Kat Tsun

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Hello,

I searched the forum and haven't found a thread about this topic, and it appears no one has discussed it in any other threads either, so here it is. Anyway, a while ago I was perusing Andreas Parsch's website and I found mention of the apparently obscure Douglas Arbalist in the missile scrapbook.


This was an anti-armour rocket project (around 1960). It is not referenced in any of my sources, but Mr. Jacobus Coetzee provided the following information:

"Immediately after the cancellation of the D-40, Douglas offered the US Army an infantry anti-tank missile called the Arbalist. Arbalist was a hyper-velocity missile, this solution decided on to tackle the low muzzle-velocities generated by the then current crop of unguided anti-tank rockets by making it as fast as possible. Leaving its launch tube at 1550 m/s the missile needed no warhead except a kinetic tungsten-carbide penetrator. A very promising design the weapon did suffer some serious, and in the end determinative drawbacks. Two of the more terminal was that the high velocity would tend to magnify even the slightest irregularities in the trajectory, while the footprint of the missile at launch meant that it would be extremely dangerous to the crew serving it."

Bill Colburn, working for Thiokol during Arbalist development, adds:

"The Arbalist was about 4 inches in diameter. It was spin stabilized, launched from a tube with a styrofoam sabot. The spin rate was so high that motors sometimes were hoop-stressed beyond their yield and the paper-thin cases ruptured."

Unfortunately, there appears to be little else available on the Internet, aside from a brief mention of a progress report by one J.L. Brogan, tucked away in a bibliographical reference in one of the old engineering handbooks the Army wrote; and an article in the Sept. 1964 Missiles and Rockets Vol. 15, #10, discussing either Arbalist, or an offshoot thereof, being considered for the MAW and pitted directly against the future FGM-77, or a precursor. The article is unclear.

Brogan, J.L.: "Arbalist Progress Report;" (Confidential Report), Douglas Aircraft Company Report No. E250-AN-3022, 17 July 1964, AD 366 572, for U.S. Army Missile Command.

(Unclassified Abstract) In this 21st progress report, the general status of the program is given. Launching techniques and tests are discussed. Drawings of the arbalist rocket and forward supporting damping sabot are shown.

(...)

A Medium Antitank / Assault Weapon would fill the gap between the M-72 light antitank weapon with a range of 500-600 yards and TOW (Tube- launched, Optically tracked, Wire-guided), which is being developed to reach out to ranges of 2,000 yards. Nominally then, the range of MAW would be 500-1,500 yards.

Approval for the MAW exploratory development program was given during the week of Aug. 10. The previous week, Missiles and Rockets had strongly criticized the pace of the Army's anti- tank development effort (M/R, Aug. 3, p. 10).

• McDonnell effort — After evaluation of a number of proposals from industry, the Army selected McDonnell's wire-guided missile as the best approach to the MAW requirements. The company has proposed essentially a shoulder-fired TOW, according to official sources.

The missile and launcher would be lighter than the 160-lb. TOW launcher and missile, but would presumably use the same optical system in which the gunner sights on a target and as he tracks it, a linkage feeds correction commands to the missile in flight.

TOW uses a small motor to eject the missile from the launch tube and a second to sustain the missile in flight. It is likely that the same approach would be used in the McDonnell MAW.

• Missile Command approach — In the Missile Command version of MAW, there is no requirement for guidance after launch. It, too, is a shoulder-fired weapon. The use of high-energy propellants has been made possible through development of a means to control the hypervelocity missile. While some Army officials advocated use of high-burning- rate propellants, control of the missile in flight had always been a problem.

Directional control of the missile apparently will be achieved through the use of the two-degree-of-freedom, free- rotor gyroscope. Such a system would be constrained around the roll axis and would sense deviations in the pitch and yaw axes. Translation of these deviations in the missile trajectory into missile corrections could be achieved through the use of a circular ring in the nozzle, which, functioning like a jet tab, would divert the stream in the desired direction.

Burning rates of approximately one- half inch per second were expected from the Arbalest program and would be applicable to MA W . Some 40 test rounds were delivered to the Army by Douglas Aircraft Co. for firing at Aberdeen Proving Ground to investigate the potential of high-burning-rate propellants for high-acceleration, hypervelocity missiles. The results of this program are said to have been extremely good.



MAW has been carried on the Army's books as a requirement for more than three years. However, the combination of TOW development, which relieved the pressure for a medium weapon, and a disagreement between the Army's Combat Developments Command and the Material Command over the characteristics of such a weapon, has delayed its development until the recent action.

http://www.dtic.mil/dtic/tr/fulltext/u2/903789.pdf (p. 211)

I'm curious if anyone on the forum has any more information about this weapon. Did the overpressure present any substantial hazard to the operator, or were the testers more concerned with the firing signature/plume being readily visible to the enemy? Are there any images or drawings still extant? etc. etc.

Thank you for your time.

- Kat
 
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In the book 'Men Against Tanks' by John Week, the Arbelist gets a paragraph on page 173. The test shots touted 5000+ fps, with problems in aiming the thing. The worst side effect for the shoulder launched rocket was that the shock of firing would kill everyone with a few feet of the launch.
 
Yes, I've heard that before but I wonder how true it is. Especially given that the Arbalest was apparently fired by man-operators during the MAW trial or its immediate run-up.

It doesn't seem to have affected those shooters at least, unless Mr. Weeks means it would injure people behind the backblast, which is usually a thing that has to do with flying objects kicked up (rocks and such) more than overpressure per se. I suppose if you're close enough you could get burned by the motor blast though.

Anyway I'd read a patent which I forgot the link to a long time ago that described a "rocket driven punch" that seemed to fit Arbalest's rough description.

I suspect the issue with the missile was less the aiming errors, or the backblast itself (and that the "backblast kills you" thing is a conflation of "large launch signature" [again, shared with FGM-77] of a hot-launch plus high speed, even though an Arbalest wouldn't go full speed out of the tube as it would burn the operator's hands and face) and more that the weapon had a long run-up/acceleration period. The danger in this case being less you get injured by a rocket ignition and more that the enemy sees the titanic backblast kick up a mountain of dirt and immediately directs all available guns on it, leaving little time for the operators to skedaddle. Given it's an HVM that's supposed to let you "shoot and scoot", that's a bit of a downer if you can't scamper any better than a Dragon team.

Anyway I think its minimum range was described as being somewhere around 250 or 500 meters. This fits with most kinetic energy ATGW having large minimum distances, on the order of several hundred meters, as I recall AdKEM having something like a 500 meter acceleration phase below which it would be useless for punching through armor. So I'd imagine Arbalest's large launch signature (perhaps likely comparable to the much [4" versus 6"] fatter Dragon) and long minimum range are what killed it in the end.

But I was mostly just wondering if anyone had a picture of the test articles that Douglas built TBH.
 

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