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).



The first Ensign G-ADSR is towed out by hand. Note how large the passenger windows are.



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 the production of Whitley bombers for the RAF. Instead, production of the Ensign was shoehorned into two old hangars 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 hangar 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 the 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 Blackburn Shark torpedo-bombers and 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 (Indian serial numbers were allocated to some of the Ensigns). 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!


G-ADSU Euterpe being recovered from the road (Harbury Lane) alongside Bonniksen's Airfield. Note the strange, hastily applied, camouflage pattern. The heavy frost or snow must have added to the difficulty of recovery (the Winter of 1939/40 was particularly harsh).


The Ensign G-ADSW Eddystone put in an appearance at the inauguration of Birmingham's Elmdon airport in July 1939.

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 through which an electric current would be passed. When such an aircraft flew low over the sea it would "fool" the magnetic mine into thinking a ship had passed overhead and detonate it. 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. Another notable mission by an Ensign was on 21st May when one flew in a party of men, headed by Louis Strange, to recover Hurricane fighters abandoned on Merville aerodrome in the path of the German advance. From descriptions of these operations, it seems the Ensigns involved were stripped of all interior fittings (seats etc) to allow the maximum flexibility in carrying equipment. Passengers had to sit on the floor.

But the Ensign fleet took losses. On the 23rd May Ensigns returned to Merville aerodrome to try to fly in desperately needed anti-tank ammunition in company with Siai Marchetti S 73 airliners of the Belgian airline Sabena that had taken refuge in Britain. No sooner had the aircraft landed than the airfield was attacked by Messerschmitt Bf109s. One of the S73s and Ensign G-ADSZ
Elysian were destroyed by strafing. Returning to England another Belgian S73 was shot down and Ensign G-ADTA Euryalus was attacked and had two engines disabled and had to crash-land at Lympne airfield in Kent.⁵ 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 badly damaged by a bombing raid while on the ground at Le Bourget airport near Paris and had to be abandoned; photos show it was completely destroyed (despite reports to the contrary it was never repaired and used by the Germans). ⁸

It is evident that the ad-hoc employment 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."

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 in 1939, 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 a follow-on order for 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 few British Airways Lockheed L-10 Electras and Lodestars along with RAF 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.⁷ How things had changed!

Hamble was an incredibly exposed site for aircraft production. Situated 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 updated to Mk 2 standard at the BOAC maintenance facility at RAF Bramcote near Nuneaton, 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.


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.

The other built-as-new Ensign Mk2,G-AFZV
Enterprise, developed engine trouble on its flight to Bathurst in Gambia on 1st February 1942 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 as F-BAHD and renamed Nouakchott (after the name of the town it was recovered to, now capital of Mauritania). Their use of the aircraft was only made possible by the discovery of a stash of spare parts left at Le Bourget airport by BOAC when they had briefly used the Ensign on the London to Paris route in 1939. It was used in French West Africa for a while and was then flown to France in October 1942. The following month it was seized by the Germans when they occupied the Vichy territory. The Germans were only interested in its Wright Cyclone engines, which they needed as spares for a number of pre-war DC3 aircraft they still operated. It was stripped of its engines in June 1943 and scrapped in late 1943.⁸


G-AFZU Everest again, pictured coming in to land at Heliopolis in Egypt in 1943.

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.

G-ADSW Eddystone being recovered at Castel Benito in Libya (now Tripoli International airport). Notice the silver finish with BOAC "speedbird "logo and the crudely applied dark (black?) leading edge to the fin. The short engine cowlings show it has been upgraded to Mk II standard..

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. 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. On January 1st, 1946, G-ADSW Eddystone had undercarriage failure and had to do a wheels-up landing at Castel Benito in Libya. Pits had to be dug to allow the undercarriage to be lowered. With its wheels locked-down it was flown back to Cairo for full repairs and then flown back to Hamble in June 1946, the last flight by an Ensign.

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 (the Avro York, which entered limited production in 1943, proved to be ill-suited for dropping paratroops).

Individual Ensign Histories

G-ADSR Ensign: Built to "Empire" (20 seat sleeper) configuration, First flight 24th January 1938. Damaged at Apapa in Nigeria on 4th September 1942. Full extent of damage not revealed until an overhaul in September 1944. Scrapped at Cairo, 3rd January 1945.

G-ADSS Egeria: Built to Empire configuration. Originally planned to be used by Indian Trans-Continental Airways as VT-AJE Ellora. First flight 26th May 1938. Scrapped at Hamble, 13th April 1947.

G-ADST Elsinore: Built to Empire configuration. First flight 7th November 1938. Prepared for one-way sabotage mission to Norway in April 1940 (called off). Scrapped at Hamble, 28th March 1947.

G-ADSU Euterpe: Built to Empire configuration. Originally planned to be used by Indian Trans-Continental Airways as VT-AJF Everest. First flight 12th January 1938. Crashed at Bonniksen's airfield near Leamington Spa on 15th December 1939. Repaired and updated to MK II standard it flew again on 8th July 1942. Scrapped at Cairo, 21st April 1946.

G-ADSV Explorer: Built to Empire configuration. First flight 24th November 1938. Scrapped at Hamble, 23rd March 1947.

