| Condition:
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| Engine BMW 801 D/2/25453
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| Tight engine cowl.
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| Split flaps with reinforced actuator under 40 kg pre-load.
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| Armament: 2 MG 17, 2 MG 151 with ammunition
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| MG-FF belt hatches.
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| 1.) |
Level speeds at height with combat power and closed split flaps, or open split flaps near ground level.
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| 2.) |
Climb performance with full flight weight.
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| 3.) |
Ram pressure calibration.
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| 4.) |
Pressure in front of and pressure drop in the radial
cylinder block in climb and level flights with split flap position
"open" and "closed".
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| 1.) |
The level speeds, boost pressure and propeller position obtained
with combat power up to 29,528 feet (9000 meters) are plotted on
Graph sheet Nr. 1, under CINA conditions.
Results with closed split flaps are:
|
| Vwc at Sea Level (0 meters) |
= 331 mph (532 km/h)
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| Vwc full throttle height |
= 398 mph (640 km/h)
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| Full throttle height = 19,029 feet (5800 meters).
|
|
The speed loss with the split flaps fully open at this power is 22 – 25 mph (35 – 40 km/h).
It should be noted that the aircraft is slower by ~6 mph (10 km/h) compared to Serial Nr. 711, also equipped with split flaps.
Special attention must be paid to the split flaps actuator set up under 40 kg pre-load, since the pre-load decreases with
time and then the flaps stand open in level flight.
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|
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| 2.) |
Climb rate (Graph No. 2)
could be flown only with split flaps open, otherwise the maximum
cylinder temperatures would have been exceeded under the currently prevailing
outside air temperatures.
The service ceiling with closed split flaps was therefore determined by
considering the known rate of climb loss with open flaps (~ 1.5 m /
sec).
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|
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| 3.) |
Graph 3 shows the airspeed
indicator error obtained on the test course which was taken into account
in the plot of the speed profile on page 1.
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|
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| 4.) |
Cooling pressure drop Δ px and pressure in front of cylinder radial block px in climb and level flight with combat power are given on Graphs 4 and 5.
|
Because of the urgent need to make the aircraft
available as a performance machine for E-Stelle, Rechlin, it is once
again pointed out here that engine difficulties significantly interfered
with the course of the trial.
Even now they are not yet completely resolved, so that occasional power
fluctuations are to be expected, in particular at high altitudes. The
engine related faults during flight began with the fact that the engine
power suddenly dropped sharply while climbing at 10 km altitude, so
that the aircraft could not be held at this altitude. At 8000 meters,
the power returned and the engine ran normally. Later, this phenomena
occurred at ground level, where it was no longer possible to achieve
higher engine power (pL = 0.9 ata). The change of the
Kommandogerät led to no success. During fuel consumption control,
it turned out that the fuel pump filter was crushed and very dirty.
Performance measurements could be completed after addressing these
faults.
Above full throttle height the engine was characterized by pronounced
rough running, especially with economical power. |
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