Control and stability at the stall.

Loading:- Extended aft limit

Flaps and undercarriage Up.
Tests 1,2 and 3
Stalling speed 92 m.p.h. A.S.I.
There is little warning of the stall, except for the high position of the nose. The force on the control column is very light, the control column being only just aft of central. As the speed drops below 100 m.p.h. A.S.I. the aircraft becomes increasingly left wing low until at the stall about half aileron is necessary to keep level

Immediately before the stall there is a shudder throughout the airframe and the aircraft starts to pitch and rock laterally. All the controls are effective and the aircraft can be controlled by coarse movements. At 1.2 times the stalling speed, the aircraft will glide in a straight path and on an even keel with ailerons and rudder held fixed. If disturbed, the flight path can be regained by normal movement of either control.

If the control column is pulled slowly back from a slow glide, with ailerons and rudder fixed, the left wing gradually falls; more and more aileron is necessary to keep level as the speed decreases. With the control column right back the aircraft pitches considerably accompanied by the tendency for the left wing to flick downwards. This can be controlled at first but as it increases in violence there is insufficient control and the aircraft falls away. There is no tendency to spin.

Flaps and undercarriage down.
Tests 1,2 and 3
Stalling speed 80 m.p.h. A.S.I.
The control column is central at the stall, and there is no warning except that immediately before the stall a sharp shudder is felt throughout the airframe. At the stall, the nose and right wing fall fairly quickly together.

The aircraft is stable at 1.1 times the stalling speed. Gliding at 1.1 times stalling speed, the aircraft can be kept straight and level with ailerons and rudder held fixed. If disturbed, the flight path can be regained by use of either control used separately.

If the control column is pulled slowly back form a slow glide, the aircraft keeps straight and level with the ailerons and ruidder held fixeddown to the stalling speed. Before the controlcolumn is right back, the right wing falls sharply and cannot be picked up by the use of ailerons. The aircraft then falls into a spiral which might develop into a spin.

Test 4.
For a sustained turn with 30 deg. bank, the minimum speeds are 102 m.p.h. A.S.I. to the left, and 98 m.p.h. A.S.I. to the right. The limit in decreasing the speed is imposed by the aircraft's unbanking against full aileron.

To the left the contol column is central, and to the right about half aileron is maintained throughout the turn.

The controls are sluggish but effective.

Test 4.
For a sustained turn with 30 deg. bank, the minimum speeds are 90 m.p.h. A.S.I. to the left and 84. m.p.h. to the right.

The behaviour is similar to the flaps and undercarriage raised position.

....4.9 Dives. Dives were made at both normal and extended aft positions of the centre of gravity. At the extended aft loading the dive was only continued up to 480 m.p.h. A.S.I. as the hood showed signs of breaking away. At normal load two dives to 500 m.p.h. A.S.I. were made on a new aircraft A.L.973. Details of these two dives are :-

Throttle positionHeight
in feet
Max A.S.I.
Max R.P.M.Height start
out feet
Height out
Full throttle15,000500300090008500Full throttle level flight
1/3 open19,000500260090008700"

Dive limitations: A.S.I. 505 m.p.h. R.P.M. 3125

....Behaviour in the dive. In the full throttle dives at both centres of gravity positions the aircraft is stable. The dives were very smooth and steady except for the cutting of the engine, which persisted intermittently throughout the dive at full throttle on A.L.973; the cause of this engine cutting is unknown, but, as it is not experienced on other Mustangs in dives up to 480 m.p.h. A.S.I., it is not considered serious. The push force required to hold the aircraft in the dive is very light (approximately 5 lb.) No change of trim is felt on any of the other controls. Recovery is effected easily with no sign of vibration of the controls by releasing the force on the control column. There is no tendency to tighten up unduly on recovery even when at the extended aft C.G. limit.

...........All the controls are effective in the dive. The ailerons become heavy as the speed increases, but they are still usable. The effect of applying 10 deg. of yaw was not noted on this dive.

...........At 1/3 throttle, the dive is very steady and smooth, but it requires a much stronger push force to hold into the dive (approximately 20 lb.) The right wing drops and requires about 10 lb. force on the control column to hold it up. The aircraft also tends to swing to the right and requires a considerable push force on the left rudder to hold it straight. On account of this, no yaw was applied in the dive.

...........In all dives the hood locking is very unreliable and needs modification of the holding down pins since at high speeds a half inch gap appears between the hood and the frame and shows signs of being sucked completely out.

....4.10 Landing. Approach and landing is easy and straightforward. The best approach speed with flaps and undercarriage down and engine on is 95-100 m.p.h A.S.I.; reduction in weight due to expenditure of fuel does not appreciably affect the best approach speed. When the flaps and undercarriage are lowered, the aircraft tends to become slightly nose heavy. There is sufficient elevator control to make a satisfactory tail down landing at all loadings, but at the forward centre of gravity position the limit is just about reached in this respect. The aircraft touches down at about 80 m.p.h. A.S.I. when using full flaps at normal load. There is no tendency to nose over when the brakes are applied, even when loaded to the forward limit.

...........Direct cross wind landings were also carried out in winds up to 30 m.p.h. Most difficulty was experienced in the approach and was due to the lack of aileron control at sideslipping speeds, making it difficult to correct the drift and obtain a straight approach as would be necessary for a runway. However, there was no feelingof drift at the touch down when the aircraft was levelled off laterally and the aircraft rouched down normally, running quite straight under rudder control alone with the tail wheel locked. Locking the tail wheel reduces any swing that may arise. Satisfactory landings can be made however with the tail wheel free, but the tendency to swing into the wind is more pronounced and can be checked by use of the brakes, rudder alone not being sufficient.

...........Landing at night down a flare path presents no difficulty and is quite straightforward.

....4.11 Baulked Landings.

...........The climb away from a baulked landing is good. The flaps and undercarriage can be raised at 120 m.p.h. A.S.I. without any appreciable sink. The aircraft becomes slightly tail heavy when the engine is "opened up", but the change if trim can be easily held.


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