All language subtitles for The Insane Engineering of the F-16

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A fully loaded F-16 is a force to be reckoned
with. An air superiority machine that countries

the world over use to patrol their skies.
A low cost, lightweight, single engine fighter,

specifically designed to out maneuver its
opponents while carrying state of the art

missiles that would, hopefully, mean it would
never have to.

The F-16 was born out of the Vietnam war.
Large, heavy, complex US fighters like the

F-4 Phantom were the norm, but the F-4 found
itself in pearl frequently, at a significant

disadvantage when taking on the smaller maneuverable
soviet-made MiGs of the Vietnamese Air Force,

like the Mig 21.

The Mig 21 was a small, single engined, lightweight
aircraft with thin delta wings. The F-4 was

fast, flying up to Mach 2.2, traveled further,
and carried more missiles, with a powerful

radar.

But, its lack of maneuverability at low speed,
poor pilot visibility and easy identification

due to jet engines that billowed black smoke
trails, made it vulnerable to sneak attacks

from the soviet interceptor.

MiG 21s frequently flew close to the ground,
under radar, and ambushed incoming F-4s. Making

a single attacking run with their Atoll infrared
guided missiles, and then, using their low

speed maneuverability to out turn and escape.

From August 1967 to February 1968, US losses
in Vietnam were staggering.

Losing 18 aircraft while downing just 5. [REF]
[1]

For a nation accustomed to absolute air superiority,
something was off.

The MIG 21s introduction in 1966 forced the
US to adapt. Its large, heavy fighter bombers,

while useful, were at a disadvantage against
these smaller, cheaper planes, and something

needed to be done.

The Red Baron study, commissioned by the US
Military, began to identify and address the

tactical and technical issues causing the
heavy losses that both the US Navy and Air

Force were experiencing in the Vietnam war.

And their findings led to the development
of one of the world’s most ubiquitous fighter

planes. A plane designed with a new physics
based doctrine at its core.

Entering service in 1978 and standing the
test of time, it is now confirmed that the

aircraft will be entering the battle for Ukraine’s
freedom, taking on the modern day counterparts

of the MiG.

This is the Insane Engineering of the F-16.

The F-16 was built from the ground up with
this classified 1966 paper as its guiding

light. A paper full of mathematical models,
graphs, and equations, designed to answer

one question.

How to win a close quarters dog fight. Created
with the help of military supercomputers,

it defined a new concept. Energy Maneuverability.

Created by Colonel John Boyd, an air force
veteran of the Vietnam war, and one of the

members of the so called fighter mafia, with
the help of a civilian mathematician Thomas

Christie. [REF][2]

These graphs were the basis for defining a
plane's maneuverability through its full range

of speeds. Mach number on the x-axis. Turn
rate on the y.

A theory underlined by the management of both
kinetic and potential energy, speed and altitude.

In order to change direction a fighter aircraft
must trade energy from these reservoirs, and

doing it as efficiently as possible is the
key to out maneuvering an enemy. .

This is the energy-maneuverability diagram
for the F-16. It’s a complicated graph to

read without some basic understanding. This
line is defined by the maximum lift of the

aircraft.

This is important because it determines the
maximum turn rate at a particular speed in

this region. We need lift to turn.

To begin a turn an aircraft will roll in the
direction of the turn. This splits the lift

the plane is generating into two components:
a horizontal component that causes the plane

to turn and a vertical component that keeps
the plane in the sky.

A steeper bank angle will increase the horizontal
component and increase our rate of turn, while

stealing lift from the vertical component.

This vertical component needs to equal the
weight of the aircraft, or the plane will

lose altitude. To compensate for that the
pilot will need to increase lift by increasing

the angle of attack. This is where the maximum
lift issue arises. More lift means more available

force to turn.

To determine the max turn rate for an F-16
at mach 0.4 we simply draw a line straight

up and across to our turn rate. 13 degrees
per second. Now, this is where things get

interesting. This is the graph for an F-4E.
At the same speed the F-4 can make a maximum

turn of just 5 degrees per second.

