| Engine BMW 801 D 2/20208.
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| Close engine cowling.
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| Split cooling cowl flaps with opening angle indicator.
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| Armament: 2 MG 17, 2 MG 151, with ammunition.
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| Take-off weight: 8,532 pounds (G = 3870 kg)
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| Short or long exterior intake
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| 1.) |
Dynamic pressure calibration on test course.
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| 2.) |
Level speeds with combat power, with split flaps closed:
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a.) Long exterior intake,
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b.) Short exterior intake.
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| 3.) |
Climb rate with combat power, with split flaps open and closed:
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a.) with long exterior intakes
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b.) with short exterior intakes.
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| 4.) |
Pressure in front of (px) and pressure drop in (Δ px) the radial cylinder block with combat power:
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a.) During climb with split flaps open,
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b.) During level flight with split flaps closed.
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| 1.) |
The check of the airspeed indicator system showed no position error at 3 different speeds on the test course.
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| 2a) |
The determination of level
speed was not difficult with the long exterior intakes.
The plot shown in Graph 1 is flawless.
At a CINA full throttle height of 22,802 feet (6950 meters), a speed
of Vwc = 405 mph (652 km/h) was obtained.
The earlier measured values of Werk No. 528, also with the long
exterior intakes, show good agreement with these measurements in the low
supercharger gear.
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In high supercharger gear of Werk No. 528,
however, the trend was much shallower, so that with a full throttle height of
22,310 feet (6800 meters) a speed of 416 mph (670 km/h) could be
obtained.
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| 2b) |
It was considerably more difficult to determine the
speed with the short exterior intakes.
There were differences of up to 19 mph (30 km/h), probably due to the
intake of warm air from the cooler, or flow separation at the scoop.
Therefore, only the maximum values are plotted on the graph and
connected with each other up to full throttle altitude, which also
could not be determined properly. According to the pilots, in addition
to the mentioned phenomena, the engine ran much worse with the short
intakes compared to the long intakes. It is therefore advisable to
envisage the long intakes for production aircraft.
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| 3.) |
As a result of encountered difficulties, the climb performances with
open or closed split flaps were properly flown only with long intakes and are shown in Graph 2.
This results in service ceiling heights of 34,941 feet (10650
meters), or 36,745 feet (11200 meters) at a full throttle altitude
of 20,013 feet (6100 meters).
Rate of climb is also in good agreement with the Werk No. 528.
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4a)
b) |
Pressure in front of, as well as pressure drop in the
radial cylinder block for the climbing flight with cowl flaps
"open" are shown on Graph 3 and for level flight with cowl flaps
"closed" shown on Graph 4. Further test flights with normal intakes
will investigate, how large the increase of the precompression caused
by the loss of the internal intake of intake air is.
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Wenzendorf, 1 March 1943
Gt/Kl.
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