These tactical trials reproduced below were performed with the first airworthy Bf 109F aircraft to fallen into British hands.
Given the circumstances of its capture, it is of little surprise that 'the aeroplane with the engine as it is, in a rather poor state' gave constant troubles during the trials, and the British considered the results as a 'useful guide to the minimum performance of the aircraft', rather than absolute performance figures.
For a graphical comparison with the official German specifications for the Bf 109F-2 type from the F-1/F-2 Kennblatt from October 1941, please refer to HERE.
The aircraft - Bf 109F-2, W.Nr. 12 764, produced by AGO - itself was flown by Hptm. Rolf Peter Pingel, Gruppenkommandeur of I./JG 26, a Ritterkreuzträger with 22 victories to his name, who flew this aircraft since just two days. On 10 July 1941, he force landed near the Deal to Dover road, and was promptly captured with the aircraft more or less intact.
Subseqently, it received rudimentary repairs and the performance was tested at R.A.E, then transferred to the A.F.D.U. for tactical trials, which could not be completed as the aircraft went out of control in a dive test and crashed. The aircraft bear the designation ES 906 while being tested in Britain.
It`s worthy of note that Hptm. Pingel`s Bf 109F-2 was special in the way that it was re-fitted with a 20mm Mauser MG 151/20 instead of the standard 15mm MG 151/20.
The original report`s layout have been preserved as much as possible.
The report was reproduced available in AIR 16/350 at the National Archives.
Images and information on Hptm. Pingel`s aircraft are via Mombeek-Wadman-Pegg, Jagdwaffe, Vol. Two, Section 4. Battle of Britain, Phase Four, November 1940 - June 1941. Luftwaffe Colours series. Classic Publications Limited, 2001. ISBN 1-903223-05-9. Pg. 380-381.
||The Me.109F, ES.906, was
collected from R.A.E., Farnborough, arriving A.F.D.U. 1200 hours.
On refuelling it was discovered that the petrol tank cap, which is a metal casing, was broken. This was repaired by welding the two parts together.
||It was intended to fly the
airraft in the morning, but on running up it was found that a stud
securing the top engine cowling was loose. It was neccesary to have
this fixed before the aircract could be flown.
A Spitfire VB was collected from Debden in the afternoon to do comparative trials against the 109F. The two aircraft took off together to do flat out level speeds at 15,000 and 20,000 feet, but the oil pressure on the 109 droppped 4 kg/sq.mcm. below permissable minimum by the time the aircraft had reached 15,000 feet. The oil pressure had been dropping gradually throughout climb. It is thought that this may be due to the fact that the oil cylinder in the hydrostatic control for oil and coolant temperature is leaking. The gradual loss of oil pressure with height may be due to the fact that the hydrostatic control system has more work to do the higher the aircraft goes.
Throughout the climb the oil and coolant temperatures remained constant at 70° C and 100° C, respectively.
||S/Ldr. Smith flying. Took off
and flew at 1 a.t.m. 2100 rpm (Automatic) between 1000 and 1500 feet.
Oil pressure all this time was well above minimum. Temperatures normal.
Controls at indicated speeds at 220 - 250 were all light and
responsive. After 20 minutes an easy climb to 19,000 ft. was made (time
10 minutes). Oil pressure at 2200 revs. fell just below the minimum
mark on indicator at 15,000 ft., but on increasing them to 2400 in the
manual control, pressure was regained, and held until 19,000 ft. This
pressure was just maintained at 19,000 ft. for 2 or 3 minutes, still at
2400 revs. During the descent, pressure was built up higher than it had
ever been during the trip, and the aircraft was dived at 420 indicated and the
aileron control still found to be quite good, though considerably
heavier. Elevators quite good but not very light.
On return to base at 1,000 ft., when a few miles away, pressure dropped completely off the clock and quite long period of surging took place. Pressure was never regained and after landing it was found that the oil leak from the thermostatic temperature control was more serious than usual.
The aeroplane is not pleasant to take off and land.
||Me.109 brought into hangar. All
oil filters examined; small hole found in oil scavange pipe and
thermostat piston repacked with rubber joint; small hole in scavange
pipe welded. Engine ground run and hydraulic fluid tank leaking badly.
