Quest for Performance: The Evolution of Modern
Part II: THE JET AGE
Chapter 11: Early Jet Fighters
Through the Transonic Range
 Many knowledgeable engineers
once thought that reasonably safe and controllable flight past Mach 1.0 was
highly unlikely, if not completely impossible. By the mid-1940's, much had
been written in the popular press about the so-called "sonic barrier." That
an aircraft could successfully fly past Mach 1.0, however, was convincingly
demonstrated on October 14, 1947 by Captain Charles E. Yeager flying the rocket-propelled
Bell X-1 research airplane. This historic event set the stage for an intensive
research and development effort, which had as its objective the production
of jet fighters capable of passing through Mach 1.0 and into the once forbidden
supersonic speed range. During this stimulating time period, from the late
1940's to the mid-1950's, a number of supersonic fighter aircraft were developed
that later served in the United States air forces as well as those of a number
of other countries. Some of these aircraft types saw extensive action in the
Vietnam conflict, and some are still in service.
To put the firs t-generation supersonic fighters in
proper perspective, these aircraft should be thought of as basically high-performance
subsonic machines with design features that allowed flight through Mach 1.0
and at supersonic speeds for very brief periods of time. In no sense were
they designed for sustained cruising flight at supersonic speeds. The following
considerations of drag, thrust, and specific fuel consumption readily show
this to be so. As the supersonic fighter accelerated from high-subsonic speed
to supersonic speed, the drag coefficient usually increased by a factor of
2 or more. The increase in actual drag force, however, was much larger than
that of the coefficient. For example, the dynamic pressure at Mach 2.0 for
a given altitude is about five times that at Mach 0.9 for the same altitude.
Thus, the actual drag force and the thrust required to balance this force
in steady flight increases by a factor of at least 10 as the Mach number increases
from 0.9 to 2.0. Further, the specific fuel consumption (pounds of fuel per
pound of thrust per unit time) of the afterburning turbojet at Mach 2.0 is
two to three times the value of that for the nonafterburning engine at subsonic
Mach numbers. At Mach 2.0 the actual fuel consumption per unit time may accordingly
be 20 to 30 times that at Mach 0.9. To compound the problem further, the time
required by the early supersonic  jet fighters to accelerate from Mach 0.9 to Mach 2.0 was
usually in the range from 3 to 10 minutes depending on the aircraft, engine,
and altitude. The long acceleration times, which resulted from the relatively
small margin between thrust and drag, when coupled with the high fuel consumption
per unit time during acceleration, severely restricted the time available
for cruising flight at maximum Mach number. The range available to fighter
aircraft operating at supersonic speeds was accordingly quite limited. For
these reasons, even modern supersonic fighters spend most of their flying
lifetime at subsonic speeds. Most of the design features of the supersonic
fighters, however, also increased the operational capability of these aircraft
at high-subsonic speeds. Accordingly, these aircraft should really be thought
of as highly effective subsonic fighters with a supersonic dash capability
that is useful and important in certain military missions. For example, a
short burst of supersonic speed might be necessary in overtaking or escaping
from a hostile aircraft or in avoiding antiaircraft fire in a bombing run
at low altitude.
The supersonic fighters developed in the 1950's shared
a number of important technical features. All the aircraft had afterburning
engines that provided a substantial boost in thrust as well as fuel consumption
throughout the speed range. A large increase in thrust as the Mach number
increased was also characteristic of the afterburning engines. Both fixed-
and variable- geometry inlets were used. Power-operated control surfaces with
artificial "feel" provided to the pilot were standard features; and, in some
cases, rudimentary stability augmentation was incorporated to improve the
inherent stability characteristics of the aircraft. The increased control
effectiveness of the all-moving horizontal tall at supersonic and transonic
speeds dictated its use rather than the more conventional elevator. Wing thickness
ratios fell in the range from about 7 to 4 percent. By comparison, the thickness
ratio of a typical World War II propeller-driven fighter was about 14 percent.
Wing planforms were usually of the swept or delta type, although one fighter
of this period had a straight wing.
