The engineers working on Concorde calculated that TB2 would actually have been able to fly, even with forward facing wings. Apparantly the first public unveiling of Concorde was accompanied with the Thunderbirds theme tune. As for TB1 and TB3, I hope that some clever people can provide you with the answers whilst not shattering my childhood illusions at the same time. (ps - when I saw the cinema trailer for the new film with the CG craft, I was literally gobsmacked - I am not at all sure about having humans in the film, but the craft look awesome)