An idle question regarding RAAF Beaufighters

[dad's lad]

I'm well acquainted with the rather prominent bulge for the Sperry autopilot on RAAF Beaufighters but being the curious type, I've always wondered what was the specific reason that RAAF aircraft needed these and Beaufighters operated by different air arms didn't.

 

I could assume it was due to large distances having to be flown over the Pacific but beyond that, I'm stumped. Any experts care to enlighten me please?

 

Thanks, Clive.

[Drop Bear]

As I understand it, it's even more curious......................I believe the Sperry's were not fitted.  All bulge and no autopilot.  🤔

 

[Ed Russell]

According to the RAAF Museum only one Beaufighter was fitted with an autopilot (for trials) in WW2. it was a Jack and Heintz autopilot not a Sperry, although production models were intended to be fitted with the Sperry unit and all Mk.21 planes seemed to have had the bulge. Their guess is that the RAAFs position in the supply queue was such that they would not be available in WW2.

https://clevelandhistorical.org/items/show/153

https://aeroantique.com/products/autopilot-directional-gyro-type-a-3a-jack-heintz?variant=7279346057246

Your assumption is probably correct about it being useful for long distance flying which fits with extra fuel tank capacity.

I could go on about other changes but too often simple questions are answered with irrelevant guff.

[dad's lad]

6 hours ago, Drop Bear said:

As I understand it, it's even more curious......................I believe the Sperry's were not fitted.  All bulge and no autopilot.  🤔

 

Well you live and learn...

[dad's lad]

10 hours ago, Ed Russell said:

According to the RAAF Museum only one Beaufighter was fitted with an autopilot (for trials) in WW2. it was a Jack and Heintz autopilot not a Sperry, although production models were intended to be fitted with the Sperry unit and all Mk.21 planes seemed to have had the bulge. Their guess is that the RAAFs position in the supply queue was such that they would not be available in WW2.

https://clevelandhistorical.org/items/show/153

https://aeroantique.com/products/autopilot-directional-gyro-type-a-3a-jack-heintz?variant=7279346057246

Your assumption is probably correct about it being useful for long distance flying which fits with extra fuel tank capacity.

I could go on about other changes but too often simple questions are answered with irrelevant guff.

Thank you, any other external differences from the Mk.X that I need to be aware of? The number of machine guns I believe.

 

Clive.

[Geoffrey Sinclair]

I suppose the first point is what were the autopilot arrangements of British built Beaufighters, plenty of references about the Sperry in the mark 21, nothing else found so far.

 

Beaufort V, Appendix A equipment, Automatic controls, about two pages of components, starting Item 136C, Reference 37K/8, Automatic controls, three axes Mk. IV, air compressor, engine driven. Type E Mk. I.  There is no Appendix A Automatic controls section for the Beaufort VIII.

 

A letter between the Department of Air and Department of Aircraft Production dated 30 March 1943 lays out the Beaufighter requirements.  Deletion of wing guns, US or UK torpedo, provision for wing bomb racks, rockets to be decided later, fuel tanks to replace wing guns but be easily removable were the armament specifications.  Instruments "As this aircraft intended for a fairly long range with only a crew of 2, the installation of a Sperry automatic pilot (A3 or A4 depending on availability) is a definite requirement."  The final paragraph of the letter states "One very important change given above is the fitting of an automatic pilot and it is desired now to particularly stress the need for design to be initiated immediately, so that there shall be no alteration to the present intended manufacturing schedule."  The first Australian built Beaufighter was officially delivered in May 1944.

 

The official list of major modifications done is

Wing guns, two 0.5 inch replacing the 0.303 ones
Cannons, Pneumatic cocking control.
Torpedo equipment deleted.
Wing bomb installations added
Rear gun of greater range installed
Fuel controls repositioned and extensive modifications.
Sperry Autopilot, redesign carried out to enable installation if required.
Tail wheel fitted with anti shimmy device
Fabricated nacelle doors replaced by pressed metal doors.
Ball bearings revised and many alternatives substituted.
Electrical installation redesigned to meet RAAF requirements.
Radio replaced by Australian made equipment for general purpose operation, other changes made.

 

Mark 21, with 1,000 pounds of bombs and flame damping exhausts fitted, 700 gallons of fuel gave 570 sea miles range, 900 gallons gave 780 sea miles, including 30 gallons for warm up, taxying and climb, 120 gallons for 30 minutes cruising over the target area and 100 gallons reserve.  The Beaufighter I, II and VI are reported to have a fuel capacity of 550 gallons, their long range versions replace the wing guns with a 66 gallon fuel tank in each wing in the I and VI, 36 gallons in the mark II.

[dad's lad]

1 hour ago, Geoffrey Sinclair said:

I suppose the first point is what were the autopilot arrangements of British built Beaufighters, plenty of references about the Sperry in the mark 21, nothing else found so far.

 

Beaufort V, Appendix A equipment, Automatic controls, about two pages of components, starting Item 136C, Reference 37K/8, Automatic controls, three axes Mk. IV, air compressor, engine driven. Type E Mk. I.  There is no Appendix A Automatic controls section for the Beaufort VIII.

 

A letter between the Department of Air and Department of Aircraft Production dated 30 March 1943 lays out the Beaufighter requirements.  Deletion of wing guns, US or UK torpedo, provision for wing bomb racks, rockets to be decided later, fuel tanks to replace wing guns but be easily removable were the armament specifications.  Instruments "As this aircraft intended for a fairly long range with only a crew of 2, the installation of a Sperry automatic pilot (A3 or A4 depending on availability) is a definite requirement."  The final paragraph of the letter states "One very important change given above is the fitting of an automatic pilot and it is desired now to particularly stress the need for design to be initiated immediately, so that there shall be no alteration to the present intended manufacturing schedule."  The first Australian built Beaufighter was officially delivered in May 1944.

 

The official list of major modifications done is

Wing guns, two 0.5 inch replacing the 0.303 ones
Cannons, Pneumatic cocking control.
Torpedo equipment deleted.
Wing bomb installations added
Rear gun of greater range installed
Fuel controls repositioned and extensive modifications.
Sperry Autopilot, redesign carried out to enable installation if required.
Tail wheel fitted with anti shimmy device
Fabricated nacelle doors replaced by pressed metal doors.
Ball bearings revised and many alternatives substituted.
Electrical installation redesigned to meet RAAF requirements.
Radio replaced by Australian made equipment for general purpose operation, other changes made.

 

Mark 21, with 1,000 pounds of bombs and flame damping exhausts fitted, 700 gallons of fuel gave 570 sea miles range, 900 gallons gave 780 sea miles, including 30 gallons for warm up, taxying and climb, 120 gallons for 30 minutes cruising over the target area and 100 gallons reserve.  The Beaufighter I, II and VI are reported to have a fuel capacity of 550 gallons, their long range versions replace the wing guns with a 66 gallon fuel tank in each wing in the I and VI, 36 gallons in the mark II.

Excellent, thanks so much.

 

Clive