By the end of 1956, prototypes of seven supersonic fighters
for the USAF had been developed and flown. Six of these aircraft reached production
status and operational service. In the same period, two supersonic fighters
were developed for the Navy. To illustrate interesting design features of
supersonic fighters developed during the 1950's, four USAF and one Navy aircraft,
all capable of supersonic flight, are briefly discussed in the following paragraphs.
Some of the physical and  performance characteristics of these aircraft are given
in table V.
Where two values of engine thrust are given (16 000/10 000, for example),
the first value indicates the sea-level static thrust with maximum afterburning
and the second value indicates maximum thrust without afterburning. Also note
that the values of zero-lift drag coefficient CD,O, drag area f, and maximum
lift-drag ratio (L/D)max are for subsonic speeds.
As mentioned, the values Of CD,O increased by a factor of
2 to 3 as the Mach number increased from subsonic to supersonic values. The
maximum lift-drag ratio at supersonic speeds for the fighter aircraft discussed
were usually in the range from 3 to 4.
A glance at the data in table V indicates that the weights, wing loadings, and thrust loadings
of the supersonic fighters were usually greater than those of earlier subsonic
machines. The afterburning supersonic fighters were designed to achieve both
their maximum speed and corresponding Mach number at high altitudes. The maximum
speed at low altitudes was usually restricted to values near Mach 1.0 by high
drag was well as by airframe or engine limitations imposed by the high temperatures
and dynamic pressures encountered in low-level flight at high speeds. At high
altitudes, the maximum speeds of most of the aircraft approached or exceeded
The Century Series Fighters
Because the first of their number was designated the
F-100, the USAF supersonic fighters developed in the 1950's were aptly christened
with the appellation "Century Series." Design studies of an F-86 equipped
with a thin 45° swept wing, known as the Sabre 45, marked the genesis
of the F-100; but the aircraft that finally emerged with that designation
was an entirely new machine.
First flight of the F-100, the world's first fighter
capable of sustained supersonic speeds in level flight, took place on May
25, 1953. Views of the F-100, known as the Super Sabre, are shown in figures
11.11 and 11.12. The low-mounted wing had a sweepback angle of 45° a
taper ratio of 0.25, and an airfoil-section thickness ratio of about 7 percent.
Like the wing of its ancestor the F-86, the leading edge was equipped with
automatic slats for stall control and the trailing edge incorporated plain
flaps. Location of the ailerons mounted a short distance inboard of the tip
reduced adverse wing twisting due to aileron deflection. (Under conditions
of high dynamic pressure, adverse wing twist due to aileron deflection can
become so large that, on some...
 Figure 11.11 - Alorth American
F-100 Super Sabre single-engine jet fighter.
[ukn via AAHS]
....aircraft, roll takes place in a direction opposite
to that intended. This condition is known as aileron reversal.)
The low-mounted horizontal tail of the F-100 is clearly
shown in figure 11.12. As discussed in chapter
10, this tail position assists in preventing
pitch-up. As a further assist to stall control, most models of the F- 100
had wing fences. Also shown in figure 11. 12 is the variable-area nozzle necessary
for efficient operation of the afterburning engine; the nozzle is in the nonafterburning
configuration in figure 11. 12. The petals of the nozzle open to a larger
diameter for afterburning. The boxlike structure on the vertical tail about
one-third of the span from the tip, evident in figure 11. 12, housed a radar
The oblong nose inlet shown in figure 11. 11 provides
an immediate recognition feature of the F-100 series of aircraft. As compared
with a circular inlet, the oblong design provides better pilot visibility
over the nose and, since the duct passes under the pilot's seat, the vertical
dimension of the fuselage is reduced at this location. No area ruling was
incorporated in the design of the F-100.
All new aircraft encounter problems of varying degrees
of seriousness, particularly in new and largely unexplored regimes of flight
or with new configuration concepts, and the F-100 was no exception. An unanticipated
problem was encountered during flight tests of the F-100 that resulted in
loss of the aircraft as well as its well-known North American test pilot.
Compared with piston-engine fighters and earlier jets, aircraft such as the
F-100 had much higher values of the ratio of....
