Dinger's Aviation Pages
Armstrong Whitworth Ensign
Britain's 40 seat behemoth transport.

One of Britain's forgotten aircraft of World War Two, it was the largest British landplane when it first flew.


Press advert for the Ensign, showing its curious "nose-down" flying attitude. A characteristic shared with Armstrong Whitworth's Whitley bomber.


The AW type 27 Ensign was designed by Armstrong Whitworth who had their main factory complex in Coventry in the heart of England. They had built a reputation for safe, reliable, if not exactly ground-breaking airliners with their three-engined
Argosy biplane and the much sleeker AW15 Atalanta four-engined monoplane. Imperial airways wanted a fleet of big, four-engined landplanes to supplement their flying boats on "Empire" routes to the Far East and Africa, but also operate European routes with a greater capacity. So was born the Ensign, able to carry 20 passengers in an overnight "sleeper" arrangement on Empire routes or 40 passengers (in remarkable leg-stretching comfort by modern standards) on shorter routes. This order was placed in 1934, at a transitional time in aircraft design. The new stressed-skin monocoque monoplane designs of airliners were just coming out of the USA. The Ensign featured many of the new design features pioneered in American airlines. It was a streamlined monoplane with a largely monocoque fuselage. It had a retracting undercarriage, then still very much a novelty. It also had flaps to cut down its landing speed. It had a fabric covering on the wing aft of the main spa, and the fin and control surfaces were also fabric-covered; something that would begin to look anachronistic within a few years. The Ensign differed from most US airliners of the period in having the wing mounted on top of the fuselage. This meant the retracting undercarriage was a huge affair. However, it gave the passengers an unobstructed view of the ground (the scenic aspect of aircraft flight was then seen as an important selling point against trains and ocean liners) and made loading and unloading the aircraft via the rear doors possible without high air-stairs. This high wing configuration was apparently specified by Imperial Airways in preference to Armstrong Whitworth's original design which featured a low wing . Interestingly, at the same time, Armstrong Whitworth were chasing orders from Czechoslovakia and Belgium for the low-wing twin-engined transport/bomber AW-30 design, which looked very much like the American Douglas DC-2 (the AW-30 was never built).



Ensign Forward Cabin



Ensign in Imperial Airways "Empire Route" Sleeper mode.



Ensign in "European Capital" 40-seat mode.



Perhaps the decision that affected the long-term career of the Ensign most was where to build these mighty beasts? The obvious choice would have been Armstrong Whitworth's main plant at Coventry, with its airfield at Baginton. However, the existing facilities at Coventry were already committed to existing tasks, primarily the production of Whitley bombers for the RAF. Instead, production of the Ensign was shoehorned into two old hangers at Hamble, on the Solent estuary near Southampton. A site owned by the larger Hawker-Siddeley group of which Armstrong Whitworth was a part. Here production could take place on two Ensigns at a time. The major subassemblies were built and "laid-out" in one hanger before being moved to the other for final assembly. When finished each Ensign had to be taken over a public road to a rather small grass airfield from which their maiden flight would be made. The first ensign (G-ADSR) first flew on 24th Jan 1938.


The prototype Ensign G-ADSR

The setup at Hamble precluded any sort of mass production of the Ensign. It seems that from the start it was anticipated that only the order for 12 of the type for Imperial Airways would ever be built and the whole project was costed on this basis (a fair assumption considering that AW's previous airliners had only ever been sold to Imperial Airways). A delivery rate of one aircraft per month was stipulated by Imperial Airways.



The low rear of Ensign allowed passengers to alight with only a small set of steps (most able-bodied people could have simply jumped on or off the Ensign). Note the huge undercarriage and the enormous main tyres, the largest aircraft tyres produced in the UK up until that time.

Armstong Whitworth always tried to use the engines built by their sister company, Armstrong Siddeley, in their designs. So it was natural that the Ensigns had Armstrong Siddeley Tiger IX engines of 810 horsepower, a medium-supercharged engine made to a military specification, but initial reliability was woeful (as it also was on the early Whitley bombers which also used the type). An attempt by three Ensigns to get the Christmas mail to Australia in 1938 ended up with all three aircraft failing to reach their destination. Alarmed by this unreliability, Imperial Airways returned all its fleet (by then numbering five) to Armstrong Whitworth for rectification. This involved replacing the Tiger IX engines with a modified version called the Tiger IXC (the "C" stood for "civil") which were reported to give better reliability, albeit with very slightly less power (805 horsepower) ¹. This mark of the engine was made specifically for the Ensign. At the same time, the Ensigns were fitted with constant-speed propellers and it was probably this that improved reliability and performance more than the new engines. There were also refinements to the rudder, ailerons and control cable runs that made the aircraft lighter on the controls.


