AOPA Pilot Magazine - August 2023 - 84

RUDDER & WRENCH
AOPA
CREATE
YOUR LEGACY
Join members like
Michael-a Cirrus pilot and
Legacy Society member-
who support the future of
GA with a gift designated
to the AOPA Foundation in
their estate plans.
"
the Airplane Flying Handbook I keep on my
iPad and set to work. The exposition is a
bit verbose and could benefit from additional
editing, but learning to visualize an
airplane as an energy system is important
for every pilot.
To describe the system, consider an
aircraft contained inside a region of air
particles that surrounds its flight. The aircraft's
kinetic energy (mv2
/2 where m is
the mass) is proportional to the square of
its velocity, so the airspeed indicator is the
best way to measure this energy. Its potential
energy (wh where w is the weight and
h is the altitude above a fixed plane) is proportional
to altitude and is measured on
the altimeter. Kinetic energy plus potential
energy constitutes the aircraft's mechanical
energy.
The aircraft's engine uses fuel to provide
I hope in some small
way my planned gift
allows AOPA to provide
the kind of support and
services to GA that I've
benefitted from for the past
50 years. "
- Michael Samp
AOPA Foundation
Legacy Society member
Visit aopafoundation.org/
legacy to learn more, or visit
aopafoundation.org/will to
access FreeWill*-a will-writing
resource available at no cost to
friends of AOPA.
* FreeWill is one of many
companies that offer online
self-help solutions for common
estate planning needs and
related educational content. Such
companies are not law firms and
their services are not substitutes
for an attorney's advice. Estate
planning can involve both state
and federal laws, and estate
planning needs will differ based
on personal circumstance and
applicable law. If you need estate
planning legal or tax advice,
the State Bar Association that
oversees lawyers in your state of
residence can help connect you
with legal resources.
power (chemical energy per unit of time).
Drag (induced and parasitic, for example)
stirs and heats the air and releases energy in
the aircraft's wake. The net energy (chemical
minus drag) can be used to increase
airspeed, altitude, or a combination of the
two by adjusting the elevator control. The
conservation of energy law implies that the
total energy of the system remains constant
even though one form might be traded for
another. The pilot controls the total energy
with the throttle and distributes it using
the elevator control to meet airspeed and
altitude goals.
In constant-speed cruise flight, the
kinetic and potential energies remain
constant, and the energy produced by the
engine matches that energy released into
the atmosphere because of drag. While
mechanical energy remains constant,
the pilot can use the elevator control to
exchange potential energy for kinetic
energy. Langewiesche calls this the " law of
the roller coaster. " Pushing forward on the
yoke increases the airspeed and descent
rate and pulling back on the yoke has the
opposite effect.
The collection of parallel curves in the
figure below describes the roller coaster
effect. For example, the pilot flying at 150
knots at 4,000 feet can push the yoke forward
and achieve 250 knots around 2,000
feet with no change in mechanical energy
(A to B). Moving from one point to another
along one of these curves can be accomplished
using only the elevator.
16
PA=Excess Power Available
14
12
10
8
6
4
2
50
C
A
B
Vy
100 150 200 250 300 350
Airspeed (kts)
84
AOPA PILOT / August 2023
Altitude (1000 ft)
PA=0
PA=200
PA=400
PA=600
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AOPA Pilot Magazine - August 2023

Table of Contents for the Digital Edition of AOPA Pilot Magazine - August 2023
