Liberator Mk I ( AM series ) and Liberator Mk II ( AL series)

[krakus57]

To everybody which can help me !

A looking for ANY materials to my book about first Liberator's duty in RAF and BOAC ( documents , technical drawning , design , photos and s.o ) about Liberator Mk I( series AM) and Liberator Mk II ( AL series )

1./ David F MacIntyre Collection ( owner Scottish Aviation Ltd at Prestwick - SAL )
and about archive SAL's archive ( now BEA ) , information at wartime's production at SAL during 1940 -1942 .( first of all about design of rebuild Liberator for transport and technical date after rebulding )
2./ Any informations about SAL - especially wartime 1940 - 1943
3/ All informations about AM , AL series and their duty in SAL Prestwick and REA Farnborough since delivery date .
4./ About REA Farnborough 1940 -1943
5./ RAF Lyneham - Station of 511 Sqn and crews
6./ Whole Flight performance of Liberator Mk I , Mk II by take -off and engine Pratt&Whitney Double Wasp R -1830 - 33 ( !)


Thanks for all Mike

 

[Peter C]

To everybody which can help me !

A looking for ANY materials to my book about first Liberator's duty in RAF and BOAC ( documents , technical drawning , design , photos and s.o ) about Liberator Mk I( series AM) and Liberator Mk II ( AL series )

1./ David F MacIntyre Collection ( owner Scottish Aviation Ltd at Prestwick - SAL )
and about archive SAL's archive ( now BEA ) , information at wartime's production at SAL during 1940 -1942 .( first of all about design of rebuild Liberator for transport and technical date after rebulding )
2./ Any informations about SAL - especially wartime 1940 - 1943
3/ All informations about AM , AL series and their duty in SAL Prestwick and REA Farnborough since delivery date .
4./ About REA Farnborough 1940 -1943
5./ RAF Lyneham - Station of 511 Sqn and crews
6./ Whole Flight performance of Liberator Mk I , Mk II by take -off and engine Pratt&Whitney Double Wasp R -1830 - 33 ( !)


Thanks for all Mike

Hopefully better late than never.
Flight deck of Liberator I AM917 F/120 Squadron.

 

[Peter C]

Some time ago I believe there was a request for details of the Liberator II. The following is taken from my notes......

Notes Concerning Liberator Mk.II Aircraft. Taken from REPORT ON ATTACHMENT TO NO.120 SQUADRON, by Flt.Lt. A.F. Martindale, Royal Aircraft Establishment; 25 May to 8 June 1942.

"Liberator IIs. . . . .operationally carry 2,066 gallons in theory, but 1,800 gallons in practice, the reduction being caused by the 12 self-sealing cells put in the same two tanks and grouped in threes for feeding the engines. A fuel transfer system is provided. It carries the usual depth-charges, both bomb bays being available and 14 Browning 0.303 machine guns. Four are in the rear Fraser Nash turret, one free gun is in the tail shooting downwards, two pairs of guns fire beam shots, there is a Boulton & Paul upper turret with 4 guns and a free gun in the nose. The crews have great faith in their ability to defend themselves. No ASV is fitted. The layout of the Liberator II......the navigator sits in the elongated nose and has chart board, astrodome and Sperry bomb sight. The pilots have all the engine controls. The wireless operator is in the front compartment, the engineer has no definite function or place. Ammunition. . . .the tension in the long belts of 2,000 rounds causes the links to open, due to the 70-lb. feeder pull. If this is a serious cause of stoppages, it could be remedied by an auxiliary spiral spring-loaded sprocket at a suitable point in the belt. The gun turrets have no covers, the guns go rusty and water gets on to the electric contacts. Landing. . . .with the Mk.I there is a tendency to fly it straight on to the ground at 110-mph, which is the approach speed, whereas...(with the Mk.II)...they touch down at a lower speed after a partial hold-off. The difference in technique is probably due to the difference in weight distribution of" the I's and II's.

