Aeroplane and Armament Experimental Establishment
Martlesham Heath

April 1936

Hawker Monoplane, F.36/34 K-5083.

Merlin C6

SUMMARY

At Full Throttle
Height FeetSpeed M.P.HTime to Climb MinsRate of Climb ft/min
S.L253 0 2550
2000261.50.752650
5000274 1.892810
10000295.53.632680
15000314 5.702150
20000311 8.401620
25000301.512.08 1100
30000282.518.10 >570

Complete K.5083 Report here

Aeroplane and Armament Experimental Establishment
Martlesham Heath

21st January 1939

Hurricane L.1547.
Trials with 2-pitch metal aircsrew

SPEED TRIAL with a 2-pitch metal airscrew
Weight:- 6363 lb.
Height in
Standard
Atmosphere
Feet 		True
Air
Speed
M.P.H. 		A.S.I.
M.P.H. 		Compressibility
and
Position
Error
Correction 		R.P.M. Boost
lb./sq. in. 		Remarks
Sea Level Eight guns with
flash eliminators
fitted.
Coolant flap
in position for
minimum drag.
1,000
2,000
3,000
5,000
6,500
10,000296 266 -1.7-10.0 2775+6.25
13,000305.5262 -2.3-9.92850+6.25
15,000312 260 -2.7 -9.92900+6.25
16,500317 258.5-3.0-9.82940+6.25
18,000319.6254 -3.2-9.82960+5.8
20,000318 245 -3.4-9.62935+4.0
23,000312.5229 -3.5-9.52880+2.0
26,000
17,500*320 257 -3.2-9.82965+6.25

Complete L.1547 Report here

Aeroplane and Armament Experimental Establishment
Boscombe Down

12th June 1940

Hurricane L.2026.
(Merlin III)
(Rotol Constant Speed Airscrew)
Comparitive Performance Trials
under
Normal and Overload conditions

SUMMARY

At Full Throttle
Height FeetSpeed M.P.HTime to Climb MinsRate of Climb ft/min
S.L 0 0
20000.752610
5000276 1.9 2625
10000291 3.8 2640
15000307 5.852250
20000316 8.351675
25000307 12.0 1100
30000292 18.3 530
Complete L.2026 Report here


The following performance estimate for the Hurricane I is a consolidation of various aircraft and engine performance data sets and was kindly provided by Henning Ruch.

Supplemental

  • Hurricane I Data Sheet

  • Calibration of Hurricane L1717 Merlin II Engine

  • Postagram from Air Ministry 2/10/39: Dispatch of 100 octane fuel for Service trial on Hurricanes at 12 lbs boost.

  • Fighter Command's policy regarding +12 lbs boost, 14 November 1939

  • Merlin II and III - Use of + 12 lb./sq.in. Boost Pressure, 20 March 1940:

  • 111 Sqdn. Operations Record Book, 15 February 1940: "Main tanks drained for change over to 100 octane fuel."

  • 151 Sqdn. Operations Record Book, 16 February 1940: "All the aircraft in the squadron have now been modified and the new 100 Octane fuel is being used enabling 12 lbs. boost to be used in cases of emergency without damage to the engine."

  • 504 Sqdn. Operations Record Book, 24 February 1940: "Test on 100 octane spirit also carried out on two machines."

  • 605 Sqdn. Operations Record Book, 28 May 1940: "100 octaine fuel..."

  • Merlin II and III Aero-Engines, Air Publication AP1590B

  • Emergency +12 lbs./sq. in. Boost Operation: Pilot's Notes, Merlin II, III and IV, 4th Edition, April 1940, page 6.

  • Handling of Merlin in Hurricane, Spitfire and Defiant Aircraft, H.C.T. Dowding, C-in-C Fighter Command, 1 August 1940:

  • 56 Squadron Combat Report noting +12 boost for Hurricanes, 9 May 1940
  • S/L J.O.W. Oliver, 85 Squadron, 10 May 1940 "... I pulled the plug."
  • F/O Paul Richey, 1 Squadron, 11 May 1940 "...boost-override pulled."

    Paul Richey DFC, Fighter Pilot (Redwood Press, Wiltshire 1990) p 76. (first published in Great Britain by B.T. Batsford Ltd., 1941.)

