It is true that carrier-basing imposes a weight penalty. The FJ-2 Fury weighed approximately 1,000 lbs more than the F-86 on which it was based, resulting it being underpowered with the Sabre's engine. (That was solved by putting an engine with more thrust in the FJ-3.)
It's not clear which service was responsible for the side-by-side seating arrangement. It is true that the Navy's two-seat jet night fighters, the F3D and the stillborn F6D had side-by-side seating, in part because shortness is a virtue on a carrier and their radar antennas were humongous. However, I've seen no documented evidence that the Navy required side-by-side seating, other than stipulating a maximum length, which the Grumman F-14 accommodated with tandem seating. On the other hand, the Air Force insisted on a heavy and complicated escape capsule that the Navy had no use for. It was best accommodated with side-by-side seating.
The Air Force also insisted on a bomb bay for nuclear stores and its unprepared field requirement (look up California bearing ratio at your leisure) dictated really big, low-pressure tires. Both of those features resulted in big compartments in the airframe that added empty (no pun intended) weight.
However, the biggest Air Force weight penalty was probably imposed by the Mach 1, low-level ingress on a nuclear strike. That results in the need to design for a very high "q" (dynamic pressure) and gust loading of the structure, neither of which were a requirement for a Navy missile-truck loitering on a Combat Air Patrol station at altitude and then dashing off toward an incoming raid. Moreover, given that the Navy's F-111B was not a true fighter, it probably could have been designed for a load factor of 4 rather than 6.5, further saving weight.
It should be noted that one reason for the F-14 being somewhat lighter than the F-111B was that it didn't have any of those Air Force features other than the variable-sweep wing and moreover, the weight of the big Phoenix missiles over and above that of Sparrows was considered an overload from a structural strength standpoint.
The whole episode illustrates the folly of the doesitall aircraft. Even designs with good initial focus tend to get barnacled with bells as whistles by the brass. Even designs that did turn out to be multi purpose were usually designed for simple mission. e.g. B 52, Pages and pages of specs yield pages and pages of fantasy proposals and overly complicated designs. KISS to start because once reality is encountered there will be add ons. Even when you thought of everything, you didn't.
ReplyDeleteThat was a good read. I would never had thought that the weight problem was driven by Air Force requirements and not Navy. The swing wing is understandable for Navy storage but the escape capsule, high flotation landing gear, non-tandem seating, etc. was an eye opener as far as contributing to the weight situation if used as a carrier A/C.
ReplyDeleteMy dad was an aviation ordnanceman back in the day and was at sea doing workups for a cruise when an F-111 came aboard for, I assume, tests of some sort. Like everyone else on board, he took time to check it out. Having a thorough working knowledge of racks and pylons and things under the wings, he told me later of being very surprised at the weight of the structure associated with the four hardpoints on the wings -- he characterized them as heavy steel plates built into the wings that were always there whether the airplane carried stores or not. Whether my memory of what he told me is accurate or not, pivoting hardpoints designed for heavy aerodynamic and landing loads could not have come cheap in either weight or complexity. It is interesting to note that Grumman apparently learned their lesson when it came time to design the F-14 and attached all the stores to the fuselage, leaving the wings clean.
ReplyDeleteThe Old Bald Guy
Rome, Ga