If there is an interest I have a report on the Liberator I.

 

[Snautzer01]

If there is an interest

Yes please.

 

[Peter C]

Yes please.

Will do, just need a couple of days.

 

[Peter C]

Found a bit of time..... I hope this makes sense

Liberator I AM910

AROPLANE AND ARMAMENT EXPERIMENTAL ESTABLISHMENT BOSCOMBE DOWN

Liberator I A.M. 910.(Four Twin Wasp S3C4G)Acceptance trials with A.S.V. Installation. A.A.E.E. Ref:– 4497/49 – A.M.63.Introductory:

This aeroplane is a trial installation and had been modified at Heston to take LR.A.S.V.,4-20mm cannons and 4 depth charges. Urgent trials were reouired to check the effect ofthe A.S.V. masts and gun installation on handling and stability, and the determination of maximum speed at a height of 5,000 feet. Tests of a minor nature were also required. Separate, trials of the A.S.V. and armament installations have been made. Loading: The aeroplane has been weighed and the C.G. determined. There are two alternative loadings: Loading A, with 2,000 gallons of fuel plus 4 depth charges, 50,805 lb., C.G. 55.5 inches aft of the datum point. Loading B, with 2,500 gallons of fuel plus 6 depth charges, 56,007 lb., C.G. 57 inches aftof the datum point.The aftmost C.G. results from loading '3', due to expenditure of cannon ammunition, together with sea and submarine markers and is at 57.3 inches for a weight of 55,262 lb. The foremost C.G. results from either loading, due to expenditure of rear and beam gun ammunition and depth charges, with fuel and oil reduced to hour supply, and is at 49 inches for a weight of 35,092 lb. The trials were made at a weight varying between 45,000 lb. and 47,000 lb with the C.G.at 49 inches aft of the datum point. Handling and Stability. The aeroplane has been flown at all speeds from the glide to 300mph, I.A.S and no appreciable difference in handling and stability between this aeroplane and a normal Liberator was noticed. The handling qualities on two and three engines are very good. Speed Measurement The speed was measured at a height of 5,000 feet in M blower, under the emergency boost condition (45" Hg.) and under maximum economic cruising conditions. The results are given below, together with the estimated speed for maximum all—out level conditions. Condition. R.P.M. P,00st Height Weight. I.A.S. in. Hg. (ft.) (110.) m.p.h. All—out emergency 2700 45 5,100 45,700 262.5All—out level 2700 41 5,000 45,000 293*Max. econ. cruising 2250 28 5,000 45,700 216.5*Estimated. Position Error: This has been determined and is given in Fig.13. Relative to the position error curve obtained from Consolidated Aircraft, the position error is negative by 101/2 m.p.h. at 240m.p.h. A.S.I. and by 6 m.p.h. at 140 m.p.h. A.S.I. In both cases the curves are straight lines. This discrepancy will be investigated further if a suitable occasion occurs. Pilots Windscreen Glycol Spray As originally set the pipes sprayed too far inboard. They were re—set approximately 10degrees outboard, the nozzles being 31 7/8 inches apart, and in this setting they provide an efficient spray for the 1st. and 2nd. pilots. The area covered by the spray is only just sufficient and it is felt that it should be enlarged by means of an increase in the flow and pipe bore. Co Contamination Throughout the gun firing trials there was no noticeable vitiation of the air within the aeroplane and CO contamination is not therefore suspected. Navigation Compasses: The compasses have been swung, and the deviation has been checked unde rall combinations of the electrical services. The main source of deviation change is the Steward—Warner heating system, there being large magnetic fields around the electric distributing fans. With the heating system on, the maximum change of deviation is 31/2 degrees in the pilot's P9 compass, and 15 degrees in the navigator's Pioneer 1801 compass. The other source of deviation change is the magnetic field set up by the engine–driven generators when charging the accumulators, and this trouble is complicated by the fact that the deviation varies according to the amount of the charging current. -;'ortunately only the navigator's compass is affected, the Pilot's compass remaining unaffected at allrates of charging. The effect of retraction of the nose wheel has been tested, and it was found that no appreciable deviation change was present in either compass. As the