Civil Aviation
De Havilland Comet
The Comet was the first jet-engined passenger airliner and made its first test flight on 27 July 1949, the British Overseas Airways Company (BOAC) having already committed itself to the purchase of 10 aircraft.
A clean, low-drag design had swept wings, integral wing fuel tanks, a pressurised cabin and two pairs of de Havilland H.2 Ghost turbojet engines buried in the wing roots. Reclining seats for 36 passengers, large picture windows, a galley serving hot and cold food, bar and separate men and women’s toilets afforded a previously unusual feeling of luxury.
The Comet entered service with BOAC in May 1952, but within a year, three Comets were lost in fatal mid-flight accidents. The first was deemed to be due to the airframe being overstressed through bad weather and the others by structural failure resulting from metal fatigue.
The effects of metal fatigue in a fuselage that undergoes cycles of pressurisation and depressurisation was not fully understood at that time and it is a common misunderstanding that the fault occurred at the corners of the windows which were more square than in modern aircraft. In fact, the fault occurred at apertures for the ADF Antenna, but a major cause of these accidents was a manufacturing fault.
The Comet’s thin metal skin was both riveted and chemically bonded, and the design called for the rivets to be inserted in pre-drilled holes. In manufacture the rivets were simply punched through the metal, leaving cracks that worsened and led to catastrophic failure.
All Comets were withdrawn from service while de Havilland launched a major effort to build a new, larger and stronger version. Comets would not return to service until 1958 and continued to be operated by some airlines until 1981. Much was learned from the tragic accidents suffered by the Comet, and American manufacturers like Boeing & Douglas quietly conceded that if had not been for the Comet, the same disaster could have befallen their early jet airliners.
The basic airframe continued to fly until 2011 as the RAF’s Nimrod, primarily used for maritime surveillance and anti-surface/anti-submarine warfare.
A.V.Roe Triplane
Designed by Alliot Verdon Roe, and patented in January 1909, this was the first all-British aircraft to fly (Roe’s earlier biplane used a French engine). It made it’s first flight on 5 June on Walthamstow marshes, where Roe had rented two railway arches to use as workshops.
The three tailplanes were lifting surfaces only, pitch control being effected by altering the angle of incidence of the mainplanes and lateral control by wing-warping (twisting the trailing edges of the wings in opposite directions). Directional (yaw) control was provided by a rectangular rudder. The engine was a 9 hp V-twin built by J.A. Prestwich & Company Limited of Tottenham, London, under the trade name JAP.
Roe’s first triplane is on display in London’s Science Museum and my illustration of that aircraft is in the “Flight” galley section of this website.
This illustration was commissioned by the Lea Valley Experience for the Pump House Museum in Walthamstow.
The pilot’s seat and fuel tank were suspended on rubber webbing made by Roe’s Bulls Eye Braces factory, hence the inscription on the fuselage covering (now missing). This would become the Avro trademark so well known today.
Aircraft Comparisons
Cross-sectional cutaways of various executive jets.
Civil Aircraft: The Essential Aircraft Identification Guide
From top to bottom:
Boeing 737-800
Airbus A321
Arbus A319
Douglas DC-10-30
From top to bottom:
Cessna 126
Cessna Caravan
MD Helicopters Explorer
Cesna 162
Pitts Special S-1S
Part of the Science Museum’s “Flight” collection, this S-1S variant was certified for competition aerobatics and has a round aerofoil section, four ailerons and powered by a 180 hp Lycoming AEIO-360 engine and is one of 60 built.
Designed by Curtis Pitts this light aerobatic biplanes have achieved many competition wins since their first flight in September 1944.
Today’s Pitts are very similar to the original design and may be purchased as finished aircraft from Aviat Aircraft, Wyoming who will also sell the plans to allow homebuilders to make their own aircraft from scratch. Steen Aero Lab, Florida also sell the planes in kit form for self-assembly.
Hawker Siddeley 125
Also part of the Science Museum’s collection, the 125 is a small business jet designed by De Havilland, who were then owned by Hawker Siddeley, but the legacy brand was used throughout development. Production aircraft were initially marketed as HS.125, but corporate changes meant that the aircraft have variously appeared under the names British Aerospace, Beechcraft-Hawker and Raytheon.
One of the first generation of executive jets, the 125 has been operated by a wide variety of customers including corporations, governments and military forces. The RAF operated the aircraft as a navigation trainer under the name Dominie T.1.
