1. Mensa XE (Extra Efficiency) High Efficiency Family Airplane
Michael Duffy
Due: December 11th, 2007
Georgia Tech – AE 6343 Aircraft Design I, Project 2
Presented to: Prof. Dimitri N. Mavris
Honor Code Statement: “I the above signed certify that I have abided by the honor code of the Georgia Institute of Technology and followed the collaboration guidelines as specified in the project description for this assignment."

2. Introduction

3. Introduction - Requirements
Mensa XE is a High Efficiency Family Airplane
A four seat, low-cost, high efficiency family aircraft. 20 year entry into service.
Design Mission:
Payload: 2+2 Pax + baggage ( lbs = 800 lbs total)
Block Fuel Burn: > 30 miles per gallon
Range: 700 miles (608.3 nm)
Loiter: 45 minutes, end of mission
Performance Requirements:
Cruise Speed: > 200 mph (174 knots)
TOFL: 3000 ft, over 50 ft obstacle
V_stall < 61 kts Stall
V_TO >= 1.1 V_stall Takeoff
V_CL >= 1.2 V_stall Climb
V_A >= 1.3 V_stall Approach
V_TD >= 1.15 V_stall Touchdown
Climb: 300
Miscellaneous Requirements:
Glass cockpit flight instruments
VOR/ILS/GPS navigation w/on-board map
Limited auto-pilot features (altitude and heading hold)
Emergency parachute system, and air-bag system (Cirrus SR20/22 safety features)
Source (1)

4. Introduction – Mensa XE
Range = 700 miles
Cruise = 200 mph
Fuel Consumption = 39.7 mpg
Engine = 250 HP
V_stall = 51 knots
Take off distance = 2,227 ft
Landing distance = 2,817 ft
FINAL FLOPS SIZING AND PERFORMANCE RESULTS
OPERATING WEIGHT EMPTY LB
PAYLOAD LB
MAXIMUM FUEL LB
GROSS WEIGHT LB
REFERENCE WING AREA SQ FT
WING LOADING LB/SQ FT
THRUST PER ENGINE LB
ENGINE SCALE FACTOR
THRUST-WEIGHT RATIO
Geometry:
Span = 38 ft.
Wing Area = 138 sq.ft.
AR = 10.4
Taper Ratio = 0.446
Sweep = 7.0°
Dihedral = 20°
Thickness to chord of wing (weighted ave.) = 0.12

5. Conceptual Sizing and Synthesis

6. Conceptual Sizing and Synthesis - Summary
Using project 1 sizing and synthesis Fixed Wing Conceptual Design Tool:
Mission analysis (summary, table)
Constraint analysis (plot)
Final design point and estimated TOGW
Briefly Summarize sizing exercise and document key assumptions
Design point (from conceptual design tool):
T/W = 0.14
W/S = 17.0
W_0 = 2,348 lbs
W_E = 1,408 lbs
W_C+P = 2,209 lbs
Wing Area = 138 sq.ft.
Required Thrust = lbs.

7. Conceptual Sizing and Synthesis – 3-View
Graphical Model (3-view)
38’
Wing Area = 138 ft.sq.
24’
8’ – 4 bladed

8. Conceptual Sizing and Synthesis – Mission Analysis
800 lbs of payload
Take-Off Gross Weight = 2,348 lbs
Weight Empty = 1,408 lbs
* Note Source

9. Conceptual Sizing and Synthesis – Mission Summary
700 miles range (608.3 nautical miles)
139 lbs of Fuel (23.2 gal)
30 mpg (Design requirement)
* Note Source

10. Conceptual Sizing and Synthesis – Constraint Analysis
Design Space
Landing distance 3,000 ft, V_TD >=1.15 V_stall
Thrust Loading, T/W
Design Point
Take off 3,000 ft, 50 ft obstacle, V_stall < 61 kts
T/W = 0.14
W/S = 17.0
Climb 300 fpm, V_CL >= 1.2V_stall
V_stall < 61 kts
Service Ceiling 15,000 ft
Cruise Speed > 200 mph
Wing Loading, W/S

11. Preliminary Sizing and Synthesis - Input

12. Preliminary Sizing and Synthesis - Input
Construct Working FLOPS File
Convey information and assumptions form conceptual phase have carried over to FLOPS: started preliminary sizing with output from conceptual design phase:
T/W 0.14 and W/S 17.0
What information (assumed or inferred) from the vehicle concept description
Sizing Mission –
Payload: 2+2 Pax + baggage ( lbs = 800 lbs total)
Block Fuel Burn: > 30 miles per gallon
Range: 700 miles (608.3 nm)
Loiter: 45 minutes, end of mission
Design Constraints –
Cruise Speed: > 200 mph (174 knots)
TOFL: 3000 ft, over 50 ft obstacle
V_stall < 61 kts Stall
V_TO >= 1.1 V_stall Takeoff
V_CL >= 1.2 V_stall Climb
V_A >= 1.3 V_stall Approach
V_TD >= 1.15 V_stall Touchdown
Climb: 300
Source (2)

13. Preliminary Sizing and Synthesis - Input
Design Point
Started preliminary sizing with T/W = 0.14, W/S = 17.0
Attempt to match the 329 lbs of thrust requirement
30 mpg
Max Cruise Altitude =12,000 ft.
3,000 ft. runway
Geometry parameters (from output of conceptual design)
Wing:
Span = 38 ft.
Wing Area = 138 sq.ft.
AR = 10.4
Taper Ratio = 0.446
Sweep = 7.0°
Dihedral = 20°
Thickness to chord of wing (weighted ave.) = 0.12
Fuselage
Length = 24 ft.
Width = 3.44 ft.
Depth = 4.59 ft.
Vertical = 25.0 sq.ft.
Horizontal = 23.7 sq.ft.
Source (2)

