Cunliffe-Owen OA-1 "Flying Wing"
One of the most striking looking aircraft ever to fly the Cunliffe-Owen OA-1 's chances of success were stifled by the outbreak of WWII.
Having a tail, the Burnelli designs were not "Flying Wings" in the true aeronautical sense; the correct term would be "lifting fuselage". However, they were referred to as "Flying Wings" in contemporary newspaper and magazine articles, (even the British registration papers for G-AFMB give the aircraft type as "Flying Wing"). So, for simplicity, I will refer to them as such.
The only Cunliffe-Owen OA-1 built shown in flight over Southampton harbour. Designed to carry 15 - 20 passengers it was a compact design. It had retracting main and tail-wheels The cross-bracing of the tail-booms can be clearly seen.It is sometimes erroneously referred to as a "Clyde Clipper", a name for a previous Burnelli-inspired aircraft project undertaken by a different company, the Scottish Aircraft and Engineering Company.
During the late 1920s and 1930s, American aircraft designer Vincent Burnelli had conceived and built a series of aircraft that sought to combine the attributes of a true "flying wing" with the practicalities of stability and size. These culminated in the UB-14 which first flew in 1934. A fuselage of wing profile provided a spacious and strong passenger cabin. A twin boom tail provided the lateral stability impossible in true flying wing designs until the use of "fly-by-wire" technology. Closely grouped twin engines minimised asymmetric handing problems. The first prototype crashed in spectacular fashion but the passenger cabin escaped with little damage, vindicating the designers claims for the inherent safety of the design. A second prototype was soon flying (the UB-14B) and attracted world-wide interest.
Spectacular shot of the Burnelli UB-14B over Manhattan. The UB-14B was slated for a transatlantic record flight, but in the event travelled to Europe as freight on a cargo ship and ended up impounded by customs in the UK before onward shipment to Holland. It was re-assembled in Holland and embarked on a European demonstration tour. It returned to the USA in preparation for a round-the-world record attempt which was thwarted by the outbreak of war. It was then used for regular freight carrying flights over the Caribbean from Miami. Its ultimate fate appears to be unknown.
Nice photo of the Burnelli UB-14B. Compare it with the photo of the Cunliffe-Owen OA-1 outside the factory (4 images below) . You'll see sunstantial changes. The OA-1 looks a lot larger. The cockpit is completely different and the tail-booms of the UB-14B are much more slender than those of the OA-1.
This cover to an American aviation magazine shows an approximation of the Burnelli UB-14 in a particularly exotic colour scheme. Clyde Pangborn was a pioneer U.S. aviator who gave considerable backing to Burnelli and who had planned to use the UB-14 on record-breaking flights. Pangborn worked for Cunliffe-Owen in the UK and was the test-pilot for the first flight of the OA-1. Later he joined the RAF where he was instrumental in setting up the Atlantic Ferry organisation. A true hero and friend of the UK you can read about him in this wikipaedia article <click here>.
Burnelli never succeeded in getting his brainchild into production in the USA, (there is a conspiracy theory about this failure you can read about by clicking on <this link>). However he had little problem attracting interest in other countries. Unfortunately in each case he ended up negotiating licence production with companies that wanted to break into the aviation marketplace rather than ones already established in it. A deal with the Canadian Can-Car company led to only a single aircraft that only flew in 1945 (the CBY-3, to read about it click <this link>), while production in the Netherlands by the Aviolanda company, fell through altogether. In the UK the "Scottish Aircraft & Engineering Company" was formed to build the UB-14 with British Rolls-Royce Kestrel engines. At the time there was huge unemployment in Scotland in the aftermath of the economic depression and there were various schemes to subsidise the setting up of factories in Scotland, especially in the Glasgow area (Blackburn Aircraft was one company that took advantage of this, setting up a flying-boat factory at Dumbarton). It seems the Scottish Aircraft & Engineering Company was set up to take advantage of these schemes, although the only addresses listed in its many press advertisements were in London. These press adverts were prodigious and a lot of interest was whipped up for their 16-seat version of the Burnelli which they called "The Clyde Clipper", no doubt a reference to where they hoped to produce the aircraft (there was also to be a cargo-carrying version to be called the "Clyde Carrier"). With war clouds looming they also advertised a Bomber version¹, apparently to be called the "Clyde Corsair" and a fighter version, armed with 37 mm cannon, to be called the "Clyde Comet". All of this came to naught, the company collapsed with only a wooden mock-up of the Clyde Clipper to show for its efforts. The receivers were called in on the 26th July 1937.
