NASA is developing a 19-passenger commuter aircraft that uses Distributed Electric Propulsion (DEP) technology to outperform conventional turboprop aircraft. The DEP aircraft is designed to have a range of 875 miles, cruise speed of 250 mph, and service ceiling of 28,000 feet. It will be powered by 10 electric motors and have a maximum takeoff weight of 16,860 pounds. NASA estimates it will cost $1.06 billion to develop the aircraft, but it could generate $292.6 million in profits if 310 are sold.

1. NASA’s Distributed
Electric Propulsion Aircraft
Final Presentation
Harley Austin, Nathan Brockett, Joseph Damis, Darren Slotnick, Ian
Fitzsimmons, John Macnamara, Nicholas Noell, Mitansh Shah

2. Aircraft Mission and Design Requirements
❖ To design a commuter aircraft that applies
Distributed Electric Propulsion (DEP)
technology to outperform a conventional
turboprop in one or more key areas.
❖ Aircraft should be ready for service by the year
2025.
Objective: Requirements:
❖ Passenger capacity of 19 with a 31-inch seat pitch. Assuming
passenger baggage weight of 225 lb.
❖ All-weather capability, including the ability to fly in icing
conditions.
❖ Cruise Speed: 250 mph
❖ Service Ceiling: 28,000 ft.
❖ Range Requirement: Capable of capturing at least 90%
of the 19 passenger commercial commuter aircraft
market.
❖ Takeoff & Landing Field Length no greater than 3000 ft.
at maximum takeoff weight (sea level)
Design philosophy:
❖ Stability & Safety
❖ Operating cost
❖ Cruise efficiency
❖ Takeoff and landing performance

3. Benefits of DEP
❖ Integration of electric motor driven propellers on airframe
➢ Increases dynamic pressure across entire wing surface
❖ DEP allows for control of lift distribution across span by individually controlling
propeller speeds and the resulting slipstream.
❖ More efficient throughout flight
http://www.jobyaviation.com/LEAPTech(AIAA).pdf

4. Trade & Concept Studies
Propeller Design
❖ Advanced Ratio
❖ Variable Pitch
Turbine Location

5. Three View Drawing

6. Top-Down View

7. Inboard Profile View

8. Aircraft Specifications - Sizing
Wing Parameters
Wing area 286 ft2
Span 58 ft.
AR 11.8
Taper Ratio 0.57
MAC 5.05 ft.
Airfoil LS(1) -0417
(GA(W)-1)
Vertical Tail
Span 15 ft.
Area 106 ft2
Chord 7.1 ft.
LVT 21 ft.
Horizontal Tail
Span 19 ft.
Area 106 ft2
Chord 5.5 ft.
LHT 19 ft.

9. Aircraft Specifications - Weight Estimation
Weights
Maximum TOGW 16860 lbs
Payload 4950 lbs
Empty Weight 9240 lbs
Fuel Weight 1250 lbs

10. Aircraft Specifications - Engines
Weigh
t
Takeoff
Thrust
Continuou
s Thrust
CTSFC Heigh
t
Widt
h
Length
665 lb 1970 shp 1785 shp 0.591
lb/shp
2.71 ft 3.61
ft
5.51 ft
PT6T-6B Turboprop
Number
of
Motors
RPM Power Weight
10 2500 RPM 200 hp 60 lbs
Siemens Electric Motor

11. Performance

12. Constraint Diagram
Design
Space

13. Drag Buildup (Sea Level)

14. Drag Buildup (Cruise @15,000 ft)
Cruise Speed @ Max L/D:
215 knots = 247 mph

15. Power Required vs. Power Available

16. Power Required vs. Power Available (15,000 ft)
Cruising Altitude

17. Rate-of-Climb vs. Altitude
Service Ceiling: 28,300 ft.
Absolute Ceiling: 30,600 ft.
Time to climb to cruise: 11 minutes

18. Aircraft Specifications - Range
Requirement: Secure 90% of 19 passenger commercial commuter aircraft market
Target Range: 875 miles
Range at Cruise: 925 miles
Using Breguet Range Equation

19. LS(1)-0417 (GA(W)-1) Airfoil & Lift-Curve Slope
CLmax (with flaps) 4.24
Wing CLalpha 0.098/deg
Horizontal Tail CLalpha 0.061/deg
LS(1)-0417 (GA(W)-1) Airfoil Reynolds Number = 6,000,000 Mach=0.36

20. Aircraft Specifications - Performance
Max Lift coefficient of 4.24 Landing Configuration: Single-
slotted Fowler Flaps
Stall speed = 98 ft/s
Parameter Sea Level Cruise (15,000 feet)
Stall speed w/ Fowler flaps deployed 98 ft/s = 67 mph 137 ft/s = 93 mph
Stall speed w/o Fowler split flaps deployed 135 ft/s = 92 mph 170 ft/s = 116 mph

21. Takeoff & Landing Distances
Takeoff
Ground Distance 590 ft.
Roll Distance 262 ft.
Transition Distance 1330 ft.
Climb Distance 74 ft.
Total 2257 ft.
Landing
Air Distance 1213 ft.
Free Roll Distance 339 ft.
Braking Distance 849 ft.
Total 2402 ft.

