RAF SE5a (Windsock Datafile Special)

In DATAFILE No.30, The Royal Aircraft Factory SE5/W it was noted that the identifying titles on Royal Aircraft Factory design drawings indicate that the designation SE5a basically applied to the type with the modified mainplanes, regardless of the power rating of the engine fitted. This DATAFILE SPECIAL confines itself to providing coverage of the main production aircraft with the 200/ 220-hp Hispano-Suiza or Wolseley Viper engine, for this was by far the most numerous and best-known form of the SF5a.
The design, development and production of aero-engines in World War 1 was at all times of critical importance: aero-engine efficiency, reliability and availability affected the performance, production and operation of aircraft as nothing else did. Of no aeroplane of the period was this more true than of the SE5a Surviving records suggest that the first production-type 2()()-hp SE5a was A8923. which had. as initial fit. the Wolseley built engine (therefore a W.4b Adder) No. 782 2233 W.D.8357; it was submitted for its final inspection on May 30 1917. and apparently flew that clay It was approved on May 31. At least 14 other aircraft of the batch A8898-A8947 were completed with the Adder or the 200 hp Hispano-Suiza 8B as their power unit. A8923 was immediately allocated to the Expeditionary Force in France on May 31 1917, and went to No.jO .Squadron. It was lost, with Captain WA Fleming on August 10, b> which timi ts engine
was the Peugoot-made Hispano-Suiza No. 115059/WD10252.
All the SKs built by contractors had the geared 200-hp Hispano-Suiza engine, in one form or another; or. later, the direct-drive Wolseley Viper. When production began in 1917 there was no suitable alternative engine, consequently the SESa depended for its very existence on the Hispano-Suiza and its derivatives. Deliveries of the Wolseley-built version of the 200-hp Hispano-Suiza. the Adder, started in March 1917; first deliveries from France came from Peugeot in April, from Brasier in June, from DFP. Delaunay-Belleville and Mayen in August, and from Fives-Lille in November. Deliveries from DFP and Fives-Lille were negligibly few. By the end of 1917. a total ol 1546 SK.las were still to be delivered against existing orders from the Royal Aircraft Factory and five industrial contractors, and further contracts were in prospect.