F-4 PHANTOM II FLIGHT CHARACTERISTICS

[Applause] [Music] [Applause] [Music] [Applause] [Music] [Music] [Applause] [Music] Heat. Heat. [Music] [Applause] That guy's got some ejection system. Yeah. And he's got no shoot either. Well, let's get to work. Hey, that analogy is pretty good. Once a fighter pilot straps in, he's part of the machine. Good. We thought that would work. So today, Doug, we want to go over the first draft script on our film. Now, I know you've got a fly this afternoon, so we'll get you out of here as soon as we can. Would you show us that rough title, Dave? Now, this will be on a blue background with a drop shadow. That looks good. Now, I used your course outline as a guide, but as we discussed earlier, we can't put all this material in a halfhour film. Now, I I didn't cover forces acting on aircraft. That's okay. It's the same old forces of thrust, weight, lift, and drag that act on any aircraft. Yeah, but I didn't cover lift and drag either. You know, things like center of gravity, aerodynamic force, parasitic drag, induced drag. That's okay. They're easily covered in the classroom. Yeah, but there's one exception, Doug. AOA, angle of attack. Have you got that picture ready, Dave? I think we uh should clearly define it. And here are some of the words that are going to be over that sketch that Dave's putting up now. [Applause] Between the cord line of the wing and the relative wind, an angle is formed that is called angle of attack. The angle is expressed in units. In this example, 19.2. Or to put it a different way, it's a difference between where the aircraft is pointed and where it's actually going. When you've had a lot of hours in the hardwing bird, you really become a believer in watching for excessive AOA. Well, now next we talk about AOA displays. First, the indicator and indexer. Sid, would you light her up? Sure. Thank you, Doug. I understand this chart is in your -1. This chart shows the F4 with gear down in five different attitudes with five variations of air speed and angles of attack. The indicator on the left shows the AOA in units while the indexer symbols change and illuminate in different combinations as AOA increases or decreases. It'd be good to mention that the aircraft has a different feel to it with the gear and flaps up. Although you can still use the indexer and the AOA indicator. Good point. Now, the angle of attack oral tone system comes next. The oral tone is present under all flight conditions above 15 units AOA. We won't listen to all of the tones and pulses. Uh, but for example, U Dave, would you put that drawing up, please? In the range between 19.7 and 30 units AOA, the generator produces a very high frequency with pulse increases as AOA is increased. Now listen to this. [Laughter] You might also mention that once you get above 20.3 units AOA, you can't shut off the volume control. Oh, another point. The oral tone is particularly valuable when you're in a landing configuration. You've got a hundred other uses for your eyes, so letting the ears do some of the work helps. But John, let's make sure we get that in. Right. Right. Sh. You might also mention the pedal shaker which cuts in at 22.3 units. The left rudder pedal and the front seat tells you to wake up. Now, the only thing you have to be careful with on the shaker is that when you're buffeting, the whole airframe can be shaking so badly that you can't feel the pedal shake. We move on now to the stall. Now, the star, if I remember your script, don't you have a section further down on angle of attack? Yeah. Yeah, it uh starts on page 22. Well, wouldn't it be better to stay with AOA now that we're into it? Well, there's no sweat in moving it up. Okay. To cover low, medium, and high AOA, I'd like to use you, Doug, flying one of these models. Okay. Let's assume this tabletop indicates a direction of relative wind. Not the ground, mind you, but relative wind. Now, in low angle of attack, the F4 can be maneuvered just like the T38 or the F104. Ailerons can be used to roll the aircraft and uh it's got a very good roll rate. That is to say, it's extremely fast. At 3 to 5 units AOA, we get max acceleration. For normal cruise, we use about 8 units AOA. And remember, at these AOAs, it's impossible to stall the aircraft. A good rule to remember is that if you get in trouble with excessive AOA, simply return the aircraft to a lower AOA, then you'll recover. Okay, I've got that down. Now, in the medium AOA region, you've got good control and the aircraft's not too sensitive. But once you reach 15 units AOA, you need to start applying rudder in order to coordinate your