Semroc Mark II

Semroc - Mark II {Kit} (KV-1)

Contributed by Dennis McClain-Furmanski

Construction Rating: starstarstarstarstar
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstarstar
Diameter: 1.04 inches
Manufacturer: Semroc
Skill Level: 1
Style: Clone, Sport
Semroc Rock-A-Chute Mk II

Brief:
A reproduction of the very first model rocket built by Orville Carlisle in 1957. Single stage, parachute recovery. This is a very faithful reproduction of the original which now resides in the Smithsonian along with a few component updates.

Construction:
The kit includes:

  • 1 main body tube, 1.04" diameter
  • 1 18mm motor tube
  • 1 Balsa nose cone
  • 1 set laser cut fins
  • 2 centering rings for MMT
  • 1 thrust ring
  • 1 engine hook
  • 1 screw eye
  • 1 elastic cord
  • 1 Kevlar® thread
  • 1 plastic parachute
  • 1 set tape discs for chute construction
  • 1 set of pre-cut shroud lines
  • 1 "empty casing", actually a small tube used as the oversize launch lug

Semroc's instructions are as superb as their kits. Each step is illustrated with very professional quality pictures, sometimes several pictures in a single step. As an example, in the finishing steps is a series of pictures of how wood filler and sanding progressively fills and smoothes wood. You not only see how, but it teaches you why. Who else does this? Too few. Even their very complete listing of tools and materials needed was illustrated. This kit, as with most of their kits, could be built from the instructions by someone who'd never seen a model rocket before. Also, the instructions include biographical and historical data about Orville Carlisle and the original Rock-A-Chutes Mk I and Mk II, so complete that they note that the nose cone on the original Mk II was a plastic pencil sharpener. A very few kit builders have instructions this good. The rest should.

As noted, a complete beginner could build this. There were no hitches or problems. The pre-cut fins were far better cut than many other LPR models. A few changes from the original were used: 12" hex chute rather than 18" square, MMT to fit today's 18mm motors rather than Carlisle's original motors, MMT includes Estes style engine hook, and the shock cord anchor is Kevlar® thread attached to the top end of the engine hook. Everything fit properly the first time. As a reproduction of the original, built before there were lighter weight components, the parts are comparatively very sturdy. In fact, it's solid as a rock.

Finishing:
Complete finishing instructions are included, even giving the paint scheme of the original (international orange with a red nose). A decal is included that shows the Semroc logo, the name of the rocket, and even the dimensions of the original. Even the model itself becomes a learning experience. I finished mine per the instructions, including the original paint scheme. I'm glad I did.

Construction Rating: 5 out of 5

Semroc Rock-A-Chute Mk II

Flight:
Recommended motors are A8-5, B6-6 and C6-7. Estes wadding was used. Motor retention is by engine hook.

For the first flight I used an A8-3 because that's what I had. I would have been better to get the longer delay. Ejection was before apogee, but deployment was fine. The boost was fast and arrow straight, a perfect and beautiful maiden flight.

Second flight was on a B6-4. Again, ejection was before apogee, but the flight was otherwise great. It impressed the crowd. I too was impressed by the success of this "old" design. So much so that I resolved to build an upscale. And so I did (the Rock-A-Chute Mk III). Having done so, I retired the Mk II to serve as an honored flight veteran and display piece.

Recovery:
The 1"+ body fits the 12" chute easily. However, the body is fairly short, so it's a tight fit to get plenty of wadding in to protect the chute that close to the motor and fit the nose on top.

I'm not fond of the recovery system design due to the Kevlar® anchor being attached so close to the ejection gasses. Kevlar® is flame resistant but not flame proof. I've had it burn through on my Mk III, an upscale of this design, due to the close exposure to ejection charges. Motor mount anchoring is fine, but the Kevlar® should be protected for a bit above the top of the motor tube.

Flight Rating: 4 out of 5

Summary:
The only CON of this design is the shock cord anchoring method (same used in other Semroc models), however, this is easily fixed.

Everything else about this kit and Semroc's work in general is a great big PRO. A beginner would benefit by starting with a Semroc kit. A seasoned veteran will appreciate the historical value and the superb job on the kit and instructions. It's a rare rocket that I want to preserve to just sit on a shelf and show off. This is that rare rocket.

Overall Rating: 5 out of 5

Other Reviews
  • Semroc Mark II By Alan Tuskes

    The Mark II is a single stage Retro-Repro kit of Orville Carlisle's Rock-A-Chute Mark II model rocket. It is, as noted by the history sheet that came with the kit, not a clone kit, but rather a reproduction of a classic kit updated with the latest technology and building components. Opening the packaging and laying out the contents revealed what would be an easy build, using the high ...

  • Semroc Mark II By Bill Eichelberger

    ( Contributed - by Bill Eichelberger - 01/29/06) Brief: The Mark II is the Semroc take on the model rocket that started all this mess, Orville Carlisle's Rock-A-Chute Mark II from 1957. It is a fairly blunt, simple little rocket that's a surprising performer and a definite conversation piece at the pads. Construction: The parts list: Main body tube Balsa nose cone ...

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