mounting for the Mark IX C.S.3.S. has not been installed, the effect of nose wheel retraction on the compass in the C.S.B.S. has not been tested. An improvement to both the 1st. and 2nd. pilot's view of the P9 compass would be made by enlarging the ball pivot of the compass mirror, allowing a larger movement of the mirror, and giving the pilots a view of the magnet system free from the effect of parallax. Navigator's seat: The navigator's seat will not rotate when the chart table is folded, as it fouls the front edge of the folded part of the table. The only remedy is to unbolt the seat pillar from the floor of the compartment, and move the seat two inches towards the nose of the aircraft. Theback of the seat fouls the navigator's steering control for the Sperry Gyro pilot. This fault has already been commented on in a Form 555 dated .4.7.,41, but Fara.34 of this :Form555 incorrectly stated that it was the navigator's compass corrector which was fouling the back of the pilot's seat and needed raising 4 inches, whereas it is the navigator's steering control which needs raising, to clear the back of the navigator's seat. Astro–dome and Observer's Platform: The Astro–dome and observer's platform are satisfactory, but the beam carrying the Astro–compass standards is rather too high. If it were lowered 2 inches, the observer could use the Astro–compass as a pelorous without standing on tip–toe, and the Astro–dome hatch locking handle could be operated with the Astro–compass mounting beam in the starboard position, which at present is not possible. Drift Recorder: The mounting for the drift recorder was found to be most unsatisfactory, excessive vibration causing a complete blur in the field of view of the instrument. On examination, it was found that the periscope tube of the recorder was resting on the lower edge of the hole cut in the skin of the aircraft. 'Then this hole had been enlarged to clear the instrument, the images of objects on the ground, although still slightly blurred, were sufficiently clear to enable drifts to be taken.`then the instrument is withdrawn to its stowed position, the spring—loaded flap over thehole in the fuselage does not close and a much stronger spring is needed. Bomb and Pyrotechnic Installation. Bomb Load: To fulfil the special recuirements for the Liberator I, four 20 m.m. guns are carried, and the guns, together with their auxiliary equipment, entirely fill the front bomb cell. Thus only the rear of the two bomb cells is available for carrying bombs. The bombs in this cell are supported in two vertical tiers laterally disposed. Each tier contains five bomb stations. Provided certain modifications described in Report A.A.E.E./A.T.0./017 dated 2.8.41. are incorporated, the installation will accomodate the following load.(i) Four 500 lb. A.S. bombs and two 250 lb. A.S. bombs.(ii) Four depth charges Mark VII fitted with bands No.11 and old type parachutes.(iii) Six depth charges Mark VII fitted with bands No.12, with either nose and tail fairings or new type parachutes. Bombing Equipment: The bomb stations are intended to accomodate the standard American carrier with two point suspension but in order to carry British bombs a carrier has been specially developed in America. This carrier is in many respects unsatisfactory and recommendations are contained in Report No. A.A.E.3./A.T.C./017 dated 2.8.41. for its improvement. The American method of bomb release is retained, but in place of the American mechanical fusing the aircraft is wired for the standard British fusing. The bomb winches used are the standard American winches described in detail in the Armament Report on Boeing Fortress A.N.531 (A.A.B.E./A.T.0./014 dated 29.5.41.)Pyrotechnic Equipment: Neither a launching chute nor stowage for flares was provided in the Liberator under trial at this 'establishment. It is understood that the positioning of these items is still under discussion. A signal pistol is installed to the 2nd, pilot's righthand and it is understood that he must fire the pistol through an adjacent window. Stowage for sixteen cartridges is provided beneath the pistol. The installation of pistol and cartridge stowage is repeated to the rear gunners right hand. Satisfactory stowage for twelve sea markers Mark III is provided in the pilots cabin. Gunnery Offensive Guns: This aircraft mounts four 20 m.m. Hispano