Semroc - IQSY Tomahawk {Kit} (KD-2)

Contributed by Chan Stevens

Construction Rating: starstarstarstar_borderstar_border
Flight Rating: starstarstarstarstar_border
Overall Rating: starstarstarstar_borderstar_border
Diameter: 0.91 inches
Manufacturer: Semroc
Skill Level: 1
Style: Scale
Semroc IQSY Tomahawk

This is one of Semroc's first offerings in the Deci-Scale line, which represent semi-scale models roughly 1/10th the size of the real thing. The IQSY and D Region Tomahawk's generally represent among the easiest entry level scale models, and this kit is certainly easy to build. But in terms of scale-like accuracy, I'd have to pan it slightly unless the modeler wants to go to significant extra effort. It's a fine kit for basic sport flying, but for scale fans it needs minor improvements.

Components were generally good although a bit of a mixed blessing--I was impressed by the laser-cut basswood fins (greatly reducing the amount of effort required to fill grains) and the balsa nose cone was excellent, but the two body tubes featured spiral grooves significantly deeper than the typical Semroc tubes, which normally barely require any work to fill the spirals.

Instructions are very well written and illustrated and come in Semroc's new format designed to fit in a 3-ring binder for easy reference. This is definitely a skill level 1 kit, and I had mine ready for finishing in about an hour.

One word of caution: if you happen to be building in "batch mode" with many kits on the table concurrently like me, you might want to make sure you don't have a Semroc Marauder on the table at the same time--they use nearly identical nose cones and they're pretty easy to mix up.

Semroc IQSY Tomahawk The motor mount is standard BT-20, metal hook, block, and a pair of centering rings. Note that there is no Kevlar® shock cord anchor on this model. The body tube is marked for 4-fin configuration using a template on the instruction sheet, and the motor mount bonded inside the body tube.

The four fins are mounted with their aft edges at 0.150" forward of the aft end of the body tube. Construction tip: mark that line first around the whole tube using a piece of paper wrapped around the tube to hold a straight line. After mounting the fins, the launch lug goes in between two fins towards the aft end.

The main body tube is actually two-piece construction, which is something I find a bit annoying in a scale kit--especially one that's so short to begin with. I can understand the appeal of holding down the package size for the kit, but we're only talking about a 9" and 6" tube here. In any case, the tubes are permanently joined with a coupler, which also serves as the anchor point for the elastic cord. My anal-retentive craftsman beef with this approach is that I've got a seam/joint to treat, also one tiny bulge where the shock cord pushes out the body tube a little bit. A single piece tube, with a Kevlar® anchor to the forward centering ring would eliminate both of these cosmetic flaws.

If you don't have access to scale data such as Rockets of the World (an excellent resource) or the plan pack available from NAR's Technical Services online store and all you have to go by for finishing is the cover art and instructions, you'll be a bit challenged and it'd be better to just consider this a sport model "inspired by" the real thing.

Semroc IQSY Tomahawk Glaring "would-be-nice-to-have" #1 is the plate and bolt details that run between the fins. It's shown on the cover art and is a key part of the scale appearance, but all that's covered in the instructions is "several gray bolts" and "refer to the photo on the cover". For comparative purposes, ASP sells a smaller (13mm) version of the IQSY and includes a waterslide decal for the bolt pattern with the total kit price of $9.

Nice-to-have #2 would be a printed decal for the upper black band which would include both the bolt pattern and the white stripe. These are beyond the hand-painting skills of the typical leisure modeler and the instructions offer no guidance on the height of the black band (hint--it's about 7/8", actually 0.9").

Glaring "why is this thing in here" is the decal that is supplied--a Semroc log and IQSY Tomahawk label, which is probably helpful if you tend to forget the name of your models, but completely wrong in terms of scale--the real model had no lettering (and the instructions do at least point this out).

In any case, I painted mine with a gloss white base then the top band black and one fin black. The nose cone got a gloss red. I printed out a close enough set of bolt pattern decals on my own over white peel 'n' stick, which adds the 3D effect of the plate. The only downside is that the white does not perfectly match the white paint, so I should probably have shot the decal paper with white paint first.

Construction Rating: 3 out of 5

The first flight went up on a slightly windy day, puffing 6-8mph on the ground but hitting 12-15mph in upper air. I loaded up a B6-4 hoping to keep the rocket within a roughly 500 yard field boundary. It went up dead straight then arced over slightly into the wind during coast. Deployment was slightly early but not enough to go with a different delay.

The 12" plastic chute is fine for this, even slightly more than what is necessary, and I wound up dancing in and out of a couple thermals on the way down. It did turn out to be a lengthy recovery walk but not too bad.

Semroc IQSY Tomahawk Upon finding the rocket, I noticed one small nose cone dent from where it appears to have snapped back and struck the body tube but there was otherwise no damage at all. I'll probably slip in a little extra shock cord for subsequent flights.

Flight Rating: 4 out of 5

OK, bear in mind I'm a scale nut and not exactly the typical casual builder. With that in mind, I'd have like to see slightly better scale accuracy on this in the form of decals as well as a paint guide. It's still a perfectly fine kit but could be a much better kit with that little bit extra.

If anyone's interested in a copy of my bolt pattern decal file, shoot me a PM over on either TRF or YORF rocketry forums, where I go by the handle of chanstevens.

Overall Rating: 3 out of 5


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