Before we go on, I asked our own Andy
Bush to give us a good summary of how he feels the F-104 and
F-4 handle since he has extensive stick time with both aircraft.
Overview
The question is one of how do the
F-104 and the F-4 fly in the sim as compared to real life.
Well, folks…that can be a tricky question depending
on what we are talking about. Here’s why.
We begin by considering just what
the average simmer expects to see when he flies the two
aircraft. What is he looking for in the way of performance,
and what is he using as measuring stick? The fact of the
matter is that few if any of the simming crowd have any
experience at all in these jets. Oh sure…they may have
heard things…they may have read things…but, let
me tell you from personal experience, what folks have often
heard or read is misstated at best and is complete hooey
at worst!
So…what is it that the typical
simmer expects to see in these two jets? High speeds? Yes.
Good acceleration? Yes again. Hmmm…I’m running
out of ideas! Other than these two characteristics, what
do you want to see? As an answer, let’s start by telling
you what I see.
Think of a flight model as a bell
curve. Add to this that the curve looks at both speed and
behavior under G. Most of the curve is within the region
that goes from the "flaps up" speed to the maximum
speed…and from one G to the onset of the stall. The
outside boundaries include slow speed performance and acceleration
when unloaded on the left side to stall/departure characteristics
on the right side.
As a general statement, the Strike
Fighters F-104 and F-4 do reasonably well in the center
portion of their flight envelopes. The jets fly as fast
as their real life counterparts did, and they fly as high
as well. If that were all they we were interested in, then
things would be grand. But, that is not the case…because
it is in the two outside portions of the flight model bell
curve that things go astray. There are three major areas
of concern…roll performance, slow speed/drag performance,
and high speed/accelerated stall performance. Let’s
look at this by taking a typical flight from takeoff to
landing.
Ground Operations and Takeoff/
Acceleration To Cruise Speeds
Ground operations with these two
fighters is much the same as with the A-4 and F-100. The
jets are responsive to throttle input. Ground steering is
done using the rudder, and care must be taken that you limit
your taxi speeds to avoid high-speed turns that take you
off into the "boondocks"!
Takeoff performance is acceptable.
We have to remember that these aircraft could be loaded
with a wide range of external stores. Both takeoff weights
and drag values could, and did, vary considerably. When
I fly these sims, my objective is just to get airborne…so,
as long as the takeoff performance is anywhere close to
what I would expect in real life, then I’m happy. SF
presents no significant problems in this area of the flight
model.
General Flight Characteristics
This area discusses what we can
expect to see in the "heart of the envelope" part
of the flight model. Two items come immediately to mind…pitch
and roll performance.
Pitch performance is over-modeled
in SF. Now, that’s a bold statement! Just what do we
mean by that?
What we mean is that it is possible
to exceed the pitch performance of the real life aircraft
by a considerable margin. The problem here is not under-performance
or over-performance. It is, instead, the pitch response
that you get from the typical flight stick movement. In
this sim, these jets can reach pitch rates and G levels
that were unattainable in real life. Why? Because in real
life, the pilot would not deliberately over-G his plane
to the extent that the sim pilot can in SF. In this regard,
SF is not too different from other sims. We need something
that limits the simmer’s ability to command unrealistic
pitch and G rates. Blackouts just don’t cut the mustard.
The simple fact is that no real life F-104 or F-4 pilot
would yank back on the stick to command a 10 G pitch up.
Some other pitch rate constraint is needed other than the
blackout effect. Until we get such a feature, we’ll
likely continue to fly our sim aircraft in an unrealistic
manner.
As an interim fix, we can only ask
the simmer to pay attention to back stick inputs…the
jets have G meters…use them to control excessive pitch
rates. Remember, these two jets had a G limit of about 7
Gs. So, if you want to fly these jets correctly, use the
G meter to get a feel for how hard you can pull on the pole.
An over-G in real life was a big deal...a potential showstopper
if the limit was busted too badly since the jet was likely
busted too.
Roll performance is the next problem
area. Roll inertia refers to the plane’s tendency to
resist the initiation of a roll…and its tendency to
continue a roll when the aileron is neutralized. Initial
roll rate is good. These jets roll at rates that approximate
real life. No problem there. The problem comes in when we
want to stop the roll.