  • F/O E. J. Kain, 73 Squadron, 14 May 1940 "...pulling his boost cut out..."

    Noel Monks, Fighter Squadrons, (Angus and Robertson, Sydney : London, 1941), p 98-99 (See also Cull,Twelve Days in May), pg 124.

  • P/O D. W. A. Stones, 79 Squadron, 14 May 1940 " I now pulled out the emergency boost-plug for the first time ever..."

    Donald Stone, Dimsie, (Wingham Press, Canterbury, 1991), p 32.

  • Sgt. R. C. Winlkinson, 3 Squadron, 14 May 1940 "12 P.S.I."

    Kenneth James Nelson, C.D., Spitfire RCD, The Wartime Exploits of Royce Clifford Wilkinson O.B.E, D.F.M. & Bar, Hignall Printing Ltd., Canada, 1994). p. 6.

  • P/O R. P. Beamont, 87 Squadron, 15 May 1940 "I pulled the tit'* for over-boost... *Emergency boost over-ride on the Merlin engine."

    Roland Beamont, My Part of the Sky, (Patrick Stephens Limited, Wellingborough, Northamptonshire), pg 30.

  • S/L E. M. Donaldon, 151 Sqdn., Combat Report, 18 May 1940 "I pulled the plug and climbed at 10 lbs boost…"
  • P/O John Bushell, 151 Sqdn., Combat Report, 18 May 1940 "I used full 12 lb boost (pulled the plug) and overtook EA rapidly."

    (Note: these 18 May 1940 combats of 151 Squadron occurred while operating from Vitry, France.)

  • P/O F. B. Sutton, 56 Squadron, 18 May 1940 Vitry, France: "...I had to pull the tit... Emergency boost control giving extra power"

    Barry Sutton, The Way of a Pilot, (MacMillan & Co, Ltd., London 1943) pp. 79-80

  • F/O C. F. G. Adye, 17 Squadron, 18 May 1940 "...pulled emergency boost control..."

  • F/Lt I. R. Gleed, 87 Squadron, 18 May 1940 "At about 100 feet I straighten up, pull the tit *; a jerk as my supercharger goes up to twelve boosts."

    W/C Ian Gleed D.F.C., Arise to Conquer, (Random House, New York 1942) p. 49.

  • F/Lt I. R. Gleed, 87 Squadron, 19 May 1940 "Here goes with the tit. A jerk - the boost's shot up to twelve pounds; speed's increased by 30 m.p.h."

    Ibid p. 61.

  • F/O C. F. G. Adye, 17 Squadron, 19 May 1940 "...pulled emergency boost..."
  • Sgt. L.H.B. Pearce, 79 Squadron, 20 May 1940 "Pulled tit..."
  • Sgt. J. C. Harrison, 229 Squadron, 28 May 1940 "I pulled the emergency boost and followed him down still firing."
  • P/O K. B. McGlashan, 245 Squadron, 28 May 1940 "We’d boost an extra four pounds, from eight to twelve…"

    S/L Kenneth Butterworth McGlashan with Owen Zupp, Down to Earth, (Grubb Street, London, 2007), pg 29.

  • P/O C. M. Simpson, 229 Squadron, 29 May 1940 "...I followed it down with boost out and pulled."

  • Sgt. P. Ottewill, 43 Squadron, 1 June 1940 "...automatic boost cut-out pulled."

  • F/Lt. R. G. Dutton, 145 Squadron, 1 July 1940...pulled the plug..."

  • P/O G. Page, 56 Squadron, July 1940 "Pulling the "Tit"*... *An emergency knob for supplying additional power to the engine."

    Geoffrey Page DSO, OBE, DFC and Bar, Shot Down in Flames, (Grub Streeet, London, 1999), pg. 58.

  • P/O G. E. Goodman, 1 Squadron, 18 August 1940 "...I pulled the plug..."

  • P/O Wicks, 56 Squadron, 30 August 1940 "With full throttle & emergency boost..."

  • P/O J. R. B. Meaker, 249 Squadron, 6 September 1940 "...so I pull the plug..."