guns under the fuselage in four separate cradles. The gun mountings are completely faired in by panels which, in production, trill be quickly detachable. The guns are fed by 60—round drums. and in addition to those already on the guns, 18magazines can be accomodated in racks in the bomb compartment. The guns are readily accessible for re—arming from the bomb compartment and this operation can be performed in just over one minute in the air for all four guns. Stoppages are cleared in the air without difficulty. The firing system is the same as that employed inthe Beaufighter, namely electro—pneumatic and is already well tried. The control panelwhich enables the gunner to set the guns to fire or safe, and to cock each gun separately, isconveniently positioned just forward of the guns.The sight fitted is the G.M.2. but this is considered to obscure the view of the blind flying panel and should be replaced by simple ring and bead since difficult deflection shooting is considered to be impossible. Attacks have been made against sea markers when the guns were fired and against a Lancaster aircraft without firing. The attack against fixed targets is easy and accurate but against other heavy aircraft good results can only be expected from astern or almost astern attacks. A detailed Report on this installation has been submitted (A.A.E.E.A.T.O.A.13 dated 1.8.41.)Defensive Guns: Three twin Browning gun positions are provided, one in each beam and one in the tail of the aircraft. The guns are mounted to twin Bell adapters and are fed from100—round boxes. Large panels remove on the sides of the aircraft and sliding doors open at the tail position in order to go into action with these defensive guns. Judged by present day standards, this defensive armament is very poor; moreover, the provision of only 100 rounds per gun to belt—fed guns is considered retrograde. It is thought that a continuous belt supply should not present great difficulty. A complete report containing details of the trials has been submitted, (A.A.E.3./A.T.O./C.10, 18.8.41.).Radio Trials Equipment: The aeroplane was equipped as follows:-American equipment .Liaison Sets. Transmitter BC 375-CReceiver BC 348-BMF Receiver RA 10-DBCommand Sets. Transmitter BC 353-AReceiver BC 352-ARadio Compass. Receiver BC 401-B.British equipment A.S.V. Installation. Transmitter T 3040-DReceiver R 3039-AControl panel type 3Indicators type 6A Engine-driven Generator SI.F.F. Installation. R 3003Communication sets: Tests were carried out using the American communication equipment, and its functioning was satisfactory. When the A.S.V. installation was switched on, however, the radiated field from the A.S.V. transmitter caused interference to an extent that communication became impossible. This has been investigated by the R.A.E. and suppressed sufficiently for the sets to be operated. The interference has not been eliminated, however, for all frequency bands. Special Installations: Both of the special installations (R 3003 and the T 3040-D - R3039-A) functioned satisfactorily .Intercommunication: Intercommunication is obtained from the Command Receiver, and its functioning was satisfactory at all points. A full Report on the Radio Trials is in course of preparation.20-mm Hispano Cannon Installation In Liberator Mk.I Aircraft.1. The cannon installation was based on that used in the Bristol Beaufighter. As installed in the Liberator I aircraft, it consisted of a box or pack fairing under the forward bomb-bay, containing four 20-mm Hispano cannon firing forward through blast troughs. The guns were fired simultaneously by a single electrical push button on the pilot's control wheel, in conjunction with a compressed-air system which actuated the gun cocking and firing units.2. A loader was necessary to change the ammunition magazines and to operate the gun control unit, which embodied the cocking controls and the FIRE and SAFE levers of all the guns, allowing for pre-selection of the guns to be fired and for isolation when clearingfaults.3. Ammunition was carried in drum-feed magazines of 60 rounds capacity, each gun carrying one magazine; spares were carried on racks in the bomb-bay near the gunstations.4. Normal ammunition stowage in the Liberator I was provided for 18 drum-magazines, in addition to those carried on the guns, i.e. a total of 22 magazines carrying 1,320 round

