Kurfürst - Bf 109G/trop Middle East trials: Dimesnions, Weights and Performance

With reference to A.I.2(g) Report No. 2142 of 31/12/42,
certain additional information and data have been obtained from
German official documents.

DIMENSIONS AND AREAS:

The main airframe dimensions of the Me 109 G are as
follows :

Wing span                      32.6 ft.
Lenght                         29.3 ft.
Undercarriage track             6.5 ft.
Mean wing chord                 5.7 ft.
Wing area                     172 sq.ft.
Total flap area                11.2 sq.ft.
Total slot area                 6.7 sq.ft.
Total radiator flap area      8.6 sq.ft.
Total area of ailerons          8.3 sq.ft.
Span of the tail unit         9.8 ft.
Tailplane area               15.7 sq.ft.
Elevator area                  9.25 sq.ft.
Fin area                        7.5 sq.ft.
Rudder area                     5.9 sq.ft.

UNDERCARRIAGE:

Type of undercarriage leg: VDM 8-2787-05
Tyre size: 650 x 150 (Conti, Metzeler, Dunlop).
Tyre pressure: 57 lb./sq.in.
Pressure in oleo-leg (no load): 355 lb./sq.in.

TAIL WHEEL:

Leg with helical spring and hydraulic damping.
Tyre size: 290 x 110.
Tyre pressure: 64 lb./sq.in.

PROPELLER:

Three-blade propeller, type VDM 9-12087 A.
Direction of rotation, clockwise, as viewed from
the pilot's cocpit.
Weight complete with blades, hub and v.p. mechanism:
375 lb.
Diameter: 9.8 ft.

ENGINE:

Engine: DB 605, A or B series. Inverted 12-cylinder
liquid-cooled "V", with a volumentric compression ratio of
7.3 to 7.5. The reduction gear ratios are as follows:

Series A 1 to 1.685
Series B 1 to 1.875

The maximum permissible engine speed in level flight is
2,800 r.p.m and 3,000 r.p.m. in a dive. The German octane
rating of the fuel used is 87.

The engine ratings as given in one of the German
documents are shown in Table 1:

TABLE 1

RATING	R.P.M.	BOOST		ALTITUDE ft.	POWER b.h.p.	FUEL CONSUMP- TION, gall/hr.
		ata	lb/sq in
1 Take-off 2 Climb (30 min.) 3 Max. continous 4 Max. Emergecy 5 Combat(30 min.) 6 Max. continous 7 Economical	2,800 2,600 2,300 2,800 2,600 2,300 2,100	1.42 1.30 1.15 1.42 1.30 1.15 1.00	+ 5.5 + 3.8 + 1.7 + 5.5 + 3.8 + 1.7 - 0.5	S.L. S.L. S.L. 18,700 19,000 18,000 18,700	1,455 1,290 1,060 1,335 1,235 1,065 880	102.5 85.5 68.75 93.75 81.5 69.25 54.25

        It is known, however, that the ratings 1 and 4 were
temporarily cancelled, and the engine was not supposed to
operate in excess of the "climb and combat" ratings 2 and 5.

        It is to be expected that this restriction will eventually
be removed, as engine cards were found on crashed aircraft
where the full ratings, i.e. 1 and 4 were given without any
restrictions.

        The take-off power (rating 1) is 1,455 b.h.p. at 1.42 ata
and 2,800 r.p.m. At the same boost and engine speed, but at a
height of 18,70 ft., the power given is 1,355 b.h.p. No
reliable estimate of the maximum output can be given until such
time as a DB 605 engine has been examined and tested in this
country, but it is likely that the actual maximum power is
about 1,500 b.h.p. at a lower height then that given in Table 1,
i.e. say 15,000 ft. instead of 18,700 ft. (rating 4.).

        The oil consumption is given as .009 to .016 lb./hp/hr.

The weight of the engine, dry, is 1,540 lb. +3%.

OIL COOLER:

One oil cooler is fitted, type SKF/Behr FO 820.

The cooling surface is 125 sq.ft., capacity 0.9 gallon
and weight 60 lbs. The test pressure is given as 71 lb./sq.in.

COOLANT RADIATORS:

Two light metal radiators, type SKF/Behr. Al.F.750 B.

The coolant used is a mixture of water and glycol.

The cooling surface is 125 sq. ft., capacity 1.4 gallons
and the weight is 131 lb. The test pressure is 28.4 lb./sq.in.

