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Old August 24th 05, 02:36 AM
Dudley Henriques
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Below I've pasted in part of a tutorial I did on slow rolls for the flight
sim community on the Griffon Spitfire package from RealAir. The tutorial is
patterned after the way I did slow rolls while demonstrating the P51 Mustang
in real life, but you will find the information pertains to a Pitts or the
Decatholn as well.
Hope it helps a bit.
Dudley Henriques


Slow Rolls in High Performance Prop Fighters

Dudley Henriques
International Fighter Pilots Fellowship

With the entry of the Realair Griffon Mk 14 Spitfire into the WW2 military
market for MSFS, a whole new world of flight experience is now possible in
MSFS for those sim pilots interested in this area of aviation.
I receive a lot of email from sim enthusiasts asking me for information
about the technique required to fly the hot prop fighters. Since I did a
fair amount of this type of flying in real life, I try and answer these
requests when I can.
It has occured to me that you folks at Avsim might wish to share in this
information, so I’m pasting in this tutorial for you as well.
I sincerely hope this information serves to make your flight simulation
experience more educational and enjoyable.

This tutorial deals specifically with the slow roll, which I touched on in
an earlier tutorial about rolls in general.
From my mail it has become apparent that a more detailed tutorial on doing
slow rolls specifically in prop fighters, in particular the Realair Griffon
Spitfire, might be helpful. Along those lines, I have prepared the following
information for those of you who have the Spit, or are possibly thinking
about purchasing this absolutely marvelous and beautiful addition to MSFS.

First off, let me say a few things about controllers used in the sim and
aerobatics.
A slow roll requires some cross controlling, and this is best accomplished
with a stick, separate throttle, and rudder pedals. I realize that some of
you don’t have this. I’ll explain the roll using the optimum controller
setup and those of you using other controllers can “adjust” to do what’s
necessary with your individual controllers.
Actually, aside from a slow roll, a hammerhead, snap rolls, and spins, you
single controller folks can do almost anything else in the book; Aileron
Rolls, Loops, Cubans, Reverse Cubans, Barrel Rolls; almost anything that
doesn’t require cross controlling the airplane, so don’t dispair. There’s
enough aerobatics in the book for everybody
I did try a slow roll with a Sidewinder , and although it was unusual, I
could do it all right. practice is the key.

The following is a tutorial on how to fly a good slow roll in a prop
fighter. Although it’s edited for the simulator, it basically contains the
same information I used in demonstrating these airplanes in real life.

To understand the slow roll is to understand the airplane and proper control
use. Of all the aerobatic maneuvers possible, the slow roll is perhaps the
hardest to master. It requires flying the airplane diliberately and smoothly
through 360 degrees on it’s longitudinal axis. It requires placing the
airplane at an exact place in the sky and keeping it there through control
use that is totally unique to the slow roll, and in many cases completely
foreign to a pilot’s natural instinct as that instinct relates to
coordination.
To fly through a slow roll correctly requires a high degree of concentration
and skill.

Although a slow roll can be executed from almost any flight attitude, I will
use a level flight entry for our example. If you can perform a level slow
roll, you can perform one anywhere in the flight envelope.
The first thing we learn in discussing rolls of any kind in a high
performance prop fighter is that the direction of prop rotation establishes
what we call a torque side. What this means basically is that due to the
various forces in play with propeller rotation and engine combination, a
prop fighter is “handed” with a side that will result in a faster roll rate
available to a specific side. In the P51 for example, the propeller rotates
to the right as seen from the cockpit. The torque side for the Mustang is
the left side. It rolls faster and easier to that side. The reverse would be
true for the Griffon Spitfire, as it’s Rotol propeller rotates to the left,
making it’s torque side the right side. It rolls better to the right.
Now, using the Griffon Spitfire and rolling to the right, let’s visualize
where we have to put the airplane in the sky to do a decent slow roll.
Visualize a capital letter D. This is the key to visualizing our slow roll.
The first thing we learn here is how that letter D relates to the roll.
Imagine a horizontal line going right through the center of this D from left
to right like this -------D-------- . That line is the horizon. Now let’s
define how this D relates to the nose attitude of the Spitfire from start to
finish through the roll.
The vertical line of the D on the left side represents the nose attitude at
the bottom of that line for level flight below the horizon. The top of that
vertical line represents the distance above the horizon where we will
execute the first half of the slow roll; from right side up to inverted.
Now notice the curved line on the right side of the D. That line represents
the second half of our slow roll. The reason we have to raise the nose to do
the first half of the roll is because the Spitfire, and most any WW2 era
prop fighter will have a higher nose attitude inverted in level flight than
for normal level flight due to a required higher angle of attack on the wing
in inverted flight. The reason for the curve on the D is because the
airplane has to return to it’s normal level flight nose attitude below the
horizon line at the completion of the roll.
So what have we learned right off the bat? The roll isn’t done in level
flight at all. It’s done by raising the nose to a distance equal above the
horizon to where it is normally in level flight below the horizon.. Then
after rolling inverted on the exact top of that vertical line of the D, we
perform the second half of the roll allowing the nose to return to level
flight below the horizon.
Got the visualization?? Now, how do we do all this?



