Saturday, December 30, 2017

More scale modeling...

Hawk missiles on their launcher (Click to enlarge).
At the December HARA meeting, Elliot Laramie gave a tech talk on the Hawk anti-aircraft missile, which was first deployed way back in 1959. Despite being nearly 60 years old, the missile system has undergone improvements over the years - the last major one being in 1995 - and is still in use by several countries, including Egypt, Israel, Saudi Arabia, Turkey, South Korea, and Greece. The U.S. phased out the Hawk in favor of the much more capable - and way more expensive - Patriot in 2002. However, the cost of the Patriot is such that many countries with Hawks are opting to go with far cheaper upgrades to their existing missiles rather than buy Patriots. This is for good reason - the Hawk has proven itself to be a decent anti-aircraft weapon over the years, with over 80 kills. Jane's gives a single shot kill probability of 85% for the 1995 Hawk. However, as any missile man could tell you, Hawks are launched in pairs or more, adding to the lethality of the system.

There have only been a few flying scale kits of the Hawk produced - Estes produced a not-even-close-looking Army Hawk from 1990 to 1992, and The Launch Pad put out a much better kit of the MIM-23A version, but this one is very hard to find with the company now out of business. However, scratch builders have better luck, as Peter Alway gives plans and tips in his "Scale Bash" booklet for constructing a Hawk in one of 4 different sizes (BT-5, BT-20, BT-50, and BT-55). This Hawk information is shown in the scanned image below.

Hawk page from Peter Alway's "Scale Bash" (Click to enlarge).
Acting on a whim, I took the dimensions from Peter's BT-55 version and entered them into Open Rocket. I found that the rocket required a lot of nose weight - 70 grams - to get a decent margin of stability with a D12 motor. This amount of weight jives pretty well with the Alway notes, which state that the CG needs to be 9.4" from the nose; my CG is 9.0" from the nose with a D12-5. I went with a 24 mm motor mount because you can always adapt down to smaller sizes, and because I liked the performance (900 feet) on the D12.
Open Rocket sim of a BT-55 based Hawk (Click to enlarge).
Open Rocket rendering of Hawk in flight (Click to enlarge).
I suppose that I must add this rocket to the build list, given that I went to the trouble of simming it in Open Rocket and also because it would make a nice addition to my collection of scale models. If you happen to be interested in building one for yourself, my Open Rocket file can be downloaded from here.

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