Ensigns in their pre-war Imperial Airways livery.

After these modifications, the growing fleet of Ensigns started to settle down to earn their keep. They were used primarily by Imperial Airways on their European routes. The plan to use them for the leg of the "Empire route" across India in association with Indian Trans-Continental Airways never came to fruition. This may be because the Ensigns were deemed to be somewhat underpowered and struggled to cope with the "hot-and-high" conditions encountered on the sub-continent. In service, the Ensign was famed for its short-field performance. Despite its size, it was quite happy landing on quite small grass airstrips, although once airborne it was very slow to climb, due to the drag of its massive undercarriage which took an extraordinarily long time to retract (some 70 seconds).


Loading air-mail onto G-ADSU Euterpe. Apparently, she was known affectionately as "You Twerp!". This was the aircraft that came to grief on Bonniksen's Airfield. Note the large radio aerial mast and the radio direction finding (DF) loop mounted above the cabin.

With the outbreak of war the Ensigns were camouflaged (it would seem one wag went so far as to paint a flock of sheep on the wings of one!) and operated by the
National Air Communications service. The Ensigns were used to provide a regular service to Paris but also carried out supply flights for the RAF and Army. Some Ensigns seem to have been operated by, or under the control of, number 24 squadron of the RAF. The Ensigns gave valuable service through the severe winter of 1939/40. On December 15th 1939 the fleet had its first casualty when G-ADSU Euterpe overshot the tiny landing ground called Bonniksen's airfield (owned by Major Julius Bonniksen) near Leamington Spa in Warwickshire.² It seems this tiny airfield was just too small for even the Ensign's renowned short-field performance, particularly as the pilot seems to have assumed the road and ditch he ended up in was a "painted on" camouflage feature! The aircraft was returned to Hamble by road in March the following year. It's hard to imagine the huge airframe being manoeuvred down the narrow twisting roads of pre-motorway Britain!

When the war began the Germans started dropping their new magnetic mines in the approaches to Britain's harbours. One solution to the problem was to fit an aircraft with a large annular structure with wire wound around it that had a current flowing through it. When such an aircraft flew low over the sea it would "fool" the magnetic mine into thinking a ship had passed overhead. It was planned to convert the Ensign fleet to this task and wind-tunnel tests of a model Ensign with the ring were conducted. The equipment was developed by Barnes Wallis at Vickers and it was eventually decided to use Vickers' own product, the Wellington bomber, as the carrier for the equipment. So the Ensigns narrowly missed having to spend their life as "mine-sweepers". ³



G-ADSV Explorer in wartime camouflage. Note the fuselage serial number underlined with red, white and blue.

When the Germans invaded Norway in April 1940 apparently an Ensign (G-ADST
Elsinore) was selected for a one-way mission to crash-land on a frozen lake to deliver Royal Engineers and a load of explosives to blow up the railway between Andalsnes and Dombas to slow up the German advance. Bad weather delayed the mission and it was cancelled when it was found that the Germans had already overrun the landing site. ⁴

When the blitzkrieg broke on the Western Front in May 1940 the Ensigns came into their own, flying daring missions to recover personnel from France. It was now that the Ensign's short take-off and landing ability came to the fore. In his book "Skies to Dunkirk"
Air Marshal Sir Victor Goddard tells of his party of six being rescued from the approaching Germans by an Ensign that landed and took off from a field; its take-off at night being guided by the headlights of their abandoned Chevrolet car.

But the Ensign Fleet took losses, G-ADSZ
Elysian was destroyed by straffing Messerschmitt Bf109s at Merville aerodrome on 23rd May. This may have been one of the aircraft that flew in a party of men, headed by Louis Strange, to recover Hurricane fighters abandoned on the aerodrome in the path of the German advance. On the same day, G-ADTA Euryalus had two engines fail on the way back across the channel from Merville and had to crash-land at Lympne airfield in Kent. Euryalus was recovered by road to Hamble where she was broken up to provide parts to repair Euterpe the following year. On the 1st June, G-ADSX Ettrick was damaged by a bombing raid while on the ground at Le Bourget airport near Paris and had to be abandoned (despite reports to the contrary it was never repaired and used by the Germans).

It is evident that the ad-hoc use of these giant aircraft created a bit of resentment and it was felt that a more organised use of them could have saved more people and equipment from capture by the Germans. An anonymous Army officer wrote bitterly in his diary, " A good example of the chaos is the despatch in error of No 24 Communication Squadron. This squadron left yesterday without passengers. The squadron could have carried back 800 men. They took none. One officer returned home in a large 30-seater aircraft alone." ⁵

During the Battle of Britain, the Ensigns were often used to help move Fighter Command squadrons around the UK. Exhausted and depleted units would be withdrawn from the South and rested squadrons would be flown in from the West and North. A single Ensign could carry all the ground servicing personnel of a squadron in one go. Again its short-field performance was a big help during this period, able to land on the smallest, and often bomb-cratered, airfields.

