3. Mission Goals
● Increase the effective max takeoff weight by 36% from the B-1’s value of 477,000 lbs to our max
takeoff weight of 650,000 lbs allowing us to carry a larger payload
● Aircraft will ideally be able to cruise at low supersonic speeds (around Mach 1.2)
● Cruise at 50,000 ft
● Have an effective mission radius of at least 3,000 miles
○ Example mission would be from Ramstein AFB in Germany to a conflict region in the Middle
East, Baghdad for reference. This would require a 2100 mile radius + loiter time.
● Stealth is a priority
5. Reference Engine Selection
Kuznetsov NK-321
Cruise Thrust: 31,000 lbf (137 kN)
Maximum Thrust with AB: 55,000 lbf (245 kN)
Pressure Ratio: 28.4
Bypass Ratio: 1.4
TSFC: .72 kg/hour in Subsonic flight, 1.70 kg/hour in Supersonic flight
Thrust to Weight Ratio: 7.35 kgf/kg
Turbine Inlet Temperature: 1630 K (1357 C)
Mass Flow Rate: 805 lbm/s
6. Length: 181 in. (460 cm)
Diameter: 55 in. (140 cm)
Dry weight: 4,400 lbf (1995 kg)
Compressor: Axial, 2 stage fan, 9 stage high pressure compressor
Combustors: Annular
Turbine: 1 stage high pressure turbine, 2 stage low pressure turbine
Maximum power output: 31,000 lb (138 kN) (with afterburner)
Overall pressure ratio: 26.8:1
Specific fuel consumption: 2.46 lb/lbf-hr (max thrust)
Thrust-to-weight ratio: 7.04:1 (afterburner)
GE F101 Engine Specifications
7. Engine Characteristics
Physical Dimensions
Length - 304.8 in / 7.74 m
Diameter - 73.0 in / 1.85 m
Weight - 12096.8 lbf / 53.8 kN
Mass Flow Rate - 1298.4 lbm/s
Performance
Total Max Uninstalled Thrust (4 Engines) - 322580 lbf / 1434 kN
Thrust/Weight (at TO) - 0.496
8. Engines Cont.
● The fully scaled engines produce a total amount of uninstalled thrust equivalent to 322,580.65lbf
with afterburners for takeoff.
● With this amount of thrust, we were able to increase our fully loaded takeoff weight from 477,000lb
to 650,000lb.
● This represents an increase of 36 percent, well beyond our initial goal of a 20 percent increase.
● The other brilliant characteristic that our engines facilitate is that based upon the mission
requirements, this plane can perform as an excellent Long Range aircraft, while also exhibiting
certain STOL characteristics during takeoff.
● Historically required values for the thrust to weight ratio for various missions are as follows:
9. Engines Cont.
● If we utilize full afterburners for takeoff and landing, we are able to achieve a thrust-to-weight ratio of
.496, putting us squarely in the middle of the range for STOL aircraft.
● Furthermore if we then decide to not utilize our afterburners during cruise conditions, we are able to
achieve a thrust-to-weight ratio of .307, also putting us in the middle of the range for a long range
aircraft.
● What happens to be of note is that although our scaled engine has increased in length and diameter
by 27%, the thrust output of the engine increased by 61% in cruise thrust and 59% in maximum
afterburner thrust.
10. Wing Design
● Initial research showed that to achieve the high amounts of lift we require with a supercritical airfoil
(for efficient supersonic flight) a large Aspect Ratio (AR) wing would be needed.
● At takeoff conditions:
■ Dynamic Pressure at sea level = q = 7546 kg/m^3
■ Takeoff Velocity - 111 m/s | 248 mph
■ Weight = 2545 kN
● Our wing design will require that at these conditions a CLmax value that can lift the weight of the
aircraft + payload off the ground
11. XFLR Model of Wing & Body
Geometry
Wing Span- 48m
Wing Area- 1013 m^2
Root Chord- 50m
MAC- 26.1
Tip Twist- -1.2°
AR base- 2
AR tip- 14
Taper Ratio- 25
Root-Tip Sweep- 59°
Aerodynamics
CLmax (Takeoff)- 1.0
CLmax (Cruise)- 0.82
Cd (Cruise)-0.113
14. Main Airfoil Portion
Wing Characteristics
● thin airfoil with camber
● large aspect ratio
● sweep of 50 degrees sees
an incoming mach of 0.7 at
cruise of 1.2
15. Wing Tip Portion
Wing Characteristics
● supercritical airfoil with
small camber
● large aspect ratio
● Twist allows wingtips to
stall first
16. Active Lift Devices for Takeoff
● To increase the takeoff CLmax of the plane trailing edge (TE) single slotted
flaps were added to help get the aircraft off the ground.
● For takeoff the B-3 will use a 10° flap deflection and can increase the Clmax
to a value of 1.2
18. Fuselage
● Utilizing a blended wing body to get the most aerodynamic shape to reduce
the amount of flow separation.
● Given the size of the aircraft more lift is required so using a blended fuselage
allows for the body to contribute to the lift.
● With a blended body there is less wasted space and an opportunity for more
payload
19. Stability & Control
● In order to prevent instability while dropping
payload, the bombs will be loaded such that the
center of gravity is located at the aerodynamic
center of the wings.
● This point will also be the center of gravity after
bombs have been dropped.
● This was done to avoid a pitching moment as
there is no horizonal stabilizer to balance out the
lift from the main wing.
20. Stealth Considerations
Low Engine Profile
- embedded inlets and shielded nozzles reduce detection
Special Paint
-Low emissivity paint reduces infrared cross section at engine nozzle
25. References
1) Corke, Thomas C. Design Of Aircraft. Upper Saddle River: Pearson Education, 2003. Print.
2) Nicolai, Leland M., and Grant E. Carichner. Fundamentals of Aircraft and Airship Design. Vol. 1. Reston: American
Institute of Aeronautics and Astronautics, 2010. 2 vols. Print
3) Yechout, Thomas R., Steven L. Morris, David E. Bossert, Wayne F. Hallgren, and James K. Hall. Introduction to
Aircraft Flight Mechanics: Performance, Static Stability, Dynamic Stability, Classical Feedback Control, and State-
Space Foundations. 2ndnd ed. Reston: American Institute of Aeronautics and Astronautics, 2014. Print.
