Subject: Number 106 in the Series--Convair F-106 Delta Dart (1 of 4)

From: [email-masked]
Date: 18 Feb 94 17:13:51 GMT

>From [email-masked]

The Convair F-106A Delta Dart is regarded by many as being the finest 
all-weather interceptor ever built.  It served on active duty with the 
US Air Force for almost 28 years, much longer than most of its 
contemporaries.  

The F-106 had its origin in an early-1949 request by the USAF for an 
advanced interceptor capable of supersonic performance that would 
surpass the speed and altitude performance of new Soviet 
intercontinental bombers which intelligence services warned would soon 
be available.  The North American F-86D Sabre, the Northrop F-89 
Scorpion, and the Lockheed F-94 Starfire were all subsonic aircraft, 
and were deemed to have insufficient growth potential to be able to 
meet this new threat.  This project came to be known as the "1954 
Interceptor", after the year that new interceptor would supposedly be 
entering service.  

At that time, the Air Force recognized that the increasing complexity 
of modern weapons made it no longer practical to attempt to develop 
equipment, airframes, electronics, engines, and other components in 
isolation and to expect them to work properly when they were put 
together in the final product.  To address this problem, the Air Force 
introduced the "weapons system" concept, in which components of the 
the new interceptor would be integrated with each other from the very 
beginning, making sure that the various systems would be compatible 
with each other when they were incorporated into the final aircraft.  
The project was given the designation WS-201A, where WS stood for 
"Weapons System".  As originally conceived, WS-201A was a weapons 
system consisting of air-to-air guided missiles, all-weather search 
and fire control radar, all housed in an airframe capable of 
supersonic flight.  

The electronics package for the new WS-201A system came first.  
Project MX-1179 was the designation given to that portion of the 
project dedicated to the armament and electronic fire-control system 
of the 1954 Interceptor.  In October of 1950, the Hughes Aircraft 
Company was named the winner of the MX-1179 contract.  The Hughes 
proposal consisted of a MA-1 fire control system acting in conjunction 
with GAR-1 Falcon air-to-air guided missiles.  For a brief time, the 
Falcon missile was known as the F-98, a fighter designation.  

The airframe part of the project was designated MX-1554.  Proposals 
for the airframe portion were requested by the Air Force on June 18, 
1950.  When the bidding closed in January of 1951, nine proposals had 
been submitted by six different manufacturers.  Republic submitted 
three separate proposals, North American submitted two, and single 
proposals were made by Chance-Vought, Douglas, Lockheed, and Convair.  

On July 2, 1951, the Air Force announced that designs by Convair, 
Lockheed, and Republic had been selected to proceed with preliminary 
development.  All three companies were to proceed with their designs 
all the way to the mockup stage, with the design deemed most promising 
at that time being awarded a production contract.  Later, the USAF 
deemed it too costly to carry through with three concurrent 
development programs, and it cancelled the Lockheed project in its 
entirety.  The Convair and Republic entries were given the go-ahead to 
proceed.  

The Republic entry bore the company designation of AP-57, where the AP 
stood for "Advanced Project".  It called for an extremely advanced 
aircraft capable of achieving a Mach 4 performance at altitudes of up 
to 80,000 feet.  This was clearly a quantum leap in the state of the 
art for the early 1950s.  

The Convair entry in the MX-1554 project was closely related to the 
experimental XF-92A which Convair had built in 1948 as a test bed to 
provide data for the proposed F-92 Mach 1.5 fighter.  This work had 
been performed in consulation with Dr. Alexander Lippisch, who had 
done pioneering work in Germany on delta-winged aircraft during the 
war, and Convair had become convinced that the delta configuration 
provided a viable solution to the problems of supersonic flight.  The 
XF-92A had been the first powered delta-wined aircraft to fly, but the 
F-92 project had itself been cancelled before any prototype could be 
built.  

On September 11, 1951, Convair received a contract for its delta 
winged design which was assigned the designation F-102.  Work on the 
competing Republic design was also authorized, and that aircraft was 
assigned the designation XF-103.  However, the XF-103 was so far ahead 
of the state of the art that it was deemed too risky to be a serious 
contender for the 1954 Interceptor project, which made the F-102 for 
all practical purposes the winner of the contest.  

The Air Force authorized the fitting of a Westinghouse J40 turbojet in 
the first few examples of the F-102, but later production aircraft 
were to be powered by the appreciably more-powerful Wright J67 
turbojet, which was a license-built version of the Bristol Olympus.  
The J40-powered F-102 was to be capable of a speed of Mach 1.88 at 
56,500 feet, with the J67 production version capable of Mach 1.93 at 
62,000 feet.  

