Mosquito Performance

Aeroplane and Armament Experimental Establishment
Boscombe Down
28 April 1942

Mosquito F. Mk. II. W-4076
(2 Merlin 21's)

Level speed measurments made with matt and
smooth black finishes

SUMMARY

Table I
Level speed measurments with matt black finish (RDM/2A).

Height in
standard
atmosphere
(feet)		True Air
speed
(M.P.H.)		A.S.I.
Ø
m.p.h.		Position
error
correction
m.p.h.		Compressibility
correction
m.p.h.		R.P.M.
(Mean)		Boost
lb/sq.in.
(Mean)		Supercharger
gear
18,000345.5245   +19.1-4.530008.3F.S.
20,000352.5243.5+18.8-5.0"8.3"
  21,400*358   241.5+18.7-5.4" 8.3"
22,000357   239   +18.4-5.5" 7.8"
24,000354   229.5+17.6-5.6"6.4"
25,000352   224.5+17.1-5.6" 5.7"

Table II
Level speed measurments with smooth black finish (D.T.D.308)

Height in
standard
atmosphere
(feet)		True Air
speed
(M.P.H.)		A.S.I.
Ø
m.p.h.		Position
error
correction
m.p.h.		Compressibility
correction
m.p.h.		R.P.M.
(Mean)		Boost
lb/sq.in.
(Mean)		Supercharger
gear
18,000355.5253.5+19.8-4.830008.5F.S.
20,000361.5250   +19.5-5.4"8.5"
  21,400*366   247   +19.2-5.8" 8.5"
22,000365.5244.5+18.9-5.8" 8.0"
24,000362   234.5+18.1-5.0"6.6"
25,000360   229.5+17.6-5.0" 5.9"

*    Full Throttle height.
Ø   A.S.I. and Position Error Corrections are for the A.S.I. connected between
      pressure and static sides of the Mark VIII head.

Level Speeds and Boost at Heights

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
3 February 1943

Mosquito NF. Mk.XV. MP.469
(2 Merlin 61's)

Short performance and handling trials

SUMMARY

        This aircraft has extended wings, a low pressure cabin, four blade metal propellers, four 0.303" Browning guns in an external fairing below the fuselage and is intended for high altitude night fighter work. Short tests to determine its climb and level speed performance were made at the normal load of 17,465 lb. with the centre of gravity at 7.0" aft of datum; an assessment of the principal handling qualities was obtained.

        At normal maximum climbing conditions the time to reach the service ceiling of 43,000 ft. is 32½ minutes; it is possible to climb about 800 ft. above this by closing the radiator flaps if care is taken with regard to the engine temperatures. The top speeds are 397 m.p.h. at 16,500 ft. in M.S. gear and 408 m.p.h. at 27,800 in F.S. gear. Owing to unreliable gauges no accurate assessment of the cooling can be obtained but the indications are that the maximum allowable coolant temperature may be exceeded under E.S.M. conditions whilst the oil cooling is satisfactory for T.S.M. conditions.

        The handling is satisfactory, there being no tendency for any of the controls to freeze up at height, nor is the extent of icing inside the cabin at all serious; there is no marked difference in behaviour when compared with normal Mosquito aircraft.

 
Full Throttle Climb
Full Throttle Level Speeds

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
20 May 1943

Mosquito B. Mk. IV D.K.290/G
(2 Merlin 21's)

Level speed performance and position error trials
with and without stores carried.

SUMMARY

ConditionWeight
(lbs)		Height
feet		All-out level powerMax. weak cruising power
R.P.M.Boost
(lb/sq.in)		T.A.S.
(m.p.h.)		R.P.M.Boost
(lb/sq.in)		T.A.S.
(m.p.h.)
Stores IN20,000  2,000
*11,700  
15,000		3000+12    
+12    
+8.9		321
364
360		2650+4272
-
323
18,600  2,000
*11,700  
15,000		"+12    
+12    
+8.9		323
366
362		""274
-
325
Stores OUT17,820  2,000
*11,700  
15,000		"+12    
+12    
+8.9		323
366
362		""274
-
325
16,500  2,000
*11,700  
15,000		"+12    
+12    
+8.9		326
369
365		""277
-
329

* Full throttle height under all-out level power conditions.

Level Speed Performance at Height

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
11 June 1943

Mosquito B. Mk. IX. LR.495
(2 Merlin 72's)

Performance trials without external bombs
or fuel tanks

SUMMARY

       Climb and level speed performance trials have been completed on this aircraft at a take-off weight of 21,910 lb., a loading corresponding to full fuel and oil and four 500 lb. bombs carried internally, but no external bombs or fuel tanks fitted.

