Friday, January 21, 2011

Reviews: Micro Viking and Micro Titan III-C MOL

This post presents a review of semi-scale Micro Viking and Micro Titan III-C MOL  models.

Micro Viking

This is an easy to build, semi-scale model of the Viking sounding rocket for MMX-II motors.

While waiting for my Nano Rocketry kits and tubes, I decided to rummage around my junk pile to see what I could use to make my own nano-sized rocket. I quickly found one of the tubes that the Aerotech First Fire igniters come in. A little too big for a Micro Maxx engine and maybe a little too heavy, but what the hey? I then started thinking about nose cone material, and discovered that a 3/8" dowel is exactly the right diameter. Next, I had to decide what to build. I wanted a simple 3/4FNC rocket and after thumbing through "Rockets of the World", I soon settled on the Viking. When I checked the length of tubing required, I found that the tube was less than a tenth of an inch off. No cutting required! I put my drill in the vise, a chunk of dowel in the chuck, and within a few minutes had a nice nose cone. I drilled a hole in the back end and glued in a piece of 100lb. tubular Kevlar®. I made the fins from 1/16" balsa and soaked them in CA for added strength. For the launch lug, I split a standard Estes lug in half and CA'd it on.

The whole rocket is painted white and the nose cone silver. I had no brush-on black paint and this rocket is too small to try to mask (for me), so I substituted my favorite color, metallic purple, for the black trim.

A couple of wraps of masking tape and the Micro Maxx engine fit nicely. I also cut a thin strip of tape and made a thrust ring. I have flown this rocket six times   My make-shift launch lug worked fine and the rocket rose straight and to an impressive altitude, much higher than the stock Tomahawk or my converted micro (10.5mm) rockets.  The tumble recovery works fine on grass fields.

The tubing used to package the Aerotech igniters makes a good airframe for Micro Maxx rockets. Coupled with the ease of making nose cones from 3/8" dowel, you end up with a nice, easy-to-build model. The resulting rockets may not be the best performers due to their weight, but they still fly well and look nice.

Micro Titan III-C MOL

This Micro Maxx rocket is a semi-scale model of the Titan III C Manned Orbiting Laboratory (MOL) mock-up, which included a stretched version of the Titan III C topped with a Gemini capsule. Although the actual MOL never was built, the mock-up did fly on November 3, 1966. For more info, see "Rockets of the World", by Peter Alway.

After the success of my Micro-Viking, I decided to build a second rocket using the tubing from the Aerotech First Fire igniters. This model uses one 5 ½" tube for the main airframe and two 2 ½" sections for the strap-on boosters. The nose cones were all turned from 3/8" dowels. I was not terribly careful with the dimensions but the overall look of the rocket is about right. I used Estes launch lugs for the side pods and thin packaging plastic for the fins.

The recovery system includes a section of thin Kevlar® twine and as much streamer material as I can stuff in (to be installed at launch).

I used a small hook-eye on the nose cone because I was afraid some extra weight might be required. The CG of the finished model is 4.125 inches from the tip of the nose.

I used a mix of glues - carpenter's glue for the wraps and boosters, thick CA for the clear fins, and Liquid Nails for the side pods. I also used some Liquid Nails on one fin, which for some reason refused to be bonded with CA. This was odd since the other three fins adhered just fine.

I painted the capsule black, the booster cones silver, and the side pods red. The tubes are covered with paper wraps that I printed on my Inkjet. Again, I did not try to be too detailed; for instance, I increased the size of Air Force emblem and text to make them more visible. Before cutting out the wraps, I shot on a coat of Krylon clear polyurethane spray to try to help prevent smudging. From a distance, the finished product looks good (my opinion of course!) but up close, there are a few smudges, wrinkles, etc. With some practice, however, I think this technique will work fine on small models. Prior to launch, I also added American flag stickers to the clear fins (after the photos were taken). My new launch policy is to have at least one flag displayed on every rocket I fly!

The engine is meant to overhang to the bottom of the fins and is held in place with masking tape. I have flown flew the rocket three times on the MMX-II motors. The flights were stable and fairly low. I forgot the streamer stock so I decided to fly with only nose cone separation. It survived the first flight just fine, but one fin broke off on the second flight. This was not a big surprise since the rocket is relatively heavy and comes down fast.

Despite a few finishing flaws, I am quite pleased with this rocket. The materials and techniques I used worked well, and the resulting rocket looks nice and flies fine.