AERODYNAMIC DESIGN

HIGH SPEED SUBSONIC BUSINESS JET

What is a “Business Jet”?“Business jets are turbojet aircrafts weighing less than 100,000 pounds maximum gross Takeoff weight, with wingspans less than 100 feet that are used by companies to conduct their business” [GAO (Government Accountability Office USA), August 2007].

Motivation for the topicIn today’s corporate world long unexpected intercontinental flights are unavoidable. Though a luxury high speed private jets like our’s are the only solution.

It can also be used by sports persons, cases of medical emergencies etc

Mission Requirements ➔ Intercontinental(long range)

lightweight medium sized Business Jet

➔ High comfort of passengers

Technical Specification➔ 10 passengers(executive

arrangements)➔ 4 crew (Pilot, Co-Pilot and 2 flight

attendants)➔ Cruise Range 11000km➔ Cruise Mach no : 0.9

Mission Profile

First Weight Estimate

Second Weight Estimate

Third Weight Estimation

Criteria➔ Maximum CL/CD

➔ Maximum CL

➔ Maximum stall angle

➔ Minimum drag➔ Minimum

moment coefficient

Suitable airfoils➢ NACA 64(3)-618➢ NACA 64(4)-421➢ NACA 63(4)-421➢ NACA m9

NACA 64(3)-618• High Maximum lift coefficient• Very low drag over the range of operating conditions

• Optimized for high speed

GEOMETRY

FUSELAGE DESIGN

FUSELAGE

WIDTH = 2.4 m● 2 seats abreast● 0.7 m executive seat ● 0.8 m aisle width● 0.2 m pressure

cabin structure

LENGTH = 27 m

● Empirical relation● Coefficients from

plots

WING GEOMETRY

Wing Area (93.7 m2) ● From gross weight and wing loading

Aspect Ratio = 7.5

Wing span(26.51 m)● using wing area and AR

Taper Ratio (0.2)● to be efficient● reduction in root bending moment● decrease the structural weight

Sweep Angle(34o)● To delay Drag Divergence Root chord length = 5.89 m

Tip chord length = 1.178 m

TAIL GEOMETRY

The T-tail configuration

This is mainly to avoid the interference of the flow from aft mounted engine interfering with the tail.

Horizontal Tail Vertical Tail

Volume Coefficient 0.95

Aspect Ratio 5

Area 25.8

Span 11.38

Root chord length 3.03

Tip chord length 1.517

Volume Coefficient 0.0855

Aspect Ratio 1.2

Area 17.48

Span 4.58

Root chord length 4.08

Tip chord length 3.616

CONTROL SURFACES➔ AILERON● span =10.604● chord length =0.7068➔ RUDDER● span =4.12● chord length =1.335➔ ELEVATOR● span =10.24● chord length =0.796

STRUCTURAL LAYOUT

3D DIAGRAMS

Front View

Top View

Side View

Power Plant Selection

Engine SizingCriteria

➔ T/W Take-off = 0.269

➔ WO = 27094.28 kg➔ Max Thrust req = (36099.89 * 2) N

Aircraft Powerplant Maximum Thrust Bypass ratio

Cessna Citation X Rolls-Royce AE 3007 30 KN 4

Gulfstream G550 Rolls-Royce RB.183 Tay

62.8 KN 3.04

Citation longitude Snecma Silvercrest 49 KN 5.9

Dassault Falcon 200lx Pratt & Whitney Canada PW308C

28.6 KN 4.2

Bombardier Challenger 850

General Electric CF34-3B1 turbofans

42 KN 6

Engine Sizing

After Sizing➔ Length = 2.44m➔ Max Diameter = 1.11m➔ Dry Weight = 626.8 kg

Inlet➔ Pitot inlet is used taking advantage of

the transonic flow-->RAM EFFECT➔ Vanes are provided at inlet to induce a

vorticity which helps in compression➔ Inner lip radius is greater than outer lip

radius, useful for high angles of attack and sideslip

➔ The capture area was found to be 0.3 m^2

Drag Polar❖ Equivalent Skin Friction method➔ Cd0 using wetted area➔ e using sweep angle and aspect ratio

❖ Component Build up method➔ component form factor➔ component interference factor

Induced Drag➔ Leading edge- suction method

Drag Polar

Trim AnalysisTrim -> Obtained from equilibrium equations for forces and moments.

The trim obtained is subjected to stability analysis

Stability Analysis➔ The trim is subjected to small

perturbation analysis and the constraints for CG wrt Neutral Point is obtained (SM--Static Margin)

➔ The most aft location of CG is found to be 14.64m corresponding to a SM of 0.23 .This also determines the maximum elevator deflection.

CG Estimation

CG calculations➢ Approximate

Group Method Xcg = 15.86 m Zcg = 2.35 m

➢ Statistical Group Method

Xcg = 14.32 m Zcg = 2.5 m

Landing Gear - Tricycle/Nosewheel

➔ Stable design➔ Less demanding

on the pilot➔ Small angle of

attack➔ Better visibility

over the nose

FLAPS - SLOTTED FOWLER TYPE➔ Increased chord length➔ Slot to delay flow separation

Difficulties faced in Design

Suggestions for improvement

Winglets Noise Reduction - Nozzle redesign

Fuel Tank

Are the design requirements met?

Flight PerformanceThrust Required at cruise 10.38 kN

Vmin (Tr) 238.93m/s

Min Thrust required at cruise 10.152 kN

Vmin(Pr) 181.55m/s

Minimum Power Required at Cruise 2.13 MW

Max Range 13461 km

Sustained Turn Rate 3.51o/sec

Take Off distance 533.56m/s

Total Landing Distance 842.754m

Flight Performance

Long Range 11,000 km

Medium Size

Compact Geometry

Light weight 27,094 kg

Comfort