To determine a sustained turn we look to this
line labeled with a 0. Meaning no loss of

altitude is required to make the turn. We
can see the F-16s best sustained turn is 14.2

degrees per second at 0.85 Mach at 7 g. The
F-4s best sustained turn is 10 degrees per

second at 0.85 Mach at 5 g.

This is what that looks like in practice.
It takes the F-16 25 seconds to complete a

full 360 degree turn. While it takes the F-4
36 seconds. 11 seconds in the difference.

The F-16 was a radical new way of thinking
about fighter aircraft and that

design philosophy can be seen with how the
engine inlet has been designed to deal with

supersonic flow. To learn more about the F-16,
we spoke with F-16 test pilot David Wren.

so the F 16 inlet is one of those things that
tells you about the design philosophy of the

aircraft because up until that point, the
thought process was we wanted to go faster,

we wanted to go higher, and nobody stopped
to ask why, because it turns out that not

a lot of fights, not a lot of air combat was
happening in that mach two plus range. In

fact, very little of it was happening and
it didn't have a huge amount of tactical application.

And so as John Boyd and the rest of the team
was looking at this lightweight fighter design,

which became the F 16, they said, well, where
do we think that the dog fights of the future

are really going to happen? And they said,
well, it's probably going to be somewhere

in that 0.8 mach to 1.2 mock regime.

That's really where we need to be in terms
of optimizing the performance of the jet.

And we see that here in terms of the specific
excess power chart where it's got this advantage

right here in that range of 0.8 M to 1.2 mach.
That's where the fat part of the chart sits.

That's where your fat on energy, that's where
you have that advantage. And so the F 16 propulsion

system is not optimized to go over mach two,
although it can, and I've flown the F 16 at

Mach two, you run out of gas pretty quick,
but you can go that fast. But in that what

we call transonic regime of 0.8 to 1.2 mach,
you've got a different design problem than

some of the previous jets. And you can see
that in terms of the inlets. The inlets on

the F four have this extension that goes sort
of along the cheeks of the aircraft forward,

and then the actual inlet is inlets are set
back, and what that's designed to do is attach

a shockwave to the front of that inlet lip
and then it goes backwards and expands along

the body.

And that shockwave is basically going to cover
up the inlet that has some thermodynamic effects

in terms of pressure recovery for the fan
face because you don't want supersonic air

getting all the way in to your turbine. If
you have supersonic airflow hitting the front

face of that jet engine, the jet engine's
going to disintegrate. It's designed to ingest

subsonic airflow. And so you have to attach
that shock wave at the front of the inlet.

That's part of what slows down the airflow
to eventually a normal shock inside the inlet.

It expands a little bit and then it gets to
the front face of the compressor or the fan

face of the compressor. Well, the F 16, and
you can see it right here, has what we call

a peto inlet. It's basically a flat face air
scoop. It is not that sort of overhang with

a lip and then an inlet that's further back
like you see on the F four or the F 15 or

the F 14, the big 29, the s U 27, all of those
have more of that inlet that's set up to put

an oblique shockwave across the front of the
inlet.

Those are designed to go faster. The F 16
has a little bit of that. If you look at it

on a side view, you can see how it's got a
little bit of an overhang on the lip and the

nose helps to attach a shockwave, but it's
not as efficient to go above Mach 1.2. And

that's okay. Actually it can go that fast,
it can go faster, but the engine is working

a little bit harder as it gets into this 1.4,
1.5 mock range compared to something like

an F four or an F 15. That's where they start
to really stretch their legs and run.

These design optimizations for optimizing
maneuverability at these speeds can be seen

elsewhere too.

It’s air intake placement underneath the
aircraft, a stark difference to the side mounted

twin intakes of the F-4. And the thin elongated
wing that blends smoothly into the fuselage

with these wing extensions forward of the
main wing. These are called leading edge strakes

.

This air intake ensured the F-16s engine was
not starved of air during high angle of attack

maneuvers. With the forebody of the aircraft
helping to funnel and divert air directly

into the air intake.