Tank removed and repaired.
||Engine ground tested and found
||No flying - weather unsuitable.
||Me.109F and Spitfire VB (AD.315)
flew together to 19,000 ft. for comparative speed trials. At 18,880
ft., the Me.109F was about
21 mph. faster than the Spitfire with a true speed computing to
362 mph. which agrees with Farnborough's figures. The Spitfire however,
was only giving a true
341 mph. with emergency boost of only 8 1/2 lbs, which does
not seems enough.
At 15,000 ft. the Me 109's engine was vibrating at full power and it was not possible to find its superiority in speed, but the Spitfire was giving 350 mph. true (this agrees with Boscome) at plus 13 emergency boost.
The Me.109 computed to 345 at this height, which agrees with Farnborough again.
Weather not being fit for high altitude work, the Me.109F then did a comperative speed run against the Spitfire VB at 1,000 ft. The Spitfire's maximum level speed at 1,000 ft. computes to 292 mphand the Me.109 was about 10 to 15 mph faster, but it was not possible to judge the difference in speed more accurately, as the weather was very bumpy.
||Comparative speed runs were
attempted. At 5,000 ft. the Me.109 appeared to be 15-20 mph. faster, at
15,000 ft. about 10 mph. faster. The aircraft then climbed to 22,000
ft. but it appears that the Me.109's oil pressure failed as he gave
signals to loose height. Oil pressure was regained presumably before
12,000 ft. and the Me.109 then carried out slow rolls, which were
perfectly executed, it then dived losing height over base. The dive
suddenly steeped almost to vertical and it never recovered,
crashing near Fowlmere.
S E C R E T
To :- Headquarters, Fighter Command.
Copy to :- Air Ministry (D.D.A.T.).
Headquarters, No. 12 Group.
Date :- 28th October 1941
Ref : - AFDU/3/19/44
TACTICAL TRIALS - Me.109F AIRCRAFT
a Messerschmitt 109F which forced-landed in this Country on 10th July 1941, was
delivered to this Unit on 11th October 1941, for comperative trials with full
war load against a Spitfire VB. This aircraft had sustained some damage and had
been repaired by the R.A.E., Farnborough. Unfortunately the trials were not
completed as the aircraft was destroyed in a crash nine days after arrival, but
the following points were foind from the few tests which were carried out.
Brief Description (See photograph at Appendix 'A')
2. Externally, the Me.109F is much cleaner than the Me.109E, altough similiar
in appearance, the main differences being that the airscrew spinner is much
larger, the wing tips rounded similiar to those of a Spitfire, and the tailwheel
fully retractable. The tailplane being fully cantilever is not strutted as on
the Me.109E. The armament is situated in the fuselage and there is no provision
for fitting of wing guns. The normal full load of the aircraft is
approximately 6090 lbs.
3. Pilots's Cocpit. The cocpit is cramped and is only comfortable for small
pilots. They layout of the instruments and controls is excellent and is similiar
to that of the Me.109E, with the following exceptions:-
(i) The constant speed airscrew is fully automatic and requires no operation
by the pilot, as r.p.m. and pitch setting are governed by the throttle opening
and engine load. This is a great advantage in combat, being one thing
less for the pilot to worry about. He can, however, control the pitch
manually in the event of failure of the automatic control.
(ii) The oil and coolant temperatures are thermostatically controlled.
(iii) The view forward is rather better than in the Me.109E, but is still poorer
than in the Spitfire, altough the straight perspex panels on each side
of the windscreen are preferable to the curved panels of the Spitfire.
The view to the rear is greatly restricted by the 9mm. section of armor
plate which protects the pilot's neck and the back of his head.
4. The controls are well balanced and the aircraft is pleasant to fly, but is
not so easy to take off as the Me.109E. The elevator control is fairly heavy
but the rudder control is light and is effective even at low speeds, the aircraft
being very sensitive to over-correction on the rudder during take-off. The
Me.109F is not as easy to land as the Spitfire, altough it is a little easier
than the Me.109E, due to its slightly better forward view. The speed of approach
for landing is about 110 m.p.h., and the angle is rather steep, which necessitates
a big change of attitude before the final touch down. Altough the landing
speed is high, the resultant run is short and brakes can be safely applied as
soon as the aircraft is on the ground.