roll. Now it's impossible to install the aircraft in medium AOA just as it is in low AOA. However, as we approach 14 15 units in the subsonic region, onset buffet will start. Now this buffet will disappear once you go transsonic. At 10 12 units, we reach optimum turn. save the most energy. Speaking of energy, your outfit made a movie recently called Energy Maneuverability. It's a good film that anyone who ever wants to dog fight should see. That's the film Jack made. Oh, I remember seeing that. Doug, before you tackle high AOA, I thought we should explain dihedral effect and adverse yaw. We dug up some animation out of stock we thought might work. Uh, take a look at this on the viewer. Uh John will read the words that go with this. First let us examine the aerodynamics of air flowing over a straight wing versus the air flow over a swept wing. The air flowing over the swept wing curves outward while the air over the straight wing flows directly across the wing. Thus, the straight wing produces more lift. Now, if you apply left rudder, the aircraft will yaw to the left. It is now obvious that the left wing has even a more pronounced sweep, while the right wing has less sweep and comes closer to being a straight wing. Since the right wing has greater lift, there will be a tendency to roll left. At low AOA the dihedral effect will be small. However, if we move to a high AOA, say 19.2 units, we will have a more pronounced dihedral effect and the roll will be strong and definite. Hold it a minute, Sid. Up to 15 units, you can fly without using the rudders. But in the F4, over 15 units AOA, beware. You have to use your rudder in order to coordinate your roll. If you don't, you could get yourself in real trouble. Oh, this next section on adverse yaw should explain it. In a high angle of attack situation, if the pilot employs aileron as primary for directional change, he will induce a roll in the direction away from the intended turn. When aileron is used, this is what happens. If the pilot intends to roll left, he moves the stick left. This causes the left wing spoiler to come up and the right wing aileron down. [Applause] This condition imposes additional induced drag on the right wing and the aircraft yaws toward the high drag area. The aircraft will roll in the direction of the yaw. Actually, the F4 pilot must learn to fly it using two different techniques. One for low AO8 where he flies it using ailerons in the conventional manner. But at high AOA, he must center the stick and not use ailerons at all. The rudder alone will be used to roll the aircraft. And let me tell you, learning to not use ailerons is a difficult thing to overcome. Moving the stick in the direction of your turn is just a condition reflex for most pilots. Okay, now does that pretty well cover high AOA? Except for one final thought. In uh fighter versus fighter combat, maneuverability is a key to success. Inability to handle adverse yaw will lead to unexpected and unwanted results. I wonder if this guy was troubled with adverse yaw. Have you ever seen this? Gather around. You too, Dave. I make a collection of these. [Music] [Music] That must have been an early prototype of the swingwing. For this next section, we're going to try something a little bit different. Dave here can sketch pretty fast. And while he hits the highlights, I'll read the narration. For takeoff, use sufficient aft stick to rotate the nose to takeoff attitude. However, for a heavyweight takeoff, the flight manual recommends the full aft stick technique for lowest nose wheel lifttoff speed and shortest ground run. Nose wheel lifttoff speed will be determined by the location of the center of gravity or CG and the gross weight of the aircraft. The further forward the CG is, the higher the liftoff speed will be. In a heavyweight configuration, such as on a combat mission, it is possible to have a nose wheel lifttoff speed that is greater than takeoff speed. As the aircraft accelerates and obtains nose wheel lifttoff, sufficient aft stick should be applied to maintain a 10 to 12° climb with an FCG condition or with an abrupt control movement. It is possible to overrotate the aircraft. The problem is more pronounced with the slotted stapilator on the E- model. When the F4 travels in the subsonic region in a clean configuration, basic longitudinal stability exists but is the lowest of any regime. This coupled with high stabilator effectiveness causes the airplane to be rather pitch sensitive, especially at high Q. The faster the aircraft goes, the less stable and more pitch sensitive it becomes. [Applause] A small amount of stick