However, this does come with some problems
that needed to be engineered around.

On take off and landing this air intake is
just 100 centimeters of the ground, this combined

with the extremely thin wings make placement
of the landing gear difficult.

The forward landing gear could not be mounted
ahead of the air intake, as they would kick

up debris into it, and they couldn’t fit
into the wings, as the thin aerodynamically

optimized wing didn’t have enough space.

The F-16s landing gears are stored just behind
the air intake, and in order to provide enough

stability and bracing on landing, they need
a unique folding mechanism to swing them outward

to create as large a wheelbase as possible.

The front landing gear, which is steerable
during taxi, also rotates 90 degrees to lie

flat just under the engine inlet.

Above the inlet is a boundary layer diverter
channel. This ensures the engine gets consistent

laminar flow.

As air travels along the length of the aircraft
it forms a layer of slow moving turbulent

air called a boundary layer. If this air is
allowed to enter the engine it not only lowers

performance, it can also damage the engine.
As the turbine rotates it will pass through

the slow boundary air on one side and then
fast free stream air on the other. This means

the force on the turbine blade changes for
each and every rotation, causing cyclical

bending. A recipe for fatigue failure.

This boundary layer diverter separates this
layer and diverts it underneath the wings.

All of this ensures the engine can operate
at as high a thrust as possible, even when

the F-16 is performing extreme maneuvers,
which is exactly when it is needed most as

the plane bleeds energy to produce lift.

It’s essential that a plane like this can
continue to generate effective lift during

these maneuvers,

but typical wings lose lift as angle of attack
increases beyond a certain angle, as flow

separates from the wing. This is called a
stall.

These leading edge strakes help to mitigate
that.

They act similarly to the canards of the SU-34,
one of the planes the F-16 will likely be

going up against in Ukraine, with 19 of them
reportedly being taken down thus far in the

war.

Canards and leading edge strakes help produce
lift during high angle of attack maneuvers.

Canards placed close to the wing, like the
Saab 37 Viggen, create a vortex that passes

over the wing, ensuring the wing continues
to get high energy airflow during high angle

of attack maneuvers which allows it to continue
generating lift

During the development of the F-16, General
Dynamics did consider a canard configuration,

testing different configurations and geometries
including versions with no strakes or canards

with subscale models in wind tunnel, testing
through its optimum maneuvering speeds between

0.4 and 0.8 mach.

The goal was to maximize lift and minimize
drag at high angles of attack, producing graphs

like this, and these were used to compare
designs.

As they were narrowing down on the design
they consulted NASA, and they found one area

to improve on.

The sharpness of the leading edge.

General Dynamics had rounded the leading edge
of the wing to weaken these high angle of

attack vortices[REF][3] , but NASA advised
them to sharpen the leading edge in order

to strengthen them.

The F-16 underwent a great deal of iterative
design in the wind tunnel phase before eventually

landing on the design we are familiar with
today. With the long blended leading edge

strake that makes the F-16 immediately recognisable,
and this comes with an added benefit.

It provides enough space for the barrel of
F-16s powerful 20 mm rotary cannon. [REF][4]

You can see the barrel of M61 Vulcan hiding
here, a minor clue to the weapon hidden within

the fuselage of the tiny plane.

One of the early conclusions of the Red Baron
report was that lackluster armament of the

F-4 made it difficult for it to compete in
close quarter battles. It lacked an internal

cannon, which left the F-4 without offensive
options in close quarter battles, where missiles

could not be safely used. The F-4 was eventually
retrofitted with the M61 slung underneath

the plane.

But, the F-16, looking to fix the problems
of the past, came with General Dynamics M61

Vulcan rotary gatling cannon as standard,
and was packaged neatly inside the plane,

creating minimal aerodynamic drag.

The M61 is the smaller cousin of the A-10s
GAU 8/A, and while its rounds are tiny in

comparison. The noise it emits still packs
a punch. A massive cannon for a tiny aircraft.

