SAE INTERNATIONAL
Objectives
• Emphasize a “gap” in the capabilities of modern aircraft
• Introduce the challenge Mr. Frank Harris posed in his
presentation, The V/STOL Performance Gap (VTOL-sf.org), to fill
this gap
• Explain the need for VTOL commercial transport
• Present a novel VTOL configuration
• Highlight how this design stands out from what currently exists
• Discuss a preliminary look into the technology
• Get people to start thinking of ways to close this gap
Objectives
2
SAE INTERNATIONAL
The complicated
problem called VTOL
• Fixed wing type
certificates issued at
a much greater rate
than VTOL
machines
The Complicated Problem Called VTOL
3
THERE ARE A LOT OF CHALLENGES TO OVERCOME WITH VTOL
SAE INTERNATIONAL
The performance gap
• For the same ESHP
(equivalent shaft
horsepower) per unit
weight, fixed wing aircraft
are remarkably faster
• Setting ESHP aside,
there is an obvious
separation between the
cruise speed of fixed
wing and VTOL aircraft
The Performance Gap
4
CURRENT VTOL DESIGNS INHIBIT HIGH CRUISE SPEEDS
SAE INTERNATIONAL
NASA-identified aviation
mega drivers
• Global mobility
• Accessibility
• Cost
• Speed
• Technological convergence
• Safety
• Comfort
• Noise reduction
• Environmental challenges
• Efficient
• Reduced fuel burn
NASA-Identified Aviation Mega Drivers
5
DESIGN NEEDED TO FLOURISH CROSS CULTURAL
DEVELOPMENT
SAE INTERNATIONAL
Current concepts’
runway dependence
• Runway dependent
aircraft have a strong
relation between max
speed and landing
speed
• Higher landing speeds
require longer runways
Current Concepts’ Runway Dependence
6
CURRENT COMMERCIAL DESIGNS MAKE TRANPORATION
VIABLE ONLY WITH LONG RUNWAYS
SAE INTERNATIONAL
Benefits of VTOL capability
• Gate-to-gate time reduced
• No taxiing leads to lower
fuel consumption
• Users can get from point A
to point B quickly without
needing a runway
• Vertiports can begin to
appear everywhere and
anywhere
• Reduces noise levels for
airport neighbors since the
aircraft’s ascent and
descent occur directly over
the LZ
Benefits of VTOL Capability
7
FAST AND ACCESSIBLE MEANS OF TRANPORTATION
SAE INTERNATIONAL
Past and current concepts
• There have been many
ideas to bring increased
speed to the VTOL realm
• Majority of new concepts
lack enough benefits to
pursue commercially
Past and Current Concepts
8
NEW CONCEPTS ARE COMMON AND POSSIBLE
SAE INTERNATIONAL
Making progress, but
we’re not there yet
• In recent years some
new VTOL concepts
have begun to close
the speed gap
• Still much room to
cover
Making Progress, but We’re Not There Yet
9
A NOVEL APPROACH NEEDED TO SOLVE THE PROBLEM
SAE INTERNATIONAL
A novel concept: Project pt. 85
• VTOL capable runway independent aircraft
• High subsonic, low transonic cruise speeds
• Range of configurations possible
• Boeing 737 size shown below in hover configuration
A Novel Concept: Project pt. 85
10
A POTENTIAL SOLUTION TO CLOSE THE SPEED GAP
Not To Scale
SAE INTERNATIONAL
Turbolift engine technology
• Lifting surface placed in fan exhaust stream
• End plate design used to combat low AR
• Controllable angle-of-attack
• Turbine exhaust directed above (away from) Turbolift wing
Turbolift Engine Technology
11
USING THE EXHAUST ENERGY TO OUR ADVANTAGE
Rear Engine
Exhaust
Flow
Not To Scale
𝑉∞
SAE INTERNATIONAL
Conversion method/ VTOL
& cruise
• The 4 Turbolift engines
allow for a vertical ascent
from the terminal
• The thrust of the front
two engines is
decreased to provide a
net forward thrust
accelerating the aircraft
• Once adequate lift is
established on the wing,
the forward two engines
spool down and stow
Conversion Method/ VTOL & Cruise
12
STOWED ENGINES ACT AS TIP MOUNTED TANKS FOR MAIN
WING AERODYNAMIC BENEFITS
Front Engine
Exhaust
Flow
𝑉∞
SAE INTERNATIONAL
Configuration size, speed,
range
• Regional or mainline
• Commercial transport
• 150 pax
• VTOL, high subsonic,
low transonic cruise
• 300-450 knots at
altitude
• Can be configured to
short, medium, or long
range
Configuration Size, Speed, Range
13
TARGETS LARGE PERCENTAGE OF FLIGHTS TAKING OFF IN THE
U.S.
SAE INTERNATIONAL
Metric Project pt. 85 Boeing 737-700
Runway Requirement 0 ft 5,520 ft
Seating Capacity 149 pax 149 pax
Max. Gross Weight 157,000 lbs 155,000 lbs
Wing Area 646 ft^2 1340 ft^2
Wing Loading (MGW) 244 lbs/ft^2 115 lbs/ft^2
Max. Cruise Speed 450 kts 450 kts
Cruise Altitude 35,000 ft 35,000 ft
Engine LEAP-1A CFM56-7B20
Performance Comparison
15
A COMPETITIVE VERTICAL TAKE OFF AND LANDING CONCEPT
SAE INTERNATIONAL
Safety
• 1 engine out
considerations
• Option 1 (emergency
conversion): Accelerate forward to
establish lift, then fly to
nearest capable
runway
• Option 2 (emergency
landing): In the event
of being too low to carry
out option 1, a hard
landing is performed
Safety
16
FAA TYPE CERTIFICATE POSSIBLE
SAE INTERNATIONAL
Conclusions
• There is obvious need for an efficient commercial VTOL vehicle
• New ideas and concepts continue to close in on the “Speed Gap”
between fixed wing and VTOL
• Project pt. 85 helps put into perspective what it would truly mean to
have a means of transportation as described
• Commercial V/STOL configurable for multiple airliner
configurations with flight envelope to Mach .85
• Zero length runway requirement
• Taxiing is essentially eliminated
• Creates the accessibility to open vertiports almost anywhere
• Decreased noise impact on surroundings during climb and
descent to/from cruise
• The design presented competes favorably with a 737 type transport
Conclusions
17
SAE INTERNATIONAL
Next steps/ vision
• Further develop
the current
configuration
• Continue thinking
of out of the box
ways to close the
speed gap
Next Steps/ Vision
18
VISION: A WORLD WHERE EVERYONE FLIES EVERYWHERE