 Figure 11. 12 - Rear view
of North American F- 100 Super Sabre single-engine jet fighter.
[USAF via Martin Copp]
....lengthwise to spanwise mass. As a consequence, a
gyroscopic couple that caused large yaw excursions occurred during dive pull-out
maneuvers accompanied by large rolling velocities. During the performance
of such maneuvers in an early model F-100, the angle of vaw became so large
that the aerodynamic loads on the vertical tall exceeded its structural strength
and the tall separated from the aircraft. A larger and stronger vertical tail
solved the problem on the F-100. All new fighter aircraft under development
at that time, however, were carefully scrutinized for possible "rolling pull-out"
problems; this maneuver is now a standard one that must be analyzed on all
new fighter designs.
Maximum speed of the F-100D was 927 miles per hour,
or Mach 1.39, at 35 000 feet; at sea level, the maximum speed was just below
the sonic value. Maximum sea-level rate of climb was 22 400 feet per minute,
or about three times that of the F-86, and the service ceiling was 51 300
feet. With a lift-drag ratio of 13.9 at subsonic speeds, the F-100 had a ferry
range of 1971 miles. According to reference 200, the combat radius was 599 miles with maximum external fuel
load and 279 miles with only internal fuel and six Snakeye bombs.
Originally intended as an air-superiority fighter, the
F-100 was used operationally as a fighter-bomber and saw extensive service
in this  role with the USAF in
the Vietnam war. As a fighter-bomber, armament consisted of four 20-mm cannons
mounted in the bottom of the fuselage below the cockpit with provision made
for up to 6000 pounds of external ordnance such as bombs and rocket pods.
Before production was terminated, a total of 2194 F-100
aircraft were manufactured. Although no longer a part of the USAF inventory,
the type was still in service in 1980 with four foreign air forces (ref. 177).
Since the end of World War II, the primary mission of
interceptortype aircraft has been to prevent attacking enemy aircraft from
reaching targets on United States territory. Several subsonic jet-powered
interceptors, including the F-86D Sabre, filled the air-defense role until
the supersonic Convair F-102A Delta Dagger entered the inventory in 1956.
As described in chapter
10, the F-102, which first flew in 1953, was
able to fly in the supersonic speed range only after being redesigned according
to the precepts of the transonic area rule. Even with this modification, however,
the F-102A was underpowered and could achieve a maximum Mach number of only
about 1.2 at 35 000 feet.
First flight of a vastly improved Convair interceptor
with the same general configuration layout as the F-102A took place on December
26, 1956. Known as the F-106 Delta Dart, this aircraft is pictured in figures
11. 13 and 11. 14 and is described by the physical and performance data given
in table V.
Instant recognition features of the F-106 are the distinctive
low-mounted delta wing, fuselage-mounted inlets just forward of the wing,....
Figure 11.13 - In-flight view of Convair F- I 06A
Delta Dart interceptor. [mfr via David A. Anderton]
 Figure 11.14 - Convair F-106A
Delta Dart interceptor. [USAF via Martin Copp]
....and absence of a horizontal tail. The F-102A can
be distinguished from the F-106 by its pointed vertical tail and by inlets
located farther forward and lower down on the fuselage than on the F-106.
(See fig. 10.19.) As with the F-102A, the F-106 was carefully area ruled to
reduce the drag rise accompanying an increase in Mach number from subsonic
to supersonic values. This careful attention to drag reduction, together with
the large 24 000-pound-thrust (with afterburning) Pratt & Whitney J75
turbojet engine, gave the Delta Dart a maximum speed of 1525 miles per hour
(M=2.31) at 40000 feet and the capability of climbing to its combat ceiling
of 51 800 feet in 6.9 minutes; service ceiling was 52 700 feet. Together with
excellent handling qualities, the high maximum speed and good climb characteristics
of the F-106 have made it an outstanding interceptor that first began to replace
the F-102 in 1960. As a result, the F-106 is still in use today with many
interceptor squadrons (ref. 177).