[REF] [5]

The 6 barrelled cannon fires from the top
position. Spinning 16 times a second, the

gatling cannon spews 100 20 mm rounds per
second. [REF] [6] With an ammunition drum

capable of holding just 511 rounds, the full
ammunition drum can be unloaded in just over

5 seconds.

The drum fits neatly behind the pilot here,

and the vibration of gun firing on the pilot's
left side is jarring for many new pilots.

It is such a small fighter, and I think I've
said this before, when you get into an F 16,

you sit down and you strap into that. It's
not like you're sitting in the jet. It's like

you're wearing the jet and the gun is right
here. As I sit there in the cockpit, the gun

barrels, the muzzles are right back here.
It's just out of reach. It's so close though.

And so when you shoot the gun and you're shooting
a hundred rounds a second of 20 millimeter,

it is unbelievably violent in the jet, but
you're thinking about the target that you

have to go and shoot.

And so one of my experiences flying the F
16 was I was teaching as an instructor pilot

at Luke Air Force Base in Phoenix, Arizona.
And so I had the privilege of taking in Air

Force pilots, they're wearing wings, they've
graduated Air Force pilot training, but they're

not fighter pilots yet. And putting them into
an F 16 and then we would make sure that everybody

shot the gun in training. In fact, they had
to qualify with the gun as a weapon. And so

the first time experience for anybody shooting
the gun in an F 16 is a little bit of an emotional

experience. People would say funny things,
they would cuss. It was all on the tapes,

the HUD tapes, the heads up display recordings,
and we come back in the debrief and we kind

of laugh at the students because they knew
that they were going to go shoot the gun and

it was always shooting at a target on the
ground is when they would do this for the

first time, raf.

And so it's a little bit intense. You're diving
at the ground, you're doing 4 50, 500 knots

pointed at the ground. Obviously there's a
survival instinct that kicks in there. You're

trying to put the pepper on the target, you
pull the trigger for the first time and the

whole jet shakes violently. It's like somebody
started up a chainsaw just in your left ear

and the whole jet is shaking and your hand's
on the throttle there. And I can always remember

every time I would shoot the gun, there's
this hard foam insulation that's just behind

the closeout panel, but the vibrations would
cause some of those little bits of foam to

fleck off, to flake off. And they would come
around the closeout panel and every time I

would go shoot the gun for practice a straight
I'd come back, and as I'm getting out of the

airplane, I'd see these little yellow flex
of foam all over my green flight suit on my

left arm.

The vibrations were so intense, you get used
to it after the first time you shoot it, it's

a little bit of an emotional event. And then
after that you're focused on, I need to put

those rounds on target. So the F 16 is incredibly
well integrated as far as a weapon system

with that gun. And I'll tell you that both
for air to ground and also for air-to-air,

the gun sites on the F 16 are incredibly precise.
And even with dynamics on the aircraft, even

under maneuvers in terms of air-to-air shoots
where we're shooting at a banner, there's

not been a lot of actual air-to-air dog fighting
with the gun in recent memory. But the F 16

is accurate when it shoots at air-to-air practice
targets to the point of it's almost not even

fair. It used to be kind of a scoring kind
of a skill thing.

And now you can just park the Pippa on the
target open up and it just t shreds anything

you pointed at in terms of an air-to-air target.
And then in terms of airto ground, you can

be extremely precise with it. It's not quite
a laser beam, but you can be extremely precise.

And there's even ways that you can couple
up other sensors on the aircraft and share

information, even in a at night blacked out
type of close air support roll, you can hit

what you want to hit on the ground.

All from a gun hidden away in this tiny fighter
plane.

If we follow this leading edge strake down
the wing we come to another device designed

to increase lift at high angles of attack.
The leading edge flap. It deflects downwards

during high angle of attack maneuvers to delay
stall, allowing air to remain attached to

the wing surface.

When performing a sustained turn at 0.9 Mach
at cruising altitude, it increases lift by

18% and decreases drag by 22%. You can see
them actuate here during the 5 g take off

I performed with the Thunderbirds back in
2019.

