This collection includes BTH Company report which details the estimated cost of buildings and equipment required to build and maintain 50 Whittle engines per week and includes 3 layout plans; Reginald Wright’s notebook containing a technical record of work he carried out, dated 6 October 1939 – 5 April 1940 and two pages of later notes; Letter from Frank Whittle, apologising for some oversight in publicity, 10 January 1944 and three copies of AEI news, October 1938; June 1944; January 1945. The later issue has an article on Whittle and BTH/Power Jets involvement.