In November 1940 a German bombing raid on Whitchurch airfield (now Bristol airport) destroyed Ensign G-ADTC
Endymion and slightly damaged others. With the drawing to a close of the Battle of Britain the Ensigns settled down to providing regular services throughout the UK. In particular, they were used on the route to Foynes in the Republic of Ireland to meet up with the Boeing Clipper flying boats from the USA.

When Britain went to war in1939 production of all transport aircraft by British industry stopped, the Air Ministry thought the war would be decided in a matter of months by massive bombing raids by both sides, so all resources were thrown into supplying bombers, fighters and the training aircraft needed to prepare their crews. They simply did not appreciate that a global war was going to need hundreds, if not thousands, of transport aircraft. So production of the promising DH Albatross and Flamingo airliners was stopped, and even production of the Bristol Bombay bomber-transport was curtailed. Armstrong Whitworth had received an order for a follow-on order of two more Ensigns for Imperial Airways before the start of the War. When War was declared work on the two new aircraft at Hamble stopped and they were mothballed. By the start of 1941, with the sea route across the Mediterranean blocked, an air route across the middle of Africa to transport vital personnel and parts to the British forces in Egypt was opened. The small fleet of Bristol Bombay aircraft available to fly the route needed reinforcing and an aircraft in the class of the Ensign was desperately needed, although the limited power available from their Tiger engines would be a liability in the hot-and-high climate of the route. So it was decided to start work again on the two Ensigns mothballed at Hamble and fit them with more powerful American Wright Cyclone engines (as used on some marks of the Douglas DC-3). Only a couple of years earlier it would have been unthinkable to fit a British airliner with US engines, any such move would no doubt have produced a sneering editorial in
The Aeroplane magazine from CG Grey.⁶ How things had changed!

Hamble was an incredibly exposed site for aircraft production; right on the coast on the Solent estuary, it presented an easy target for both day and night bombing. The Supermarine factories at Woolston and Itchen, both further up the estuary, had been put out of action by bombing in 1940. But Hamble seemed to lead a charmed life, only one person was killed on the airfield (that was in Febuary 1943 by a strafing attack) but numerous attempts to bomb the airfield all failed to hit anything. The first of the "new" Ensigns (G-AFZU
Everest) with Cyclone engines took to the air in June 1941, followed by G-AFZV Enterprise in November of the same year. These aircraft were joined by G-ADSU Euterpe which was repaired at Hamble and upgraded with Cyclone engines. This new form of the Ensign was called the Mark 2. The remaining Ensigns were sent to Hamble one-by-one to be updated to Mk 2 standard, then they were sent off to operate the trans-Africa air route.

Everest and Enterprise were the only large airliners to be built in Britain from 1940-42 (a trickle of production of Avro Yorks began in 1943). The upgrade of the fleet to Mark 2 gave slight increases to the maximum speed (up to 210 mph from 205 mph) and cruising speed (up to 180 mph from 170 mph), a significant increase to speed of climb (900 feet per minute from 600 fpm) and maximum ceiling (up to 24,000 feet from 18,000 feet, although being unpressurised the increase in ceiling was of little use when carrying passengers). The quoted range of the Mk 2 (1,370 miles) is considerably greater than the Mk 1 (800 miles), but it is likely that that figure is using removable fuel-tanks in the centre cabin.

The first Ensign to attempt the trip to Africa almost did not make it G-AFZU
Everest ran into a Heinkel He111 bomber over the Bay of Biscay. The defenceless Ensign was raked with gunfire, only escaping by going into a high-speed dive (so fast the cockpit glazing cracked under the air pressure). Levelling out just above the sea, Everest returned to the UK where she was repaired to later complete her flight to Africa.

The other built-as-new Ensign Mk2,G-AFZV
Enterprise, developed engine trouble on its flight to Bathurst in Gambia and had to put down on a beach in West Africa controlled by the Vichy French. The crew and passengers were rescued by Sunderland flying boat but the Ensign was recovered by the French, repaired and put into service by them. Back in France, it was seized by the Germans when they occupied the Vichy territory in 1943. It apparently saw service with the Luftwaffe, perhaps with its engines replaced by German ones.


Ensign G-AFZU Everest, first of the Mk 2s to be built as new. The Wright Cyclone was a single-row radial engine, unlike the AW Tiger which had two rows, you can see the cowling is shorter. This is the Ensign that was attacked by a He 111 bomber over the Bay of Biscay.