 

[Peter C]

Found a bit of time..... I hope this makes sense

Liberator I AM910

AROPLANE AND ARMAMENT EXPERIMENTAL ESTABLISHMENT BOSCOMBE DOWN

Liberator I A.M. 910.(Four Twin Wasp S3C4G)Acceptance trials with A.S.V. Installation. A.A.E.E. Ref:– 4497/49 – A.M.63.Introductory:

This aeroplane is a trial installation and had been modified at Heston to take LR.A.S.V.,4-20mm cannons and 4 depth charges. Urgent trials were reouired to check the effect ofthe A.S.V. masts and gun installation on handling and stability, and the determination of maximum speed at a height of 5,000 feet. Tests of a minor nature were also required. Separate, trials of the A.S.V. and armament installations have been made. Loading: The aeroplane has been weighed and the C.G. determined. There are two alternative loadings: Loading A, with 2,000 gallons of fuel plus 4 depth charges, 50,805 lb., C.G. 55.5 inches aft of the datum point. Loading B, with 2,500 gallons of fuel plus 6 depth charges, 56,007 lb., C.G. 57 inches aftof the datum point.The aftmost C.G. results from loading '3', due to expenditure of cannon ammunition, together with sea and submarine markers and is at 57.3 inches for a weight of 55,262 lb. The foremost C.G. results from either loading, due to expenditure of rear and beam gun ammunition and depth charges, with fuel and oil reduced to hour supply, and is at 49 inches for a weight of 35,092 lb. The trials were made at a weight varying between 45,000 lb. and 47,000 lb with the C.G.at 49 inches aft of the datum point. Handling and Stability. The aeroplane has been flown at all speeds from the glide to 300mph, I.A.S and no appreciable difference in handling and stability between this aeroplane and a normal Liberator was noticed. The handling qualities on two and three engines are very good. Speed Measurement The speed was measured at a height of 5,000 feet in M blower, under the emergency boost condition (45" Hg.) and under maximum economic cruising conditions. The results are given below, together with the estimated speed for maximum all—out level conditions. Condition. R.P.M. P,00st Height Weight. I.A.S. in. Hg. (ft.) (110.) m.p.h. All—out emergency 2700 45 5,100 45,700 262.5All—out level 2700 41 5,000 45,000 293*Max. econ. cruising 2250 28 5,000 45,700 216.5*Estimated. Position Error: This has been determined and is given in Fig.13. Relative to the position error curve obtained from Consolidated Aircraft, the position error is negative by 101/2 m.p.h. at 240m.p.h. A.S.I. and by 6 m.p.h. at 140 m.p.h. A.S.I. In both cases the curves are straight lines. This discrepancy will be investigated further if a suitable occasion occurs. Pilots Windscreen Glycol Spray As originally set the pipes sprayed too far inboard. They were re—set approximately 10degrees outboard, the nozzles being 31 7/8 inches apart, and in this setting they provide an efficient spray for the 1st. and 2nd. pilots. The area covered by the spray is only just sufficient and it is felt that it should be enlarged by means of an increase in the flow and pipe bore. Co Contamination Throughout the gun firing trials there was no noticeable vitiation of the air within the aeroplane and CO contamination is not therefore suspected. Navigation Compasses: The compasses have been swung, and the deviation has been checked under

