The document summarizes the design process for a business jet capable of carrying 6 passengers up to 1500nm. Calculations were done to determine the required wing design based on the jet's weight and performance parameters. A transonic airfoil was selected, and calculations determined the wing should have an aspect ratio of 7 and wingspan of 27.487m. CFD analysis found the lift force was close to calculations but drag force was much higher, likely due to difficulty calculating drag by hand. The rest of the aircraft was designed around the selected wing.

1. Introduction
A design challenge was presented. The challenge was to design a business jet that
could fly at 0.8 Mach, carry 6 passengers (with 2 crew), and be capable of flying at least
1500nm. With these parameters set, the first task that was tackled was to find what kind
of wing design was needed in order to provide enough lift for a business jet with a certain
weight. Starting with an approximate weight (based on similar style jets) of 176.6kN and a
factor of safety of 25%, the calculations began.
Calculations
Loading Factor: Mass of aircraft: Gravity effect at 40,000 ft
LF 1.25 w 18000kg g 9.81
m
s
2

Weight of Aircraft: Lift needing to be generated by wing:
W w g 1.766 10
5
 N L W
Once it is known how much the aircraft is going to weigh, a decision on what airf
use in order order to generate this lift is now needed. Considering the speed at which the
aircraft will need to be traveling, a transonic airfoil design (NACA 63-412) was decided
upon.
Mach #: Speed of sound at altitude Density of air at altitude:
M 0.8 V 294.9 M
m
s
 ρ .304
kg
m
3

Coefficient of lift at α 0 Zero Lift angle of attack
CL .3423 αL0 3
Coefficient of lift vs. angle of attack slope
a0d
CL 0
α αL0
 a0 a0d
180
π
 a0 6.537
Setting an Aspect Ratio of AR 7
And a sweep angle of Λ 22
π
180
 0.384

2. Kuchemann's Lift slope for swept wings
a
a0 cos Λ( )
1
a0 cos Λ( ) 
π AR






2

a0 cos Λ( )
π AR

4.617
ad a
π
180
 0.081
Maximum Coefficient of lift for the angle of attack specified, with this geometry
CLmax ad α αL0  0.242
Rearranging the coefficient of lift equation to find the Plan form Area (S)
S
L LF
1
2
ρ V
2
 CLmax

The Plan Form area (for both wings):
S 107.93 m
2

And rearranging the equation to find b, the wingspan can be found
b AR S 27.487 m
b1wing
b
2
13.743 m
A typical tip chord to root chord ratio is known
Ct 0.2 Cr Cr
Rearrange the area of a trapezoid using the above relation:
Cr
2 S
1.2 b
6.544 m

3. Again...
Ct 0.2Cr
Ct 1.309 m
Coefficient of Drag Reference Area for Drag calculations
CD .00562
DA
Cr .12 Ct .12
2
b1wing 6.476 m
2

Coefficient of Drag Induced
CDi
CLmax
2
π AR
2.657 10
3

Coefficient of Drag from Pressure
Total Coefficient of Drag
CDP .00110 CDT CD CDi CDP 9.377 10
3

Drag Force
D CDT ρ DA
V
2
2
 513.737 N
Induced Angle of Attack Effective Angle of Attack
αi
CLmax
π AR
0.011 αeff α
180
π
αi 0.63
Now that a wing design has been decided on, a comparison of the hand
calculations versus the CFD will be done.
In order to make up for the induced angle of attack, an addition of 1 degrees
to the angle of attack was added to the CFD.
After running the CFD the lift and drag forces were extracted. A lift force of
approximately 93377N and a drag force of approximately 1944N were found (for one
wing). The maximum velocity over the wing was 309.4m/s. The percent error is 5.75%
for the lift force and 278% for the drag force. The lift force is very close, within a good
error percentage, but the drag force is very far away from the calculated value. The

4. difference, is probably due to the difficulty in calculating drag forces by hand. All valu
can be found in Table 1 located in the appendix.
Finally, the rest of the design of the aircraft was done. A tricycle style landing g
layout was used, and an empannage with 2 horizontal rear stabilizers, and a rudder set u
as shown in Figure 5, and capable of counteracting the moment about the center of grav
caused by the wings. Two Honeywell HTF7500E were selected for propulsion due to
high thrust and efficiency. Capable of approximately 6000lbf per engine, with a fuel ta
of 2,100, the business jet design is capable of over 2000nm, much higher than the range
specified for the project. The cabin was designed with the ability to house up to 7
passengers comfortably. With an internal height of approximately 2m, and an internal w
of approximately 2m as well, this is on the top end of comfort.
Conclusion
The design of the aircraft has taught a lot about computer based design and fluid
dynamics. The results of the CFD and the hand calculations were reasonable, outside o
the drag force, and were within a safe margin of error.