    Brian Cull, 249 at War, (Grub Street, London 1997) p. 17.

  • F/Lt J. A. Kent, 303 Squadron, 9 September 1940 "...I pulled the boost override plug..."

    Group Captain J. A. Kent, One of the Few, (Corgi, London 1975) p. 108.

  • P/O T. F. Neil, 249 Squadron, 18 September 1940 "Plug pulled..."

    Wing Commander Tom Neil, DFC, AFC, AE, Gun Button to 'Fire', (William Kimber, London 1987), pg 115.

  • P/O R. G. A. Barclay, 249 Squadron, 27 September 1940 "I had to use automatic boost cutout to catch up the 109."
  • P/O K. W. MacKenzie, 501 Squadron, 5 October 1940 "With the tit pulled for absolute full power..."
  • S/L A. A. McKellar, 605 Squadron, 7 October 1940 "I followed one, pulled my boost control, and speedily made up on him."
  • Sgt. G. A. Stroud, 249 Squadron, 29 October 1940 "I chased one pair which I overhauled with use of boost..."
  • Conversion of Hurricane Aircraft D.H. Two-Pitch Airscrews to Constant Speed.
  • F/Lt I. R. Gleed, 87 Squadron, 19 May 1940 Rotol constant-speed airscrew used in France.

    W/C Ian Gleed D.F.C., Arise to Conquer, (Random House, New York 1942) pp. 62-63.

  • 1 Sqdn. Operations Record Book, 18 April 1940: "A new Hurricane was delivered to the Squadron, equipped with a constant speed airscrew and was flown by the C.O. and other pilots, all of whom were greatly pleased with it's superior performance.
  • 1 Sqdn. Operations Record Book, 2 May 1940: "Five machines flew to Amiens and four were exchanged for the new constant speed airscrew Hurricanes."
  • F/O Paul Richey, 1 Squadron, 15 May 1940 France: "I was flying a new aeroplane with a Rotol constant-speed prop..."

    Paul Richey DFC, Fighter Pilot (Redwood Press, Wiltshire 1990) p 93.

  • 151 Sqdn. Operations Record Book, 14 April 1940: "Hurricane R3310 with Rotol Airscrew flown from No. 20 M.U. at Aston Down by F/O. Newton."
  • 151 Sqdn. Operations Record Book, 15 May 1940: "The squadron can now put up 12 Rotol Hurricanes if required."
  • 32 Squadron, 19 May 1940: "No. 32 (F) Squadron, based at Biggin Hill and flying Hurricanes with Rotol propellers, went into action on 19th May over Cambrai…"

    Francis K. Mason, The Hawker Hurricane, (Doubleday, New York 1962) p 48.

  • 229 Squadron Operations Record Book, 23 May 1940: "Rotol Hurricane"
  • 213 Squadron Operations Record Book, 25 May 1940: "Rotol Airscrews"
  • 79 Squadron Operations Record Book, 9 June 1940: "Rotol airscrew"
  • 242 Squadron, June 1940: "Rotol constant speed propellers had been fitted to the Hurricanes in early June, replacing the two-position propellers of earlier models."

    • Hugh Halliday, No. 242 Squadron, The Canadian Years, (Canada's Wings, Ontario, 1981). p.78.

  • P/O T. F. Neil, 249 Squadron, June 1940: "It had a constant-speed Rotol propeller..."

    Wing Commander Tom Neil, DFC, AFC, AE, Gun Button to 'Fire', (William Kimber, London 1987), pg 48.

  • June 1940 - one of 249's first Hurricanes, with metal wings and Rotol airscrew
  • The Latest Rotol Airscrew, Flight, May 23,1940
  • 17 Sqdn. Operations Record Book, 5 October 1939: "bullet-proof section in the windscreen."
  • 1 Sqdn. Operations Record Book, 12 March 1940: "All aircraft in squadron have been fitted with rear armour."
  • 145 Sqdn. Operations Record Book, 18 May 1940: "armour plated aircaft"
  • 151 Sqdn. Operations Record Book, 11 May 1940: "Rear Armour plating has now been fitted to all the Hurricanes at present held by the squadron."
  • OpChar: "Operational Characteristics of Hurricane Aircraft."