In order to expedite the development of its 1954 Interceptor program, 
the Air Force adopted the so-called "Cook-Craigie" program, named for 
its originators, Generals Laurence C. Craigie and Orval R. Cook.  
During the late 1940s, these two officers had developed a concept of 
an aircraft development program in which the usual prototype stage 
would be skipped.  Instead of waiting to start full-scale production 
until the prototypes had passed flight testing and the bugs had been 
ironed out, the Cook-Craigie plan called for the delivery of a small 
number of production aircraft during the flight testing phase so that 
any major changes could be incorporated into permanent factory tooling 
in order for combat-ready aircraft to be delivered when mass 
production started.  This program is inherently risky--it can produce 
a new combat aircraft in a hurry if everything goes according to plan 
during flight testing, but can result in a lot of costly and 
time-consuming fixes in the field if unexpected problems turn up.  The 
Cook-Cragie plan is really viable only if there is a high degree of 
confidence that the aircraft is really going to go into production.  
Since the F-102 was basically a scaled-up XF-92A, the risk was deemed 
work taking.  

By December of 1951, it was apparent that the Wright J67 engine and 
the MA-1 fire-control system would not be ready in time.  This forced 
the USAF to change its plans.  At that time, the Air Force decided to 
proceed with an interim version of its 1954 Interceptor, one which 
could be introduced into service at an early date, pending the 
availability of the fully-developed version at a later time.  The 
interim version was to be designated F-102A, with the fully-developed 
advanced version being designated F-102B.  The F-102A was to be 
powered by the less-powerful Pratt & Whitney J57 turbojet, but the 
F-102B was to retain the high-thrust J67.  The F-102A would be 
equipped with an interim fire-control system, but the F-102B would be 
equipped from the outset with the highly-sophisticated fire control 
system being developed by Hughes under project MX-1179.  

Although the F-102A was considered only as an interim version pending 
the availability of the F-102B, the F-102A ran into some unexpected 
developmental difficulties and fell behind schedule.  A lot of money 
that had originally been planned for the F-102B now had to be diverted 
into fixing the F-102A's problems.  Consequently, the F-102B fell even 
further behind schedule and began to lose some of its original high 
priority.  

By mid-1953, the MX-1179 fire control system (later to be known as the 
MA-1) was slipping badly, and it took another year before an 
experimental installation could be installed aboard a T-29B for 
testing.  At the same time, the Wright J67 engine was experiencing 
difficulties of its own.  The Air Force had to consider alternative 
powerplants, and finally settled on the Pratt & Whitney J75, which was 
an advanced version of the J57 which was used in the F-102A.  The 
substitution of the J75 engine for the J67 was approved in early 1955.  

Seventeen F-102Bs were ordered in November of 1955.  Their serials 
were 56-0451/0467.  The F-102B mockup was ready for inspection in 
December of 1955.  On April 18, 1956, the Air Force finalized the 
F-102B production contract of the previous November, earmarking all of 
the 17 aircraft ordered exclusively for testing.  One prototype was to 
be delivered in December of 1956, with the others to follow in January 
of 1957.  

On June 17, 1956, the designation of the F-102B was changed to F-106A.  
This redesignation was a recognition of the past technical differences 
that had distorted the original F-102 program and also a recognition 
that the F-102B was by now a completely different aircraft from the 
F-102A and was far more advanced.  

In September of 1956, the Air Force specified that the F-106A would be 
available by August of 1958 (some four years later than initially 
planned) and that it had to compatible with the Semi-Automatic Ground 
Environment (SAGE) up to a radius of 430 miles and as altitude of 
70,000 feet.  Interceptions would be accomplished at speeds of up to 
Mach 2 at 35,000 feet.  It was to be capable of launching air-to-air 
guided missiles and rockets under the control of the Hughes MA-1 fire 
control system.  

The wing of the F-106A was virtually identical to that of the F-102A, 
but the fuselage had a much more streamlined shape.  The variable-ramp 
air intakes were moved well aft of the nose and mounted closer to the 
engine.  The shape of the fin and rudder were changed and a new 
undercarriage was fitted with steerable twin-nosewheels.  As on the 
F-102A, the all-missile armament was housed internally in a spacious 
ventral weapons bay.  The all-missile armament consisted of a single 
Douglas MB-1 (Air-2A or 2B) Genie unguided missile equipped with a 
nuclear warhead plus four Hughes GAR-3 radar- homing or GAR-4 
infrared-homing (later redesignated AIM-4E and AIM-4G respectively) 
air-to-air missiles.  The Falcons were equipped with conventional 
high-explosive warheads and could be launched in salvo or in pairs.  
The unguided 2.75-inch missile armament of the F-102A was omitted.  

