George Mackie
George flew B-17s at night above the RAF main force on RCM operations, not as a day bomber. These are his writings. George features quite a bit in the book: ‘A Thousand Shall Fall’ written about RAF 100 Group. This first article introduces readers to the Stirling, followed by an account of what it was to fly, finishing with a comparison between this aircraft and the B-17.
The Nature Of The Beast
Short Stirling TR03
At nineteen, you are challenged to fly your first four-engine aircraft. Den Cash rose to the task of mastering the RAF’s first four-engine monoplane bomber, and it is sad there is no example today, static or airworthy, of what was Britain’s first four-engine bomber!
Conceived as early as 1936, a half-scale wooden version, powered by four 90hp engines, capable of carrying two pilots only, flew as an aerodynamic testbed in 1938, with the full-size aircraft reaching Squadron service in late 1940. Awesome and enormous! That just about summed up the impression gained when standing alongside the Stirling for the first time. With its huge single tail fin, high nose attitude, four giant radial engines and the largest tyres ever used in the RAF, it really did look big, seemingly more so than the Halifax or Lancaster. In fact, it was longer than either of them and shorter in span, but only just.
The design path of the Stirling had been somewhat chequered. In correcting one problem it caused another which, when rectified, highlighted something else. It was a chain reaction, not unlike that of the Tiger Moth. In the case of the Tiger, it ended up with its wings staggered, swept back and non-parallel. With regards to the Stirling, it went something like this. For the projected all-up weight, it was the intention to use the already proven engine and wing installation of the Sunderland flying boat, which would have provided four Bristol Pegasus engines and a wingspan of 112 feet. But the Air Ministry of the day laid down that it must be possible to get the Stirling in a hangar, the widest of which at the time was just over 100 feet. For this reason, the wingspan was reduced to 99 feet. To retain the same all-up weight, this immediately increased the wing loading, and even with an engine change to the Bristol Hercules, the take-off run, and maximum ceiling suffered badly. To improve the take-off run, the wing incidence and undercarriage length were increased, the latter placing the pilot’s cockpit some 22 feet above the ground. Because of its increased length, it was not possible to rotate the undercarriage backwards into the available space in the inner engine nacelles, not to mention the enormous hydraulic loads that would be required to do so. The undercarriage was therefore modified, so that the bottom halves could be telescoped into the top halves, and the then shorter assemblies retracted into the nacelles, which accounted for the curious-looing cage affairs halfway up the undercarriage legs when they were in the down position.
Due to the complexity of this arrangement, any idea of still driving it hydraulically became highly questionable, hence electricity came to the rescue in the form of two extremely large electric motors, but they too were to contribute problems.
Entry to the aircraft was via a door in the port side aft followed by a clamber over the long bomb bays to reach the flight deck, from which, except directly forward, the view was excellent.
Immediately behind the flight deck canopy was an unmistakable radio mast as thick as an arm, followed by the streamlined housing of the direction finding (DIF) loop; and then running down to the tail-plane and the rear gun turret, the long flat-topped fuselage, wide enough to take a casual stroll to the end and back without fear of falling over the edge. The same view aft revealed that the flight deck canopy was directly in line with the top of the tail fin, for which another problem was looming.
On or near flight deck were the cockpits for the two pilots, plus stations for the navigator, wireless operator, flight engineer and a bomb aimer. The front and rear turrets were homes for the gunners. To keep the crew down to the usual seven, a certain amount of doubling up had to be done inasmuch the navigator could also be a wireless operator or even a bomb aimer, one of the gunners could be a wireless operator, or the flight engineer could perform as a second pilot. The pilot’s control columns were like large steering wheels taken from a bus or lorry, where in front of the left-hand one was the usual T-panel of flight instruments surrounded by others relating to undercarriage status, D/F loop, oxygen supply, blind approach indication, and so on; together with warning lights for this, that and everything else. On the left-hand side of the fuselage were banks of auxiliary controls which included those for the automatic pilot. Ahead of the right-hand control column were the engine instruments, ignition switches and booster starters, quadrupled in every respect, there being four engines.
