|Handley Page O/400|
An O/400 landing at RAF Andover in 1918
|Passengers|| *14 (O/7 variant)
|Entered service||April 1918|
|Length||62 ft 10¼ in|
|Wing area||1,648 ft²|
|Maximum takeoff||13,360 lb|
|Engine||2 × Rolls-Royce Eagle VIII inline piston|
|Power (each)||360 hp|
|Maximum speed||97.5 mph (84.7 kn)|
|Range||608 nmi (700 mi)|
|Rate of climb||23 min to 5,000 ft|
The Handley Page O/400 was a 1910s British heavy bomber, and one of the first strategic bombers. The O/400 was an improved version of the O/100.
The development of the O/400 can be traced back to the 4 prototypes and the first production batch of 6 Handley Page H.P.11s (Handley Page O/100) of 1915. These aircraft were the first delivered by road to RAF Hendon on 9th December 1915.
(for more on the development of the O/100, see Handley Page O/100)
After the successful deployment of the O/100 Handley Page worked on the larger, improved model, the O/400.
The Handley Page O/400 was part of the Handley Page Type O line which had started with the O/100 in 1916. The O/400 started to enter service with Royal Naval Air Service/Royal Air Force in April 1918, the O/400 was an improved version of the Handley Page O/100 which had entered service in late 1916. The O/400 carried a maximum payload of 2,000 lbs of bombs and could carry a new 1,650 lb bomb, the O/400 was equipped with a new bombsight called the "Drift Sight Mk 1A bombsight". They were usually deployed in force, with up to 40 taking part in a raid.
Besides from providing support to the ground forces they took part in some of the first strategic bombing raids in history, as part of the RAF's "Independent Air Force", which was branch of the RAF which conducted strikes against German railways, aerodromes and industrial centres without co-ordination with the Army or Navy.
Not all O/400s fought in Europe, a single O/400 served with 1 squadron, Australian Flying Corps in the Middle East, where she conducted night attacks against the Turkish and supplied the small number of aircraft flying in support of Lawrence of Arabia.
When the war ended eight O/400 were converted into VIP transports and were operated by the 86th (Communication) wing at Hendon, which provided quick transport between London and Paris for officials engaged in the negotiation of the Treaty of Versailles.
The RAF continued to operate the O/400 until they were replaced by the Vickers Vimy near the end of 1919. War-suplus O/400s were converted for civilian use and nine ex-military O/400s were used by the pioneering airline "Handley Page Transport".
Six were assembled in Republican China under designation "O/7", where they carried airmail and passengers between Beijing and Tientsin, the first such service taking place on the 7th May 1920, the services were disrupted by the outbreak of the Chinese Civil War and eventually the O/7s were taken over by various warlords.