The first F-106A (56-0451) was finally available by the end of 1956.  
The first flight was made by Richard L. Johnson at Edwards AFB on 
December 26, 1956.  The second aircraft (56-0452) followed on February 
26, 1957.  They were both powered by the J75-P-9 engine.  Early 
testing reached a speed of Mach 1.9 and an altitude of 57,000 feet, 
but this was still below expectations.  In addition, the F-106A's 
acceleration was well below Convair's estimates, and it took almost 4 
1/2 minutes to accelerate from Mach 1 to Mach 1.7 and another 2 1/2 
minutes to accelerate to Mach 1.8.  With such poor acceleration, it 
was felt that Mach numbers above 1.7 would not be tactically usable.  

The poor speed and acceleration was cured by altering the aircraft's 
air intake cowling and charging ejectors.  The capture area of the 
intake ducts was enlarged and the duct lips were thinned down.  There 
were also problems with the reliability of the J75-P-9 engine.  
Eventually, the more powerful J75-P-17 engine was substituted, which 
was rated at 17,200 lb.s.t. dry and 24,500 lb.s.t. with afterburner.  
There were further problems with the MA-1 fire control system and with 
the cockpit layout.  Originally, the control column had occupied the 
traditional center location, but was later moved to the side at USAF 
insistence in order to ensure an unrestricted view of the Horizontal 
Situation Indicator.  This arrangement turned out not to be viable, 
and the control column was later moved back to the center and provided 
with a two-handed grip for both radar and aircraft control.  

Initial aircraft had boundary layer fences as on the F-102, but 
production aircraft had wing leading-edge slots instead.  The first 
twelve aircraft were temporarily designated JF-106A for flight tests, 
but a total of thirty-seven (including the first two aircraft) were 
used for flight test development.  

In mid-1957, the F-106A was given the popular name Delta Dart.  

Originally, the Air Force had planned to acquire 1000 Delta Darts to 
equip some forty Air Defense Command (ADC) squadrons.  However, by 
1957 the delays in the F-106 program and the problems with the engine 
and the fire control system had resulted in the necessity of other 
interceptors such as the McDonnell F-101B Voodoo having been ordered 
as a stop-gap measure, and the F-106 had lost some of its urgent 
priority.  For a while, serious consideration was given to cancelling 
the entire F-106 program, or else to redesigning the aircraft as a 
long-range interceptor.  Although the F-106 survived intact, shortages 
of funds caused a drastic cutback in the number of F-106As on order.  
By September 1958 the total order of F-106 interceptors had been cut 
by a factor of three, enabling only fourteen squadrons and a training 
unit to be equipped.  As a result, only a further 260 F-106As were 
ordered.  Since the cutback was so drastic, a decision mas made in 
August of 1959 to convert all of the existing 35 F-106A test aircraft 
to operational status (Model 8-24 standards) and turn them over to the 
interceptor squadrons.  

In September of 1958, an early F-106A (serial number 57-0235) was 
allocated to Ames Research Center at Moffett Field in California for 
tests of the MA-1 fire control system.  

The first deliveries of the F-106A were made in May of 1959, initially 
equipping the 498th Fighter Interceptor Squadron based at Geiger AFB 
in Washington.  This was no less than five years later than originally 
planned.  Even then, numerous problems kept the Delta Dart from being 
declared fully operational until October 31, 1959.  The remaining 13 
squadrons were re-equipped with the F-106A by the end of 1960.  

Initial operational deployment turned up all sorts of 
problems--generator defects, fuel-flow deficiencies (particularly 
acute in cold weather), and fuel-combustion-starter malfunctions.  In 
December of 1959, after a canopy had been accidentally jettisoned in 
flight, all F-106s were temporarily grounded until the problem could 
be fixed.  

Production continued until December of 1960, the last aircraft off the 
line being delivered as Model 8-31s.  which were equipped with 
improved MA-1 fire control systems, supersonic ejector seats, vertical 
instrument displays, wings with revised camber (first tested on 
57-0246), and with provision for 230 US-gallon external fuel tanks 
mounted on pylons underneath the wings.  The last 37 F-106A production 
aircraft were provided with a better supersonic ejector seat that 
would also work safely at low speeds.  This new seat featured a dual 
timing system one for low-altitude/low-speed ejection and one for 
high-altitude/high-speed ejection.  