Both of these jets exhibit too much
roll inertia. This simply means that they continue to roll
when the aileron input is taken out (neutralized). In real
life, these aircraft tended to stop rolling quickly, particularly
if a little opposite aileron was used to counter the roll.
This flight model feature was necessary to achieve the ability
to point the jet quickly at a target. The roll axis needed
to be easily controlled. Not so in this sim. Both jets will
over-shoot the roll out point unless the aileron input is
taken out early in the roll. The tendency to continue rolling
is likened to a pendulum effect…once the roll is established,
the roll will try to resist an attempt to stop it. The result
is typically an over-banked attitude that the pilot must
then correct. This is both irritating and a waste of time
when time is often critical. The only correction for the
simmer is to moderate roll inputs so that the pendulum effect
is minimized.
Slow Speed Performance
Let’s look at two things here.
One is drag…how these jets either hold their energy
or lose it. The other is the actual response to flight control
inputs at slow speed. First the drag issue.
In one G flight, drag is significantly
under-modeled in the F-104 and F-4. Simply put, these jets
don’t want to slow down. This is the case clean or
dirty (speed brake, gear, and flaps down). When you come
in for a landing, you must allow extra time and distance
to get these jets down to your approach speeds. In our opinion,
the rate of deceleration is only about a third of what would
be expected in real life. Once configured, the power setting
needed to hold the approach speed is much lower than would
be expected…almost idle in some configurations.
The second issue of slow speed performance
is the response of the jet to control input. To more accurately
discuss this subject, we should substitute the term "high
AOA" for "slow speed". The F-4 in real life
was very sensitive to rudder input at high AOA. In fact,
in the non-slatted versions (C, D, and "hard wing"
E models), the rudder, not the aileron, was the primary
roll control at high AOA. The reason was that the aileron
under high AOA contributed too much adverse yaw. The F-4,
being a swept wing aircraft, responded to rudder input with
a roll at high AOA, and this is powerfully modeled in the
sim. Push the rudder in at high AOA and you’ll get
a good roll rate. That’s the good news.
The bad news is that the same roll
inertia that was present in aileron rolls is again present
in rudder rolls. It is easy to overshoot the roll out point
when using rudder to roll the F-4, and if the rudder is
not carefully used, it can easily progress into an out-of-control
situation.
Rudder as currently modeled in the
F-104 is incorrect. The aircraft rolls when rudder is applied…unfortunately,
the roll is opposite the direction of rudder input. Not
good! Hopefully this error will be fixed in future patches.
Rudder effectiveness in the real life F-104 was relatively
inconsequential as compared to the F-104. It would not roll
the aircraft to any degree at high AOA. The F-104 was rolled
with aileron, plain and simple.
Stall and Departure Characteristics
The F-104 and F-4 had completely
different stall and departure characteristics in real life.
In the sim, they are basically the same.
In real life, the F-104 experienced
a phenomena known as a "pitch up" when flown at
too high of an AOA. This pitch up occurred before a traditional
stall. Pitch up is not modeled in SF. Because of this, high
AOA maneuvering is very unrealistic in the F-104. The sim
pilot can fly the F-104 into pitch attitudes and conditions
that the real life pilot would have never reached. The SF
F-104 can be hauled around with relative abandon.
The F-4 stall and departure characteristics
are modeled much better than the F-104. If pushed too far,
the jet will begin an uncommanded roll and may enter a spin
if forward stick is not used to break the stall. Departures
in the real jet were very unpredictable, and their nature
was dependent on entry speed. High speed and high G/AOA
departures could be very violent. The SF F-4 models this
to a limited degree, but the overall effect is a reasonable
replication of real life.
In both aircraft, flaps are effective
when maneuvering at slow speeds, just as was the case in
real life. Flap limiting speeds are recognized when lowering
the flaps, but once down, the flap limiting speed can be
exceeded without any apparent damage.
Summary
The flight models of both
aircraft provide a moderately challenging replication of
real life jet flying. While some specific errors do detract
from a realistic depiction of real world performance, the
overall effect is a scalable flight model that enhances
gameplay and player enjoyment without being so demanding
that discouragement results.
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