Subject: Number 105 in the Series--Republic F-105 Thunderchief (2 of 9)

From: [email-masked]
Date: 2 Feb 94 21:42:25 GMT

>From [email-masked]

The F-105B was the initial production version of the Thunderchief.  It 
was designed to take full advantage of the new Pratt and Whitney J75 
turbojet, and had a fuselage that was reconfigured according to the 
Area Rule devised by Richard Whitcomb.  It also differed from the 
YF-105A prototypes by having air intake ducts with swept-forward outer 
lips.  These were designed to take in air at high speeds without 
choking the engine with supersonic shock waves.  The area of the 
vertical fin was increased and made taller.  A ram-air intake was 
fitted to the base of the vertical fin, capturing air for the cooling 
of the aft end of the aircraft.  

The distinctive swept-forward air intakes became the signature
of the F-105.  A boundary layer fence was located in front of each
intake next to the fuselage.  There was a variable plug inside each
duct which could be moved forwards or backwards to provide proper
airflow to the engine as a function of Mach number.  A set of
auxiliary air inlets were provided that could be opened automatically
whenever negative pressure existed in the ducts to provide needed
airflow at low speeds.  These air inlets could be opened only when 
the landing gear was extended, an interlock keeping the doors fully
closed whenever the landing gear was retracted.  Just in front of
the engine compressor stage there were a set of bleed doors in the
intake ducting that could dump any excess airflow which would tend 
to force the shock wave out of the duct throat.

Four YF-105B service test prototypes were built (serials were 
54-0100/0103).  They were powered by the YJ75-P-3 turbojet, rated at 
16,470 lb.s.t.  dry and 23,500 lb.s.t.  with afterburning.  The first 
YF-105B (54-0100) flew on May 26, 1956, It flew for one hour but was 
damaged on landing.  It had to be returned to the factory for repairs.  
The maximum speed reached during tests was Mach 2.15, which was 
remarkable considering the weight of the plane.  

Further slippages and excessive costs generated numerous changes in 
USAF procurement planning.  In March of 1956, the Air Force released 
funds for the acquisition of 65 F-105Bs and 17 RF-105Bs.  The RF-105B 
was a photographic reconnaissance version of the F-105B fighter 
bomber.  In June, five two-seat F-105Cs were added to the program.  

The first production F-105B (54-0104) took off on its maiden flight on 
May 14, 1957, Henry G. Beaird Jr.  being at the controls.  

The F-105B was equipped with the MA-8 fire control system, which
consisted of an E-50 sighting system operating in conjunction with an
E-34 radar ranging gunsight mounted in the extreme nose and an E-30     
bomb toss computer.

The roomy fuselage had a capacious bomb bay in the belly.  It was 
originally intended to carry a nuclear weapon, since the original role 
of the Thunderchief was tactical nuclear strike.  Later, as the use of 
nuclear weapons in warfare became less likely, the internal weapons 
bay was redesigned so that it could carry an additional fuel tank or 
other types of conventional weaponry.  Conventional weapons could also 
be carried on four underwing hardpoints and on one ventral hardpoint 
underneath the fuselage.  

The fuel was carried in seven separate fuel tanks lined up along
the upper rear fuselage behind the pilot.  Total internal fuel capacity
ws 1160 US gallons, of which 25 gallons of useful fuel is located in
the fuel lines.  Two 450-gallon drop tanks could be carried under the
inboard underwing pylons, and an additional 450 or 650-gallon drop tank
could be carried on a hardpoint underneath the fuselage.  In addition,
the bomb bay could accommodate a 390 gallon fuel tank in place of the
"special store".  Total fuel load (internal plus external) could be as
high as 3100 US gallons. 

A retractable probe-and-drogue type of midair refuelling probe was 
mounted on the left side of the fuselage nose just ahead of the
pilot's cockpit.

Petal-type airbrakes were mounted on the rearmost section of the tail, 
at the end of the afterburner exhaust pipe.  These tailpipe airbrakes 
were in four sections, and opened out to a maximum angle of 90 
degrees.  

On December 11, 1959, an F-105B piloted by Brig. Gen. Joseph Moore 
set a world speed record of 1216.48 mph over a 100-kilometer closed 
course at Edwards AFB.  

Production F-105Bs began to roll off the line at Farmingdale in 1958, 
and the Air Force officially accepted its first machine on May 27, 
1958.  The first unit to receive the F-105B was the 335th Tactical 
Fighter Squadron of the 4th Tactical Fighter Wing of the TAC.  This 
outfit was first based at Elgin AFB, then later at Semour-Johnson AFB.  
The 335th began to work up with the F-105B in 1958, and in January of 
1959 the unit was declared operational with the type.  However, 
because of maintenance difficulties and production slippages the 335th 
did not become fully operational with the F-105B until 1960.  There 
were significant problems with the autopilot, the central air data
computer, and the MA-8 fire control system.  In addition, there was
an acute shortage of spare parts which kept many aircraft from flying.
Nevertheless, the F-105B did manage to complete its first year of 
service without a single major accident, becoming the first aircraft 
in USAF service history to be so fortunate.