        The principal results are as follows:-

 
       Max. rate of climb in MS gear (2850 rpm) +12 lb/sq.in. boost = 2060 ft/min at 14,000 ft.
       Max. rate of climb in FS gear (2850 rpm) +12 lb/sq.in. boost = 1310 ft/min. up to 26,700 ft.
       Service ceiling (FS gear, 3000 rpm) = 37,000 ft.
       Absolute ceiling (FS gear, 3000 rpm) = 37,800 ft.
       Max. speed in MS gear (3000 rpm, +18 lb/sq.in. boost) = 393 mph at 13,800 ft.
       Max. speed in FS gear (3000 rpm, +18 lb/sq.in. boost) = 405 mph at 25,700 ft.
 
Climb Performance
Level Speed Performance

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
19 September 1943

Mosquito FB. Mk. VI. HJ.679
(2 Merlin 25's)

Brief Performance trials

SUMMARY

Climb performance
 
(i)     Loading I       (21020 lb.)Max. rate of climb in M.S. gear = 1740 ft/min @ 10400 ft.
Max. rate of climb in F.S. gear= 1440 ft/min @ 17000 ft.
Time to reach 20,000 ft.= 12.85 mins.
Time to reach 25,000 ft.= 18.8 mins
Estimated service ceiling= 29800 feet
Estimated absolute ceiling= 31000 feet

(iii)   Loading III   (21,985 lb.)Max. rate of climb in M.S. gear = 1560 ft/min @ 10400 ft.
Max. rate of climb in F.S. gear= 1300 ft/min @ 17200 ft.
Time to reach 20,000 ft.= 14.25 mins.
Time to reach 25,000 ft.= 21.05 mins
Estimated service ceiling= 29,100 feet
Estimated absolute ceiling= 30,400 feet

Level speed performance

ConditionS/C
gear		Max. T.A.S. (mph)Respective full
throttle height
All-out
level 		Max.
cruising		All-out
level		Max.
cruising
  Loading I
  (Aux. tanks on)		M.S.3513214,70012,200
F.S.36333211,90018,600
  Loading II
  (Aux. tanks off)		F.S.36833812,00018,700

Performance on Climb
Level Speeds at Height

For the full report see HERE

DeHaviland Aircraft Co. Ltd.
Hatfield Aerodrome
20 September 1943

D. H. Mosquito Mk. VI. (Merlin 25) HJ.679

Tests carried out at Hatfield to check the
Maximum Level Speed obtained in previous tests

Conclusions

        Both check tests (Tests 1 and 2) are substantially in agreement with the original Hatfield tests (April 1943) - in point of fact the speed obtained in Test 2 is about 3 m.p.h. faster in F.S. Gear and about the same as the original tests in M.S. Gear, when allowance is made for the fact that external fuel tanks were not fitted on the original tests (April 1943).

        It will be seen that about 3 m.p.h. in maximum speed was picked up due to cleaning up the aircraft between Tests 1 and 2.

        All these tests show the speed obtained at Hatfield to be about 15 m.p.h. above that obtained at Boscombe Down.

 
Fully Corrected Level Speeds

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
22 September 1943

Mosquito IV D.K.290
(2 Merlin 21's)

Comparitive level speeds
with ducted saxaphone and multi stub exhausts

SUMMARY

HeightS/c
gear		True air speed (mph)
Ducted saxaphone
system		Multi stub
system
  6,000
15,000
18,000		M.S.
M.S.
M.S.		324
    358**
  351*		340
    373**
369
16,000
21,600
24,000		F.S.
F.S.
F.S.		346
    367**
358		360
  380*
374

          *     It will be seen from Fig.1 that above 15,000 ft. using MS gear, i.e. above the full throttle height, the boost pressure with ducted saxaphone was 0.7 lb/sq.in. lower than for the speeds with multi stub exhausts but when employing FS gear the comparitive difference was only 0.3 lb/sq.in. It is thought that the larger difference of 0.7 lb/sq.in. encountered was due to a great extent to a defect in the carburettor possibly in the butterfly mechanism and hence the speeds in MS gear above the full throttle height should not be used for determining the comparitive effect of the exhausts.

          **     It will be seen that at constant boost the effect on true air speed of fitting the multi stub exhaust system is a gain of 15 mph in MS supercharger gear and 13 mph in FS supercharger.