The seam between the leading edge flap and
the main wing is barely noticeable and fitting

a control system into this wing, which is
only around 4 centimeters thick where the

actuator system needed to fit, proved a challenge.

The amount of torque needed to actuate a control
surface like this at 0.9 Mach is not trivial.

To solve this problem power is transferred
from two hydraulic motors, which convert the

pressure in the hydraulic system into rotational
motion. The hydraulic drive motor itself is

tucked away behind the M61 Rotary cannon,
next to the hydraulic motor that drives the

cannon's rotation and ammo drive system. [REF]
[7] This power has to be transferred to the

wing, and this is done through a series of
torque shafts, angular gearbox, and down another

series of torque shafts with rotary actuators
in between.

[REF] [8]

This leading edge flap is not controlled by
the pilot however, it’s controlled automatically

by the flight computer, and the F-16 was ground
breaking in this regard. The F-16 was the

first fighter aircraft to have a fly by wire
system controlling every control surface.

The leading edge flaps, the flaperons, the
rudder, and the horizontal tail of F-16 are

not controlled directly by the pilot.

A fly by wire system using a network of sensors,
wires and computers as well as the pilots

own input to control the plane. The F-16 was
employing this new technological wizardry

to allow it to efficiently spend the energy
its single jet engine provided.

Traditional flight control systems, up to
this point, used a mechanical system

connected directly to the pilot's controls
to manipulate the flight surfaces. This is

footage of the F-4s control system. A heavy
and complicated network of cables, rods, linkages

and hydraulics. It even has a 2 kilogram bob
weights attached to the pilot's stick. A mechanism

designed to make it harder to pull the stick
as gs increase, an analog feedback system.

To provide the pilot with an analog feedback
on speed the F-4 also featured a diaphragm

that deflected with ram air taken from this
probe on the vertical fin. This introduced

a force that acted to push the stick backwards,
and indicated to the pilot to adjust a trim

setting. [FOOTAGE]

This system not only added a huge amount of
weight to the F-4, reducing it’s maneuverability,

it added workload to the pilot and was more
vulnerable to damage in dogfights with little

redundancy.

With a fly by wire system, none of this was
needed. The first batch of F-16s actually

had a stick that was immovable. It was just
force sensing. Later a small amount of movement

was added after pilots complained.

So the non movable stick kind of little known
fact, you know the original F 16, it wasn't

a Lockheed Martin product, it was general
dynamics and they had made the F one 11 previously,

tand the weapon system operator on the F one
11 had a small joystick that they could use

to steer the attack radar and that was a force
based movement. It wasn't really a joystick

that would move, it was just the apply force.
And so they took that same concept and then

they put it into the F 16 stick. So it was
sort of a general dynamics thing of we've

got a force transducer, a control in scepter
is what you'd call that.

So what it turns out though is that the human
body, does really well with knowing where

your limbs hands are moving, knowing the position
of your body is something that you naturally

do pretty well, and that is something called
proprioceptive feedback. Well, when I have

a force based inceptor, I don't get that proprioceptive
feedback anymore and it's really hard to judge.

It's something that I think if you challenge
yourself to go pick up a small weight at the

gym and ask yourself, how much does that weigh
without looking at it, it's actually kind

of hard to guess when you're down in those
few pounds range.

And the maximum force you can put on the F
16 sidestick is 25 pounds. So it's kind of

hard to tell the difference between 15 pounds
and 15.2 pounds. We don't do very well with

that. We do a lot better with knowing how
far we've pulled something. And so the original

F 16 controls didn't move, and what pilots
found was that they were having a difficult

time. The test pilots at Edwards were having
a difficult time judging exactly how hard

they would move the controls, and so they
would think they were going to get a certain

response from the jet and then they weren't,
and then they'd pull harder too hard and then

they'd get a different response. there is
a phenomenon called pilot induced oscillations

or pilot in the loop oscillations. Sometimes
it's just shortened to p i o and the F 16,

even to this day, particularly if you have
a lot of wing stores, can have a little bit

of a wing rock on landing. And if you look
at some videos of F sixteens landing, sometimes

you can find if they have wing tanks or they're
bringing back some bombs that they didn't

expend, you'll find an F 16 that'll sort of
do this little back and forth wing rock. And

that is still, to this day, it's an artifact
of having a sidestick that doesn't move very

much because it's one of those things that
in terms of the mind to the hand, eye hand

coordination, you start to make a movement.

