Subject: New Fighter Series--McDonnell Douglas F-15 Eagle (8 of 26)

From: [email-masked] (Joe Baugher)
Date: Fri, 3 Feb 1995 15:12:17 GMT

The F-15C was the next major single-seat version of the Eagle.  
Externally, it was virtually identical to the F-15A which preceded it, 
but internally there were a number of significant differences that 
made it a much more capable fighter aircraft.  

The only external difference between the F-15A and the F-15C was the 
introduction on the F-15C of the capability of carrying FAST (Fuel And 
Sensor Tactical) packs attached to the side of the fuselage outside of 
each air intake.  The tanks conform to the aerodynamic shape of the 
side of the fuselage, and when they are installed, there is very 
little adverse aerodynamic effect and very little degradation in 
performance.  When the FAST packs are removed, the F-15C is externally 
indistinguishable from the F-15A, and the two variants can be 
distinguished only by a knowledge of their serial numbers.  However, 
on the F-15C, the FAST packs are only very rarely actually taken off 
the aircraft.  The FAST packs are now referred to as Conformal Fuel 
Tanks (CFTs). 

Each FAST pack can carry an additional 849 US gallon of fuel.  
Alternatively, sensors such as reconnaissance cameras, infrared 
equipment, radar warning receivers and jammers, laser designation, and 
low-light TV cameras can be carried in place of some of the fuel in 
these packs.  The FAST packs were first tested on an F-15B on July 27, 
1974.  They can be installed or removed in 15 minutes on the ground.  

Even when the FAST packs are installed on the sides of the aircraft, 
the F-15C still retains the capability of carrying Sparrow or AMRAAM 
missiles on the lower corners of the fuselage.  When the FAST packs 
are fitted, the four Sparrow missiles are mounted on their corners, 
and bombs or air-to-surface missiles weighing up to 4400 pounds can be 
carried as an alternative.  

Although the FAST packs alone carry slightly less fuel than the normal 
three external fuel tanks, they permit the aircraft to be flown at 
considerably higher speeds.  Maximum ferry range with the increased 
internal fuel capacity, the FAST packs, and three external drop tanks 
is 3450 miles.  

Internally, the F-15C differs from the F-15A in having additional wing 
leading and trailing edge tanks, and additional tanks in the central 
fuselage, bringing total internal fuel capacity to 2070 US gallons 
(not counting the fuel in the FAST packs).  The additional weight of 
fuel raised the gross weight of the F-15C to over 68,000 pounds.  
Consequently, tires, wheels, and brakes had to be strengthened to cope 
with this increased weight.  

As compared to the F-15A, significant improvements were made to the 
electronics suite of the F-15C.  The APG-63 radar of the F-15C was 
equipped with a Programmable Signal Processor (PSP) which is a 
high-speed, special-purpose computer which controls the radar modes 
through software rather than through a hard-wired circuit.  This 
allows much more rapid switching of the radar between different modes 
for maximum operational flexibility.  The use of the PSP also paved 
the way for the modification of the APG-63 to make it capable of 
carrying out radar mapping in a synthetic aperture mode.  Previously, 
such imagery had to be processed after the mission was over on the 
ground by large, high-speed computers because airborne equipment was 
too slow to produce images in real time.  SAR imagery sharpens mapping 
details and provides an overhead view of the target to the pilot as if 
he were flying directly over the target, even though he may be as much 
as a hundred miles away.  

The first F-15C (78-0468) took of on its maiden flight on February 26, 
1979.  It was later used for trials with tangential carriage of bombs 
on the conformal tanks.  

Some F-15Cs have provision for carrying up to 18 cluster bombs or six 
Mk 82 bombs, with the capability of releasing these weapons at supersonic 
speeds.  

Under the Multi-Stage Improvement Program (MSIP), upgrades were 
progressively incorporated onto the F-15C production line and then 
retrofitted to earlier production F-15Cs.  One of these improvements 
involved a significant improvement of the capabilities of the APG-63 
radar fire control system.  The memory capability of the APG-63 radar 
fire control system was increased from 96K to 1000K and the processing 
speed was trebled.  A Programmable Armament Control Set (PACS) was 
installed.  The Electronic Warfare Warning Set (EWWS) was modified 
into the more capable Tactical Electronic Warfare System (TEWS) 
equipped with an upgraded ALR-56C radar warning receiver and an 
ALQ-135 electronic countermeasures set.  An overload warning system 
was provided to prevent pilots from accidentally exceeding 9g during 
combat maneuvering.  The aircraft were fitted with the wiring needed 
to give them the capability of carrying and launching the AIM-120 
AMRAAM missile, which was introduced into service on the F-15C in the 
early 1990s.  Another part of the MSIP was the *Seek Talk* program, 
which was designed to reduce the vulnerability of the UHF radios to 
enemy jamming by introducing spread spectrum techniques and the use of 
a null steering antenna.  Yet another was the Joint Tactical 
Information Distribution System (JTIDS), which is intended to provide 
a high-capacity, reliable, and jam-proof information link between 
various elements of deployed forces and command and control centers.  
Included with this program is the integration of the F-15 with the 
Global Positioning Satellite (GPS).  