Roll and pitch control of the F-106 is provided by elevons,
which are flaplike movable surfaces on the trailing edge of the wing. Working
in phase in response to fore and aft motions of the control stick, these surfaces
provide longitudinal control moments about the pitch axis; differential deflection
of the surfaces in response to lateral movement of the stick gives roll control.
The lack of a horizontal tail for pitch trim prevents the use of high-lift
flaps on the wing. The landing speed of the 34 510-pound-gross-weight airplane
is maintained at an acceptable value (173 mph according to ref. 200) by the large wing area of nearly 700 square feet, which gives
a relatively low wing loading of 49.5  pounds per square foot.
(Compare this wing loading with that of some of the other supersonic fighters.)
Primary armament of the F-106 consists of a Genie missile
with nuclear warhead and four Falcon, radar-homing, infrared, heat-seeking
missiles. Immediately after takeoff on an interception mission, control of
the aircraft passes from the pilot to a ground controller who, by radio signals
to the autopilot, directs the aircraft to the vicinity of the enemy intruder
as displayed on a radar scope. Once within range of the enemy aircraft, the
radar on board the Delta Dart locks onto the intruder, guides the interceptor
to a favorable attack position, and initiates firing of the missiles. Then
ground control again takes over and flies the aircraft back to its base where
the pilot performs the landing. Throughout this automatic mission, the pilot
can at any time assume manual control of the aircraft.
A total of 875 F-102A's had been completed, by April
1958, as well as 111 TF-102 two-place trainer versions of the aircraft. The
last Delta Daggers were retired from the active Air Force inventory in 1973.
Only 340 of the much more capable F-106's were built, the last of which came
off the production line in 1961. The relatively few F-106's manufactured,
as compared with the number of F-102A's, reflects the changing nature of the
threat from enemy bombers to ballistic missiles that took place in the 1960's.
Although still in use after more than 20 years, the F-106 is now being gradually
replaced in the air-defense role by an interceptor version of the McDonnell
Douglas F-15 Eagle. In contrast with most fighter aircraft adapted to a variety
of missions, the F-102A and the F-106 were never employed for any role other
Based on lessons learned in the Korean war, the Lockheed
F-104 Starfighter was originally intended as a lightweight interceptor with
very high maximum speed and rate of climb. However, the aircraft saw only
limited service in that role with the USAF, perhaps because it was too small
to accommodate the sophisticated all-weather navigation and fire-control systems
required by the Air Defense Command. A redesigned fighter-bomber version of
the F-104 saw limited service with the USAF Tactical Air Command, including
action in the Vietnam war, but enjoyed spectacular success in export sales
to foreign governments. The aircraft has been in the inventory of 15 different
countries and manufactured in 7 countries including the United States.
The North American F-100 and Convair F-102/106 just
described are examples of supersonic aircraft configurations having sweptback
 and delta wings. Most
supersonic aircraft have wings of one or the other of these shapes, or some
hybrid form derived from a blending of the two types. In contrast, the Lockheed
F-104 was designed in accordance with an entirely different configuration
concept, which featured an almost vanishingly small straight wing and a horizontal
tail mounted in the T-position at the top of the vertical tail. Different
views of the F-104 are shown in figures 11.15 and 11.16, and physical and
performance characteristics of the F-104G version of the aircraft are Oven
in table V.
With an area of 196.1 square feet, the wing of the F-104
was about one-half as large as that of the F-100 and less than one-third as
large as that of the.F-106. From the side of the fuselage to the wingtip measured
only 7 feet, 7 inches. The actual thickness of the wing varied from a maximum
of 4.2 inches at the root to 1.96 inches at the tip. The corresponding airfoil
thickness ratio was 3.4 percent. Sharp leading-edge airfoil sections (sharp
enough to pose a safety hazard to ground personnel) were used to minimize
the drag rise in passing through Mach 1.0. Even so, experimental data show
that the transonic drag rise on this straight-wing aircraft with no area ruling
was about 40 percent higher than that of the F-106 (in terms of drag coefficient).
Both leading- and trailing-edge flaps were used to increase the lifting capability
of the wing. Effectiveness of the simple trailing-edge flaps was augmented
by boundary-layer control employing high-pressure bleed air from the engine.
