Magnum Clone

[DPatell]

I have recently started a new project. It's going to be a LOC/Precision Magnum clone using a carpet tube that has the same OD as LOC tubing, but is 1/8" wall. The other nice feature is that it is multiple, alternating layers of kraft paper, then a metal foil. This makes the tube incredibly strong, but a little heavier. I imagine that it is comparable to LOC tubing after being fiberglassed.

I am using the LOC long profile 5.5" cone from my original Magnum. The tubing had to be peeled a little bit at the nose end so that the shoulder would fit the thicker tube. After peeling, the inside was glazed with epoxy to harden everything up and to seal it.

The Main chute bay is 23" long, the Drogue section is 19.5" long, and the fin can is 30" long. Each coupler is 12" of the original tubing, slotted 15/16" lengthwise and glued together with Q-Cell thickened US Composites resin. Then, a layer of 4oz. Satin weave glass was laid across this joint. This resulted in an incredibly strong coupler.

I am still debating whether or not to glass the tubing. It is definately strong enough as it is, but glassing would fill the semi-deep spirals and also give a better finishing surface than the current paper layer.

It's going to have a 36", 75mm motor mount. This way I can use up to an AMW 76-6000 case or AT 75-6400 case (both will never happen), but more importantly there is room for the RATT Works K240 motor, which is going to be having a new reload certified soon, bringing the impulse up to a full K motor with a faster burn. Should be pretty cool!

Here is a picture of all of the tubes lined up.

 

[DPatell]

Here's a pic of the couplers. I'm very happy with how they came out and how strong they are.

 

[jetra2]

It looks great Dan. Great job so far! Keep the pix a comin', ok?

Jason

 

[eugenefl]

Originally posted by DPatell
I am still debating whether or not to glass the tubing. It is definately strong enough as it is, but glassing would fill the semi-deep spirals and also give a better finishing surface than the current paper layer.

I would definitely recommend that you glass this tubing. I have used 3" shipping tube before and discovered one weakness - the semi-deep spiral you mentioned in your original post. That deep spiral is the equivalent of a 1/16" thick wall tube which lends itself to being prone to flexing. On one of my 3" scratchbuild "junk rockets", upon recovery I had the corner of a fin hit the ground first. The end result was a rather large dent that travelled up the spiral about 12-14". It kind of did what an accordian does on its ridges. Better yet, it imitated the coils of a spring compressing causing a long spiral outward "dent".

Just a heads up since I know there will be a significant amount of thrust under your finished rocket. The chances of an airframe failure in midflight seem more likely.

Best of luck to you on your scratchbuilding endeavor.

 

[Ryan S.]

just glass it....it couldnt hurt

looks good man I like those couplers

 

[DPatell]

Looks like I am going to glass them. My only concern is weight, I would like to be able to fly it on a J800T minimum.

I also want it to be able to fly on that RATT motor, I predict a K500-600 or so, which should lift a 20lb. rocket.

Target weight is 20lb. without motor.

 

[Ryan S.]

how tall is it? I would say you would be fine being as The MI is 25 as of right now and I think it is a little bigger...and the fincan is like a brick

 

[DPatell]

I decided I'm going to glass it. One layer of 4 oz. on all the tubes, and one layer fin tip to fin tip. I have the resin on order.

 

[DPatell]

I have fiberglassed all of the tubes with one layer of 4.4oz fine weave glass. Also, I have cut the fins out of 1/4" birch plywood. Tonight I will be placing an order with Giant Leap for the 3" Motor Mount tube, and a 54mm tube for an adapter. I will post some pics soon!

 

[DPatell]

Here is a pic of all the tubes fitted together, and the fins placed in the slots. No internals are finished yet. Awaiting the motor mount...

The red line to the left of the rocket is a yard stick. The blue tube to the left is the RATT K240 casing, which this rocket will eventually *Dave Griffith, we want that motor! * fly on with the accelerated load. The red tube is an Dr. Rocket 54-1706 casing which will be used for the Magnum's first flight on a K695R.

All of the tubes, fins, couplers and nosecone weigh 9 pounds. Not gonna be a lightweight!

 

[DPatell]

Picture...

 

[DPatell]

Got my shipment from Giant Leap today. Started cutting out centering rings, they need to be turned down to the correct OD, and then drilled for the motor mount.

Should be done before too long.

 

[DPatell]

Fast forward quite a bit...


This beast is almost finished! The booster is completely done, ready for some paint. The tubes have been all glassed and the finishing layer of resin is outside curing as I type. The altimeter bay only needs vent holes drilled and then it is ready for flight.

All I need now is a parachute, a strong 75-54 adapter, and to sew up a 50' and 30' shockcord.

Here is a picture of the motor mount with 3 of the 5 CR's and fins attached.

 

[DPatell]

Here is the finished aft end of the rocket. 75mm motor mount and large fillets everywhere. The fins have little to no flex, even with me wrenching on them.

 

[DPatell]

This is the top view of the zipperless coupler, including 5/16" U-Bolt and a lot of epoxy!

 

[DPatell]

This is a view of the electronics bay. The sled is partially out, and will house at least a Missile Works RRC2 or RRC2X. The cylinder is the ejection cannon, and a 5/16" U-Bolt.

 

[DPatell]

Finally, this is how the rocket will deploy. I am using dual zipperless recovery. The main chute bay slides off of the altimeter bay, instead of the traditional nose-pop method. The nose is held to the tube with three 8-32 screws.

 

[eugenefl]

Nice fin can! This looks like a very clean and solid scratchbuild. I think you'll be glad that you glassed the tubes. The extra effort kinda removes all doubt. If anything, the rocket will incur injuries from an awry flight and not the flight itself. Nice work!

 

[DPatell]

The first flight of this model should be 6/19 at CTRA/NARCONN on a K695R. On 6/20, it will fly again on a circa-L1600 Fast experimental 75-3500 motor at METRA. If successful after that, it will fly at LDRS 23 on a K1275R.

This rocket is going to get it's butt kicked

 

[Ryan S.]

cool Dan, looks good, kinda like the Terrier with different fins

 

[DPatell]

Here is a picture of the completed rocket before painting. All that needs to be done now is finish the venting situation for the altimeter.

The lattice behind the rocket is 7 feet tall. I actually underbuilt this rocket somehow, as it is 12 pounds without recovery or motors...interesting...

 

[DPatell]

Here it is painted! I still need to paint the electronics bay tube. This is the red base coat, I hope to try some flames on it...or leave it how it is. We'll see.

Should fly before too long!

 

[Ryan S.]

sweet

 

[DPatell]

I never got a test flight up before LDRS on this rocket...so it's first flight will be tomorrow!

K695R on Friday
K1100T on Saturday
K1275R on Sunday

This is going to be a fun LDRS

600 POSTS!

 

[Ryan S.]

all in that rocket? Cool, I will be there when it shreds ;-)


Just kididng but I look forward to some good flights