| Engine BMW 801 D2/25543
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| Close engine cowl
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| Split cowl flaps with reinforced drive linkage, with a pre-load of 40 kg at 0° angle.
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| Split cowl flap adjustment manually by E-motor and automatically by thermostat.
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| Armament: 2 MG 17, 2 MG 151, MG FF belt hatches.
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| C-rear fuselage with 1:1,3 differential from 15.1.43.
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| Landing gear pre-load spring from 26.1.43.
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| Cylinder temperature measuring equipment.
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| Pressure drop in the radial cylinder block Δ px
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| Pressure in front of radial cylinder block px
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| 1.) |
Cylinder temperatures in climb and level flight with combat power, depending on the split cowl flap opening angle.
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| 2.) |
Assessment of the thermostatic split cowl flap control.
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| 3.) |
Landing gear speed limits for the landing gear with
pre-load springs in comparison to the standard production pneumatic
pre-load system.
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| 4.) |
Level speeds with combat power.
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| 1.) |
For comparison with the cylinder temperature
of the previously flown Fw/0028, data in climb and level
flight was initially determined for the split flaps positions "open"
and "closed.
The results: tzyl = 255 / 260° for climb with combat power and split flaps closed, and tzyl
= 220° with flaps fully open, showed good agreement with the measured
temperatures of 0028 (Comparison report: "Fw 190 with split flaps from 9.6.42 ").
Level flight values were determined at 1,640 feet (500 meters) with tzyl max = 180° or 175° and at 26,247 feet (8000 meters) with tzyl
max = 200° or 190° for split flaps "closed" or "open".
This shows that the cooling effect of the split flaps in level flight
is minor but increases somewhat with increasing height.
This fact is, however, not relevant, since the split flaps remain
closed in level flight at all altitudes, even in the tropics.
Further investigations, such as the determination of the
temperatures in climb with split flap opening angle between 0° and 40°
and the determination of, - without exceeding the maximum permissible
cylinder temperatures, - flap opening angle for best climb speed at the time
period 1.11.42 – 1.2.43, are incorrect and do not appear in this report.
From 1.11.42 on the measured temperatures were up to 50° below the level
determined at the start of testing.
Frequent checking of the measurement equipment, recalibration and
replacement of the indicators did not change the result.
Only the use of a highly sensitive precision instrument on 1.2.
resulted in an improvement and the temperatures were so determined in
their old magnitude. (comparison graph of 1.2., and 7.10.).
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| 2.) |
The first test with thermostatic split flap
control
with a sensor for 90° control temperature was negative. The
position of the sensor, chosen because of the low control temperature
of the thermostat, between cylinder head and engine cover, was subject
to strongly fluctuating air flows, depending on the size of the
split flap opening angle, which caused active swinging of the flap. The
testing will now be conducted with a homemade thermostat with a much
higher control temperature. The cylinder temperature measuring pin of
cylinder 4 was chosen for the location, which causes the indicated
temperature of this cylinder to appear somewhat lower.
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| 3.) |
The established speeds for the production landing gear
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When retracting |
= 270 mph (435 km/h),
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When lowering |
= 146 mph (235 km/h),
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With maintenance-free spring,
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When retracting |
= 224 mph (360 km/h),
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When lowering |
< 124 mph (200 km/h),
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Thus, the spring pre-load seems to be stronger.
The force-displacement diagrams are still being created and will appear in the next report.
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| 4.) |
In comparison with the level flight speeds with covered gills
(winter emergency equipment) documented in
Report No. 1, the speeds were flown at altitude with
split flaps closed and plotted on the attached graph, corrected for
CINA-conditions.
There were no significant differences.
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Wenzendorf, 6 February 1943
Gt/Kl. |
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