Ailerons were used for lateral control. Clearly shown....
 Figure 11.16 - Front view
of Lockheed F-104 Starfighter. [Clyde Gerdes via AAHS]
...in figure 11.16 is the pronounced wing anhedral angle
(droop) that served to partially offset the rolling moment due to sideslip
induced by the tall surfaces. During the flight test program, the aircraft
was found to have a severe pitch-up problem at the stall. Immersion of the
highmounted horizontal tail in the wake from the stalled wing and long fuselage
nose undoubtedly caused the problem. A stick shaker/pusher (see chapter 10) to limit the maximum attainable angle of attack eliminated
the pitch-up problem.
The side-mounted inlets incorporated a fixed conical
centerbody whose vertex angle and position were chosen so as to place the
oblique shock from the nose of the centerbody on or just above the lip of
the inlet at the maximum design Mach number. The conical centerbody inlet
along with appropriate auxiliary inlet doors provided the proper engine airflow
through the design Mach number range. Of lower performance than the production
aircraft, the prototype XF-104 had normal shock inlets without the centerbody.
 Photographs of this
version of the aircraft are frequently seen in various references.
Armament carried on the F-104 consisted of one six-barrel
20-mm Vulcan rotary cannon. This weapon can be likened to the 19th-century
Gatling gun but was, of course, power operated instead of hand cranked. Four
thousand pounds of various types of external stores could also be carried.
On a typical ground-attack mission, the aircraft was capable of delivering
2510 pounds of bombs at a combat radius of 620 miles. Both pylon and tip-mounted
fuel tanks were dropped during the course of the mission, which was carried
out at an average speed of 585 miles per hour. Cruise altitude varied from
about 22 000 feet at the beginning of the mission to 34 000 feet at the return
to home base. Weapons delivery took place at near sea-level altitude.
The data in table V show the F-104G to be significantly lighter than the other Century
Series fighters and, with its small wing, to have the highest wing loading
of the group. Maximum speed is Mach 2.0 at 35 000 feet and Mach 1.13 at sea
level. Initial rate of climb at sea level is a spectacular 48 000 feet per
minute. In May 1958, a world speed record of 1404 miles per hour was set by
an F-104, and a record zoom-climb to an altitude of 91243 feet was made.
Before ending this discussion of the Lockheed Starfighter,
some mention of its flying characteristics must be made. In many quarters,
the F-104 has the unenviable reputation of being a difficult and dangerous
aircraft to fly, an aircraft with unforgiving handling characteristics. Certainly,
it has had an appallingly poor safety record in use with some air forces but
a relatively good one in others. In fairness, the record seems to suggest
that the aircraft can be flown with reasonable safety if the pilots are properly
trained and the aircraft is maintained and flown strictly in accordance with
the manufacturer's recommendations. Apparently, however, the aircraft can
be terribly unforgiving of any departure from these recommended procedures.
An interesting discussion of the F-104 and its safety record is contained
in reference 186.
First flight of the F-104 prototype took place on February
7, 1954, and production aircraft first entered service with the USAF in January
1958. By the time the last Starfighter was built in Italy in 1978, a total
of 2536 units had been constructed in this multinational program. A final
question and observation on the somewhat controversial F-104: Why did the
aircraft receive such wide acceptance by foreign air forces while, at the
same time, it was essentially rejected by the USAF? Relatively light in weight,
the aircraft offered a very high performance at a  reasonable price. These
were no doubt important ingredients in the formula that assured its widespread
safe abroad, as was the highly aggressive and effective sales campaign mounted
by the Lockheed organization. Limited payload and range, however, restricted
the usefulness of' the F-104 in service with the USAF - an organization that
could and did pay for exactly what it wanted.