First, let’s climb the Spit up to 5000feet and level off. Bring the power
back to about 0 boost with the prop in automatic. Stabilize the airplane in
level flight at cruise. Now, let’s learn to do a slow roll the right way.
For ease of explanation, I’m going to take the slow roll and split it into
conveinent sections of 45 degrees each so we can examine the control inputs
vs the roll as it progresses. We’ll have the first 45 degree point, the
second 45 degree point at the first knife edge at 90 degrees, the third 45
degree point (at 135 degrees), the forth 45 degree point at full inverted at
180 degrees, the fifth 45 degree point (at 225 degrees into the roll), the
sixth 45 degree point at the second knife edge at 270 degrees, the seventh
45 degree point (at 315 degrees into the roll), and then back again to level
flight.
Keep in mind this isn’t a hesitation roll. I’m just using the points for
reference during what will be a smooth continious fluid maneuver without
hesitation from start to finish.

In the Spitfire, you want an entry airspeed of 250MPH IAS for the roll
initiation.
The secret in doing aerobatics in a warbird of any kind is smoothness. There
should be no quick movement of the controls, either in real life, or in the
simulator.
Now, ease the nose down gently and pick up your entry speed at 250. The nose
will now be lower than your normal level flight attitude below the horizon.
Remember that vertical line on the D. You’re starting a bit below the bottom
of that line, but where you want to put the nose at the top is equal above
the horizon line to where it was in NORMAL LEVEL FLIGHT, not where you’re
beginning the roll!
Now, gently raise the nose and go up the vertical line of the D and PIN IT
at the top. In the Spit, this will be about 20 degrees above the horizon.
THAT SPOT is where you will do the first half of your slow roll by PINNING
the nose right at that spot as you roll through the first 180 degrees of the
roll.
Now, you set the nose by neutralizing the controls for just an instant. You
want all back pressure removed from the stick...NONE! Now let’s stop right
here for just a moment and discuss what happens as you initiate the roll. We’ll
be rolling to the right for two reasons. First, it’s the Spit’s torque side
and the roll is easier in that direction. (You should also note that the
Spit will roll quite nicely to the other side, but without the aid of the
prevailing torque forces) Secondly, because our capital D defines a roll to
the right and is easier to visualize as a teaching aid.
It helps a great deal here if you completely understand what happens in the
roll entry and how you can take advantage of what happens. This next
sentence is VITAL, so memorize it cold!! In a slow roll, you will be
applying aileron at a constant smooth and steady rate until you are at max
deflection. You will be VARYING control inputs for the elevators and rudder
all through the roll while changing rudder from one side to the other. This
can take some practice to do well, so don’t get discouraged. PRACTICE!!!
As you apply rolling aileron (right in this case) you will generate adverse
yaw to the left.
A slow roll entry gives us a very interesting situation. To counter the
adverse yaw, we need right rudder applied with the aileron. That will take
care of a coordinated entry, but if we hold that right rudder in there too
long, we’ll begin to pull the nose down, which is exactly what we DON’T want
to do. We want the nose pinned; so how do we do this?
Ok...we’re applying right aileron and just a touch of right rudder to
coordinate the roll entry.......then almost immediately, we switch feet and
go to the left rudder. This holds the nose up during the first 45 degrees of
roll. As we pass through 45 degrees, we’re applying aileron and now entering
some forward stick with the left rudder. If you visualize what’s happening
to the airplane, you will see that the left rudder is taking the role of the
elevators during the first 45 degrees of the roll and holding up the nose.
Now as you go through that 45 degrees of roll, the forward stick is helping
the rudder keep the nose pinned. You are in effect trading off the elevators
and the rudder as needed to keep that nose pinned where it is AS you are
applying the aileron, which is the control producing the roll!!
Remember....it’s the aileron that is producing the roll. Keep the aileron
applied!!!!!
Now, we’re at the first knife edge. Here you should have maximum left rudder
and some forward stick. As you roll past knife edge, the STICK FORWARD now
becomes the prime control keeping the nose pinned ss the elevators are now
holding the nose up. You apply as much forward stick as you need while
keeping the aileron applied to max at this point. The stick should be well
in the right front corner of the cockpit by now and you should have on left
rudder.
As the roll goes through the .next 45 degree point, you are headed toward
inverted at the top of the roll. You now have to begin coming off that left
rudder timing it so that you are exactly at a neutral rudder as the nose
passes through the inverted position.
Now.....(and you thought this was going to be easy )))
As the airplane passes through inverted flight at the top of the roll, it
will be, (if you have pinned the nose correctly that is) at it’s natural
nose attitude for inverted flight above the horizon an equal distance that
it would be below the horizon in normal level flight.
Now, you switch rudder to the right rudder as you are holding in forward
stick and rolling aileron. Now you are starting the airplane down from the
top of the roll and back down that curve in the D toward level flight again.
You’re rolling and letting the nose come down by easing off the inside
rudder and forward stick to time everything to again be neutral as the nose
returns back to level flight. By easing off the forward stick and the
rudder, in effect, the last part of the roll will be just like a turn
recovery. Getting this exactly right takes practice.

Well, you now know how a slow roll is done in a Griffon Spitfire, or in any
WW2 era prop fighter for that matter.
I sincerely hope you get interested in this type of flying. It’s different.
It’s unusual, it's challenging, and it will produce for you a great deal of
flying education.

End of tutorial


"Nobody" wrote in message
...
I'm curious to know how others do slow rolls in a Super D. I learned to
do
them without rudder. I was told that for a full deflection slow roll, no
rudder is required. To me, they look fine. I draw the lolipop on the
horizon. It just seems odd that they don't require rudder.

Here's how I do them.

1. Establish entry speed, 130 mph.
2. Pitch slightly nose high, neutralize, then full deflection.
3. At 90 degrees, vertical bank, begin slow push.
4. At 270 degrees start stick back.
5. Roll level.


TIA






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