An image of the Scottish Aviation & Engineering Companies "Clyde Clipper" wooden mock-up at their "Scotia Works" in Willesden, West London. The in-line Kestrel engine would appear to have been air-brushed in. The use of the Kestrel would have given a better view for the pilots than that afforded by the Perseus radial-engined Cunliffe-Owen OA-1. The Cunliffe -Owen retained the large passenger "picture windows" and the passenger door arrangement. There was a recess in the underside of the wing to allow full access to the door which would otherwise have had to be uncomforably small. You'll see that the Scottish Aviation "Clipper", with its slender tail booms, looks much more like the original Burnelli than the later Cunliffe-Owen OA-1.
A Youtube video of a contemparary newsreel shows the mock-up of the "Clyde Clipper".
Magazine Cover illustration of Scottish Aviation and Engineering Company "Clyde Clipper" with in-line Kestrel engines.
To pick up the pieces in stepped Sir Hugo Cunliffe-Owen, a flamboyant industrialist and race-horse owner who had been planning to use a "Clyde Clipper" for his own attempt at winning a New York to Paris air race. He purchased the rights to produce the Burnelli design and invested a huge amount of money to build a brand new state-of-the-art aircraft factory at Eastleigh airport near Southampton, which was formally opened by the Mayor of Southampton on the 23rd January 1939. The choice of Southampton may seem strange in view of the subsidies available in Scotland, but in the late 1930s "Red Clydeside" had a bad reputation for industrial relations. Meanwhile the Southampton and Solent area was already the home of many aviation companies like Supermarine, Saunders Roe and Airspeed and promised to have a ready-made skilled workforce available.² Sir Hugo had the Burnelli redesigned to use two of the new Perseus sleeve-valve radial engines made by the Bristol Engine Company. The Cunliffe-Owen "Flying-Wing" design was in fact substantially different in structure to the original Burnelli UB-14 and was far from the slavish copy that it is often represented as. The future of the new aircraft initially looked bright. It promised to have a similar performance and load-carrying capacity to the Douglas DC-2. It took up substantially less hanger space than the DC-2 and offering passengers a comfortable "wide-body" cabin with large picture window views of the ground unobstructed by the wings (the novelty of air-travel and the better views of the ground available at the lower altitudes airlines then flew at meant the view for passengers was considered a very important factor in selling tickets).
On the wet tarmac at Eastleigh outside the stunning brand-new Cunliffe-Owen factory (soon to be the target of German Luftwaffe bombing) the Cunliffe-Owen OA-1 "Flying Wing" prototype G-AFMB is inspected by factory staff and admirers. You can appreciate how the twin Perseus radials cut off large parts of the pilots forward view. Note also the much thicker wing booms than the earlier UB-14 and "Clyde Clipper" mock-up. The OA-1 was designed to float if it had to ditch in the water. There were doors in the roof of the cabin to allow passengers to clamber out onto the top of the wing in such an eventuality.
Another benefit of the Benelli layout was that, with suitable ballast in the rear of the passenger compartment, you could detach the twin tail-booms while still leaving the fuselage standing on the tail-wheel. They built provision for this into the design. (you can make out the join-line for the tail running between the "A" and "F" serials on the tail boom in the photo above).
Unfortunately, Sir Hugo's timing for starting construction of a new aircraft type could not have been worse. As war clouds gathered all the established aircraft companies found themselves with full order books and aircraft designers, production staff and skilled workmen became scarce. This was to have dire consequences for the new OA-1 Flying Wing. The building of the prototype took much longer than anticipated and it was subsequently slated for a host of detail design flaws and bad workmanship in its construction. By the time the prototype first flew on 12th January 1939, piloted by Clyde Pangborn, the new Douglas DC3 had long replaced the DC2 on the production line and set new standards of performance and economy. British rivals like the deHavilland DH91 Albatross and DH95 Flamingo and the big four-engined Armstrong Whitworth Ensign looked set for success and new designs in the pipeline with pressurised passenger compartments like the Douglas DC-4, Curtiss CW-20 and Fairey FC1 looked set to make the OA-1 obsolescent even before it entered service. It is clear now that the OA-1 was three or four years too late to make any impact on the civil aviation marketplace.