HEADER TANKS:

Two light-metal header tanks are fitted, type NKF. The
capacity is 1.1 gal. of coolant and 1.1 gal. air space.

The total weight of the two header tanks is 7.3 lb. and
the test pressure is given as 7 lb./sq.in.

OIL TANK:

One light-metal oil tank, type NKF. Oil capacity 8.1
gallons with an additional air space of 1.3 gallons.
Weight 12.75 lb. Test pressure 5 lb/sq.in.

FUEL TANK:

One fuel tank, made by Karl Otto Raspe & Co. Capacity
88 gallons; weight 121 lb.; test pressure 2.8 lb./sq.in.

JETTISONABLE FUEL TANK:

One jettisonable fuel tank, type Ju 87/NKF. Capacity
65 gallons, weight 55 lb.; test pressure 8.5 lb/sq.in.

WEIGHTS:

Table 2 gives the empty and flying weights of the
Me 109 G-1 equipped as fighter and as a fighter bomber:

Me 109 G-1

(Armament: 1 x MG 151/20 + 2 x MG 17)

TABLE 2

        Differences in total flying weights shown in Tables 2
and 3 are due to certain additional equipment fitted in the
Me 109 G-1.

        While both the G-1 and G-2 have sealed cocpits, the G-2
is not fitted with the high-altitude pressurizing equipment
carried in the G-1.   Moreover, the Me 109G-1 is fitted with
what is described as a GM-1 installation, probably a develop-
ment of the bi-fuel equipment which was found in the Me 109 E-7
brought down at Worth Maltavers on 9/6/41.

PERFORMANCE TRIALS.

    Flying trials have been carried out in the Middle East
with a Me 109 G-2 (tropical version).   These figures are
preliminary and full report will be issued on the performance
of this aircraft as soon as the neccesary data become avail-
able.

    In the meantime the following are extracts from the test
report received from Middle East:

    "The aircraft had been restored to standard good condition
except that the oil radiator flap was locked open as received,
as the functioning of the thermostatic control was apparantly
bad; no oil therometer was available; there was a splinter
hole and score mark in one airscrew blade........"

       "During take-off, there is a marked swing to the left
which occurs towards the end of the run as full power is
given. Acceleration is quick and take-off run fairly
short........"

       "The air filter was cut out at about 8,000 ft. and was
put in again after all tests had been done, before coming in
to land......"

       "The radiator flaps were left in automatic and kept the
temperature at 80* C most of the time in the easy condition
of cruising used between the test runs.   The maximum temperature
seen was 100* ............"

       "The engine has some rough periods, but usually, and
particularly at high r.p.m., runs sweetly ......."

       "Owing to the high rate of climb, it is neccesary to allow
a margin up to 3,000 feet to settle down into a steady
climb: thus for timing a climb from 15,000 feet to 17,000 ft., it
is desirable to pull up to climbing speed (e.g. 150 m.p.h.) at
12,000 ft.   In full speed level flights, speed is picked
up quickly."

       "The control is steady and it is easy to maintain
accurate speed with reasonable care."

       "After almost 45 minutes of flying the red fuel shortage
(15 minutes to go) warning light showed.   Owing to the fuel
swishing about, the light shows intermittently and is an
effective warning".

       "In the approach to land, torque can be distinctly felt
and so the engine should be opened up slowly when "rumbling"
......."

       "The cooling flaps on the radiator are automatically
controlled and they open as the engine temperature rises.
They are big enough to cause considerable drag when wide open.
Therefore they will cause more drag on a long continous climb
and so decrease the performance............."

       "During the climb from 30,070 to 32,000 feet, the cooling
flaps were seen to be wide open, owing appearantly to a sticky
thermostat. They were adjusted to normal position by using
the manual control but the rate of climb obtained must have
been somewhat reduced by this......."

       "The rated height of the engine was found by doing a steady
climb at 200 m.p.h. indicated and noting the boost pressure at
each thousend feet.   The automatic boost control keeps the
boost constant below rated height, and it decreases above.
By plotting a graph of boost against height, the line of the
decreasing boost can be drawn and this meets the position of
1.3 boost at 21,700 feet (true) which is taken as the rated
height at governed r.p.m. (2750)."

       "Level speed was tested at 23,200 feet (true) which
gave 262 m.p.h. indicated, equal to 378 m.p.h. computed."

---------

       Tables 4 and 5 give speed and climb data calculated from
the Middle-East Test report.

                           Table 4.

