Flight Log - 2012-06-10 - Rich DeAngelis's Tomahawk SLCM

The Tomahawk: This is a sport-scale model of the Surface-Launched Cruise Missile (SLCM) used by the US Navy, painted in colorful red-white-blue that was probably for marketing but not very likely used on the missiles used in service. I believe that this model is not to-scale as it appears to be a bit too long and has smaller wings and a smaller air intake so that this model will fly well as a rocket. It also doesn't usually explode at the end of its flight like the real thing (one would hope).

BUILDING:
The air-intake is made from a light cardboard. I considered re-making this out of a thin balsa wood, but figured it was unlikely to get damaged during flight because of its location.  As it happened, I pressed a little too gingerly on the rocket while applying decals, and bent it a bit. It returned to shape, but not before it cracked the white gloss finish on it. The cracks are not very noticeable on the photo. If you build this model, I suggest soaking the folds of the cardboard with CA glue to harden them. Mine started to split while handling the rocket while sanding the finish.

You may notice I tapered the launch lugs on this model; partly for cosmetic reasons, and partly because it might reduce air drag, but I don't know that it's been scientifically proven. The air-intake adds drag I'm sure, but I am banking on it not being that much of a problem, so I didn't go through with my thoughts of providing vent holes on the back of the scoop, which would make the model look a bit odd and would not entirely reduce the drag anyway.  We'll just have to see if this model can hit the 600 foot apogee as claimed by Quest.

FINISHING:
The color difference in the blue Testors paint and the decal's blue shade doesn't look too bad in this photo, but in person you will be able to see the shade difference easily. Take a close look behind the air-intake where the square panel decal is. Behind that there was a gap in the blue decal which I covered with the blue from a second set of Quest decals. Even in this photo, you can see the obvious shade difference between the two blues of the decal sheets from Quest. The purple-ish square is from a set of Quest decals I didn't use.  If you build this kit, I wish you the best of luck getting the paint and decal shades to match, but don't count on it.

Quest's instructions do not tell you where to place all the decals. You have to get a little creative. Also, the geometry of the rocket and decals does not match, so you will have to be careful and flexible when applying them.  The locations of the decals and the air-intake, wings and other features do not line up as shown in the illustrations (which don't exactly match themselves!).  I used Testors spray paints. The red came out as a very close shade to the decal shade, but the blue was pretty far off the mark. I had a second set of decals from Quest, and the blue on the decals looked quite a bit different than the blue decals I used on this rocket. I think color matching the decals and the paint will probably be something of a crap-shoot.

Sadly, I also applied a clear-coat on top of the decals to protect them. This was also Testors brand, the same as all the paint. Perhaps I sprayed it on too thick, but even though the decals had several days to dry, the clear-coat seemed to soak in to the decals and wrinkle them all up (after the photographs at least). So while this model looks good from a distance at launch, up close it's more like a wrinkled old man.

FLIGHT TESTS:
As expected, this model didn't perform close to Quest's prediction. In light winds with a C6-3, it reached 492 feet, on a B6-4 it only reached 132 feet. Flights were made with an Altimeter 2 inside clipped to the nosecone. In spite of the altitudes, the flights went very well and were quite satisfying; I expect to be flying this model a lot. This rocket has flown higher than the Great Pyramid of Giza in Egypt, even before it lost about 26 feet from erosion. It could have flown over the Kingda Ka Roller Coaster in Jackson.

Flight Date: 2012-06-10
Rocket Name: Tomahawk SLCM
Kit Name: Quest - Tomahawk {Kit} (3007) [1994-]
Flyer's Name: Rich DeAngelis
Motors: C6-5
Launch Site: Halifax, PA
Actual Altitude: 338.00 Feet

I wanted to give this rocket one more test flight on a C6-5. It did seem to be the best motor for this model, but a third flight would nail that assumption down. In light winds I expected the flight path of the rocket would remain vertical and not turn to the wind as it always has done (and like a cruise missile would do anyway).
This flight peaked at 12 Gs, heading up quickly. The motor burned for 1.9 seconds with an average acceleration of 2.7 Gs.  It reached a speed of 111 mph – a new record for this model. Even with very little wind this model curved over and started flying more horizontal than up. After 4.5 seconds of delay (another short delay time!!) the ejection fired at 290 feet, still moving quite fast. It reached its apogee 1/10 second later at 338 feet. It appeared to have a good parachute and came down at 9 mph, about 600 feet away; not downwind and not upwind, but crosswind.  This kind of tells me that the rocket itself causes it to arc over in flight, I suspect because of the air scoop.  I suppose this can happen at any angle because the rocket does spin a lot on boost. The spin is probably from the imperfect alignment of the two wings and the fins. Total flight time was 26.1 seconds. The Quest crinkly parachute had a single straight-line tear from the edge towards the apex to about ¼ of the radius. Perhaps the very thin but strong shrouds sliced it open.

StageMotor(s)
1Estes C6-5

 

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