The famous Handley-Page “Type O” heavy bombers resulted from a December 1914 Royal Navy requirement for a large two engine aircraft with folding wings of 114ft span capable of lifting six 112 lb bombs and a two man crew at a speed of at least 65mph. The initial prototype design was intended to be powered by two 150hp Sunbeam engines mounted between the wings in armour plated nacelles that also contained the petrol tanks. Armour plating was also provided for the two man crew inside their fully enclosed cockpit. Engine technology was developing rapidly and the intended engines had been supplanted by two counter rotating 250hp Rolls-Royce Eagle engines early in the design phase which increased the bomb load to sixteen 112 lb bombs which allowed the wingspan to be reduced to 100ft, inspiring the name “Handley-Page Type O/100”. Initial prototype Handley-Page O/100 1455 made its maiden flight on 17 December 1915. Additional testing resulted in the fully enclosed cockpit and armour plating for the crew being replaced with the familiar open cockpit & front gunner’s position, superior streamlined radiators being added to each side of the engine nacelles and the tailplane being strengthened. Improved 2nd prototype 1456 featured a strengthened fuselage and made its maiden flight with 10 passengers on board in April 1916. The 3rd prototype 1457 featured an opening for an additional rear gun in the fuselage and took to the air in late June 1916 while 1458, the 4th prototype, was brought up to production standard with unbalanced elevators and ventral gun openings in the rear fuselage. This allowed near all around defense and prompted Manfred von Richthofen to refer to it as “a flying fortress” in the 1918 book “The Red Battle-Flyer” upon inspecting a captured early production O/100. The first dozen early production aircraft were essentially built in this configuration (including the initial 3 prototypes after they were rebuilt before entering service) although a 130 gallon petrol tank was added above the bomb cells from 1461 onwards. The first half dozen or so aircraft from the 2nd production order received shortened nacelle rear fairings that did not need to be folded to avoid fouling the rigging when the wings were folded. The remaining 2 dozen or so late production aircraft from the 2nd production order featured unarmoured engine nacelles that were fitted with a frontal radiator. Rolls-Royce Eagle engines of increased performance were fitted as supply allowed which brought the top speed up to just over 70mph fully loaded. Late production O/100 3117 was experimentally fitted with 320hp Sunbeam Cossack, 260hp RAF 3a and (4x) 200hp Hispano-Suiza engines while 3142 was fitted with 260hp Fiat and then 260hp Sunbeam Maori engines.
Proposed modifications to the O/100 in July 1917 included 350hp Rolls-Royce Eagle VIII engines, deleting the requirement for counter rotating engines (which simplified production), an increased bomb load, replacing the petrol tanks in the engine nacelles with a 2nd 130 gallon tank above the bomb cells (which allowed the nacelles to be shortened considerably) and a redesigned fuel supply arrangement which resulted in the Handley-Page O/400. Barely a couple of Handley-Page O/100 survived until the Armistice while the O/400 was not retired from RAF service until late 1921 and those of the USAS served until at least the middle of 1923. Some aircraft were converted for civil use and continued to fly on well into the mid 1920s. A further development was the 125.5ft wingspan, 4 engine Handley-Page V/1500 which was developed for the long range bombing of German cities but the Armistice came into effect before they could take off on the first bombing raid on the morning of 11 November 1918. Any history of this important aircraft here is of necessity very brief, therefore we encourage you to seek out the references mentioned below for a more thorough understanding of this important aircraft.
WW1 aircraft colour schemes are contentious at the best of times and we have done our best to provide what we consider to be accurate painting information. Some very early O/100 were delivered in clear doped Irish linen with grey engine nacelles and metal brackets etc. Some received experimental mottle or “Giraffe” style PC10 (Protective Covering Number 10) camouflage finishes over bleached Irish linen but most O/100 and O/400 were simply doped in PC10 overall with enamel paint equivalents used on metal engine cowlings and brackets etc. PC10 was made from mixes of yellow ochre, iron oxide and lamp black pigments and could vary between dark olive green and dark chocolate brown. Luckily there are surviving O/400 wings and struts in original condition which confirm that a very dark green version of PC10 was used, on these particular samples at least. In February 1919, 207 Squadron O/400s were described as “olive green”. Some very late production O/400 (perhaps too late to see operational service during WW1) appear to have been finished in Nivo (Night Invisible Varnish Orfordness) which was a medium greyish green colour, remarkably similar to German field grey. Interior wood and linen surfaces appear to have remained in their original finish except for areas visible from the exterior which were often overpainted PC10 or maybe even black.