Astro X Black Zombie 1-B

Astro X Black Zombie 1-B

Contributed by Andy Hobbs

(by Andy Hobbs)

Rocket PicBrief:
This is a heavy mod of the Astro X Rockets Black Zombie 1-B. This kit is from Hobby Time. (They also make a Wasserfall kit.)

Modifications:
I did quite a few modifications to the kit so a standard kit review wouldn't be fair.

  • It comes with a 24mm motor mount but the number and size of the fins are similar to an Estes Phoenix so I opted to use a 29mm MMT.
  • Changed the fin material to light plywood and added fin tabs that extend to the motor mount. The original balsa fins were surface mount. I also reduced the fin count from 4 to 3 to reduce aft weight. In my opinion the 4 big honkin' fins made the Zombie rocket too tail heavy to be a versatile flyer.
  • Beefed up the centering rings
  • Added 3 internal balsa ribs (3/8" wide) lengthwise between the uppermost and middle centering rings to aid in Body Tube support during landings because the fins stick out way beyond the base of the rocket
  • Aside from the reduction of one fin, externally my build is identical to the stock kit

Construction:
The kit comes with:

  • 1 14.5" BT-80 tube
  • 1 Fat Boy nose cone
  • 1 boat tail (modified Fat Boy nose cone)
  • 1 long 24mm engine mount/stuffer tube [not used]
  • various hardware pieces
  • centering rings [not used]
  • a plastic chute kit [not used]
  • 4 very nice 11" long balsa fins, precut and stack sanded [not used]

I used a couple different glues. I wanted to try some of the Weldbond glue and used it on the centering rings and fins for the initial tack-up. Then I used yellow Titebond II glue for the remainder of the construction except for the Weldbond glue again for the final fin fillets. The Weldbond glue shrinks as much as yellow glue does but stays somewhat flexible. Finally, I added a thin layer of bondo spot putty to smooth things out a little better. I'm pleasantly surprised so far...no cracks. I also installed an Aerotech 29mm engine hook during assembly for motor retention and added an engine block that would contain a 29mm RMS reload casing. I use homemade spacers when loading EconoJets or other SU motors.

Picture

Finishing:
I used Krylon brown primer and Duplicolor black gloss enamel.

LaunchFlight:
I launched it for the first flight on an F23-7W .It flew better than I expected to about 1,500'. It did have a slight amount of squiggle at its max speed (due to the large fin surface area) but I am very happy with its performance. Maybe squiggle isn't the right term for the last part of the powered flight...it was more like short darting motions. It would change course ever so slightly but definitely noticeable...

After running through some more simulations I determined that a small amount of noseweight is needed before I put the G in it.

Recovery:
Recovery was good as it came down just right on the 15" top flight chute. The sod farm is great for recovery--wide open and soft.

Summary:
The Black Zombie sure looks great under power! Plus it's always very satisfying to hear good feedback from the fellow club members.

This rocket definitely looks unique and I can't wait to put the decals and final touches on it.

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