By the time you see the effect, it's more
than you wanted. So you take it out, you put

in a correction. By the time the correction
takes effect, it's more than you wanted. You

see it, you come back. It's a feedback loop
in our minds. And now p i o is kind of a dirty

word in aircraft design and nobody wants any
PIOs. I'll tell you PIOs pilot induced oscillations

are like snakes and some snakes are very dangerous
and some snakes are not. And so the P I O

that's remaining in the F 16 in terms of its
wing rock on final at landing is not super

dangerous.

These pilot induced oscillations can also
be naturally stabilized through passive stability.

Where the plane naturally self corrects itself
without pilot input. However the F-16 was

the first aircraft in history to do away with
passive stability and make the plane intentionally

unstable in flight. This was done because
it lowers the energy needed to fly and maneuver.

We can understand why this is with a simple
analogy. Here we have two situations, a ball

placed on top of a hill and a ball placed
in a valley. If we push the ball on top of

the hill, even a tiny bit, it will begin to
accelerate down the hill and will not stop

until we put energy in to slow it down. This
is an unstable system.

The opposite is true for the ball in the valley.
Apply a force and the ball will roll uphill

and gravity will now provide a restoring force
to bring it back. It may oscillate back and

forth a few times before coming to a stop,
but it will eventually return to its original

position. This is a stable system.

We want to tailor our stability to find a
balance between these two scenarios. Where

we can cause a rapid change in direction with
a small energy input, while also managing

the amount of energy required to get back
to our original position. This is called relaxed

static stability.

The F-16 pitch stability is one of the areas
where this idea was applied. One of the key

factors that affects pitch stability is the
location of the center of gravity and center

of lift.

The center of gravity for the F-4 is located
about here. This is the point at which all

lift will act around, it’s like the fulcrum
on a see-saw. As a result of the wing design

the center of lift is slightly behind the
center of gravity. This would force the plane

to pitch downwards, but the horizontal stabilizer
provides counteracting downwards force.

This isn’t ideal, we are wasting energy
on downwards lift.

We need upward lift to fly. It also increases
the amount of energy the F-4 needs to input

to change its pitch.

When it pitches upwards the force on the horizontal
stabilizer decreases because of reduced air

flow, and as a result the weight of the plane,
acting through the center of gravity, forward

of the center of lift, wants to move the nose
down again.

But the pilot is trying to pitch the plane
up, and this natural stability is fighting

them. So more kinetic energy is wasted by
converting it to lift and drag with an increased

elevator deflection.

The F-16 is different. Its center of lift
is ahead of the center of gravity, in part

thanks to those leading edge strakes pushing
the center of lift forward. This means to

balance the plane the horizontal stabilizer
needs to create upwards lift. This is useful

lift and reduces the energy needed to keep
the plane airborne, and increases our maximum

lift pushing this line on our energy maneuverability
diagram up, increasing our turn rate.

However, it is an unstable system. When the
plane pitches up it increases the angle of

attack of the wing and increases the lift.
Because the center of lift is ahead of the

center of gravity this forces the noses up
even more.

In an air to air battle, energy isn’t just
a fuel burning problem. Energy is needed to

maneuver, and as we spend it our ability to
maneuver diminishes until we replenish it

by gaining speed or altitude again.
any fighter pilot will tell you speed is life.

And as a fighter pilot, energy management
is one of the most important things that you

can do. It's part of your situational awareness
in that combat arena. You don't want to get

slow and you don't want to put yourself in
a place where you are vulnerable and now I

can't turn, I can't move, I can't get my sensors
or my weapons engaged where I need to. And

that's not just an air-to-air thing that's
in every aspect of being a fighter pilot.