Cunliffe-Owen OA-1 in flight.
In June 1939, the Cunliffe-Owen OA-1 went to the Aircraft and Armament Experimental Establishment (AAEE) at Martlesham Heath, testing continued until after the outbreak of war. Its flying qualities, although not perfect, were generally adequate for a prototype aircraft and its short take-off and landing run were remarked upon. However, as already mentioned, many aspects of the detail design were condemned, and many aspects of the construction and workmanship were found to be woefully poor. The poor ergonomics of the cockpit, the flimsiness of the passenger windows and the lack of any anti-corrosion protection came in for particular criticism. It was refused a Certificate of Airworthiness (CofA) and returned to the manufacturer's Eastleigh factory. If Sir Hugo's timing for constructing the prototype OA-1 was disastrous his timing for building a brand-new aircraft factory could not have been better. When war was declared his factory space became much in demand and production from other manufacturers (notably Supermarine who shared the Eastleigh airfield with Cunliffe-Owen) and the need to reassemble aircraft shipped over from the USA soon filled it to bursting. There would have been no space to produce the OA-1 even if it had been a success. The Cunliffe-Owen factory was very badly damaged by the German Luftwaffe during the Battle-of-Britain, but it was repaired and continued in use throughout the war and beyond.
OA-1 coming in to land. Of particular note is the fuselage flap, this gave the aircraft a remarkably good short-field performance.
What to do with the OA-1 prototype? The company did find time to fix many of its shortcomings and so it was granted a Certificate of Airworthiness late in 1940. Since one of the major criticisms of its construction was the lack of any sort of anti-corrosion finish, if it was to be used, what better place to use in than in a desert, where corrosion would be no problem! In June 1941 it was piloted to North Africa by the dare-devil flyer Jim Mollison with a crew of three, to join the Free French Forces. It was rumoured to have been used to transport General Charles de Gaulle. It was in service until at least June 1944. On VJ night 1945 it was languishing in the salvage compound at No 2 TARU at El Kabrit in Egypt, stripped of wings, engines and most interior fittings, it was burnt on a bonfire to celebrate the end of hostilities.
And so ended the Cunliffe-Owen OA-1 "Flying Wing", although the company did continue to look into possible future developments. In particular it does seem highly likely that the design they tendered to Air Ministry S6/43, a 1943 specification for a torpedo-bomber to repace the Bristol Beaufort, had a "flying wing" layout, although no details are available. Cunliffe-Owen reverted to a more conventional layout for their "Concordia" 10 passenger feeder-liner, the prototype of which flew in 1947. There was no market for such a new aircraft in a world awash with ex-military transports and the failure of the project saw Cunliffe-Owen withdraw from the aviation marketplace.The construction of the M27 motorway separated the site of the Cunliffe-Owen factory from Eastleigh airfield (now Southampton airport). The site was occupied for many years by the Ford Motor Company, who built the Transit van there.
Engines: Two Bristol Perseus XIV-C single-speed, medium supercharged sleeve-valve radials of 710 horsepower each .
Max Speed: 218 mph (351 kph), expected to cruse around 180 mph (290 kph). (Higher maximum and cruising speeds were advertised in Cunliffe-Owens trade adverts).
Ceiling: About 20,000 ft (6,096 metres). Being unpressurised it could not have operated as a normal passenger aircraft at such heights.
Crew of two (pilot and co-pilot). Passenger capacity 20 (the prototype was fitted out for only 15 passengers in luxurious armchair seats made by the Rumbold company).
Fuel capacity: 650 gallons (2,955 litres) in eight wing tanks.
Maximum range: 1,300 miles (2092 km).
It should be noted that the Mk XIV-C version of the Bristol Perseus sleeve-valve engine used on the OA-1 was a civil-rated engine that produced substantially less power (710 hp) than the military Perseus XII. (905 hp), although some of Cunliffe-Owen's trade adverts quoted the military figure.
