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Ie_Shima

Gyroscopic Stabilization for Naval Cannons

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I’m doing some research into the navies of various countries during the late 1800’s for a pet project and this keeps bugging me.  All the sources that I can find basically state that sometime between the American Civil War and the year 1900, there was an invention now called the gun stabilizer, that utilized a gyroscope to stabilize the gun and keep it balanced despite having the ship move up and down from the waves. 

The problem is that none of these sources go into any more detail about the device, such as when it was first used, who used it first, who invented it, and how it works.  Any further searches I have done pulls information on tank gun stabilizers from WWII and beyond.  The things I’m looking for are from around 1880. 

 

Any help?

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59 minutes ago, Ie_Shima said:

Any help?

Ask the Navy; I'm sure by now it's not classified anymore.

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Edited by ExploratorOne

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Try looking at this book:

 

Supplying War: Logistics from Wallenstein to Patton

 

There had been mention of the RN looking into gyro stabilization about the time Jackie Fisher became 1st Sea Lord

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Gunfire on ships took a different approach to stabilization than what was done with tanks.  Instead of stabilizing the gun itself, which is the uncommon method on ships, the gyro stabilization system detects when the ship is level in pitch, roll, and yaw.  This eliminates the need to stabilize the gun or gun mount itself.

With this system, the firing circuit is closed but not completed until the ship comes to a level position determined by the gyro.  If for example, the ship is rolling, as it comes to zero degrees the circuit completes and the guns fire.  There is a slight delay between the fire command and the actual firing of the guns with this system.

The alternative is something like the German 8.8 and 10.5 cm AA gun mounts where the mount itself is stabilized.  This is a mechanical nightmare by comparison.  You are now trying to make stable something weighing tens of tons and taking the stress of the guns firing and make it stay level.  This theoretically gives a slight increase in the rate of fire, but exponentially increases the chances of the mount breaking down and the amount of maintenance needed.

 http://www.ibiblio.org/hyperwar/USN/ref/NavalOrdnance/index.html

A third method is to adjust the gun aim for the movement of the ship.

Edited by Murotsu

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The function of the Mk 6 Stable Element (pictured) in this fire control system is the same as the function of the Mk 41 Stable Vertical in the main battery system. It is a vertical seeking gyroscope ("vertical gyro", in today's terms) that supplies the system with a stable up direction on a rolling and pitching ship. In surface mode, it replaces the director’s elevation signal.[1] It also has the surface mode firing keys.

It is based on a gyroscope that erects so its spin axis is vertical. The housing for the gyro rotor rotates at a low speed, on the order of 18 rpm. On opposite sides of the housing are two small tanks, partially filled with mercury, and connected by a capillary tube. Mercury flows to the lower tank, but slowly (several seconds) because of the tube's restriction. If the gyro's spin axis is not vertical, the added weight in the lower tank would pull the housing over if it were not for the gyro and the housing's rotation. That rotational speed and rate of mercury flow combine to put the heavier tank in the best position to make the gyro precess toward the vertical.

When the ship changes course rapidly at speed, the acceleration due to the turn can be enough to confuse the gyro and make it deviate from true vertical. In such cases, the ship's gyrocompass sends a disabling signal that closes a solenoid valve to block mercury flow between the tanks. The gyro's drift is low enough not to matter for short periods of time; when the ship resumes more typical cruising, the erecting system corrects for any error.

The Earth's rotation is fast enough to need correcting. A small adjustable weight on a threaded rod, and a latitude scale makes the gyro precess at the Earth's equivalent angular rate at the given latitude. The weight, its scale, and frame are mounted on the shaft of a synchro torque receiver fed with ship's course data from the gyro compass, and compensated by a differential synchro driven by the housing-rotator motor. The little compensator in operation is geographically oriented, so the support rod for the weight points east and west.

At the top of the gyro assembly, above the compensator, right on center, is an exciter coil fed with low-voltage AC. Above that is a shallow black-painted wooden bowl, inverted. Inlaid in its surface, in grooves, are two coils essentially like two figure 8s, but shaped more like a letter D and its mirror image, forming a circle with a diametral crossover. One coil is displaced by 90 degrees. If the bowl (called an "umbrella") is not centered above the exciter coil, either or both coils have an output that represents the offset. This voltage is phase-detected and amplified to drive two DC servo motors to position the umbrella in line with the coil.

The umbrella support gimbals rotate in bearing with the gun director, and the servo motors generate level and crosslevel stabilizing signals. The Mk. 1A's director bearing receiver servo drives the pickoff gimbal frame in the stable element through a shaft between the two devices, and the Stable Element's level and crosslevel servos feed those signals back to the computer via two more shafts.

(The sonar fire-control computer aboard some destroyers of the late 1950s required roll and pitch signals for stabilizing, so a coordinate converter containing synchros, resolvers, and servos calculated the latter from gun director bearing, level, and crosslevel.)

https://maritime.org/doc/stablemk6/index.htm

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