Level Speeds

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
12 November 1943

Mosquito PR Mk XVI DZ 540
(2 Merlin 73's)

Performance, brief handling and pressure cabin tests

SUMMARY

        Brief handling and performance trials and tests of the pressure cabin installation have been made on this aircraft, which is the prototype Mosquito PR Mk XVI. The tests were done at the maximum permissible weight of 22340 lb. The principle results are as follows:-

Climb.     Maximum rate of climb in MS gear (2850 RPM, +12 lb/in2 boost) = 1,960 ft/min at 14000 ft.
Maximum rate of climb in FS gear  (2850 RPM, +12 lb/in2 boost) = 1,150 ft/min up to 26100 ft.
Service ceiling   (FS gear, 3000 RPM) = 36000 ft.
Absolute ceiling (FS gear, 3000 RPM) = 36700
 
Maximum all-out level speed in MS gear (3000 RPM, +18 lb/in2 boost) = 385 mph at 13000 ft.
Maximum all-out level speed in FS gear  (3000 RPM, +18 lb/in2 boost) = 401 mph at 25200 ft.

Maximum crusing speeds.     MS gear (2650 RPM, +7 lb/in2 boost) = 352 mph at 18800
MS gear (2650 RPM, +7 lb/in2 boost) = 366 mph at 30,600

Performance on Climb
Level Speeds

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
3 January 1944

Mosquito F Mk. II. W.4096
(2 Merlin 21's)

Comparitive level speed performance with standard
and tropical engine cowlings

SUMMARY

(i)Standard cowling:
 
 Max. true airspeed at all-out level power(a) M.S. s/c = 348 mph at 10,800 ft.
 Max. true airspeed at all-out level power(b) F.S.  s/c = 358 mph at 17,700 ft.
 
 Max. true airspeed at weak mixture cruising power(a) M.S. s/c = 318 mph at 16,000 ft.
 Max. true airspeed at weak mixture cruising power(b) F.S.  s/c = 324 mph at 21,700 ft.
 
(ii)Tropical cowling:
 
 Max. true airspeed at all-out level power(a) M.S. s/c = 336 mph at   9,400 ft.
 Max. true airspeed at all-out level power(b) F.S.  s/c = 346 mph at 16,000 ft.
 
 Max. true airspeed at weak mixture cruising power(a) M.S. s/c = 310 mph at 15,200 ft.
 Max. true airspeed at weak mixture cruising power(b) F.S.  s/c = 314 mph at 20,900 ft.
 
Level Speed Performance

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
1 February 1944

Mosquito FB. Mk. VI. HX.809
(2 Merlin 25's)

Level speed performance at
normal & increased boost rating

SUMMARY

            Level speed performance at +18 lb/sq.in. boost and +25 lb/sq.in. boost has been completed on Mosquito FB.Mk.VI, HX.809.

            The principal results are as follows:-

MS Gear
Max. speed at +18 lb/sq.in boost= 353 at 5100 ft.
Max. speed at max. full throttle boost (23.9 lb/sq.in.)= 354 mph at sea level.
 
            Use of +23.9 lb/sq.in. boost instead of +18 lb/sq.in. at sea level increases the speed by 22 mph.
 
FS Gear
Max. speed at +18 lb/sq.in boost= 363 at 12500 ft.
Max. speed at +25 lb/sq.in.= 369 mph at 7200 ft.
 
            Use of 25 lb/sq.in. boost instead of +18 lb/sq.in. increases the speed below full throttle height by 23 mph.

            Comparison of results @ +18 lb/sq.in. boost with those of Mosquito VI HJ.679, indicate that the speed of that aircraft is of the order of 10-15 mph below average, thus supporting the conclusion made in the 7th part of report No. A. & A.E.E./767,e, that HJ.679 was not fully representative of the type.

 
Level Speed Performance

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
20 February 1944

Mosquito B. Mk. IX. LR.495
(2 Merlin 72's)

Level speed performance
with two external 500 lbs. bombs fitted

SUMMARY

            Level speed tests have been made on this aircraft at the maximum permissible take-off weight of 22,850 lbs., corresponding to the bomber overload condition with external 500 lb. bombs on faired racks under the wings. The tests were made at the normal maximum rating of +18 lb/sq.in. boost and repeated at an increased rating of +21 lb/sq.in.
 
            The principle results are as follows:-

M.S. gear
Maximum level speed   (+18 lb/sq.in. boost) 373 mph at 13000 ft.
Maximum level speed   (+21 lb/sq.in. boost) 375 mph at 10600 ft.
Maximum crusing speed (+7 lb/sq.in. boost) 334 mph at 18400 ft.
 
F.S. gear
Maximum level speed   (+18 lb/sq.in. boost) 383 mph at 25100 ft.
Maximum level speed   (+21 lb/sq.in. boost) 388 mph at 23000 ft.
Maximum crusing speed (+7 lb/sq.in. boost) 345 mph at 30800 ft.

            Use of +21 lb/sq.in boost instead of +18 lb/sq.in. boost increases the top speed below the full throttle heights by 12 mph in M.S. gear and 13 mph in F.S. gear.
 
