F-4B/N General information & specifications
- 1 Introduction
- 2 Basic aircraft information
- 3 Handling characteristics
- 3.1 Behavior at different angle of attack regimes
- 3.2 Spins
The F-4B/N Phantom II is a two-seat all weather fighter aircraft. It is capable of speeds up to Mach 2.15 and can fulfill a variety of roles in combat. The Phantom II was developed as a long range interceptor, using the combination of its APQ-72 RADAR and AIM-7 Sparrow missile to deliver a killing strike beyond visual range. A crew of two is required for the aircraft to operate in a combat environment. The Pilot sits at the front and is responsible for flying the aircraft and utilizing the weapons systems. The Radar Intercept Officer (RIO) sits in the back and his main responsibility is utilizing the APQ-72 RADAR and assisting the pilot in navigation.
Basic aircraft information
|Designation:||F-4B/N Phantom II|
|First Flight:||May 27 1958|
|Maximum speed at sea level:||Mach 1.2|
|Maximum speed at 36000ft:||Mach 2.15|
Behavior at different angle of attack regimes
The F-4 Phantom exhibits different handling characteristics depending on the angle of attack of the aircraft. This behavior is predictable and repeatable and the pilot should know how to utilize the aircraft properly in all regimes.
Low angle of attack
When the plane is flying at an angle of attack less than 12 units all control movements provide normal responses. Stick is used to control pitch and roll of the aircraft and the pedals to control yaw.
Induced drag is minimum at approximately 5 units and is the angle of attack at which maximum performance acceleration from subsonic Mach numbers to supersonic flight can be achieved. At 5 units drag is minimal while gravity enhances the aircraft's acceleration, prividing the minimum time, fuel and distance to accelerate from subsonic to supersonic Mach numbers, to the optimum supersonic climb schedule.
When recovering from a condition of low airspeed and high pitch attitude, the angle of attack indicator becomes the primary recovery instrument. A smooth pushover to 5 units angle of attack will unload the airplane and reduce the stall speed to nearly zero. Recovery can be accomplished safely at any speed which will provide stabilator effectiveness (ability to control angle of attack). Smooth control of angle of attack is a necessity and no attempt to control bank or yaw should be made. High pitchangles with rapidly decreasing airspeed will result in loss of stabilator effectiveness and subsequent loss of control of angle of attack.
At 8 units is the optimum cruise value of angle of attack. Cruise angle of attack will vary depending on the drag created from the external stores' configuration, but when possible maintaining 8 units of angle of attack during cruise will allow you to reach the aircraft's maximum endurance.
Medium angle of attack
The area between 12 and 16 units angle of attack is where airplane response and flight characteristics transit from the normal behavior of low angle of attack flight, to the ones found in the high angle of attack regime.
High angle of attack
When flying above 16 units angle of attack, control input will present different results compared to the low angle of attack regime. The primary flight characteristics exhibited in this area are adverse yaw and dihedral effect.
Using ailerons and spoilers (lateral stick deflection) when attempting to roll the aircraft will result in yaw opposite to the direction of the intended turn. This effect becomes more severe at high angles of attack. At high angles of attack ailerons produce very low roll rates that decrease as angle of attack increases. When near stall angle of attack, aileron input will create increased adverse yaw and roll opposite to the direction intended. Use of ailerons at the point of departure will increase probability of spin entry. Thus the natural tendency of using aileron to control roll must be avoided.
Using rudder in the high angle of attack regime will produce roll in the intended direction. This effect becomes even more pronounced at high angles of attack. Above 16 units angle of attack, rudder should be used instead of ailerons in order to generate roll. This use of rudder input can be utilized to attain the maximum roll rates possible at high angles of attack.
The optimum approach angle of attack for landing is:
- 18.7-19.7 units for the F-4B aircraft without drooped ailerons (Early and APR-24)
- 18.5-19.5 units for the F-4B aircraft with drooped ailerons (Late) and F-4N
Optimum approach angle of attack is adequate for all allowable gross weight and flap configurations.
When in landing configuration, indicated angle of attack is 3 units higher than real angle of attack. This change is because of a change in the wind flow over the angle of attack probe with the nose gear extended. Landing angle of attack references are only valid when the landing configuration (gear down, flaps full).
Maximum performance manouevering
The three factors that determine maximum performance manouevering are structural limitations, stabilator effectiveness and aerodynamic limitations.
