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RAE report on the Liberator

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11 years 4 months ago - 11 years 4 months ago #69 by PeterClare
PeterClare created the topic: RAE report on the Liberator
Thought members might find the following of interest.

Regards
Peter.


The following notes are extracted from a report written "by RAE test pilot Flt.Lt. A P Martindale, following his attachment to No.120 Squadron at Nutts Corner, Northern Ireland, in May 1942.

Liberator I.

The only type of Liberator used by No.120 Squadron on operational sorties, it carries 2,500 gallons of fuel and, cruising at 160 mph, with the engines using 30 galls, per hour each, has been used for an 18-hour patrol, or about 2,800 air miles. The normal patrol is somewhat less than this, 15 to 16 hours being common. It is, therefore, a magnificent anti-submarine weapon and is used to search for U-boats in the North Atlantic well out of range for other aircraft.

It has two petrol tanks, each feeding two engines, which are not self-sealing and have no transfer or balance arrangements. It is armed with 4 fixed 20mm cannon, firing forward and mounted under the front bomb bay position, and 3 pairs of Browning 0.303-in. machine-guns, one pair in the extreme tail and one pair on each beam. It has been carrying 6 depth charges, filled with Torpex, each weighing 300 Ib. and carried in the rear bomb bay. It has ASV equipment. Some Liberator I's are armoured behind the pilot's seat.

The nose position, which has a magnificent view, is empty except when the navigator is actually dropping depth charges. The cockpit has full dual control for the pilots: a seat and desk for the navigator (from which position he can see practically nothing) and an astrodome: there is a seat, full instrument panel and all the engine controls for the engineer. Behind the cockpit are the bomb bays, and behind these the wireless and living compartment for the rest of the crew, in which is the galley. The wireless and ASV operator is thus separated from the captain.

Flying the Liberator presents certain problems. First is the question of runway length. I am in full sympathy with the pilots when they say that they need 1,600 yards minimum for night operation. The Americans say much longer runways are necessary. I was in a Liberator I which ran 1,550 yards before it was pulled off at 125 mph when loaded to 51,000 Ib. or more. There is obviously little in hand for emergencies, even with a 1,600 yard runway.

Since take-off controls the runway length, the speed at which the aeroplane is landed is of little importance. In 120 Sqdn. there is a tendency to fly it straight on to the ground at 110 mph, which is the approach speed. This high touch-down speed results in heavy braking, even on a 1,600 yard runway.

A reduction in the touch-down speed could almost certainly be effected" if the
pilots had more landing experience. A pilot who does 50 hours flying a month will only do 6 or 8 landings. An aeroplane has been lost recently due to a pilot making a poor approach, and in general there is some strain on the pilot's part when landing and a tendency to do long, flat, fast approaches. The aeroplane is under-flapped, and I think that a tail arrester parachute would be greatly appreciated.

Landling the aircraft on the ground needs considerable care when the centre of gravity is 60.4 inches aft of datum and 8 inches in front of the main wheels. The tail strut has to be put into position as soon as the aircraft stops and before the crew moves aft in a body. Similarly, the crew must be forward before it is removed. Various collapses on to the tail have occurred; one was due to the application of brakes when the aircraft was being manhandled backwards. One advantage of this peculiarity is that it prevents stalling due to wrong loadings when coming in to land as the pilots are very c.g. conscious.

The Sperry Automatic Pilot is used the whole time for flying the aircraft and is an excellent instrument. The aeroplane is very heavy to fly manually on a course, particularly in bumps, and accuracy is necessary during a long sea patrol. The Sperry is, therefore, essential. When No.3 engine fails (during one patrol I was on it had to be feathered), the Sperry fails also. This is a bad point - two engine pumps would be better. The electric hydraulic pump is not considered suitable for long-period operation.

