AOPA Turbine Pilot Magazine - December 2023 - 35

In a test, a 55-pound, fixed-wing drone
powered by one propulsor overflew microphones
at cruise speed and 200 feet agl. The
drone was so quiet it could not be detected by
sound-measuring equipment.
Whisper Aero's current propulsors generate
11 or 72 pounds of thrust but they are scalable
from 5 to 500-plus pounds. Moore says
scalability will allow the propulsors to power
an aircraft the size of a Boeing 737 and reach
speeds of 0.7 to 0.8 Mach.
Whisper Aero has created an aircraft
concept called " Whisper Jet " to illustrate the
company's propulsion technology. They don't
want to build the aircraft themselves because
they aren't aircraft builders. But they're happy
to help anyone who wants to.
The Whisper jet concept creates a unique
aircraft with takeoff weight, passenger load,
and performance similar to a Beech King Air
B200. Its 22 propulsors should push the 12,500pound
Whisper jet along at 250 knots with nine
passengers. Flying on batteries, range is listed
at 200 nm and a hybrid power version should
reach 500 nm.
Whisper Aero's technology, says Moore, " is
what aerospace engineers have always wanted
to do. And that is: completely couple the wing
lift and the propulsion system so that it is one
integrated system that is much more effective
than either by themselves. "
The Whisper jet propulsors will be built as
part of the leading edge of the 50-foot wingspan.
Each propulsor ingests smooth, undisturbed air
while maintaining wing camber. They exhaust
over the wing in a jetfoil that creates a near
continuous flow of compressed air across the
wing from wing root to wing tip. With the
propulsor internal to the wing, and with the
over wing exhausting, the setup further reduces
aircraft noise while increasing lift.
Ganged together, the Whisper Aero
propulsors are married to aerodynamics that
are at once old and new. " What Whisper [Aero]
has come up with, " said Moore, " is the idealized
equivalent of a Custer Wing with circulation
control without any of the wasted structural
weight and drag of the side walls of the duct. "
Thanks to the Coanda effect-where a fluid
jet (i.e., air) tends to stay attached to a convex
surface-the propulsor thrust follows the camber
of the wing and the mid-wing flow creates
a high coefficient of lift, up to 10 times more
lift than a conventional wing. As an edge of
excitement creeps into his voice, Moore says
One of the advantages of the Coanda Effect
is at extreme angles of attack. Moore says the
wing has been tested to nearly 45 degrees " and
still not stalled because the propulsion system
is keeping the flow attached. There is no
stall until you are at a ridiculous angle! So, all
three of those things are just enormous breakthroughs
for a GA pilot: safety, performance,
and ride quality are enormously improved. "
And for the folks on the ground, there is
the joy of silence. Tim Wright is a pilot and
freelance aviation writer from Virginia.
AOPA PILOT / December 2023
35
Whisper Aero offers a new
propulsion technology in its
Whisper Jet design.
The Whisper Jet design
features room for nine
passengers.
Whisper Jet " gets
such a fantastic CL
MAX that the wing
loading can go up to 60
to 80 pounds per square foot and still be able
to take off in 2,500 feet. That means, for the
exact same amount of power, you can cruise
about 50 knots faster because with higher wing
loading your wing wetted area decreases and
you are able to cruise at your L/DMAX. So,
you get high speed cruise efficiency, you get
great ride quality, and in terms of safety, you
get improved pattern safety speeds. "
MARK MOORE
AOPA Turbine Pilot Magazine - December 2023

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