There was also a Distant Reading (DIR) compass, a device designed to overcome the deviation effects of so much metal and electrical equipment around, which comprised of a gyro-stabilized magnetic element located in the starboard wingtip and unaffected by the all- duralumin structure there. An electrical pickoff transferred the indications of that unit to a slave unit in the cockpit. A much up-dated form of the DIR compass and not requiring a magnetic element is still in use today where it is known as a Gyro Compass.
Overhead were the flight control trimmers, flap controls and engine slow-running cut-outs, whilst between the two control columns was the engine-control pedestal. Four throttle levers stood up like sentinels – none of this business of curving the outers over the inners for ease of operation! There were four propeller pitch levers, but only two mixture controls, one for each engine pair. Alongside this pedestal was an undercarriage selector lever and a large automobile-type handbrake which likewise seemed more suited to a bus or lorry.
All engine controls were of the Exactor type (presumably named after the manufacturer) which meant they were hydraulically instead of mechanically driven. As such, the top inch or so of each throttle lever was hinged to permit movement either way by about 1/8” before picking up the main lever. To open a throttle, the black ball on the top of the hinged part was pushed through its 1/8” movement, which released a ratchet (there being no friction nut) and applied the hydraulic power.
Thereafter, the main lever was collected, which then performed as any other throttle. When the ball was released, the hinged part would return under spring tension, in would go the ratchet to lock the throttle in position and off would come the hydraulic power. As would be expected, closing a throttle was the same, but in reverse direction. As all four throttles had to be operated together on occasions, it can now be seen how almost impossible it would have been to do so if the outers were curved over the inners. The mixture and pitch levers were operated in a similar way, except that their coloured ball tops had to be pressed downwards to do the honours.
As an aside, if the hydraulic supplies to all three sets of controls were lost, say due to hostile activities; then all four engines would go to full power, rich mixture and coarse pitch, an undesirable situation to say the least. In normal use, however, these Exactor controls had to be primed regularly … that is before take-off, every twenty minutes or so in flight, and immediately prior to the landing approach.
The navigator had his usual plotting table and a drift sight mounted in the floor of the fuselage. It consisted of a large tube open at both ends, but with a rotatable grid ring on top. Whilst peering down this tube, the ring was rotated until ground features tracked along parallel lines etched in the glass, whereupon the drift was read from an adjacent scale. A craftier way of achieving the same thing existed on some of the gun turrets. Degree marks had been hand-painted on the turret rings. The gunner swung his guns until ground features tracked along them, after which the drift was read off from the painted marks.
The navigator had to carry the remainder of his equipment to the aircraft himself, prominent of which was the Dalton Computer, essentially the same as that used today, but quite a cumbersome device with the Appleyard Scale on one side and a large windable blind for plotting courses, etc. on the other, with lots of straps for fixing it to the leg if required. I still have such a thing! But then, what was this tucked away to one side? A Ground Position Indicator, something previously heard of but never seen, and not fitted to all aircraft.
A Ground Position Indicator was a mechanical computer which gave a continuously updated dead reckoning ground position on a set of dials in the form of latitude and longitude. Switches were used to enter the start position when over the airfield. The aircraft’s heading was taken from the D/R compass and airspeed from an ASI, whilst the wind velocity was entered by further switches. It was from this, the computer worked out the triangle of velocities and applied the result to the starting point to display the current position and did so progressively as the flight unfolded. Real cutting-edge stuff this!
The flight engineer’s panels were spread across both sides of the fuselage behind the pilots’ seats. They gave him control of carburettor intakes, superchargers, cabin heating, fuel jettisoning and electrical distribution. Similarly, a large array of valves and selecting cocks gave him control of fourteen fuel tanks located in the wings and a possible further three in the fuselage, the total contents of which were 2,700 gallons … enough to keep a Tiger Moth in the air for 450 hours, or one year’s flying by Group standards!
The wireless operator had the then standard T1154/R1155 radio set, plus an additional TR9 with its controls extended by Bowden cables to a panel in the cockpit, accessible to the pilot in the lefthand seat. As all long-distance communications were by high frequencies (H/F) there was also a Morse key to accommodate, which in an emergency could be screwed down tight to transmit a continuous signal in the hope that someone might trace it.
Right up front of the aircraft was the forward gun turret beneath which was the bomb aimer’s position with the MK IX bomb sight – a strange-looking piece of mechanism consisting of an eyepiece, long parallel sighting wires, and a series of rotatable knobs which allowed adjustment to cater for airspeed and wind drift.