- Structural limitations are referenced here.
- The limit in stabilator effectiveness occurs at high altitudes and supersonic speeds where full aft stick can be attained without reaching aerodynamic or structural limits.
- Aerodynamic limitations (stall) are primarily a factor of angle of attack.
Maximum performance turns can be achieved in two ways:
- Momentarily unloadg the aircraft (reducing angle of attack to between 5 and 10 units) and utilize the ailerons to roll. After rolling neutralize the ailerons and re-establish the desired angle of attack.
- If a high angle of attack must be maintained and roll is required, rudder must be used to produce roll as has been discussed above. In the high angle of attack area of flight, maximum performance turns are achieved by maintaining 19-20 units angle of attack while utilizing afterburner as required.
The F-4 will provide several stall warning cues that are discussed in the following paragraphs. The aircraft comes equipped with a rudder pedal shaker that activates at a fixed threshold and warns the pilot before approaching stall angle of attack. The angle of attack at which the pedal shaker is activated is dependent on aircraft type, as listed below:
|Aircraft||Angle of attack|
|Early F-4B aircraft:||22.3|
|Late F-4B and F-4N aircraft:||21.3|
- Normal (1G) stalls are preceded by a wide band of buffet. First noticeable buffet occurs at 12 to 14 units angle of attack and usually increases from moderate to heavy buffet immediately prior to stall or departure.
- Wing rock, if encountered, will commence at approximately 23 units and variations in bank angle of up to 30 degrees from wings level can be expected near the stall.
- Stall is characterized by a slight nose rise and/or yawing motion in either direction.
Recovery from the stall is easily and immediately effected when angle of attack is reduced by:
- positioning the stick forward
- maintaining neutral ailerons
- making judicious use of rudder to avoid inducing excessive yaw
Accelerated stalls are preceded by moderate buffet which increases to heavy buffet immediately prior to the stall. Wing rock is unpredictable, but generally starts at about 22 to 25 units. The angle of attack at stall varies considerably with loading, but is above 25 units for all loadings.
Rapidly entered accelerated stalls may occur at lower indicated angle of attack. Increasing the rate of aft stick displacement increases the magnitude and rate of yaw and roll oscillations at the stall. Applying and golding full aft stick, event with ailerons and rudder neutral, can result in a spin. Prompt neutralization of controls will effect recovery from an accelerated stall. Oscillations in roll and yaw, which may be present during recovery, should be allowed to damp themselves out and should not be countered with ailerons or rudder.
Landing configuration stalls
Landing configuration stalls exhibit no buffeting. Warning is provided by the rudder pedal shaker. Stall on the aircraft and is approximately 27 units for early F-4B aircraft and 24 units for late F-4B and F-4N aircraft.
Recovery from landing configuration stalls is initiated by placing the stick forward to reduce angle of attack to below stall and increasing throttle to MIL. Recovery attitude is usually about 30 degrees nose-down.
A spin is characterized by the aircraft rotating around its yaw axis. It is possible to enter a spin from a level flight stall, accelerated turns, vertical climbs, 60-degree dive pullouts and inverted climbs. Angle of attack is the primary instrument in determining whether a spin is upright or inverted. During upright spins, the angle of attack indicator will be pegged at 30 units and during inverted spins at 0 units. The direction of spin can be referenced using ground cues or the turn needle (not the ball).
During an upright spin the aircraft might be oscillating in pitch, roll and yaw. In such an event it is important to POSITIVELY determine the spin direction and:
- maintain full forward stick
- neutralize rudder
- full aileron in the direction of spin
- when the aircraft unloads and/or yaw rate stops, neutralize the ailerons and fly out of the unusual attitude
- do not exceed 19 units during dive pull-out
- if still out of control below 10,000ft above the terrain, EJECT
The aircraft is highly resistant to an inverted spin entry and tests indicated that pro spin controls are necessary to enter an inverted spin. The inverted spin is characterized y zero (0) units indicated angle of attack and negative G and is less oscillatory than an upright spin. The direction of spin can be referenced using ground cues or the turn needle (not the ball). To exit an inverted spin:
- Apply full rudder opposite to the direction of the spin
- Stick and ailerons neutral
- When the yaw rate stops neutralize all controls and fly out of the unusual attitude