Lockheed's NATF larger and heavier than YF-22. (Navy Advanced Tactical Fighter)
Source: Defense Daily
Publication Date: 30-JAN-91
The Lockheed/Boeing/General Dynamics Navy Advanced Tactical Fighter NATF) will have essentially
the same guts as the Air Force ATF, but, because the NATF will be carrier based and required to
carry more fuel, it will be a larger aircraft and have a heavier airframe than the Air Force derivative,
Lockbeed Vice President and ATF General Manager James "Mickey" Blackwell said yesterday.
The NATF will carry virtually all the avionics that will be used in the ATF, but will also have avionics
particular to carrier-based aircraft, Blackwell said. The NATF airframe will be considerably different
than the ATF because it will be required to land on carriers. The catapult and stopping mechanism
on an aircraft carrier places tremendous strain on an airframe, Blackwell said, which requires a
more sturdy airframe than land-based aircraft.
As in the F-14 Tomcat, the Lockheed NATF will have swing wings, which, when set in a forward
swept direction, will provide the aircraft greater lift needed for carrier launches.
The main criteria for that Navy airplane is carrier suitability, which translates into high lift, Blackwell
said. "You have to maximize the high lift of a Navy airplane in order to get on and off a Navy
carrier. That will require a different wing on the airplane rather than what we have on the ATF. But
when you look at the two airplanes from a distance they will be brother and sisters. Swing wings
let us optimize several flight regimes. Rather than going out to supercruise, air-superiority
missions for the F-15, it does that and does it well, but it also does the combat air patrol mission.
It has longer legs and it will endure longer."
The NATF will also be required to fill a limited attack role, while the ATF is purely an air-superiority
aircraft. However, Lockheed's ATF could be further modified to include an attack role.
Low Observable Capability Diminished Due To Size Of NATF
With the added size of the airframe, the low-observable signature of Lockheed's NATF will
increase. However, Blackwell said trade-offs were expected, "the airframe will be tailored to the
Navy mission." About 25 percent of the NATF airframe will be common with Lockheed's ATF. "The
Navy airplane uses 100 percent of the ATF avionics," Blackwell said. "We marinized the engines so
they will be used by both aircraft. Virtually all the subsystems will be common." Lockheed is also
studying a two seat aircraft for the Navy contract, Black-well said.
At the low and high ends of speed extremes the YF-22 ATF's thrust vectoring will provide the
aircraft with the ability to maneuver with greater efficiency than its predecessors, Blackwell said.
Thrust vectoring is the ability to guide the thrust of the engines in an up or down direction to
further enhance maneuverability of the aircraft. At very high speeds the aircraft's controlling
surfaces are limited in their ability to influence movement through the air, Test Pilot Dave Ferguson
said. Thrust vectoring provides greater control to the pilot. It is also important because it allows
for greater maneuverability at extreme high angles of attack. With vectoring controlling the
direction of the aircraft, controlling surfaces are free to manage roll and other maneuver
capabilities, Ferguson said. The YF-22 reached a 60 degree angle of attack in prototype testing
and displayed an ability to role 100 degrees at that angle of attack.
The Lockheed team's competitor, the Northrop/McDonnell Douglas YF-23, does not utilize thrust
vectoring.
Achieved Every Goal
Blackwell said Lockheed approached the ATF program with eight specific goals, which included:
building a stealthy plane; achieving supercruise; extreme maneuverability; lethality; advanced,
affordable avionics; built in growth for the aircraft; a supportable aircraft; and overall affordable.
He said the Lockheed team had achieved all its goals.
There will be minor changes in the airframe from the prototype aircraft to the production aircraft,
according to Blackwell. He said the canopy of the aircraft will be moved slightly forward, while the
landing gear doors will be more parallel to the wind. There will, however, be "massive changes"
internally. Blackwell said there will be a great use of composites. He said that all internal loads
were theoretical in the prototype stage and that attempts will be made at every opportunity to
decrease the weight of the aircraft.
To date approximately $1.9 billion has been invested in the ATF demonstration/validation program
by the Air Force, Lockheed/Boeing/General Dynamics and their subcontractors. The Air Force
provided $818 million, Lockheed/Boeing/General Dynamics split equally $675 million and
subcontractors invested $408 million. The Navy has provided $65 million for the NATF to date.
