Gyro Angle

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Gyro Angle Setting Fittings[1]

A Gyro Angle (or Torpedo Gyro Angle) is an angular turn of a given number of degrees that a torpedo equipped with a gyroscope and some additional hardware could be set to assume as soon as it gained control in the water.


The idea of angling gyros for submarine firings was proposed in 1907 by the Inspecting Captain, and four gyros (two each from R.G.F. and Whitehead) adjustable from outside the torpedo to angles of zero, 45 and 90 degrees were obtained. These were trailed at Portland Range to determine the "advance" which would determine the contours of their taking up their heading.[2]

Further tests were conducted aboard Furious in 1910 using two Mark VI* (cold) torpedoes. The initial tests allowed the gyros to work vertical rudders 0.36 rather than the customary 0.12 inch travel until the torpedo assumed its gyro angle, in order to speed its response. This resulted in a radius of turn measured at 50 yards after 7 yards of initial straight travel. [3]

Fired to Starboard, own speed 12 knots, range 1,000 yards
Gyro Angle Remarks
Straight 5 yards left
Straight short but true
10 right Quick-turn device stuck, torpedo hit bottom
10 left 15 yards left
20 left 1 yard right
20 right stirred mud, 5 yards right
20 right hit
30 right <= 2 yards right
40 right short but true
30 left 1 yard left at 800 yards
40 left 12 yards left, but wind caught target

The quick-turn apparatus was removed as unnecessarily complex, and the turn radius went to 200 yards as trials continued:[4]

Fired to Starboard, own speed 12 knots, range 1,000 yards
Angle Remarks
10 left 1-2 yards right
10 right hit
20 left 3 yards left
20 right 7 yards right
30 left 3-4 yards left
30 right short, ~10 yards right

Testing continued with a Mark VI*** H. H.B. heater torpedo from Furious steaming at 15 knots. Six shots were made, and only one shot showed diving. Vernon recommended that the initial models should be able to take up angles as large as 40 degrees on either side, in 10 degree increments, without the quick-turn gear and that trials with all eight dreadnoughts of the First Battle Squadron should follow and henceforth all submerged tubes should receive gyro angling torpedoes.[5] [6]

By 1911, they were under trial in the Home Fleet.[7] A report on their success in eight battleships within Home Fleet was generally satisfactory, and general adoption of angle gyros was approved. All Hook Bracket torpedoes then under manufacture — those for use from submerged tubes — were being fitted to take angled gyros, and cold torpedoes being updated with heaters were also to be made compatible. Torpedo craft were not to receive them.[8]

In March 1913, a Torpedo Order was issued regarding "Instructions for First Fittings of Angled Gyroscopes".[9]


By 1914, new gyros to be produced were to have 5 degree angling on short release, with priority of supply being to new battleships being built.[10]

By 1916 (likely earlier), there were "gyro angle plugs" on British 21-in tubes, and it was approved to extend the practice to 18-in submerged broadside tubes. I presume that these permitted the gyro angle on the torpedo to be altered without removing it from the tube. They did not yet, however, had a design for effecting this with flooded submerged tubes, though a captured German submarine tube was noted as having this feature, albeit only for setting the gyro in 15 degree steps which was found to be somehow a simpler case. I do not know if these "plugs" are needed on A.W. tubes, as the source only indicates issues of submerged tubes. The plugs were unnecessary in Weymouth to Centaur class at over 18 knots, or on larger ships over 22 knots, as the tubes had no real pressure at those speed with the bar extended.[11]

They were still testing various mechanisms, however. In 1916, one such offered half-degree increments up to 8 degrees, and another rejected one offered 3 degree 20 minute increments up to 10 degrees.[12] The need for a workable mechanism was needed immediately, however, and so the granularity of angles that could be set was reduced to 5 degree increments, but the limits remained as 40 degrees.[13]

The use of gyro angling had impacts on torpedo control data instruments as well as on torpedo directors and sights. In typical fashion, there was considerable over-thinking as regards tangent bars.

When extended to 21-inch torpedoes, it was found that the gyro turns had a radius of approximately 800 feet rather than 600 feet as in the 18-inch torpedoes.[14]

Other Services

Apparently, the Americans were regarded by the British around 1911 as being leaders in these innovations. [15]

See Also


  1. The Annual Report of the Torpedo School, 1910, Plate 16.
  2. Annual Report of the Torpedo School, 1907. p. 30.
  3. Annual Report of the Torpedo School, 1910. pp. 45-47.
  4. Annual Report of the Torpedo School, 1910. p. 47.
  5. Annual Report of the Torpedo School, 1911. p. 90. (D.N.O. 26th July 1911).
  6. Annual Report of the Torpedo School, 1910. p. 48.
  7. Annual Report of the Torpedo School, 1911. p. iv.
  8. Annual Report of the Torpedo School, 1912. p. 16.
  9. Torpedo Orders serial no. 16, p. 22., referenced in Annual Report of the Torpedo School, 1913, p. ix.
  10. Annual Report of the Torpedo School, 1914. pp. 27.
  11. Annual Report of the Torpedo School, 1916. p. 74.
  12. Annual Report of the Torpedo School, 1916. p. 56.
  13. Handbook of Torpedo Control, 1916. pp. 17-18.
  14. Annual Report of the Torpedo School, 1912. p. xii.
  15. Annual Report of the Torpedo School, 1911. p. viii, Section IX.