Flight testing continued until early 1961, with each phase of the test 
program turning up a whole host of problems which required important 
engineering changes.  Each change had to be defined, engineered, 
reviewed, and approved for production before modification of aircraft 
off the assembly line could begin.  The Cook-Cragie production policy 
only made problems worse, and by 1960, the Air Defense Command had so 
many different F-106 configurations out in the field that maintenance 
support was a nightmare.  

A major modification project named *Wild Goose* was initiated in 
September of 1960 to bring the earlier F-106s up to the latest 
production standard.  Early in 1960, ADC could list 63 changes in the 
F-106A's fire control system and 67 changes in the airframe that would 
be required to make early F-106s equivalent to the machines currently 
coming off the production line.  Lasting a full year, the program 
involved roving AMC field assistance teams supported by ADC 
maintenance teams working at ADC bases.  

The last Delta Dart was delivered to the Air Force on July 20, 1961.  

On December 15, 1959, a Delta Dart flown by Major Joseph W.  Rogers 
set a world's absolute speed record of 1515.6 mph at 40,500 feet.  

Throughout its long service life, the F-106A was continually upgraded 
and improved.  The *Broad Jump* modification program started in late 
1960 was a long-term program for general improvements in the F-106A.  
This program was carried out by people at the Sacramento Air Material 
Area, and it extended through early 1963.  Among the changes 
introduced by this program was the fitting of an infrared 
search-and-track sight that could operate at low altitudes and against 
varied backgrounds.  The *Dart Board* program was another retrofit and 
modification program which took place in 1961-62.  This program added 
a thermal flash blindness protection hood and a new Convair-designed 
ejector seat which rotated into a horizontal position so that the 
pilot was on his back before he ejected.  In addition, the *Dart 
Board* program finally fixed a problem with flame-outs from fuel 
starvation which had affected earlier Delta Darts.  

The MA-1 fire control system carried by the F-106A was initially quite 
unreliable and was subjected to lots of in-service modifications in an 
attempt to fix its chronic problems.  In 1960, devices for long-range 
detection and electronic counter-countermeasures equipment were added, 
along with the capability for using angle chaff, silent lobing, and 
pulse-to-pulse frequency techniques.  Anti-chaff devices were added in 
an effort to defeat enemy attempts to confuse the fire control system 
by dropping bits of radar-reflective strips.  The modification 
programs involved 314 F-106As and were completed by the end of 1963.  

In 1962, F-106As were fitted with a Sheaffer Spring Hook arrester 
system designed to engage wires at the end of the runway in the event 
of an landing overshoot, becoming the first USAF combat aircraft to be 
so equipped.  The F-106A was definitely NEVER intended for carrier- 
based operations! :-) 

In 1965, an new TACAN system was installed which used microelectronic 
circuits and was one-third the size and weight of the existing system.  
Zero-zero ejector seats were installed.  Inflight refuelling 
capability via a probe receptacle mounted on the fuselage behind the 
pilot was added in 1967.  The ability to carry 360 US-gallon 
supersonic fuel tanks was added at the same time.  In 1972, a clear 
canopy was fitted for improved vision.  

The F-106A operated in conjunction with the SAGE (Semi-Automatic 
Ground Environment) network which was linked via the Hughes MA-1 
fire-control system to the F-106.  The MA-1 system was upgraded no 
less than 60 times during the Delta Dart's long service life.  It 
operated by plotting the course needed to intercept an enemy aircraft, 
automatically sighted the target, fired the air-to-air missiles, and 
then automatically placed the F-106 on the correct course to 
disengage.  The F-106 could actually be fully computer-flown during 
most of its mission, the pilot actually being needed only for takeoff, 
landing, or in case something went wrong with the automation.  

The F-106A surprised everyone by having a good maneuverability and 
showing potential as being an excellent dogfighter.  Consequently, an 
internal 20-mm M61A1 rotary cannon was fitted internally to some 
aircraft under the aegis of project *Sharp Shooter*.  The cannon 
replaced the Genie nuclear-tipped missiles in the weapons bay.  
However, this innovation was not provided for the F-106B two-seater.  

The F-106 served mainly in the continental United States, in Alaska, 
Iceland, and in Canada, but it did serve for short spells in Germany 
and South Korea.  Although the F-106 was briefly deployed to Osan AFB 
in Korea in March of 1968 to provide air defense during the *Pueblo* 
incident, the Delta Dart never saw combat.  

>From 1972 onwards, the McDonnell Douglas F-15 Eagle gradually began to 
replace the Delta Dart in ADC squadrons.  As they were removed from 
Air Force service, they were passed along to the Air National Guard, 
serving with ANG squadrons in California, Florida, Massachusetts, 
Michigan, Montana, and New Jersey.  The last Delta Dart-equipped Air 
Force squadron, the 119th FIS based at Atlantic City, New Jersey flew 
its final alert duty on July 7, 1988.  The ANG units continued to fly 
the last few Delta Darts for a few months longer after the USAF had 
relinquished the type.  