motion will produce quite a few G's. For example, at high Q, for every inch of stick travel, about 6 G's will be imparted on the airframe. Because of sensitive pitch control, pilots need to watch for PIO, pilot induced oscillations. Rapid throttle and abrupt stick movements should be avoided in this area. How am I going to draw that? Good question. You might mention that you've got a very high roll rate when you're at high queue. Full aileron produces a a rate of roll that's much too fast to be of any practical use. Stability augmentation helps to stiffen the aircraft and it makes it less sensitive. Let's tackle the transonic region. Now the static longitudinal stability becomes more positive and stabilator effectiveness somewhat reduced. Lateral directional stability is excellent in the transonic region. The transonic world starts at 0.92 Mach and at this number there is a noticeable stick stiffening due to a shift in the aerodynamic center on the wing. This business of stick stiffening is kind of hard to illustrate. Now it's something you have to get used to. It's not too bad going from subsonic through transonic to supersonic. It's easier to react to a buildup of force. It's coming back down from supersonic. That's a bear because all of a sudden that force is gone and you're still pulling back like mad. And that brings us to the eye watering phenomena known as Mark Tuck. We thought that should be covered with animation. Take a look. The aerodynamic principle involved here works in this manner. Assuming the center of gravity is located here, the aerodynamic center could be located here. Incidentally, the aerodynamic center should always be behind the CG to have good positive stability. When the aircraft enters the transsonic region, the aerodynamic center moves aft and this results in stick stiffening. Now just the opposite happens when the aircraft moves from supersonic through transsonic. The aerodynamic center moves forward closer to the CG and the result is stick lightning. In the supersonic world, when the aircraft is in a turn, stick force is around 10 pounds per g. So if a 6G turn is being performed, the pressure is 60 lb. In the subsonic world, again with the aircraft in a turn, stick force is around 3 to 4 lb per g. So here in a 6g turn, the pressure is around 20 lb. The differential between 60 lb and 20 lb speaks for itself. Take for example in a dive recovery. If the pilot does not anticipate and ease off on the stick, he could really dig in. Well, if the uh transition's that rapid, how do you anticipate? Well, as you come down through the mock and begin to feel a buffet, that's a time to come forward on the stick a little bit. Okay. Okay to move on to supersonic. Sure. In the supersonic area there is an increase in longitudinal stability and stabilator effectiveness decreases. The aircraft becomes stabilator limited at high moach numbers at high altitude. For example, at 50,000 ft at Mach 2 with 3.5gs on the aircraft, the stick will hit the aft stop. Or at 36,000 ft at Mach 1.5, pulling 5gs, it is impossible to pull back any further on the stick. The aircraft is very stable in the supersonic area and does not develop any of the buffet tendencies found at subsonic. Roll rate of the aircraft will decrease with an increase of the mock number. However, the roll rate will be adequate all the way out to limiting mock numbers. As we said before, it takes quite an amount of stick pressure to turn the aircraft. Sid, would you heat up the projector again? We'll use a few slides to show landing configuration. In landing there is definite positive longitudinal stability but it is weak. Stick forces will be light due to low dynamic pressure caused by the slow speed of the aircraft. Lateral and directional stability will be positive but will weaken as the aircraft slows down. The adverse yaw tendency will be present with flaps up, but with flaps down, it will be counteracted by the airlon rudder interconnect, a ar. Yes, in normal landing, 19.2 units AOA and full flaps are used. The F4 can attain a relatively slow speed during final approach because of BLC, boundary layer control. Air from the engines is pushed over the wing surfaces which helps delay a stall and enables you to fly slower on final approach. In the no flap configuration, air speed will be increased by some 22 knots. In order to use your AOA indicator as a primary landing reference, you must of course be on the proper glide path. Jet wash from another aircraft can be a problem, particularly during a calm day when there is no wind to dissipate the wash. Be prepared for a rolling tendency either to the