all combinations of the electrical services. The main source of deviation change is the Steward—Warner heating system, there being large magnetic fields around the electric distributing fans. With the heating system on, the maximum change of deviation is 31/2 degrees in the pilot's P9 compass, and 15 degrees in the navigator's Pioneer 1801 compass. The other source of deviation change is the magnetic field set up by the engine–driven generators when charging the accumulators, and this trouble is complicated by the fact that the deviation varies according to the amount of the charging current. -;'fortunately only the navigator's compass is affected, the Pilot's compass remaining unaffected at all rates of charging. The effect of retraction of the nose wheel has been tested, and it was found that no appreciable deviation change was present in either compass. As the mounting for the Mark IX C.S.3.S. has not been installed, the effect of nose wheel retraction on the compass in the C.S.B.S. has not been tested. An improvement to both the 1st. and 2nd. pilot's view of the P9 compass would be made by enlarging the ball pivot of the compass mirror, allowing a larger movement of the mirror, and giving the pilots a view of the magnet system free from the effect of parallax. Navigator's seat: The navigator's seat will not rotate when the chart table is folded, as it fouls the front edge of the folded part of the table. The only remedy is to unbolt the seat pillar from the floor of the compartment, and move the seat two inches towards the nose of the aircraft. The back of the seat fouls the navigator's steering control for the Sperry Gyro pilot. This fault has already been commented on in a Form 555 dated .4.7.,41, but Fara.34 of this :Form555 incorrectly stated that it was the navigator's compass corrector which was fouling the back of the pilot's seat and needed raising 4 inches, whereas it is the navigator's steering control which needs raising, to clear the back of the navigator's seat. Astro–dome and Observer's Platform: The Astro–dome and observer's platform are satisfactory, but the beam carrying the Astro–compass standards is rather too high. If it were lowered 2 inches, the observer could use the Astro–compass as a pelorous without standing on tip–toe, and the Astro–dome hatch locking handle could be operated with the Astro–compass mounting beam in the starboard position, which at present is not possible. Drift Recorder: The mounting for the drift recorder was found to be most unsatisfactory, excessive vibration causing a complete blur in the field of view of the instrument. On examination, it was found that the periscope tube of the recorder was resting on the lower edge of the hole cut in the skin of the aircraft. 'Then this hole had been enlarged to clear the instrument, the images of objects on the ground, although still slightly blurred, were sufficiently clear to enable drifts to be taken.` then the instrument is withdrawn to its stowed position, the spring—loaded flap over the hole in the fuselage does not close and a much stronger spring is needed. Bomb and Pyrotechnic Installation. Bomb Load: To fulfil the special recuirements for the Liberator I, four 20 m.m. guns are carried, and the guns, together with their auxiliary equipment, entirely fill the front bomb cell. Thus only the rear of the two bomb cells is available for carrying bombs. The bombs in this cell are supported in two vertical tiers laterally disposed. Each tier contains five bomb stations. Provided certain modifications described in Report A.A.E.E./A.T.0./017 dated 2.8.41. are incorporated, the installation will accomodate the following load.(i) Four 500 lb. A.S. bombs and two 250 lb. A.S. bombs.(ii) Four depth charges Mark VII fitted with bands No.11 and old type parachutes.(iii) Six depth charges Mark VII fitted with bands No.12, with either nose and tail fairings or new type parachutes. Bombing Equipment: The bomb stations are intended to accomodate the standard American carrier with two point suspension but in order to carry British bombs a carrier has been specially developed in America. This carrier is in many respects unsatisfactory and recommendations are contained in Report No. A.A.E.3./A.T.C./017 dated 2.8.41. for its improvement. The American method of bomb release is retained, but in place of the American mechanical fusing the aircraft is wired for the standard British fusing. The bomb winches used are the standard American winches described in detail in the Armament Report on Boeing Fortress A.N.531 (A.A.B.E./A.T.0./014 dated 29.5.41.)Pyrotechnic Equipment: Neither a launching chute nor stowage for flares was provided in the Liberator under trial at this 'establishment. It is understood that the positioning of these items is still under discussion. A signal pistol is installed to the 