G-ADSW Eddystone: Built to European (40 seat) configuration. First flight 11th December 1938. Wheels-up landing at Castel Benito in Libya on 1st January 1946. Patched-up and flown back to Cairo for full repairs. Left Cairo for Hamble on 3rd June 1946. Scrapped at Hamble, 21st April 1947.

G-ADSX Ettrick: Built to European configuration. First flight 27th February 1939. Destroyed at Le Bourget. 1st June 1940.

G-ADSY Empyrean: Built to European configuration. First flight 19th June 1939. Scrapped at Hamble, 26th March 1947.

G-ADSZ Elysean: Built to European configuration. First flight 25th June 1939. Destroyed by strafing Bf109 fighters at Merville, 23rd May 1940.

G-ADTA Euryalus: Built to Empire configuration. Originally planned to be used by Indian Trans-Continental Airways as VT-AJG Ernakulam. Damaged by enemy fire on flight back from Merville and crash-landed at Lympne aerodrome in Kent. Broken up and parts used to repair G-ADSU Euterpe.

G-ADTB Echo: Built to Empire configuration. First flight 30th August 1939. Scrapped at Hamble, 20th March 1947.

G-ADTC Endymion: Built to Empire configuration. Originally planned to be used by Indian Trans-Continental Airways as VT-AJH Etah. First flight 5th October 1939. Destroyed by bombing at Whitchurch (Bristol) aerodrome on 24th November 1940.

G-AFZU Everest: Originally ordered by BOAC to be built in Empire configuration. Construction delayed and completed to Mk 2 standard. First flight on 20th June 1941. Attacked by Heinkel He111 over Bay of Biscay on 9th November 1941. Scrapped at Hamble, 16th April 1947.

G-AFZV Enterprise: Originally ordered by BOAC to be built in Empire configuration. Construction delayed and completed to Mk 2 standard. First Flight on 28th October 1941. Wheels-up landing on beach in French West Africa. Recovered by French and used as F-BAHD. Seized by Germans, stripped of engines and scrapped in late 1943.

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 (see sources below).

² The location of the crash is variously given as "Bonnington" and " RAF Chipping Warden" in articles and internet pages. Some articles even claim that the aircraft crashed twice that month! Sustaining major damage at the two different airfields! Two letters in Aeroplane Monthly magazine both identify the site as Bonniksen's Airfield (later expanded and 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. The first mention of "Bonnington" is in a 1957 article in "Flight" magazine (see list of sources below), and it would seem the author likely used it because he simply did not know of the existence of "Bonniksen's Airfield" and chose the nearest sounding name (he did specify it was near Leamington Spa). We know that there was at least a four-month gap between the crash at Bonniksen's Airfield and the return of the aircraft to Hamble. It would have been difficult to accommodate the huge Ensign at such a tiny airfield, and it is logical to assume it was moved by road to another location before being taken to Hamble in the Spring. The team sent to recover the aircraft in the Spring may have assumed the aircraft had crashed at the airfield it had been stored at. The site of the RAF airfield at Chipping Warden is only 16 miles from Bonniksen's Airfield and would be one suitable place to store the aircraft, albeit it would mean negotiating some twisty roads on the way (remember this was pre-Motorway). Unfortunately, it would seem that this airfield did not open until July 1941, so it is hard to see how Chipping Warden could have possibly been used to store the aircraft and it certainly rules it out entirely as a place it could have crashed at. However, there is another possibility; close to Bonniksen's airfield (only half a mile away) runs the "Fosse Way", the old straight Roman road that runs from Lincoln to Exeter. The logical way to get the aircraft back to Hamble would be along this straight road as far as possible, and after turning off this route the aircraft would pass the RAF maintenance airfield at Chipping Norton. This would seem a much more appropriate place to store the aircraft until Hamble was ready to repair it. However, again we have an issue of timing since Chipping Norton did not officially open until June 1940, although the land must have been owned by the Government well before then and building work on the site was probably well underway in late 1939.

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 A more detailed account of the events at Merville aerodrome that day can be found in the article
"An Airline at War" by Herman De Wulf in "Air Enthusiast Quarterly" magazine, issue 13 August-November 1980. A squadron of Defiant turret fighters (264 Sqdn) had been detailed as escorts for the mission to Merville but were cancelled (see the book "Defiant Mk I Combat Log" by Hugh Harkins, Centurion publishing).

⁶ 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.

⁷ 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.

⁸ The full story of the Ensign in French service is told in Philippe Ricco's article
"Flag of Convenience" (see sources list below). The article refutes the rumour that one of the Ensigns was operated by the Luftwaffe.





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. The most authoritative early overview of Ensign operations, albeit the one that started the erronious "Bonnington" crashsite story.

"AW Ensign Database" - An 18 page in-depth article in Aeroplane Magazine of March 2015. By far the biggest set of data on the Ensign out there. However, it does manage to erroniously claim that Euterpe crashed twice in December 1939.

"Flag of Convenience" - An Article by Philippe Ricco in Issue 21 of "The Aviation Historian" magazine (October 2017). It tells of the recovery and use of "Enterprise" by the French and also features photos of the burnt-out wrecks of both Elysian and Ettrick, proving that no Ensign could have been captured and operated by the Luftwaffe. It also clears up contradicting reports about what serial number the French applied to "Enterprise".

"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.