And that's even engaging in an air-to-ground
arena because oftentimes when you're engaging

air to ground, an interdiction mission, a
strike mission or close air support mission,

well you're supporting friendly troops on
the ground, but there's also people that really

don't like you in the vicinity and they have
weapons also. And so you have to maintain

that energy to be able to evade, to be able
to move out of the way if you're getting shot

at.

And so with the energy management on the F
16, it's interesting that this jet doesn't

really talk to you in terms of feedback to
the pilot. It doesn't really shake and rattle

and vibrate like a lot of other aircraft will
do. I've flown the F 16, I've also flown the

F 15, the F 18, the A 10, and those aircraft
will talk to you. Those other aircraft will

talk to you a lot more than the F 16. The
F 16 just feels smooth all the time, whether

you're 200 knots and really slow or you're
600 knots and really fast, it just sort of

does what you ask it to do. You think you
move the controls just a tiny bit and the

aircraft responds. So managing your energy
becomes a situational awareness challenge

for the fighter pilot. And so a lot of that's
helped now with the joint helmet mounted queuing

system or JE hemic is what it's called, where
right there in your right eye, you've got

your airspeed, you've got your altitude, you've
got your G, and so you can engage visually

in that fight. I can keep my eyes on the threat,
the target, keep situational awareness, and

I don't have to look back in at my heads up
display or down at the console to see how

fast I'm going and how high I'm going. You
get the feel for it. You get a feel for how

the aircraft is responding. But that's where
experience comes in and it's imperative experience

training comes in. It's imperative to maintain
that energy awareness in any kind of fight.

The unstable design of the F-16 helped fighter
pilots like David to manage energy more efficiently,

but to maintain control of an unstable fighter
a pilot would have to make constant tiny corrections.

A task deemed impossible before fly by wire
systems were invented.

The system consists of a network of accelerometers,
gyros and air speed sensors, all fed into

a central computer that manages the work.

This instability makes the plane extremely
nimble, ready to change direction with very

little energy input. We could see this in
practice on the first flight of the F-16 prototype,

the YF-16. A flight that was never supposed
to happen.

This was intended to be a short test along
the runway, but the early control logic of

the plane would not allow the engine nozzle
to open to cut thrust if the wheels had left

the ground. Meaning, even at idle, the plane
was generating too much thrust.

Then the plane rolled left, which caused the
pilot to counteract it with a roll right command,

but again the control logic of the early prototype
was not dialed in, with control input resulting

in higher roll than expected at such a low
speed. Resulting in an over correction, leading

to an oscillation.

With this being the first full fly by wire
plane, there many lessons to be learned along

the way

But the benefits it now provides are game
changing. It helps the pilot get the most

of out of the plane.

So for example, with an F 16, the airframe
is limited to nine Gs. And so I can go and

pull back on the controls on an F 16, and
if I am less than about 300 knots or so, actually

more like 400 knots, I'm not going to get
nine Gs. It's just that's how much lift the

aircraft can make. But once I get above about
400 to four 50 knots, now the wing on the

F 16 is capable of creating at least nine
Gs. In fact, it's capable of creating a lot

more than nine Gs. But what that fly by wire
system does is when I start pulling back all

the way to the stop, it goes to nine Gs and
it sits there. Even if the wing aerodynamic

effect of the whole airframe is that it could
generate 15 GSS or 20 gs, the fly by wire

system says, Hey, I know you're asking for
your best possible turn.

I'm just going to give you nine Gs because
we're not going to break the airplane. Or

again, in a slow speed fight where I'm having
to, it's less than 300 knots. I'm having to

crank the nose around to either bring my nose
onto the adversary or maybe I'm trying to

jin out of the way of an adversary's weapon
system, pull suddenly on the controls of an

aircraft and your angle of attack is going
to increase rapidly. Alright, well with a

lot of more conventional aircraft, you're
worried about things like stall. Well, the

F 16 doesn't really stall in the same kinds
of ways, but that flyby wire system says,

Hey, I know that if you get past about 26
degrees angle of attack, bad things are going

to start to happen. In terms of the controllability,
the F 16 stops behaving as predictably above

26 degrees angle of attack.