The whole of the inside of the aircraft was coloured in a matt green. Whilst it could be asked why this should have been, it is difficult to imagine any other acceptable colour. To this very day, the insides of military aircraft are so coloured. Look inside the Tiger Moth, for example. However, that just about ends the grand tour of the Stirling. Awesome? Enormous? Well, let’s just say it was big. But the saga is not yet over. It still had to be flown …
Flying Our First 4-Engined Bomber
I first flew a Stirling on 15 Squadron in June 1941. There were no Heavy Conversion Units in existence at the time and all training, such as it was, was done domestically on the two Squadrons concerned – 15 at Wyton, 7 at Oakington.
Wyton was all grass and I did not land on a runway until I went ‘solo’ one day and delivered an aircraft to Alconbury, the satellite airfield nearby with runways and bomb dumps. The approach was over the A1 and I seldom drove down the A1 motorway in later years without remembering that first solo flight, the aircraft full of ground crew unaware of my inexperience. I had 200 flying hours to my credit, of which 2 hours 30 on Stirlings. Later, when I was instructing, an average pupil pilot had something like 400 hours before venturing on ‘the Beast’.
Den Cash described in detail how the Stirling was essentially ruined in mid-design as a bomber and never became as effective in operations as the Sunderland was as a flying boat. In the process, it became a joy to fly. Yes, it could only carry 500-pound bombs. Yes, its ceiling wasn’t much, but never as bad as sometimes made out. Yes, in some circumstances it was absurdly difficult on takeoff. Yes, electrically it was a horror to keep serviceable. But it was an absolute joy to fly, exceptionally light on the controls it could be whizzed around in a tight turn so that in no time at all, you met the turbulence of your own slipstream. It could even be induced to make a stall turn, collapsing the gyro compass in the process. Its horizontal stall was benign, with no tendency for a wing to drop. It was nervy in flight, anxious to please. And in a high wind, such a joy it was to plonk down in a very, short run. Lots of engine over the boundary, stick well back, inches over the runway, throttles back, bump, no run, hardly. A fun aeroplane!
B-17s v Stirlings
Colonel Maurice ‘Mo’ Preston Commander of the 379th Bomb Group seen here with his personal ‘Hack’, a B-17 Flying Fortress.
As 414/BS/97BG Polebrook 11.4.42; flew first 8AF bombing mission with Lt. Thomas H. Borders, the Ball turret gunner: Kent West, credited with destruction of 1st German aircraft destroyed on 17 August 1942.
Courtesy: American Air Museum in Britain, Imperial War Museums
No worse model of aeroplane could have been engineered for mass-produced pilots. None better than the B-17. 214 Squadron left 3 Group and its battered Stirlings in January 1944 to join the recently formed 100 Group. It had a variety of Squadrons and aircraft, but our fate was to fly the much-publicised Fortress or B-17 which could accommodate the sometimes-enormous pieces of radically new Radar in its fuselage.
We were, it seemed, to accompany the bomber stream while attempting to disrupt communications between German night fighters and their Ground Controllers. We got a few circuits and bumps with American pilots and off we went, on our own, feeling I suppose very much up to date. Throat microphones, for example. But what a bore the Fortress turned out to be. Its throttles, beautifully designed for use, so unlike the Stirling’s clutch of levers wider than my hand, almost opened by themselves. No pushing forward of the stick to raise the rudder to get some counter to the swing. Nor any oblique opening of the throttles to counter the swing. What swing? It trundled into the air with never a suggestion of swerve, even in cross winds. Wheels up, all it wanted to do was Onwards and Upwards! But such was its stability that it became almost coy when you wanted to fling it about a bit. It was docile in landing too. A three-point landing scarcely changed its angle from normal flight.
Gone was the moment of stick in belly to stall the Stirling gently onto its three points. Gone the need to use an outboard engine to deal with a landing swing. Relax! It rolled along like a London taxi. All in all, admirable fitness for purpose, tight formation flying by pilots trained for the duration by the thousand.
Thanks to George Mackie, Jamie Woodthorpe, and John Gilder
This article is from the Autumn 2018 issue of Confound and Destroy