There is a considerable precession on the directional gyro on some of the aeroplanes, so that the pilot is constantly turning the rudder and elevator knobs, the latter to keep in the cloud base. The knobs are placed so that the arm is stretched fully when turning them and this is tiring. I noticed on one occasion that the pilot was letting the aircraft swing 5 degrees on each side of his course, and this is probably less accurate than keeping the compass spot on. Greater accuracy would probably be ensured if an extension was fitted so that the knob was down by the trim tab controls, where the pilot's hand naturally falls.
The inter-communication system is good on the whole. Occasionally it gives trouble. Few crews use it except when they have to, that is when the pilots or navigator are talking to the wireless operator. Shouting is generally used in the pilot's cockpit.

Certain medical problems arise during long patrols. On one patrol two members of the crew were sick - one was the engineer (and cook) who sits forward, and the other was W/Op AG who spent a lot of time flat on his back. The conditions were slightly bumpy. I felt no discomfort myself, but I had to prop myself up whilst cooking the dinner.

This sickness gave extra work to the other two W/Ops and the ASV watch suffered. The American system of bomb-bays (the full depth of the aeroplane) pushes part of the crew further aft than need be on a British aircraft, and the bumps are much more noticeable further aft. An anti-submarine patrol is incredibly monotonous and there is great difficulty in keeping alert and even awake. On one occasion the pilot flying the aeroplane fell asleep.

The food is of value, more as a stimulant than anything else, but the crew often refuse it and even hot drinks. I think that this is due to the poor sanitary arrangements. I can see no reason why much better arrangements could not be made and I am convinced that these would increase the crew's alertness considerably.

The anti-submarine patrols are carried out at various heights depending upon cloud conditions, 5

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11 years 4 months ago - 11 years 4 months ago #560 by PeterClare
PeterClare replied the topic: RAE report on the Liberator
Thought members might find the following of interest.

Regards
Peter.


The following notes are extracted from a report written "by RAE test pilot Flt.Lt. A P Martindale, following his attachment to No.120 Squadron at Nutts Corner, Northern Ireland, in May 1942.

Liberator I.

The only type of Liberator used by No.120 Squadron on operational sorties, it carries 2,500 gallons of fuel and, cruising at 160 mph, with the engines using 30 galls, per hour each, has been used for an 18-hour patrol, or about 2,800 air miles. The normal patrol is somewhat less than this, 15 to 16 hours being common. It is, therefore, a magnificent anti-submarine weapon and is used to search for U-boats in the North Atlantic well out of range for other aircraft.

It has two petrol tanks, each feeding two engines, which are not self-sealing and have no transfer or balance arrangements. It is armed with 4 fixed 20mm cannon, firing forward and mounted under the front bomb bay position, and 3 pairs of Browning 0.303-in. machine-guns, one pair in the extreme tail and one pair on each beam. It has been carrying 6 depth charges, filled with Torpex, each weighing 300 Ib. and carried in the rear bomb bay. It has ASV equipment. Some Liberator I's are armoured behind the pilot's seat.

The nose position, which has a magnificent view, is empty except when the navigator is actually dropping depth charges. The cockpit has full dual control for the pilots: a seat and desk for the navigator (from which position he can see practically nothing) and an astrodome: there is a seat, full instrument panel and all the engine controls for the engineer. Behind the cockpit are the bomb bays, and behind these the wireless and living compartment for the rest of the crew, in which is the galley. The wireless and ASV operator is thus separated from the captain.

Flying the Liberator presents certain problems. First is the question of runway length. I am in full sympathy with the pilots when they say that they need 1,600 yards minimum for night operation. The Americans say much longer runways are necessary. I was in a Liberator I which ran 1,550 yards before it was pulled off at 125 mph when loaded to 51,000 Ib. or more. There is obviously little in hand for emergencies, even with a 1,600 yard runway.

Since take-off controls the runway length, the speed at which the aeroplane is landed is of little importance. In 120 Sqdn. there is a tendency to fly it straight on to the ground at 110 mph, which is the approach speed. This high touch-down speed results in heavy braking, even on a 1,600 yard runway.

