WaltBJ wrote:

Slots are to raise the lift coefficient (down coefficeint on the
horizontal stab?) at low speeds. Enables raising the nose at lower TO
speeds for more AOA for liftoff at lower speeds. FWIW I never saw an E
without a slotted tail. I first flew LES birds on return to the
cockpit in 76. I was not then and am still not impressed. Can't
remember the exact top speed at 1000 ASl in AB but with 2x275 tanks it
was definitely 50-75 knots slower than our Ds at DaNang - even though
the D was carrying a CL bag, 2 MERs, 2 TERs, 2 x AIM9 and a ECM pod.
Our Ds rang up 745 KIAS at 4000 AGL getting out of Dodge after a
little SAM SEAD, and we were happy to see it. The LES bird could loop
at 300 KIAS from 15,000 in AB - BFD - worthless as a combat maneuver.
You can have all the turn you want - I'll take more speed any day. Ask
the 106 drivers who fought our Dash 19 Zippers about turn vs speed.

OTOH, considering the number of hard wing F-4s that were lost to
departures (probably at least 150. The one source I have handy lists
USMC/USN admitted losses to this cause up to August 1971 at 79. USAF
losses were probably higher) and the poor state of high alpha training in
the average USAF pilot from 1967 or so, the slats made a lot of sense as
far as keeping the average pilot from departing due to adverse yaw while
maneuvering with a heavy load. Steve Ritchie's wingman John Markle and
his WSO lost their a/c to this cause while in a fight over NVN on May
20th, 1972 (CSAR got them both out)

Owing to the lack of edge of the envelope training (to keep the safety
stats looking good), pilots often encountered the F-4's departure
characteristics for the first time in combat, and didn't know how to
recognize it until too late. Initially the navy figured that they could
fix the problem with improved crew training, but eventually they went for
the same hardware solution that the USAF had already adopted even though
it was less of a problem for their F-4s, given the different mission
distribution compared to the air force (less A/G, more FAD/AtA).

Ultimately, the departure and flight characteristics of the F-4 (and the
F-8, F-100, F-101 and F-104, among others) led the military to put a great
deal of energy and money into flight control and aerodynamic design to
idiot-proof the next generation of fighter a/c (i.e. F-15/16/18 and to a
lesser extent, F-14), to allow the average pilot carefree handling to near
or on the edge of the envelope, while keeping them out of trouble. The
F-5 was an early nudge in that direction as well. There's no doubt that
a/c like the F-16 with hard FC limits that can't be overridden will
penalize the good sticks on some occasions (I'm reminded of the Top Gun
instructor who used to deliberately depart his F-4, to allow him to make
maneuvers that no one else could match), but the average pilot can use so
much more of the envelope confidently that there's an overall improvement
in capability, and a lower attrition rate. They've also improved the
training, obviously, but training time will always be limited and
expensive.

Guy