22. Fuel Efficiency
Power Fuel
Consumption
Sea-Level at
250 mph
673 hp 397.7 lb/hr
10,000 ft. at
250 mph
564 hp 333.3 lb/hr
25,000 ft. at
250 mph
473 hp 279.5 lb/hr
Hp,lb/hr

23. Stability and Control

24. Longitudinal Stability
Neutral Point 78% MAC
C.G. 59% MAC
Static Margin 19% MAC
Stick Free Neutral Point 68% MAC
C.G. 59% MAC
Stick Free Static Margin 9% MAC

25. Horizontal Tail Sizing
CHT 1.4
SHT 106 ft^2
Chord 5.5ft
Cabin Fill Case CG Location
Full 59 % MAC
Front half full 40 % MAC
Back half full 77 % MAC
Empty 61.5 % MAC

26. C.G. Limit Representation
C.G.
Front Half Full
Back Half Full
Neutral Point
Forward Limit

27. Vertical Tail (One Side Out)
SVT 106.5 ft^2
Max deflection 20°
% Chord for Rudder 22%
Elevator and Rudder Sizing
• Thin Airfoil Theory
results:
Horizontal Tail
CL max 1.0
Max deflection 20°
% Chord for Elevator 22%

28. Aileron Sizing
• 60 degree roll
•Takeoff: 10 seconds @1.2 Vstall
•Approach: 7 seconds @Vstall
• Maximum deflection: 25 degrees
• Outboard location: 95% of half-span
• 10.05 feet in length
• 15.23 square feet

29. Structures

30. V-n Diagrams: Sea Level MTOW
Vstall VA Vc VD
Velocity Load Factor
Vstall 64 kts 1.0
VA 112 kts 3.03
VB -- --
Vc 215 kts 3.03
VD 300 kts 3.03

31. V-n Diagrams: Start of Cruise
Vstall VA VB / Vc VD Velocity Load Factor
Vstall 97 kts 1.0
VA 169 kts 3.1
VB 215 kts 3.1
Vc 215 kts 3.1
VD 300 kts 3.1

32. V-n Diagrams: End of Cruise
Vstalll VA VB Vc VD
Velocity Load Factor
Vstall 89 kts 1.0
VA 159 kts 3.1
VB 193 kts 3.1
Vc 215 kts 3.33
VD 300 kts 3.1

33. Structures: Spar Sizing
Things to consider:
● Lift distribution
● Weight of the wing
● Fuel in the wing
● Props and engines

34. Spar Area Using 6061-T6 Aluminum
14.8 in2

35. Spar Cross-Section
7 ft.
14.5 in.
14.8 in2 Total

36. Cost Analysis

37. Cost Analysis
Key Assumptions:
❖ 5 Flight test aircraft needed
❖ Avionics is 20% of the Flyaway cost
❖ We want to make a 20% profit
margin
❖ We want our cost to the customer
to be $5.66 million
➢ We can sell 310 aircraft
throughout program lifetime

38. Cost Analysis
Takeaways:
❖ We will break even after
selling 220 aircraft.
❖ Total profit of $292.6 million
after all 310 aircraft are sold

39. DEP Comparison to
Conventional Aircraft

40. Comparison to Conventional Aircraft
Aircraft compared Number built
Beechcraft 1900D 695
Fairchild Metroliner 600
Let L410 1138
Twin Otter DH6 900
Dornier Do 228 270
Harbin Y-12 105

41. Appendix

42. Aircraft Comparative Values
Aircraft Number
built
Range
(miles)
Fuel weight
(lbs)
Cruise
speed (kts)
Max speed
(kts)
Cost
Beechcraft 1900D 695 439 1961 280 392 $4,995,000
Fairchild
Metroliner
600 662 1038 278 311 $6,064,000
Let L410 1138 857 1040 197 205 $4,000,000
Twin Otter DH6 900 920 1344 150 160 $7,000,000
Dornier Do 228 270 823 1582 190 223 $7,000,000
Harbin Y-12 105 832 1238 135 177 $5,000,000

43. Aircraft Costing for Aircraft Development Plan
Parameter Cost Parameter Cost
Airframe Engineering 219.3 M Flight Tests 4.97 M
Tooling 158.5 M Materials 150.5 M
Manufacturing 626.8 M Engine 3.8 M
Quality Control 52.8 M Avionics 243.4 M
Development and
Support
547,480 -- --
For 310 Aircraft