I believe the Ventral fin was fitted by the order of the A.R.B of the time as the B.O.A.C 707s fitted with Rolls Engines would snake on take off and unless better stability was found they refused to give the plane a Cof A. if this is incorrect I'm sure it will be corrected. later 707s were fitted with a bigger fin
Last edited by avionic type; 7th Jan 2010 at 14:30.
Reason: more info