I ordered all the parts to start this project yesterday.

Before I get started I have a few questions, and recommendations.

The Cobra is three 18" BT55 tubes, should I have a friction fit center with a chute for each piece, or do it like the original and have one chute out the top?
If splitting in the middle, at which joint?
What size parachutes?

I probably should build a baffle for this. Where in the body tube should it be?
What type to build. one with offset holes, half moon alternating pieces, Or?

This is the plans for the Cobra 1500

I had one as a kid, and never launched it, tore it apart and made other rockets from it.

Put the baffle at the lowest BT-55 joint (BTW SEMROC has the baffles) and have it separate at the second joint.

Make the upper section a payload bay to separate it with a solid coupler. (SEMROC has those too!)

Oh, yea, I have the decals.

So, really, you don't have ALL of the parts.

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"I'm a sandman. I've never killed anyone. I terminate runners when their time is up." Logan from "Logan's Run"

http://sandmandecals.com/

It will be easier to transport if it separates in the middle.

The original recovered with a single 18" chute. Splitting in the middle will let you recover with a 12" on each section. SEMROC and Fliskits have 16" chutes that would work good with fairly large spill holes.

Half moon baffles work just fine and are easy to make yourself, especially with the extra 18" over the top. Some folks have scorching issues, but I never have. Just make the plates a little larger than 1/2 way across. Build it into the coupler of the lower section. The SEMROC type can't be used as a tube coupler, so you would still need a tube coupler to connect the body tubes.

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I love sanding.

Will there be enough umph in the ejection charge to blow the chutes out on such a long rocket?

Yes, it's always worked on mine. However, if you modify it to separate in the middle, it will only be filling 1/2 the volume.

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I love sanding.

This is a rocket that my brother built way back in the late 70s when we were teens. I am thinking about cloning this one as you pointed out Semroc does have all the parts. I was thinking of putting a "D" engine mount in it as the 18 mm engines seems a bit weak. Custom Rocketry Equinox is a similar rocket and uses a D engine mount.

Thanks for the info guys.
I am impatiently waiting for the mail to arrive.
want to put the three tunes together and nose come and see how tall it is.
What launch rod would you use?

A regular 1/8" rod works just fine. However, you might need to weight or stake down the launch pad if there is much wind. It flies best on B6-4s and C6-5s. I have not tried my Cobra 1500 of an Aerotech D yet.

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'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373

The Custom Rocketry Equinox is Custom's version of the Estes Mean Machine. The OOP Custom Engage was their answer to the Cobra 1500. The Engage also used an 18mm motor mount. I never bought an Engage, but I believe that its flight characteristics would be similar to the Cobra 1500. There are reviews of both the Engage and Equinox on http://www.rocketreviews.com

__________________
'Til next time,

Mike Toelle

NAR 31692 L1

SAM 0373