Later upgrades took place under the aegis of MSIP II.  MSIP II 
involved the development of a new radar, the Hughes AN/APG-70.  In 
this unit, the radar data processor memory was increased from 16K to 
24K, and its processing speed was increased by a factor of three.  The 
new unit has multiple bandwidths for high-resolution ground mapping 
using Synthetic Aperture Radar (SAR) technology.  The first aircraft 
to go through MSIP II was F-15C 84-0001, first flown on June 20, 1985.  

Most F-15Cs were delivered with Pratt & Whitney F100-PW-100 turbofans, 
but were later re-engined with more reliable but slightly lower rated 
(maximum afterburning thrust reduced from 23,830 to 23,450 pounds) 
F100-PW-220 engines.  This engine was first tested on F-15A 71-0287.  
The -220 engine introduced single-crystal turbine airfoils, an 
advanced multi-zone augmentor, an increased airflow fan and a digital 
electronic engine control system.  The new engine was introduced on 
the production line in November of 1985, and operational introduction 
took place in the spring of 1986.  For the first time, F-15 pilots 
could confidently slam both throttles from Mil to Max AB and four 
seconds later get full thrust from each engine without having to worry 
about about the dangers of engine stagnations.  

The improved F-15C/D began to be delivered to the USAF in the early 
1980s.  First to get the F-15C/D was the 32nd Tactical Fighter 
Squadron based at Soesterberg in the Netherlands, replacing the unit's 
earlier F-15A/Bs.  These more potent Eagles then were issued to the 
18th TFW at Kadena AB in Okinawa (marking the first Pacific deployment 
of the Eagle), and the 57th FIS at Keflavik in Iceland, and with a 
second squadron in the Alaskan Air command (the 54th TFS).  With the 
exception of the 49th TFW, the F-15C/D replaced the F-15A/Bs in 
service with all of the USAF units that had previously been operating 
the Eagle.  A total of 408 F-15Cs and 62 F-15Ds were delivered to the 
USAF.  Many of the F-15A/Bs replaced by the more advanced Eagles were 
passed along to Air National Guard units.  

Under the Multi-Stage Improvement Program (MSIP), upgrades were 
progressively incorporated onto the F-16C/D production line and then 
retrofitted to earlier production F-15Cs.  The MSIP is a joint program 
carried out by McDonnell Douglas and the Warner Robins Logistics 
Center in Georgia.  F-15A, B, C, and D versions are planned to go 
through the program.  The APG-63 radar will be replaced by the more 
capable APG-70 radar installed on the later F-15C/D, and improved 
avionics will be fitted.  The analog computers of the F-15A/B will be 
replaced by digital computers, and the digital computers of the 
F-15C/D will be replaced by more advanced digital computers.  The 
weapons panel will be improved, and a cathode ray terminal similar to 
that found on the F-15E.  The F-15C/D will be fitted with chaff/flare 
dispensers behind the nosewheel door.  The A models that go through 
the MSIP will not be fitted with the conformal fuel tanks of the C, 
but they will be otherwise indistinguishable.  However, some of the 
very early As (from FY 1973, 1974, and 1975) will not be upgraded 
under MSIP but will rather be retired and made available as gate 
guards or donated to museums.  Some of them will be given to Israel as 
payment for policy decisions made during the Gulf War.  

Serials of F-15C:

78-0468/0495		McDonnell Douglas F-15C-21-MC Eagle
78-0496/0522		McDonnell Douglas F-15C-22-MC Eagle
78-0523/0550		McDonnell Douglas F-15C-23-MC Eagle
78-0551/0560		cancelled contract for McDonnell Douglas F-15C Eagle.
79-0015/0037		McDonnell Douglas F-15C-24-MC Eagle
				0015,0017/0019,0023,0024,0028,
				0031/0033 transferred to Saudi Arabia
79-0038/0058		McDonnell Douglas F-15C-25-MC Eagle
				0038,0039,0043,0045,0051,0052,0055 
				transferred to Saudi Arabia
79-0059/0081		McDonnell Douglas F-15C-26-MC Eagle
				0060,0062,0063 transferred to Saudi
				Arabia
80-0002/0023		McDonnell Douglas F-15C-27-MC Eagle
80-0024/0038		McDonnell Douglas F-15C-28-MC Eagle
80-0039/0053		McDonnell Douglas F-15C-29-MC Eagle
80-0062/0067		McDonnell Douglas F-15C-28-MC Eagle 
				for Saudi Arabia, Peace Sun
80-0068/0074		McDonnell Douglas F-15C-29-MC Eagle 
				for Saudi Arabia, Peace Sun
80-0075/0085		McDonnell Douglas F-15C-30-MC Eagle 
				for Saudi Arabia, Peace Sun
80-0086/0099		McDonnell Douglas F-15C-31-MC Eagle 
				for Saudi Arabia, Peace Sun
80-0100/0106		McDonnell Douglas F-15C-32-MC Eagle 
				for Saudi Arabia, Peace Sun
80-0122/0124		McDonnell Douglas F-15C-27-MC Eagle 
				for Israel, Peace Fox III
80-0125/0127		McDonnell Douglas F-15C-28-MC Eagle 
				for Israel, Peace Fox III
80-0128/0130		McDonnell Douglas F-15C-29-MC Eagle 
				for Israel, Peace Fox III
81-0002 		McDonnell Douglas F-15C-32-MC Eagle - for RSAF
81-0020/0031		McDonnell Douglas F-15C-30-MC Eagle
81-0032/0040		McDonnell Douglas F-15C-31-MC Eagle
81-0041/0056 		McDonnell Douglas F-15C-32-MC Eagle
81-0057/0060		cancelled contract for McDonnell Douglas F-15C  
82-0008/0022		McDonnell Douglas F-15C-33-MC Eagle
82-0023/0038		McDonnell Douglas F-15C-34-MC Eagle
83-0010/0034		McDonnell Douglas F-15C-35-MC Eagle
83-0035/0043		McDonnell Douglas F-15C-36-MC Eagle
83-0044/0045		cancelled contract for McDonnell Douglas F-15C Eagle 
83-0054/0055		McDonnell Douglas F-15C-35-MC Eagle 
				for Israel, Peace Fox III
83-0056/0062		McDonnell Douglas F-15C-36-MC Eagle 
				for Israel, Peace Fox III
84-0001/0015		McDonnell Douglas F-15C-37-MC Eagle
84-0016/0031		McDonnell Douglas F-15C-38-MC Eagle
84-0032/0041		McDonnell Douglas F-15C Eagle - cancelled
				contract
85-0093/0107		McDonnell Douglas F-15C-39-MC Eagle
				0102 credited with 3 kills in Gulf War
85-0108/0128		McDonnell Douglas F-15C-40-MC Eagle
85-0132/0134		McDonnell Douglas F-15C-40-MC Eagle
86-0143/0162		McDonnell Douglas F-15C-41-MC Eagle
86-0163/0180		McDonnell Douglas F-15C-42-MC Eagle

Specification of McDonnell Douglas F-15C Eagle:  

Two Pratt & Whitney F100-PW-220 axial-flow turbofans, each rated at 
12,420 pounds dry, 14,670 pounds at full military power, and 23,830 
pounds with afterburning..  
Maximum speed:  1650 mph (Mach 2.5) at 36,000 feet, 915 mph at sea 
level.  Cruising speed 570 mph.  Initial climb rate 40,000 feet per 
minute.  Service ceiling 65,000 feet.  Maximum unrefuelled range 3450 
miles.  
Dimensions:  wingspan 42 feet 9 1/2 inches, length 63 feet 9 inches, 
height 18 feet 5 1/2 inches, wing area 608 square feet.  
Weights:  27,000 pounds empty, 40,000 pounds combat, 41,500 pounds 
gross, 66,000 pounds maximum takeoff.  
Fuel:  Maximum internal fuel 1790 US gallons.  Three 610-gallon drop 
tanks can be carried, one on the fuselage centerline and one on each 
of the underwing pylons, bringing total fuel capacity to 3620 US 
gallons.  
Armament:  One 20-mm General Electric M61A1 Vulcan cannon n the 
starboard wing root with 940 rounds.  Provision for four AIM-7F/M 
Sparrow or four AIM-120 AMRAAM missiles on hardpoints attached to the 
lower outer edges of the air intake trunks, two on each side.  Four 
AIM-9 Sidewinders infrared-homing missiles are carried on the 
underwing pylons, two on each side.  

Sources:

   McDonnell Douglas Aircraft Since 1920, volume II, Rene J.
   Francillon, Naval Institute Press, 1990.

   Combat Aircraft F-15, Michael J. Gething and Paul Crickmore,
   Crescent Books, 1992.
   
   The American Fighter, Enzo Angelucci and Peter Bowers, 
   Orion, 1987.

   The World's Great Interceptor Aircraft, Gallery Books, 1989. 

   F-15 Eagle, Robert F. Dorr, World Airpower Journal, Volume 9,
   Summer 1992.

Joe Baugher			  **************************************
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