right or left. Well, I have an aircraft ahead of me and it's a calm day. Believe me, I'm prepared. I've had my eyes watered once or twice. Speaking of getting your eyes watered, take a look at what happened to this guy. [Music] [Applause] [Music] [Music] [Laughter] We have one last section to cover. Stall, departure, and spin. Yeah, I guess you know the film Unload for Control about the F4 spin test at Edwards, right? We use it in the classroom a lot. Well, we thought we'd take the highlights from that film, particularly departures and spin recoveries. But that film doesn't have too much on stalls. Well, I think we could cover stalls rather quickly. It's simply caused by excessive AOA in the 26 to 30 unit region. Okay. Well, now here's what I've got for the 1G clean configuration stall. I have these words. Buffet will occur at about 40 knots above the stall at around 14 units AOA. This buffet will increase from moderate to heavy as AOA is increased. We have some film here on wing rock and no slices. I'll read along when we get to it. Wing rock, if experienced, normally occurs between 22 and 25 units. The AOA at the actual stall will normally be between 26 and 30 units. A nose up yawing tendency with a nose slice will also characterize this type of stall. Hey, take a look at this scene. It sure is a dig in like we were talking about under Mark Tuck. There's more to come. Uh now here's some more about stalls. A high-speed or accelerated stall is normally preceded by moderate buffet increasing to heavy buffet prior to the stall. Rapid application of aft stick could result in an immediate departure without any stall indications. What was that phrase you used about pulling back on the stick? Oh, you mean pole snatcher. Simply coming back on the stick too fast. That's good. Now, wing rock is unpredictable, but generally starts around 22 to 25 units AOA. The AOA at the stall is between 26 and 30 units. Reduction of AOA with forward stick and controls neutralized is of paramount importance to affect recovery. Sounds good. We uh we cover the portion on departures with more stock footage. Departures or post stall girrations are uncontrolled motions about any or all axes following a departure from controlled flight. Stalls can lead to aircraft departure. You can experience a rolling departure, a brief uncontrollable rolling maneuver following loss of control, or a spin, a sustained your rotation at stalled angles of attack. Whether the aircraft goes into a rolling departure or spin depends on the external stores carried, the center of gravity, the altitude, and whether or not the aircraft is symmetrical. Control inputs at the time of departure also have an influence on the spin susceptibility of the aircraft. The departure can be rapidly corrected by neutralizing the ailerons and rudder, moving the stick forward and deploying the drag chute. The most prevalent spin for the clean aircraft is a steep nose down attitude of about 45°. Hesitations in roll angle and yaw rate are obvious at every half turn. The turn needle will be pegged in the direction of the spin. The AOA indicator may come off the 30 unit peg and momentarily indicate 5 to 15 units before returning to 30 units. The spin with the heavily loaded aircraft is not as steep or nose low. Oscillations are more pronounced and hesitations occur only once per turn. Accelerations in the cockpit are higher, but are never severe enough to hinder proper control positioning. Recoveries from this spin are very prompt, usually within two turns. [Applause] Medium to high asmmetric loadings are extremely spin susceptible and characterized by comparatively violent oscillations. This mode produces the most acceleration on the crew, but again not enough to cause disorientation or to hinder application of recovery controls. Forward stick alone will recover the aircraft. The flat spin is easy to identify. It is very smooth with no significant pitch or roll oscillations. The yaw rate is high with no hesitation at all and the pitch attitude is only slightly nose down. Recovery from a flat spin is impossible. The crew will be pushed forward in their seat slightly, but this will not restrict good body position for ejection. You know, after listening to all this, I think the name of our film should be Beware of Angle of Attack. That's about right, and I've said it before. Watch for excessive AOA with the F4. I guess that wraps it up. Let's end on my favorite oddity. Bob Hope narrated over this once and he said, "My, that guy sure has a high hot foot. [Music] [Applause] [Music] [Applause] [Applause] [Music] Heat. Heat. Heat. Heat. [Music]