Designed from the outset as a fighter-bomber for long-range
interdiction missions, the Republic F-105 Thunderchief was a large, heavy
aircraft with Mach 2 performance. A unique feature for a fighter was the internal
bomb bay intended to house a nuclear weapon. First flight of' the Thunderchief
took place on October 22, 1955. After winning a flyoff competition with the
North American F-107 in 1956, the F-105 first entered squadron service in
1958. (As an interesting sidelight, the F-107 was the last of the Century
Series of fighters to fly and the last fighter aircraft to bear the name "North
American.") Two views of the F-105B are shown in figures 11.17 and 11.18,
and physical and performance data for the F-105D, the most numerous variant
of the aircraft, are given in table
V. The configuration incorporated a shoulder-mounted
45 sweptback wing with airfoil thickness ratios varying from 5.5 percent at
the root to 3.7 percent at the tip. Trailing-edge Fowler....
Figure 11.17 - Republic F-105B Thunderchief single-engine
jet fighter. [mfr via Martin Copp]
 Figure 11.18 -Front view
of Republic F-105B Thunderchief single-engine jet fighter.
[mfr via Martin Copp]
....flaps together with leading-edge flaps were used
to increase the maximum lift coefficient of the wing. Roll control was achieved
by shortspan outboard ailerons assisted by upper-surface spoilers. The all-moving
horizontal tail was mounted in the low position to aid in preventing pitch-up.
Careful fuselage area ruling reduced the magnitude of the drag rise as the
Mach number increased from subsonic to supersonic values. A most unusual feature
of the aircraft are the two-dimensional variable-area supersonic inlets mounted
in the wing-root position. The speed brake was an unusual petal-type arrangement
that surrounded the jet nozzle.
Already mentioned is the internal bomb bay designed
to accommodate a nuclear weapon. Not long after the F-105 became operational,
however, the concept of carrying a nuclear weapon in the aircraft was  discarded, and the bomb
bay was used to house additional fuel. A six-barrel Vulcan 20-mm rotary cannon
was carried in the aircraft, and there were provisions for 12 000 pounds of
external armament including bombs, rockets, and missiles. Such a large load
could be carried only on short-range missions, however, with a more normal
load being 6000 pounds. Combat radius for this load varied from 600 to 800
miles depending on the amount of external fuel carried. The F-105 was provided
with all the necessary electronic equipment for full all-weather capability.
Maximum Mach number of the F-105D was 2.08, or 1372
miles per hour, at an altitude of 36 090 feet; at sea level, the maximum Mach
number was 1.1, or 836 miles per hour. Normal cruising speed was 584 miles
per hour. Sea-level rate of climb was a spectacular 38 500 feet per minute;
only 1.7 minutes were required to reach an altitude of 35 000 feet. Ferry
range with no war load was 2207 miles. With a maximum gross weight of 52 838
pounds, the F-105D is by far the heaviest fighter so far considered, nearly
as heavy as the 55 000-pound, four-engine B- 17 bomber of World War II.
A total of 833 F-105 aircraft were manufactured before
production ended in 1964. Extensively used in ground-attack operations in
Vietnam, the Thunderchief continued to serve with the USAF for a number of
years following the end of the conflict. Last of the F-105's was withdrawn
from the Tactical Air Command in 1980, but a few are still in service with
the Air National Guard.
The Navy Goes Supersonic
A number of Navy fighters developed during the 1950's
were capable of flight at high-subsonic speeds, but only two production types
could pass through Mach 1.0: the Grumman FIIF Tiger and the Vought F8U Crusader.
Capable of a maximum Mach number of about 1.1, the Tiger was just barely able
to enter the supersonic flight regime. With a maximum Mach number of 1.75
at 35 000 feet and a Mach 1.0 capability at sea level, however, the Crusader
had much the higher performance of the two aircraft and is discussed in the
next few paragraphs.
Before discussing the F8U, however, a few words on the
change in the method of military aircraft designation that took place in 1962
is in order. Up until this time, the Navy designation system indicated the
purpose of the aircraft, the manufacturer, and details of the aircraft geneology.
For example, the designation F8U-1 is explained as follows:
indicates a fighter-type aircraft
is the identifying letter assigned to the
manufacturer, in this case Vought
indicates the 8th fighter-type aircraft developed
indicates the first model of the aircraft
The Navy system was useful for those who understood
it and knew the letter of the alphabet assigned to the various manufacturers.