In Africa, the Ensigns performed an important role. Many people must have blessed their existence, sparing them the long sea-voyage around the Cape of Good Hope. When the Mediterranian was opened to shipping again the Ensigns moved further east, providing an air link from Cairo through to the Persian Gulf and onwards, across India to Calcutta. Thus, at last, fullfilling the role they had been designed for. Around this time the fleet discarded their camouflage and reverted to their original silver finish.

An inspection of the first Ensign G-ADSR at Cairo at the end of 1944 revealed damage that was uneconomic to repair, so it was scrapped there early the following year. All the remaining Ensigns were assembled at Cairo late in 1945 to be refurbished prior to being returned to the UK.
Euterpe was broken up to provide spares for the surviving 7 that returned in 1946. There was some interest in further refurbishing them for continued use, but the cost was uneconomic, so they were returned to their birthplace at Hamble to be broken up for scrap in 1947.

For all the adventures of the Ensign fleet perhaps one thing should be remembered above all: not a single person died flying in an AW Ensign. Testament to the inherent safety of the design and the skill of the crews that flew them.



What If?


Ensign painted as if it had seen more large-scale use in the European theatre

With hindsight, the British decision to stop all production of transport aircraft at the outbreak of war was undoubtedly the wrong choice. While aircraft of dubious value to the war effort like the Blackburn Botha and Handley-Page Hereford were being produced the potential of transport types like the Ensign were ignored. Even if production at Hamble had only continued at the rate of one per month the additional thirty to forty aircraft produced over the war-years would have been a massive boost to Britain's air-lift capacity (remember that the old fixed-undercarriage Handley-Page Harrow continued to be used as a transport aircraft until May 1945). It is possible that the Ensign might have made a good paratroop dropping aircraft, its nose-down flying attitude helping avoid entanglement on the tail, and its wide fuselage and fore-and-aft doors and cabins might even have allowed jumping from two doors at once.
.

Notes

¹ Most descriptions of the Ensign list the Tiger IXC engine as having a rating of 850 horsepower. This seems to confuse the IXC with the Tiger VIII and X which were the major RAF service version of the engine, which had two-speed superchargers, giving more power than the IX and IXC versions. I have quoted the power of the IXC as listed by Lumsden.

² The location of the crash is variously given as "Bonnington" and " RAF Chipping Warden" in articles and internet pages. Two letters in Aeroplane Monthly magazine both identify the site as Bonniksen's Airfield (later called Leamington Aerodrome). The first letter by Kenneth Aitken appears in the June 1979 edition, another by B. Bailey-Hickman appears in the August 1979 edition.

³ The story of the development of the aircraft-mounted mine-sweeping ring is told in "Rings and Things" an article by Norman Parker in Twentyfirst Profile magazine, volume 1, number 9.

⁴ A letter by R.C. Hockey in the "Skywriters" Letter column of Aeroplane Monthly magazine August 1979 reveals the plan to use an Ensign on the sabotage mission to Norway.

⁵ Extract from "The Diary of a Staff Officer - Air Intelligence Liason Officer - at Advanced Headquarters North B.A.F.F. 1940" - Written anonymously and published by Methuen & Co, London Feb 1941. This entry is dated for 10.15 hours on June 17th 1940. The follow-on entry for that night reports the anonymous officer being evacuated from Nantes airfield by Blenheim bomber.

⁶ Notable for his xenophobic views CG Grey, editor of
The Aeroplane, trotted out the same tedious anecdotes about perceived unreliability of US-produced aero-engines. He was dismissed as editor of The Aeroplane when war was declared.





Sources

"Ensigns for the Empire" - a two-part article by Ray Williams in the March and April 1979 Edition of Aeroplane Monthly magazine.

"Cuckoo in the Nest - Assembling AW Ensigns at Hamble." - an article by Roy Bonser and Ken Ellis in Air Enthusiast Quarterly magazine issue 69, May/June 1997

"Ensign Class - The History of a Fleet of Airliners that went to War." - Articles by Peter W Moss in the 15 Feb and 22nd Feb 1957 Editions of Flight Magazine.

"Skies to Dunkirk - A Personal Memoir"
- by Air Marshal Sir Victor Goddard. Published by William Kimber. ISBN: 0-7183-0498-5

"What became of Louis Strange?" - An article by Peter Hearn in "Air Enthusiast Quarterly" magazine, number 43.

"British Piston Aero-engines and their Aircraft" - By Alec Lumsden, Airlife, ISBN - 1 -85310 - 294 -6

"British Civil Aircraft 1919-1959" - A.J Jackson, Putnam

"The Illustrated Encyclopedia of Propeller Airliners"
- Editor Bill Gunston. Published by Windward. ISBN 07112 0062 9.