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Message: <blockquote data-quote="robunos" data-source="post: 88996" data-attributes="member: 553">From the information given in the sources I've previously quoted,and also 'British Experimental Jet Aircraft', by Barrie Hygate, andBarry Jones's 'British Experimental turbojet Aircraft', there werethree main problems, firstly, the degree of laminar flow achievedwas very disappointing, averaging only around 5%, compared with up to 60% achieved in tunnel tests, secondly, the aircraft'sCLmaxwas low, even with full flap deflection, due tothe short moment arm available with the tailless configuration.This led to high downloads on the surfaces to correct the pitchingmoment at low speed. This was aggravated by the extra pitchingmoment generated by the lowered flaps, effectively cancelling outtheir extra lift.Thirdly, and probably most important, the aircraft proved to beextremely sensitive in pitch. In anything other than the smoothestair, rapid pitching oscillations would set in, which could, and did,become divergent. On May 26th, 1949, these pitch oscillationsdeveloped into flutter of one of the wingtips.This rapidly spread tothe whole wing,and became so violent that the pilot abandonedthe aircraft, becoming in the process, the first pilot to use a Martin-Baker ejection seat in an emergency.If such an aircraft was to be built today, then artificial stabilitywould take care of the pitch sensiivity, modern aerodynamicswould probably increase the CLmax, however, largescale laminar flow is, I believe, still not possible, but I'm expectingto be corrected!    ;Dcheers,         Robin.</blockquote>

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