The Cunliffe-Owen OA-1 Flying Wing was almost certainly too late to be a success in the civil marketplace. By the time it was ready to fly it was already 3 or 4 years behind the times in terms of performance and economy. When Burnelli had first flown his UB-14 design in 1934 it was cutting edge. If he had successfully negotiated production rights with established aviation firms he might well have produced a winning product that would have gone down as one of the greats of aviation history but the delay with dealing with "start-up" companies meant he missed the boat and the great promise of the basic UB-14 design was lost. It is interesting to speculate what might have happened if he had got companies like Avro or Vickers interested in producing his designs. Avro produced the Type 618 and later variants based on licences purchased from Fokker while Vickers produced a progression of "Viastra" airliner designs based on technology licensed from Michel Wibault, both were coming to the end of their development potential just as the UB-14 became available. Who knows, if the UB-14 and its derivatives had reached production in the USA and UK maybe it could have taken the place of the C-47/DC3 Dakota in the air forces of the Allies?
My painting shows the Cunliffe-Owen OA-1 as if it had gone into production and been used as a transport aircraft by the RAF in WWII. In this case shown dropping paratroops. I've fudged the problem of exiting by not showing the doorway the paratroops are jumping from. On the original design if you had jumped from the standard door you would have gone straight into the rear wing support strut!. I have reasoned that a smaller parachute door would have been positioned to the rear of that strut or in the floor of the aircraft.
Looking at the Cunliffe-Owen OA-1 in isolation, it is tempting to speculate that if Sir Hugo had been able to get the quality of staff he needed he might have got the OA-1 prototype flying six months to a year earlier, and without the myriad design and construction flaws it actually had. Under those circumstances, it's possible to imagine aircraft starting to come off the production line of the new factory about the time the war started. Even in those circumstances, it's probable that the Air Ministry would have only allowed a limited production run before turning the factory over to bomber or fighter production (production of all the promising British transport aircraft, DH91 Albatross, DH 95 Flamingo and AW Ensign were all stopped after only a few examples). The Air Ministry simply did not foresee that the new World War would demand huge numbers of transport aircraft; it thought the outcome of the war would be decided within weeks or months of war being declared by massive bombing by the competing fleets of bomber aircraft.
Of course, it is possible that if the OA-1 had made it into production, the design might have been adapted for more warlike uses, although only as an interim stop-gap. Hence the flight-of-fancy painting below.
This painting shows the OA-1 as it might have appeared if it had been pressed into service by RAF Coastal Command. Such a thing is not at all unlikely if it had been in production;. The Lockheed Hudson was a conversion of an airliner, as was the Avro Anson, both of which were used by Coastal Command. Also a conversion based on the Douglas DC2 airliner called the B-18 Bolo was used for coastal/ocean patrol by the Canadian Air Force (who called it the "Digby") and was also used extensively by the USAAC for the same role in the Caribbean
One thing is sure, if it had gone into production, being built in Southampton, the OA-1 would never have been called a "Clyde Clipper". Perhaps a better name would have been "Solent Schooner" !
¹ The Scottish Aircraft and Engineering Company's "bomber" was advertised with pictures of an unmodified UB-14 and seems to have been just their "Clyde Clipper" with minimum modifications to enable it to carry bombs. It should not be confused with the "Burnelli Bomber" which was a different project altogether, designed by Burnelli back in the USA with a more traditional looking fuselage nose projecting forward of the lifting fuselage with a bomb aimers position and a front turret. It also seems to have had much deeper tail-booms able to accomodate a turret in each.
² Not only were the aviation workforce in the Southampton and Solent area very skilled they were also noted for a general lack of union activity, this meant they were also relatively lowly paid (Read C.R. Russells "Spitfire Postcript" ISBN 0 9524858 O X ).
"First of the Wide-Bodies?": A 4 page article by Peter London in the July-August 1995 (No 58) Edition of "Air Enthusiast" Magazine.
"Burnelli's Lifting Fuselages": A series of articles by Richard Riding that appeared in the March to July 1980 editions of the "Aeroplane Magazine". It is the June edition that covers the Cunliffe Owen OA-1.
"Cunliffe-Owen Flying Wing": A two page article in the Aircraft Described series (No143) in the July 1965 edition of "Aero Modeller" magazine (unattributed).
"A Lift Less Ordinary": A 5 page article by Peter London in the January 2016 edition of "Aeroplane" magazine.
"British Built Aircraft, Vol2, South West & Central Southern England": By Ron Smith, First published 2003 by Tempus.
A letter from Norman Smith giving a detailed first-hand account of the ultimate fate of the Cunliffe-Own OA-1 at El Kabrit in Egypt was printed in the "Skywriters" letter pages of "Aeroplane Monthly" magazine in November 1979.