once in awhile....
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..... ya know what Im saying Norm......:lol::neener::lol::neener:

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Good looking bird!

This one ought to stay pretty low even on a big motor. Might even go slow being that it's a 4" diameter body tube.

Probably ought to make the initial launch on a big G or small H like the Cesaroni G69 Skiddy.

What's the sim apogee prediction on likely motors?
 
Good looking bird!

This one ought to stay pretty low even on a big motor. Might even go slow being that it's a 4" diameter body tube.

Probably ought to make the initial launch on a big G or small H like the Cesaroni G69 Skiddy.

What's the sim apogee prediction on likely motors?

I'm actually thinking about an H73, which is a long burn (2.6 seconds) Black Max. Thrustcurve says 1145 feet. That would give it a good ride!
 
I'm actually thinking about an H73, which is a long burn (2.6 seconds) Black Max. Thrustcurve says 1145 feet. That would give it a good ride!
True but also according to Thrustcurve your launch speed off the rail is only 52 fps. Might be something for a calm day. Even the AT H123 only pulls 73 fps off the rail and 1368' at apogee.

The CTI G69 hits 56 fps but only 816 max altitude. Definitely "Low and Slow". Loud, too.
 
True but also according to Thrustcurve your launch speed off the rail is only 52 fps. Might be something for a calm day. Even the AT H123 only pulls 73 fps off the rail and 1368' at apogee.

The CTI G69 hits 56 fps but only 816 max altitude. Definitely "Low and Slow". Loud, too.

You know, I've thought about driving to Jack's to pick up some CTI reloads. But it would cost me more in gas, so I might just as well pay the $25 hazmat fee. I'd love to put it up on an H123 Skidmark.
 
I cut the motor tube with my miter saw. That new 80 tooth blade sure cuts the cardboard better. I wrapped it with masking tape to protect the outside surface, and it seemed to work. Pretty smooth cut.

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I flooded half the coupler with CA. Also got the forward centering ring epoxied to the motor tube. I used the piece of plastic pipe to level the centering ring and position it in the correct location on the tube.

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Ive used my miter saw for cutting tubes and plastic NCs for boattails.
I think it works like a charm.
Nice coffee cup.........:wink:
 
I cut out blanks for the fins on my bandsaw, then drilled and pinned them. Pinning them makes it easier to cut and match sand them all at once.

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I cut two circles out of pine with my 4-1/4" hole saw. Boy, that sugar pine sure gummed up the hole saw. Had to keep stopping and hitting it with a wire brush. I mounted the circles on the lathe, trimmed them down, and sanded/polished the CA end of the coupler. I also flooded the inside of one end of the upper body tube with CA. I'll hand sand it after the CA dries, as usual.

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I've decided to make the lower fins bigger. They look too small to me.

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Just a quick question. What brand tubes and nosecone are you using... I like the nosecones pointed tip much more than Loc's more rounded tip.
 
Just a quick question. What brand tubes and nosecone are you using... I like the nosecones pointed tip much more than Loc's more rounded tip.

Could be wrong but it looks like a PML one. I like them more then the LOC ones, sturdier and cheaper too.
 
Just a quick question. What brand tubes and nosecone are you using... I like the nosecones pointed tip much more than Loc's more rounded tip.

Could be wrong but it looks like a PML one. I like them more then the LOC ones, sturdier and cheaper too.

I got these tubes and nose cone from Mercury Engineering. They're less expensive than LOC. The body tubes are the same thickness, 0.1", but the nose cone is a little lighter (5.1oz vs. 7.3oz). I also got the coupler from Mercury. I get a lot of my components from them, but unfortunately they don't have 38mm or long 29mm motor tubes. I get those from BMS.
 
I got the half moon baffle discs epoxied in the end of the motor tube.

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