In March of 1982, F-106A serial number 59-0123 was transferred to 
NASA's Langley Memorial Aeronautical Laboratory to serve as a spare 
for NASA's NF-106B #816 (ex-USAF serial number 57-2516).  

During its long service life, the F-106A had the distinction of 
recording the lowest single-engined aircraft accident record in USAF 
history.  

As F-106As were withdrawn from active duty, they were ferried out to 
Davis-Monthan AFB in Arizona where they were placed in storage.  
In 1986, a contract was awarded to Flight Systems Inc. to modify 192 
surplus Delta Darts stored at Davis-Monthan AFB in Arizona to QF-106A 
target drone configuration.  This program came to be known as *Pacer 
Six*, and the first flight of a converted drone took place in July of 
1987.  Most of these drones were expended at Tyndall and Holloman AFB 
from the year 1989 onward.  

Serials of the F-106A:

56-451/467		Convair F-106A Delta Dart
57-229/246		Convair F-106A-CO Delta Dart
57-2453/2455		Convair F-106A-64-CO Delta Dart
57-2456/2460		Convair F-106A-70-CO Delta Dart
57-2461/2465		Convair F-106A-75-CO Delta Dart
57-2466/2477		Convair F-106A-80-CO Delta Dart
57-2478/2485		Convair F-106A-85-CO Delta Dart
57-2486/2506		Convair F-106A-90-CO Delta Dart
58-759/771		Convair F-106A-95-CO Delta Dart
58-772/798		Convair F-106A-100-CO Delta Dart
58-799/899		Cancelled contract (believed for F-106)
59-001/030		Convair F-106A-105-CO Delta Dart
59-031/059		Convair F-106A-110-CO Delta Dart
59-060/086		Convair F-106A-120-CO Delta Dart
59-087/111		Convair F-106A-125-CO Delta Dart
59-112/135		Convair F-106A-130-CO Delta Dart
59-136/148		Convair F-106A-135-CO Delta Dart

Specification of F-106A: 

One Pratt & Whitney J75-P-17 turbojet, 17,200 lb.s.t. dry and 24,500 
lb.s.t with afterburning.  Maximum speed: 1525 mph at 40,000 feet 
(Mach 2.31), 1327 mph at 35,000 feet.  Landing speed was 173 mph 
Initial climb rate was 42,800 feet per minute.  Service ceiling was 
57,000 feet.  Combat radius was 575 miles.  Maximum range with maximum 
external fuel was 1809 miles.  Maximum ferry range was 2700 miles at
610 mph at 41,000 feet.  Weights were 23,646 pounds empty, 
38,700 pounds combat weight, 35,500 pounds gross, and 41,831 pounds 
maximum takeoff.  Dimensions: wingspan 38 feet 3 1/2 inches, length 70 
feet 8 3/4 inches, height 20 feet 3 1/4 inches, wing area 697.8 square 
feet.  Maximum fuel load was 1440 US gallons.  Armament consisted of 
one Douglas MB-1 (AIR-2A or 2B) Genie unguided missile with a nuclear 
warhead and four Hughes GAR-3 or GAR-4 (later redesignated AIM-4E and 
AIM-4G respectively) radar or infrared-homing missiles.  All these 
missiles were housed within the internal weapons bay.  In later 
installations, a single 20-mm M61A1 rotary cannon replaced the Genie 
nuclear-tipped missile in the internal weapons bay.  

Sources:

  The Illustrated Encyclopedia of Aircraft Armament, Bill Gunston,   
  Orion, 1988.

  United States Military Aircraft Since 1909, Gordon Swanborough and
  Peter M. Bowers, Smithsonian, 1989.

  The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.

  Fighters of the United States Air Force, Robert F. Dorr and
  David Donald, Temple Press Aerospace, 1990.

  American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday,
  1982.

  Post-World War II Fighters, 1945-1973, Marcelle Size Knaack,
  Office of Air Force History, 1986. 

  The World Guide to Combat Planes, William Green, MacDonald, London, 1966

  The World's Fighting Planes, William Green, Doubleday, 1964.

  The Aircraft of the World, William Green and Gerald Pollinger, Doubleday,
  1965.

  General Dynamics Aircraft and their Predecessors, John Wegg, Naval
  Institute Press, Naval Institute Press, 1990.

Joe Baugher		AT&T Bell Laboratories   	
2000 North Naperville Road      Naperville, Illinois 60566-7033