Gyroscopic Gun Stabilisation

[Les Hammond]

All the time I was into late war I never once came across gun stabilisation using gyros. Turns out later Stuarts had it and Grants and Shermans. Does this mean these tanks can fire on the move with little or no penalty? Is there info comparing Stuart non-stabilised 37mm to one with gyros? Not found much on the web.

6mm France 1940

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[Les Hammond]

Ah sounds like it didn’t work too well in combat. Explains why I never heard of it.

http://www.ww2f.com/topic/32722-main-gun-stabilizer-revealed/

• This reply was modified 5 years, 4 months ago by Les Hammond.
• This reply was modified 5 years, 4 months ago by Les Hammond.

6mm France 1940

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[Jemima Fawr]

From British memoirs, it was almost always deactivated, as it tended to injure crew due to the breech suddenly rising or descending while the tank was on the move.

My wargames blog: http://www.jemimafawr.co.uk/

[MartinR]

As above, it didn’t work very well. If it is something you really want to model, I’d give it a hefty penalty. Most tank crews figured out pretty quickly that firing on the move was waste of time and ammo (apart from MGs of course).

"Mistakes in the initial deployment cannot be rectified" - Helmuth von Moltke

[John D Salt]

The first tank to mount a gyro stabiliser was the Soviet T-26, but this stabilised the gunsight, rather than the entire gun.

WO 291/90, “Firing on the move from tanks”, says:

“With existing British tanks the effectiveness (hits per minute) of shooting on the move is never greater than 1/2 that of stationary fire under similar conditions and is often 1/20 or less. The Westinghouse gyro stabilizer produces some improvement”.

For MG fire, “…the number of machine gun bullets per minute that will come dangerously close to an anti-tank gun crew from a single tank firing on the move is very small.” The best MG results, using the shoulder-controlled mounting in the Crusader and an expert crew, showed a reduction of one-half in hitting rate. “For average gunners factors of 1/4 to 1/20 or worse would be expected.”

For the main armament, it was found that “…a comparatively high percentage of hits can be obtained with a light gun in a free elevation mounting but that the rate of fire is greatly reduced by movement.”

This reflects the British pre-war obsession with firing on the move, when gunners often trained in it; it relies on the control possible with a free mounting, as I believe all 2-pdr mounts were, and some 6-pdr. That idea died in the Western Desert. I do not believe other nations used free mountings; it is all going to be a good deal more difficult if you have to twiddle knobs and frobs while trying to take aim. And don’t forget the poor loader trying to wrestle an AP into the breech without trapping his fingers — movement reduces rate of fire as well as accuracy.

WO 291/1202 “Tank armament stabilisation: User experience and the present situation”, a post-war report, mentions the Westinghouse hydro-electric stabilisation used on the Stuart, Lee and Sherman, which stabilised the main turret armament and co-ax in elevation only.

“Owing to the limitations inherent in the system, it was used very little operationally. It gave slightly better results when shooting on the move than could be obtained with a shoulder-controlled gun; but the chances of hitting when using it on the move were so small, compared with firing from the halt, that users preferred to engage their targets from the halt rather than on the move with the stabiliser working.”

In Italy, the stabiliser was used as a shock-absorber on 76mm Shermans, as the big gun subjected the elevating mechanism to large shock loadings when moving cross-country.

“The Westinghouse stabiliser was so little used during the campaign in NW Europe, that servicing and repair of the equipment ceased after the liberation of Belgium. Replacement vehicles were sent forward classified as “fit”, regardless of whether the stabiliser was in working order or not.”

Trials with the Metrovick electrical two-axis stabiliser on 20-pr Centurions at Lulworth showed accuracy with AP 70–75% as good as at the halt, and with HE very nearly as good as at the halt. A second trial produced results slightly less favourable.

Of course I remember the boast that Centurion was the first tank to be capable of really effective fire on the move. Then the same boast for Chieftain; then Abrams; then Challenger 2. It must be true by now, surely?

All the best,

John.

[Les Hammond]

MartinR wrote:

As above, it didn’t work very well. If it is something you really want to model, I’d give it a hefty penalty. Most tank crews figured out pretty quickly that firing on the move was waste of time and ammo (apart from MGs of course).

Hmm, if tank crews didn’t use it I don’t think I’ll try to simulate it!!

6mm France 1940

http://les1940.blogspot.co.uk/
https://www.facebook.com/groups/386297688467965/

[Les Hammond]

John D Salt wrote:

WO 291/90, “Firing on the move from tanks”, says:

“With existing British tanks the effectiveness (hits per minute) of shooting on the move is never greater than 1/2 that of stationary fire under similar conditions and is often 1/20 or less. The Westinghouse gyro stabilizer produces some improvement”.

For MG fire, “…the number of machine gun bullets per minute that will come dangerously close to an anti-tank gun crew from a single tank firing on the move is very small.” The best MG results, using the shoulder-controlled mounting in the Crusader and an expert crew, showed a reduction of one-half in hitting rate. “For average gunners factors of 1/4 to 1/20 or worse would be expected.”

For the main armament, it was found that “…a comparatively high percentage of hits can be obtained with a light gun in a free elevation mounting but that the rate of fire is greatly reduced by movement.”

This reflects the British pre-war obsession with firing on the move, when gunners often trained in it

I wonder if it is possible that this firing on the move thing that the Brits were supposedly so fond of at the start of the war (at least at tank gunnery training camps) was quietly ignored in the heat of battle, or if the influx of barely trained tank crew once things kicked off properly meant that this tactic was just not feasible?

I am wondering whether to give British tanks a better chance of firing on the move at all, when compared to other nations.

6mm France 1940

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[Jemima Fawr]

John,

The Japanese also used free mountings, but that was about it.

As you say, firing on the move was generally a waste of time and especially after free-floating mountings were discontinued.  Stabilisers did little to mitigate that.  I interviewed some old chaps who served on Covenanter, Crusader, Stuart, Sherman, Cromwell, Churchill, Tetrarch and Locust and they all agreed that firing on the move was pointless.

That said, it was noted in a number of accounts from units positioned next to the 1st Polish Armoured Division that their SOP when manoeuvring in the face of the enemy, was to blaze away with HE and MGs while on the move.

My wargames blog: http://www.jemimafawr.co.uk/

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