2nd, pilot's righthand and it is understood that he must fire the pistol through an adjacent window. Stowage for sixteen cartridges is provided beneath the pistol. The installation of pistol and cartridge stowage is repeated to the rear gunners right hand. Satisfactory stowage for twelve sea markers Mark III is provided in the pilots cabin. Gunnery Offensive Guns: This aircraft mounts four 20 m.m. Hispano guns under the fuselage in four separate cradles. The gun mountings are completely faired in by panels which, in production, trill be quickly detachable. The guns are fed by 60—round drums. and in addition to those already on the guns, 18magazines can be accomodated in racks in the bomb compartment. The guns are readily accessible for re—arming from the bomb compartment and this operation can be performed in just over one minute in the air for all four guns. Stoppages are cleared in the air without difficulty. The firing system is the same as that employed in the Beaufighter, namely electro—pneumatic and is already well tried. The control panel which enables the gunner to set the guns to fire or safe, and to cock each gun separately, is conveniently positioned just forward of the guns. The sight fitted is the G.M.2. but this is considered to obscure the view of the blind flying panel and should be replaced by simple ring and bead since difficult deflection shooting is considered to be impossible. Attacks have been made against sea markers when the guns were fired and against a Lancaster aircraft without firing. The attack against fixed targets is easy and accurate but against other heavy aircraft good results can only be expected from astern or almost astern attacks. A detailed Report on this installation has been submitted (A.A.E.E.A.T.O.A.13 dated 1.8.41.)Defensive Guns: Three twin Browning gun positions are provided, one in each beam and one in the tail of the aircraft. The guns are mounted to twin Bell adapters and are fed from100—round boxes. Large panels remove on the sides of the aircraft and sliding doors open at the tail position in order to go into action with these defensive guns. Judged by present day standards, this defensive armament is very poor; moreover, the provision of only 100 rounds per gun to belt—fed guns is considered retrograde. It is thought that a continuous belt supply should not present great difficulty. A complete report containing details of the trials has been submitted, (A.A.E.3./A.T.O./C.10, 18.8.41.).Radio Trials Equipment: The aeroplane was equipped as follows:-American equipment .Liaison Sets. Transmitter BC 375-CReceiver BC 348-BMF Receiver RA 10-DBCommand Sets. Transmitter BC 353-AReceiver BC 352-ARadio Compass. Receiver BC 401-B.British equipment A.S.V. Installation. Transmitter T 3040-DReceiver R 3039-AControl panel type 3Indicators type 6A Engine-driven Generator SI.F.F. Installation. R 3003Communication sets: Tests were carried out using the American communication equipment, and its functioning was satisfactory. When the A.S.V. installation was switched on, however, the radiated field from the A.S.V. transmitter caused interference to an extent that communication became impossible. This has been investigated by the R.A.E. and suppressed sufficiently for the sets to be operated. The interference has not been eliminated, however, for all frequency bands. Special Installations: Both of the special installations (R 3003 and the T 3040-D - R3039-A) functioned satisfactorily .Intercommunication: Intercommunication is obtained from the Command Receiver, and its functioning was satisfactory at all points. A full Report on the Radio Trials is in course of preparation.20-mm Hispano Cannon Installation In Liberator Mk.I Aircraft.1. The cannon installation was based on that used in the Bristol Beaufighter. As installed in the Liberator I aircraft, it consisted of a box or pack fairing under the forward bomb-bay, containing four 20-mm Hispano cannon firing forward through blast troughs. The guns were fired simultaneously by a single electrical push button on the pilot's control wheel, in conjunction with a compressed-air system which actuated the gun cocking and firing units.2. A loader was necessary to change the ammunition magazines and to operate the gun control unit, which embodied the cocking controls and the FIRE and SAFE levers of all the guns, allowing for pre-selection of the guns to be fired and for isolation when clearingfaults.3. Ammunition was carried in drum-feed magazines of 60 rounds capacity, each gun carrying one magazine; spares were carried on racks in the bomb-bay near the gunstations.4. Normal ammunition stowage in the Liberator I was provided for 18 drum-magazines, in addition to those carried on the guns, i.e. a total of 22 magazines carrying 1,320 rounds

Photograph. Liberator I AM910 at Heston undergoing trials.