And so they fly by a wire system simply says,
that's where I'm going to stop you right there,

and I'm going to give you up to 26 degrees
or nine Gs and do with that whatever you need

to.

A plane capable of 9 g maneuvers is not much
use if the pilot cannot remain conscious during

them. The F-16 has some interesting adaptations
in the cockpit for this.

Traditionally the control stick was mounted
centrally, between the pilots legs. This made

it mechanically simpler, with the network
of mechanical linkages being central and symmetric

throughout the plane. It also allowed the
pilots to use both hands to wrestle the control

surfaces into position during high g maneuvers
as the air flowing by them tried to push them

back down.

For the F-16 this wasn’t a problem, and
the control stick was mounted conveniently

on the pilots right hand console. A comfortable
resting position that makes it far easier

for the pilot to control the plane while trying
to stay conscious at 9 gs.

The seat is also reclined by 30 degrees, this
makes the F-16 feel like an executive office

in the sky with unobstructed 360 degrees thanks
to the bubble canopy, but it also comes with

major advantages to increasing the pilots
g tolerance.

The most common g force a pilot experiences
is directly down. When flying in a straight

line even cells in your body have inertia
in that direction, and when suddenly pitching

the plane upwards, those cells want to continue
traveling in that direction.

This isn’t too much of a problem for cells
to stay fixed, but your blood cells are free

to travel through your body. And in a scenario
like this they race in the direction of that

travel, pooling in your lower extremities.

This starves the pilots brain of oxygen and
they can pass out as a result. This effect

could be minimized by placing the pilot flat
on their back, with the entire body aligned,

blood wouldn’t have to fight gravity to
get to the brain, but this position isn’t

practical.
The F-16 found a compromise with a 30 degree

recline, reducing the pressure on the heart
by the equivalent of about 1 g. The recline

also makes it easier to fit the pilot into
the diminutive forward fuselage of the f-16,

Another measure to increase the pilot's g-tolerance
is the g-suit. A pilots g-suit contains multiple

air bladders that are connected directly to
F-16. When the plane is instructed to perform

a high g-maneuver it immediately begins to
pump compressed air into these bladders. This

squeezes the pilots legs and to limit the
volume available for blood to pool into.

The F-16 is a 45 year old aircraft, and many
advances have occurred in aviation since its

maiden flight, stealth technology and interconnected
intelligence networks have been the main focus

for 5th generation aircraft like the F-35
that have been slowly replacing the F-16,

but one thing hasn’t changed since 1975.
Physics.

The F-16 pushes the boundaries of maneuverability
for a fighter aircraft and the pilots inside.

It’s a highly capable fighter aircraft that
the strongest air force in the world deemed

capable of continuing service until 2048.
The plane will be a major asset in the next

phase of the fight for Ukraines freedom, providing
essential air support to the troops on the

ground as they attempt to push forward through
entrenched Russian defenses.

Ukraine has been targeting long range anti
aircraft batteries with success, and captured

oil platforms off the coast of Crimea that
were housing Russian sensors. All to clear

the way for Ukrainian Su-24s to get close
enough to launch cruise missiles, targeting

high value Russian assets in Crimea, including
a kilo class submarine.

The F-16 can also carry these cruise missiles.
Every asset in the Ukrainian air force is

going to play a vital role in Ukraines fight
for freedom.

Having an actual fighter pilot add context
to this story was incredibly valuable, helping

us truly understand the power of those energy
maneuverability diagrams. We ended up talking

to David for nearly two hours and ended up
cutting an incredibly interesting story from

this video, about how he helped develop an
automatic obstacle avoidance system for the

F-16 that has saved lives. A fascinating system
that works in a way I didn’t expect, I had

assumed it simple uses radar to measure distance,
but that is not how it works. You can watch

that extra video on Nebula right now, along
with an uncut explanation of energy maneuverability

diagrams.

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