For the uninitiated, however, the system was clumsy and obscure. Further,
when the same basic aircraft was used by both the USAF and the Navy, two distinctly
different designations were used. For example, the USAF North American F-86
Sabre became the Navy F4J Fury. Following the introduction in 1962 of a simplified
designation system for both USAF and Navy aircraft, the F8U Crusader became
simply the F-8A where the number "8" indicates the fighter type and the letter
"A" signifies the first model. The designation F-1A was assigned to the oldest
Navy fighter then in service; Air Force aircraft then in service retained
their original designations. (See refs. 171 and 200 for further discussion of designation systems.)
Three-quarter front and rear views of the Vought F-8A
Crusader are shown in figures 11.19 and 11.20, respectively, and physical
and performance characteristics are given in table
V for the F-8H version of the aircraft. Configuration
features of the F-8 include a variable-incidence,....
....35° swept wing mounted at the top of the fuselage,
an all-moving horizontal tail mounted below the extended chord plane of the
wing, and a chin inlet to feed air to the single 16600-pound-thrust Pratt
& Whitney turbojet engine. Although not evident in the figures, the fuselage
was carefully shaped in accordance with the transonic area rule.
The two-position variable incidence wing of the F-8
is a unique feature dictated by aircraft-carrier landing requirements. With
the low-aspect-ratio swept wing of the F-8A, a high angle of attack was needed
to reach the desired lift coefficient in the carrier approach and landing
maneuver. To avoid tail scrape and possible damage at touchdown, the landing-gear
configuration of the aircraft severely limited the maximum usable aircraft
pitch angle. For this reason, and to provide the pilot with improved visibility
during the approach, the required angle of attack was achieved by shifting
the wing from the low to the high incidence position while, at the same time,
maintaining the aircraft pitch angle within the desired range. Seven degrees
was the amount by which the incidence changed as the wing was shifted from
the low to the high position. In figures 11.19 and 11.20 the wing is in the
high incidence position.
 Other features of the
approximately 6-percent-thick wing included a chord extension, sometimes called
a snag or dogtooth, beginning at about the midsemispan position and extending
to the wingtip. A vortex generated at the beginning of the snag helps alleviate
pitch-up in much the same manner as a wing fence (discussed in chapter
10). High-lift devices consisted of inboard
and outboard leading-edge flaps and plain trailing-edge flaps. To further
increase the maximum lift coefficient, the capability of the trailing-edge
flap was augmented by blowing boundary-layer control using bleed air from
the engine. Small inboard ailerons were used for lateral control; these surfaces
could also be deflected symmetrically to increase lift at low speeds.
The fixed-geometry inlet seems, at first glance, to
be somewhat incongruous on an aircraft of such high performance as that of
the Crusader. The nose of the aircraft protrudes forward of the chin inlet,
however, and probably serves much the same purpose as the fixed conical bodies
employed on the inlets of the Lockheed F-104. As compared with a nose-mounted
normal-shock inlet, the chin inlet would accordingly be expected to have better
pressure recovery at the supersonic speeds achieved by the F-8.
The Crusader was the first carrier-based aircraft to
reach a speed of 1000 miles per hour. Not quite as high in maximum speed or
rate of climb as the later-model Century Series fighters, the F-8H is nevertheless
shown by the data in table
V to be a high-performance supersonic aircraft.
As a fighter, it was usually equipped with four 20-mm cannons and two or four
Sidewinder missiles. Initially, a clear-weather air-superiority fighter, the
Crusader was later modified to have limited allweather capability.
First flight of the F-8 took place on March 25, 1955;
and before production ended, 1261 Crusaders had been constructed. In addition
to the U.S. Navy, the French Navy and the Philippine Armed Forces used various
versions of the F-8. In the Vietnam conflict, the Crusader saw extensive service
in photoreconnaissance, ground-attack, and fighter-escort roles. U.S. Navy
fighter service for the Crusader ended in March 1976, but a few are still
on duty as photoreconnaissance aircraft. According to reference 177, some F-8's are still in use with French and Philippine forces.