………The vertical tail on the YF-100 prototypes was higher than the production model. I wonder why they reduced it?
Not the first time I’ve sung the praises of Bill Gunston’s “Supersonic Fighters Of The West” (Ian Allan 1976) and he covers the problem in some detail in the chapter on the F-100.
“What seemed to be a trivial change – though actually worked out most carefully – was that the tail fin and high, narrow rudder of the first YF aircraft were cut down in the F-100A to reduce weight and drag. The production rudder was broad but squat, being arrested barely half-way up the fin by the sharpely lowered fuel vent which in the first YF-100A had been on top of the tall fin. This little change was to have a major impact on the programme.”
Later he relates how Lt-Col Frank K. ‘Pete’ Everest chief of the test flight at AFFTC, Edwards AFB “wringing out the F-100 in deliberately harsh ways they (Everest and Capt Zeke Hopkins) discovered tendencies towards control sensitivity, divergence and ‘coupling’ between roll and yaw and between pitch and yaw of a nature which, …… …. seemed to be not only undesirable in a combat aircraft but potentially even dangerous.” Everest made noises but was shouted down by the company and the Air Force.
On 12th October, 1954 NAA’s Senior engineering test pilot took off from Palmersdale in 25764, an early F-100A, to carry out a high-speed full power dive and pull out.
Following the break-up and crash an exhaustive investigation took place – rivalled only by the one into the DH Comet crashes.
I don’t suppose Lt-Col Everest got any satisfaction from being proved right.
Roger Smith.
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