                        Me 109 G-2 Trop.

While these figures are in reasonably good agreement
with the data obtained from other sources, the aircraft was
not in perfect condition; for instance the oil radiator flap
was locked open as mentionedin the extracts given above.
Moreover, the figures in tables 4 ad 5 apply to the
Tropical version fitted with an air-cleaner.

Data given below under te heading "Performance"
have been calculated for a Me 109 G-2, without Tropical
equipment.

PERFORMANCE

Me 109 G-2 with 1 x MG 151/20 (20 mm) and 2 x MG 17

(7.9 mm) guns.

Starting Weights.

Fighter :   6,670 lb.
Fighter with external jettisonable fuel tank:   7,230 lb.
Fighter-Bomber:   7,280 lb.

Maximum Speed.

Fighter: 395 m.p.h. at 22,000 ft., and 328 m.p.h.
at sea level.

Fighter with external jettisonable fuel tank:
367 m.p.h. at 22,000 ft. and 305 m.p.h. at sea level.

Fighter-Bomber with 550 lb. of bombs: 367 m.p.h. at
22,000 ft., and 305 m.p.h. at sea level.

Service Ceiling.

Fighter: at start 37,500 ft, at finish 39,000 ft.

Fighter with external jettisonable fuel tank: at
start 35,000 ft., at finish 39,000 ft.

Fighter-Bomber with 550 lb. of bombs: at start
35,000 ft., at finish 39,000 ft.

Climb.

Time to 18,000 ft:-

Fighter: 5.3 min; mean rate of climb from S.L. to
18,000 feet: 3400 ft/min at 1.3ata boost and
2,600 r.p.m.

Fighter with external jettisonable tank: 6.3 min.

Fighter-Bomber with 550 lb. of bombs: 6.3 min.

The maximum ranges at varying fuel and bomb loads are
given in Table 6:

WEIGHTS	FIGHTER		FIGHTER-BOMBER
	without ext. fuel tank	with ext. fuel tank	with 1x250 kg. bomb	with 4x50 kg. bombs	with 96x2 kg. bombs
	lb.		lb.
Empty Flying	4,983 6,983	4,983 7,558	4,983 7,597	4,983 7,511	4,983
Max. flying weight 7,606 lb.

WEIGHTS	FIGHTER			FIGHTER-BOMBER
	with 3 guns and no jetti- sonable fuel tank	with 2 addition- al wing guns in fairings	with 3 guns and jettison -able fuel tank	with 3 1x250 kg. bomb	with 4x50 kg. bombs
	lb.			lb.
Empty Flying	4,938 6,678	4,938 7,151	4,938 7,238	4,938 7,291	4,938 7,511
Max. flying weight 7,606 lb.

SPEEDS
Engine	Rating	Altitude ft.	Max. speed m.p.h.
Boost ata.	R.P.M.	Altitude ft.	Max. speed m.p.h.
1.30 1.30 1.30 1.42 1.42 1.42	2,700 2,700 2,700 2,800 2,800 2,800	S.L. 23,500 30,000 S.L. 23,000 30,000	305 375 364 317 384 372

CLIMB
Engine	Rating	Altitude ft.	Rate of climb ft/min.
Boost ata.	R.P.M.	Altitude ft.	Rate of climb ft/min.
1.30 1.30 1.30 1.42 1.42	2,750 2,750 2,750 2,800 2,800	S.L. 21,500 30,000 S.L. 21,000	3,350 3,400 1,450 3,950 3,800

	Bomb Load lb.	Fuel Tankage gall.	(a ) Normal cruising (b ) Max. range.
	Bomb Load lb.	Fuel Tankage gall.	Speed m.p.h.	Altitude ft.	Range miles	Endurance hrs.	Fuel consump- tion Miles/gall
Fighter	Nil	88	(a ) 316 (b ) 210	(a ) 18,000 (b ) 18,000	(a)415 (b)725	(a) 1.35 (b) 3.45	(a ) 5.6 (b )10.0
Fighter with external tank	Nil	154	(a ) 306 (b ) 210	(a ) 18,000 (b ) 18,000	(a)755 (b)1,250	(a) 2.50 (b) 6.00	(a ) 5.4 (b ) 9.1
Fighter- bomber	550	88	(a ) 306 (b ) 210	(a ) 18,000 (b ) 18,000	(a)400 (b)655	(a) 1.33 (b) 3.10	(a ) 5.4 (b ) 9.1