14. Preliminary Sizing and Synthesis - Input
Propulsion and power plant parameters:
TELEDYNE CONTINENTAL MOTORS - IO-360-ES (X – Modified for 2,027 tech.)
250 HP (Modified for 2,027 tech.)
Min SFC 0.35 (modified for 2,027 tech.)
Six cylinders horizontally opposed
Four strokes, Fuel injected, Spark ignition, Direct drive
Air-cooled
Wet sump engine, Incorporating a top induction system, bottom exhaust.
Height in.
Width in.
Length in.
Source (4)

15. Preliminary Sizing and Synthesis - Input
Aircraft type – Single engine, tail sitter, low wing
Aircraft class – Family four passenger
Percent of Materials used – Airframe 85% composites
Technology year
Intermediary and Final Calculations
To obtain the required efficiency the RPM was varied to achieve 30 mpg
To obtain the required rate of climb the engine power was increased from 210 hp to 250 hp
To obtain the required take off distance wing CL max was increased to CL = 2.0

16. Preliminary Sizing and Synthesis - Output

17. Conceptual Sizing and Synthesis – 3-View
Graphical Model (3-view) FINAL DESIGN
38’
Wing Area = 138 ft.sq.
24’
6.5’ – 6 bladed

18. High Efficiency Wing Design
High Aspect Ratio
Advanced Feather Tip
Combination of advance tips and high aspect ratio balance Aerodynamics with Manufacturability

19. Preliminary Sizing and Synthesis - Weight
Weight Breakdown
Table + user defined percentage of usage of composites and non-traditional materials
Emergency parachute system, and air-bag system (Cirrus SR20/22 safety features)
Source (3)

20. Preliminary Sizing and Synthesis - Weight
Weight Breakdown
Structure 85% Composites:
Wing
Tail
Fuselage
Emergency parachute system, and air-bag system (Cirrus SR20/22 safety features)
Final WE = 1,497
Final TOGW = 2,443
Source (3, 4)

21. Preliminary Sizing and Synthesis - Propulsion
Propulsion and Powerplant
Description of powerplant
250 HP
Six cylinders horizontally opposed
Low RPM (1,600 RPM)
High Efficiency (0.35 SFC)
Number of Engines = 1
Placement – Front Mounted
Source (4)

22. Preliminary Sizing and Synthesis - Propulsion
Propulsion and Powerplant
Thrust vs. Altitude curves for varying Mach number
Mach #:
Altitude (ft)
Standard Day
Thrust (lbs)

23. Preliminary Sizing and Synthesis - Propulsion
Propulsion and Powerplant
Fuel consumption curves
Mach #:
Altitude (ft)
Standard Day
SFC (lbsm/lbs hour )

24. Preliminary Sizing and Synthesis - Aerodynamics
Basic aerodynamic description of aircraft
Span = 28 ft.
Wing Area = 138 sq.ft.
AR = 10.4
Taper Ratio = 0.446
Sweep = 7.0°
Dihedral = 20°
Thickness to chord of wing (weighted ave.) = 0.12

25. Preliminary Sizing and Synthesis - Aerodynamics
Drag polar for varying Mach number (graph)
Mach = 0.2
Mach = 0.3
Mach = 0.4
Mach = 0.5 CD CL

26. Preliminary Sizing and Synthesis - Mission
Mission Performance:
Mission profile (schematic)
10,000 ft Altitude 200mph
45 min Loiter
700 Miles
SL, Standard
SL, Standard
17.6 Gallons
39.7 mpg
700 miles (608.3 nm)

27. Preliminary Sizing and Synthesis - Mission
Mission Performance:
Instantaneous cruise data:

28. Preliminary Sizing and Synthesis – Constraint Analysis
After completing the FLOPS preliminary design analysis, the required thrust went from 329 lbs to 419 lbs
Keeping the wing area the same the wing loading went up to W/S = 17 to psf
Conceptual Design Point
Preliminary Design Point
T/W = 0.14
TOGW = 2,348 lbs
WE = 1,408 lbs
Thrust = 329 lbs
T/W = 0.178
TOGW = 2,443 lbs
WE = 1,507 lbs
Thrust = 419
W/S = 17
S = 138 sq.ft.
W/S = 17.71

29. Preliminary Sizing and Synthesis – Constraint Analysis
Landing Requirements:
Take off, DFAROFF = 2,227 ft < 3,000 ft
Landing, DFARLDG = 2,817 ft < 3,000 ft.
Stall Requirements:
STALL SPEED (VS) = kts < 61 kts
1.05 VS kts
1.20 VS kts
Miles per Gallon = 39.7 > 30.0
Cost/AC = $58 Million > $150,000 Maybe I made a mistake?
Exceeded
Exceeded
Exceeded
Exceeded
Not Met

30. Conclusions

31. Conclusions
Using the FLOPS program an aircraft with the range of mph was designed: The table below summarizes the key parameters for the Mensa XE
Further detail into engine design would be the next step, specifically:
Efficiency
Fuel type
Engine size
FINAL FLOPS SIZING AND PERFORMANCE RESULTS
OPERATING WEIGHT EMPTY LB
PAYLOAD LB
MAXIMUM FUEL LB
GROSS WEIGHT LB
REFERENCE WING AREA SQ FT
WING LOADING LB/SQ FT
THRUST PER ENGINE LB
ENGINE SCALE FACTOR
THRUST-WEIGHT RATIO

32. References:
(1) AE 6343 Aircraft Design Project #2, -2007, “Sizing and Synthesis with a Legacy Tool for Distance Learning Students”, Hernando Jimenez
(2) Flight Optimization System, Release 6.12, User's Guide, Revised 14, October 2004, L.A. (Arnie) McCullers
(3)
(4)