The other two squadrons of the 4th Tactical Fighter Wing (the 334th 
and 336th) received F-105Bs by the end of 1960.  These squadrons were 
destined to be the only operators of the F-105B.  Problems with 
maintenance and serviceability continued through 1961, and the F-105B
required about 150 maintenance hours for each hour spent in the air. 

Despite the aircraft's large size and weight, in May of 1963 the 
F-105B was selected to replace the F-100C Super Sabres of the 
*Thunderbirds* flight demonstration team.  The last of nine specially 
modified F-105Bs was delivered on April 16, 1964, ten days before the 
first scheduled public performance with the new planes.  A serious 
accident, as well as the modifications directed as a result of that 
accident, prevented the *Thunderbirds* from using these planes for 
all but a very few public airshows.  Because of its heavy schedule,
the *Thunderbirds* team was hastily re-equipped with eight F-100D
Super Sabres.  The F-100Ds remained with the *Thunderbirds* until 
1969, when the team re-equipped with F-4Es.  Only a very few public
displays were actually performed with the F-105B.

The first F-105B production blocks were initially powered by
the J75-P-5 engine, but the F-105B-20-RE block was given the 
J75-P-19 engine with an additional thousand pounds of thrust.  
Subsequently, this engine was retrofitted to earlier production block
aircraft.

The F-105B's service with the USAF was relatively brief, being 
superseded by the all-weather F-105D version beginning in 1964.  The 
USAF F-105Bs were then transferred to the Air National Guard.  The 
first surplus F-105Bs reached the 180th Squadron of the ANG on April 
16, 1964.  Another ANG squadrons reequipped with the type later that 
year.  The New Jersey ANG retained a few F-105Bs until 1981, when
they were finally sent off to the boneyards. 

Although the Air Force disposed of most of its F-105Bs during 
1964-65, they retained a few F-105Bs for training purposes at 
McConnell AFB in Kansas until late 1969.  A few F-105Bs served with
the 508th Tactical Fighter Group of the Air Force Reserve at Hill AFB
in Utah, the last examples finally going off to the boneyards in
1981.

Specification of F-105B: 

One Pratt & Whitney J75-P-3/P-5 turbojet, rated at 17,200 lb.s.t. dry 
and 23,500 lb.s.t. with afterburner.   Later, most examples were 
equipped with the J75-P-19 turbojet rated at 24,500 lb.s.t. with
afterburner.  Maximum speed: 1376 mph at 36,000 feet, 864 mph at
sea level.  Stalling speed was 204 mph.  
Initial climb rate was 36,000 feet per minute.  Service ceiling was 
32,750 feet and combat ceiling was 48,100 feet.  Combat range was 744 
miles and maximum range with full external fuel was 2228 miles.  
Internal fuel capacity was 1160 US gallons internal fuel.  Additional
external fuel could be carried in drop tanks mounted underneath 
inboard underwing pylons and on a pylon mounted underneath the  
fuselage.  In addition, the bomb bay could accommodate a 390-gallon
fuel tank in place of an offensive load.  Maximum fuel load
(internal plus external) was 3100 US gallons.
Dimensions: wingspan 34 feet 11 inches, length 63 feet 1 inches, 
height 19 feet 8 inches, wing area 385 square feet.  Weights: 25,855 
pounds empty, 34,870 pounds combat, 46,998 pounds maximum takeoff.  
Armed with one 20-mm M61 rotary cannon equipped with 1075 rounds.  
Up to 8000 pounds of ordinance could be carried in the internal 
weapons bay, on four underwing pylons, or underneath the fuselage
centerline.

Serials of F-105B:

54-100/103		Republic F-105B-1-RE Thunderchief
54-104			Republic F-105B-5-RE Thunderchief
54-105			Republic JF-105B-1-RE Thunderchief
54-106/107		Republic F-105B-5-RE Thunderchief
54-108			Republic JF-105B-1-RE Thunderchief
54-109/110		Republic F-105B-5-RE Thunderchief
54-111			Republic F-105B-6-RE Thunderchief
54-112			Republic JF-105B-2-RE Thunderchief
57-5776/5784		Republic F-105B-10-RE Thunderchief
57-5785/5802		Republic F-105B-15-RE Thunderchief
57-5803/5840		Republic F-105B-20-RE Thunderchief
57-5841/5845		Cancelled contract (believed for F-105B)

Sources:

  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.

  The Thunder Factory, Joshua Stoff, Motorbooks, 1990.

  F-105 Thunderchief in Detail and Scale, Bert Kinzey, Kalmbach Books,
  1993.

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