Final Aerospace Design Report

5/26/2018 Final Aerospace Design Report

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Brazilian Bird IIITeam Luiz

5/2/2014

Kalki Sharma, Joe Pitts, Brian Harrell, Luiz Santos, David Boal, ChrisSanto


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ContentsMission Statement .................................................... 3

Base of Operations ................................................... 3

Range .............................................................. 3

Fuel Consumption ................................................... 4

Aircraft Specifications .............................................. 5

Drag Analysis ........................................................ 6

CL vs. CD .......................................................... 6

Drag at Varying Altitudes .......................................... 7

Drag at Cruise Altitude ............................................ 8

Aircraft Model ....................................................... 8

Exterior ........................................................... 8

Interior .......................................................... 10

Engine ............................................................ 11

Engine Specifications............................................ 12

Thrust at Varying Altitudes...................................... 13

Thrust at Cruise Altitude........................................ 13

Absolute Ceiling................................................. 14

Rate of Climb.................................................... 15

Time to Climb.................................................... 15

Flight Envelope.................................................. 16

Wing .............................................................. 17

Airfoil Selection................................................ 17

Aileron Design................................................... 17

Spar Design...................................................... 18

Empennage ......................................................... 19

Airfoil Selection................................................ 19

Rudder Design.................................................... 19

Elevator Design.................................................. 20

Takeoff/Landing ..................................................... 20

Cost Analysis ....................................................... 21

Cost of Aircraft .................................................. 21


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Competing Aircraft Costs .......................................... 22

Revenue & Net Profit and Market Comparison ........................ 22

Equations ........................................................... 23

Major Specifications .............................................. 23

Cost Analysis ..................................................... 23


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Mission StatementThe primary mission of the BB-3 Jet is to provide a reliable and

affordable air taxi service connecting small range airports to

larger international hubs. We aim to distinguish our product by

building a less expensive aircraft both to purchase and to

operate, as well as an aircraft that can take off and land at

smaller airports and airstrips than our competitors. A primary

selling feature of the BB-3 jet is that it seats 5 passengers

with only 1 pilot. Compared to the majority of other air taxi

jets using 2 pilots, the BB-3 jet will be able to operate with a

reduced cost of operation. Additionally, the excess power of the

BB-3 provided by an FJ44-1A Turbofan engine will allow the BB-3

to take off from very short runways.

Our target market for the BB-1 jet is the southwestern UnitedStates, consisting of a six-state area including, California,

Nevada, Utah, Colorado, Arizona and New Mexico.

Base of OperationsRangeWe plan to use Las Vegas International Airport as our base of

operation. With a 1200-mile range, we will be able to reach any

airport within our six-state territory and return to Las VegasInternational Airport without refueling. In addition, we can

transport passengers between any two points within our six-state

territory on a single tank of fuel. A map of our range and

target market is shown in Figure 1.


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Figure 1. Shows the BB-1s target market and range using Las Vegas as our base of

operation

Fuel ConsumptionIn order to determine the fuel consumption for a maximum range mission

in the BB-3 jet, we began with a Thrust Specific Fuel Consumption

(TSFC) of approximately 0.456 pounds of fuel per hour per pound of

thrust. In addition, based on a cruise velocity of 640 feet per

second, we determined that the drag at cruise and similarly, the

thrust at cruise is approximately 391.9 pounds (found in section onDrag Analysis).

We also determined that a maximum range mission in the BB-3 jet would

last approximately 3.25 hours based on a cruise velocity of 640 feet

per second, a maximum range of 1200 miles and an additional 0.5 hours

of flight time for safety reasons.

Using these calculations, we determined the fuel consumption by

multiplying the TSFC by the thrust at cruise and by the duration of

the maximum range mission (in hours). We arrived at a final value of

580.8 pounds of fuel needed to perform a maximum range mission in the

BB-3 jet. These values are summarized in Table 1 below.

Table 1. Summary of the fuel consumption calculated values

Fuel Consumption ValuesTSFC (lbs fuel/hr/lbsthrust)

0.456

Drag @ Cruise Velocity 391.9


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(lbs)

Maximum Range (miles) 1200

Fuel Required (lbs) 580.8

Aircraft SpecificationsOver the course of the design process, the BB-3 Air Taxis specs have

changed significantly. At the end of the first semester, our cruise

speed was hovering at 600ft/s and the range was 660 miles. Our range

was increased to provide service to a larger market. We also wanted

to keep the aircraft light compared to other VLJs, so we wanted our

weight to be around 4500 lbs. In the end, the maximum takeoff weight

finished at 5200 lbs, which is still in a good range for VLJs. Our

thrust to weight ratio decreased due to the increase in weight. Ourthrust of 1900 pounds was held constant. We kept the payload constant

throughout the design process. We used 1200lbs as our payload by

assuming 200lbs per passenger/pilot and luggage brought on the jet.

The biggest change came in the fuel weight department. The final fuel

weight came out to be about 230% higher than our initial value. This

is due to our range increasing. Table 2 shows the major

specifications of the Brazilian Brid-3 (BB-3) and Table 31compares the

initial and final values along with the percent difference.

Table 2. Major Specs

of BB-1Major Specs

Pilots 1

Max.Passengers 5

Weight (lb) 5200

Cruise Vel.(ft/s) 640.00

Payload (lb) 1200.00

Range (mi) 1200

CL Cruise 0.30

Table 3. Final and Initial BB-3 Specs

Current Initial %

&The equations used to determine the values in Table 3 are listed in theEquation section of the report.


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Diff.

Weight (lb) 5200 4500 14.43%Cruise Vel.(ft/s) 640.00 600.00 6.45%

Payload (lb) 1200.00 1200.00 0.00%

Fuel Weight(lb) 728 225 234%

Range (mi) 1200 660.00 58.06%

CL Cruise 0.30 0.35 16.67%

Wing Area (ft2) 114.68 146.00 24.03%

Thrust/Weight 0.36 0.42 15.38%

Wingloading(lb/ft2) 45.34 39.85 12.89%

Drag AnalysisCL vs. CD

Figure 2. Polar Plot

The aircraft cruises at a CLof 0.3 and a Reynolds number of

approximately 9E06. According to Figure 2, the BB-3 lives within

the drag bucket. A comfortable range for the coefficient of lift

to live within is 0.2 to 0.4 while keeping Cdfairly low and

constant.


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Drag at Varying Altitudes

Figure 3. Drag at Varying Altitudes

Above in Figure 3, we have the drag at varying altitudes. As

shown, at sea level, the drag plot is narrower when compared to

an altitude of 40,000ft. At our cruise speed of 640ft/s and

cruise altitude of 35,000 ft, the drag is about 392 lbs. Climbing

higher would allow for the same velocity at lower drag, but theengine chosen for the aircraft would not be able to support the

aircraft passed 45000ft. In order to keep a high thrust to drag

ratio the cruise altitude was chosen at 35000ft.

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Final Aerospace Design Report

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