A reduction in the touch-down speed could almost certainly be effected" if the
pilots had more landing experience. A pilot who does 50 hours flying a month will only do 6 or 8 landings. An aeroplane has been lost recently due to a pilot making a poor approach, and in general there is some strain on the pilot's part when landing and a tendency to do long, flat, fast approaches. The aeroplane is under-flapped, and I think that a tail arrester parachute would be greatly appreciated.

Landling the aircraft on the ground needs considerable care when the centre of gravity is 60.4 inches aft of datum and 8 inches in front of the main wheels. The tail strut has to be put into position as soon as the aircraft stops and before the crew moves aft in a body. Similarly, the crew must be forward before it is removed. Various collapses on to the tail have occurred; one was due to the application of brakes when the aircraft was being manhandled backwards. One advantage of this peculiarity is that it prevents stalling due to wrong loadings when coming in to land as the pilots are very c.g. conscious.

The Sperry Automatic Pilot is used the whole time for flying the aircraft and is an excellent instrument. The aeroplane is very heavy to fly manually on a course, particularly in bumps, and accuracy is necessary during a long sea patrol. The Sperry is, therefore, essential. When No.3 engine fails (during one patrol I was on it had to be feathered), the Sperry fails also. This is a bad point - two engine pumps would be better. The electric hydraulic pump is not considered suitable for long-period operation.

There is a considerable precession on the directional gyro on some of the aeroplanes, so that the pilot is constantly turning the rudder and elevator knobs, the latter to keep in the cloud base. The knobs are placed so that the arm is stretched fully when turning them and this is tiring. I noticed on one occasion that the pilot was letting the aircraft swing 5 degrees on each side of his course, and this is probably less accurate than keeping the compass spot on. Greater accuracy would probably be ensured if an extension was fitted so that the knob was down by the trim tab controls, where the pilot's hand naturally falls.
The inter-communication system is good on the whole. Occasionally it gives trouble. Few crews use it except when they have to, that is when the pilots or navigator are talking to the wireless operator. Shouting is generally used in the pilot's cockpit.

Certain medical problems arise during long patrols. On one patrol two members of the crew were sick - one was the engineer (and cook) who sits forward, and the other was W/Op AG who spent a lot of time flat on his back. The conditions were slightly bumpy. I felt no discomfort myself, but I had to prop myself up whilst cooking the dinner.

This sickness gave extra work to the other two W/Ops and the ASV watch suffered. The American system of bomb-bays (the full depth of the aeroplane) pushes part of the crew further aft than need be on a British aircraft, and the bumps are much more noticeable further aft. An anti-submarine patrol is incredibly monotonous and there is great difficulty in keeping alert and even awake. On one occasion the pilot flying the aeroplane fell asleep.

The food is of value, more as a stimulant than anything else, but the crew often refuse it and even hot drinks. I think that this is due to the poor sanitary arrangements. I can see no reason why much better arrangements could not be made and I am convinced that these would increase the crew's alertness considerably.

The anti-submarine patrols are carried out at various heights depending upon cloud conditions, 5

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11 years 4 months ago #562 by MartinB
MartinB replied the topic: RAE report on the Liberator
Excellent article, Peter - thanks for taking the trouble.

MartinB

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11 years 4 months ago #563 by brianj
brianj replied the topic: RAE report on the Liberator
I agree - an excellent article.

Brian

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11 years 4 months ago #564 by Gary
Gary replied the topic: RAE report on the Liberator
Nice one Peter, very informative. Do you mind if I turn that in to an article?

'Yea, Though I Fly Through the Valley of the Shadow of Death, I Shall Fear No Evil. For I am at 50,000 Feet and Climbing.'

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11 years 4 months ago - 11 years 4 months ago #565 by PeterClare
PeterClare replied the topic: RAE report on the Liberator
Don't mind at all Gary, you know best what to do with it. For some reason when posted the title - subject didn't show.

Peter.

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