            The reduction in speed due to fitting the external 500 lb. bombs on faired racks is not known exactly owing to deterioration of the airframe between the two sets of tests but it appears to be of the order of 15-18 mph.
 
Level Speed Performance

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
5 March 1944

Mosquito B. Mk. XX KB.328
(2 Merlin 31's)

Level speed performance trials

SUMMARY

            Level speed performance trials have been completed on this aircraft, a Canadian built version of the B. Mk.IV at a take-off weight of 21430 lb., the loading corresponding to 4-500 lb. bombs in the bomb bay and external fuel tanks beneath the wings.
 
  The principal results are as follow:-
 
 MS gear
 Max. all-out speed (+14 lb/sq.in boost)     =   354 mph at 7000 ft.
 Max. cruising speed (+7 lb/sq.in boost)     =   332 mph at 11200 ft.
 
 FS gear
 Max. all-out speed (+16 lb/sq.in boost)     =   364 mph at 12500 ft.
 Max. cruising speed (+7 lb/sq.in boost)     =   345 mph at 17700 ft.
 
            Comparison of the results with those of other Mosquito aircraft fitted with engines of similar power shows that the full throttle heights and performance of KB.328 are rather below average.
 
Level Speed Performance

For the full report see HERE

Aircraft and Armament Experimental Establishment
Boscombe Down
12 April 1945

Mosquito NF. Mk. 30 MM.748
(2 Merlin 72)

Position error and level speed performance trials

SUMMARY

            Position error trials, and measurement of the level speed performance under combat and cruising power have been made on Mosquito NF Mk.30 MM.748 at a take-off weight of 21,600 lb., with 2 x 50 gallon under-wing tanks fitted.

            The position error correction at 20,540 lb. varies non-linearly from +3.5 mph at 150 mph ASI to +8 mph at 180 mph ASI, then linearly to +19.0 mph at 340 mph ASI.

            The maximum true level speeds are:-

M.S. Supercharger gear.

Max. cruising power.Combat power
 
340 mph at 17,000 ft.371 mph at 12,200 ft.

F.S. Supercharger gear.

Max. cruising power.Combat power
 
364 mph at 27,500 ft.397 mph at 24,800 ft.

The performance generally is up to the expected standard for this varient of the Mosquito.
 
Level Speed Performance

For the full report see HERE

Supplemental

Mosquito B.Mk.IV, Merlin 21, Aircraft Data Sheet
Mosquito B.Mk.IV, Merlin 23, Aircraft Data Sheet
Mosquito B.Mk.IX, Merlin 72, Aircraft Data Sheet
Mosquito B.Mk.XVI, Merlin 72 & 73, Aircraft Data Sheet
Mosquito B.MK.XX, Merlin 31 or 33, Aircraft Data Sheet
Mosquito VI Tactical Trials
Use of Increased Boost on Merlin 72 Engines. +21 lbs. June 1944
Rolls-Royce Merlin 24, 25, 26, 27, 224, 225 Engines. Altitude Performance at 3000 R.P.M. with 400 MPH RAM
Rolls-Royce Merlin 63, 63A, 54, 72, 73 Engines. Altitude Performance at 3000 R.P.M. with 400 MPH RAM
Mosquito Mk VI Pilot's Notes Operating Data
Mosquito Performance RAAF, 29th November 1944
Sea Mosquito
Sea Hornet
Power Boosting By Nitrous Oxide
Injection of N2O into Merlin 25 engine fitted to Mosquito XIX aircraft
W/Cdr. J. Cunningham, 85 Squadron - Combat Report 2/3rd January, 1944: "Nitrous Oxide"
F/L N. Head, 96 Squadron - Combat Report 22 March 1944: "Nitrous Oxide"
S/Ldr. A. Parker-Rees, 96 Squadron - Combat Report 13/14th April, 1944: "Nitrous Oxide"
No. 85 Squadron Operations Record Book - "150 grade fuel, and giving +25 lbs boost."
No. 157 Squadron Operations Record Book - "The boost is increased to 25 lbs. per square inch."

Miscellaneous

Lewis Brandon of 157 squadron commented in his book:

"We were told that we would be kept on operation Diver for a while. Swift modifications were carried out to all the Mozzies. The exhaust shrouds were dispensed with, extra boost was given to the engines, we were supplied with 150 octane petrol and, of course, the noses were strengthened. With the exception of the exhaust shrouds, all these modifications were retained when we returned to our bomber support role.
Lewis Brandon, DSO DFC*, Night Flyer, p 156. ISBN 0 907579 77 9, 1961, (Republished 1999 by Crecy Publishing)

WWII Aircraft Performance