5. The Me.109F is fitted with a Daimler-Benz DB.601N engine of 1150 h.p., which
is some 150 h.p. more than the DB.601A fitted in the Me.109E. Trouble was
experienced with the engine of the aircraft under trials owing to low oil pressure
which limited flying below 20,000 feet. The engine was not in good condition
and several minor repairs had to be carried out during the brief trials. It was
possible, however, to obtain the following approximate figures which should be
treated with reserve:-
Approximate maximum level speeds
1,000 feet - 305 m.p.h., True.
14,600 " - 345 " "
18,800 " - 362 " "
The performance figures obtained by R.A.E., Farnborough, are attached as
Climb and Dive
6. The initial rate of climb and dive is better than that of the Me.109E and
from the brief trials is considered to be superior to that of the Spitfire VB.
A graph showing the partial climbs carried out by R.A.E., Farnborough, is
attached as Appendix 'C'.
7. No manoeuvrability trials were carried out against other aircraft but the
Me.109F was dived up to 420 m.p.h., I.A.S., with controls trimmed for level
flight and it was found that altough the elevators had become heavy and the
ailerons had stiffened up appreciably, fairly tight turns were still possible.
It is considered, however, that the aircraft could have been out-turned easily
by a Spitfire. At high speed the ailerons are more effective than the fabric
ailerons of the Spitfire, but are not as good as the metal ones. As a result
of the heaviness of the elevators at speeds over 400 m.p.h., violent evasion is
not possible, and the aircraft would present a simple target to a following
Spitfire. Similarly, a Spitfire attacked by a Me.109F from above, should have
no difficulty in evading if he turns sharply towards the direction of the attack.
It is considered that recovery from a high speed dive near the ground would be
difficult, as the loss of height entailed is considerable. This may account
for occasional reports of Me.109F's being seen to dive straight into the ground
without appearantly being fired at.
8. The pilot's back is protected by two plates of armour 8 mm. and 6 mm.
thick respectively, and his neck and head are covered by the 9 mm. curved plate
mentioned in para. 3 above. Additional protection at the rear is afforded by
the fuel tank which is self-sealing. No bullet-proof windscreen is fitted, and
the pilot's only protection in front is provided by the engine.
9. The normal armament of the Me.109F is one 15 mm. or 20 mm. cannon firing
through the airscrew hub and two 7.9 machine guns firing through the airscrew
dics. The installation appears to be simple and all guns are easily accessible
for maintaince. This armament differs from that of the Me.109E, which usually
consists of two 7.9 machine guns firing through the airscre disc, with a 7.9 mm.
machine gun or 20 mm. cannon in each wing. The probable ammunition capacities
are as follows: -
Me.109F 2 x 7.9 mm. machine guns - 400/500 rounds per gun.
15 mm. cannon - 200 rounds.
or 20 mm. cannon - 60 rounds.
Me.109E (a) 4 x 7.9 mm. machine guns - 700 rounds per gun.
(b) 2 x 7.9 mm. machine guns - 500 rounds per gun.
and 2 x 7.9 mm. machine guns - 500 rounds per gun.
10. The Me.109F, altough very similiar in appearance to the Me.109E is much
superior in all-round performance. The fac that the airscrew is fully
automatic, and the oil and coolant temperatures thermostatically controlled,
helps to make the aircraft a simple fighting machine, as the only things then
occupying the pilot's attention in combat are his throttle, flying controls
and guns. The aircraft has a superior initial climb and dive to that of the
Spitfire, but it is considered that the Spitfire could easily out-turn the
Me.109F, especially at high speed. The maximum speed of the aircraft at
18,800 feet is approximately 362 m.p.h., True.
[ signed ]
APPROXIMATE MAXIMUM LEVEL SPEEDS - ME.109F - NORMAL LOAD 6090 lbs.
DB. 601N Engine. R.P.M. - 2600
Figures supplied by R.A.E., FARNBOROUGH.
Partial Climbs - Me.109F
Corrected to normal load 6090 lbs.
Figures supplied by R.A.E., FARNBOROUGH.