Aerospace Engine Performance Project - Cessna Skyhawk 172

Essoufia E.

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Aerospace Engine Performance Project - Cessna Skyhawk 172

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Aerospace engine, performance, Cessna 172, Skyhawk, aerodynamic, power, velocity, Cessna Skyhawk, aircraft, max velocity, min velocity, airplane, thrust, climb, lift-to-drag ratio, drag, lift, range

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Abstract

The Cessna 172 has become a household name, particularly in the aviation community. Since its inception in the mid-1950s, the 172 quickly earned its stripes in becoming the most produced aircraft in history. These days, almost all qualified pilots start their flying career on the humble 172, and many continue to fly them. Paired with its affordability and great training features, it's no wonder the Cessna 172 is such a popular airplane.

Specifications
1. Dimensions
2. Cabin Interior
3. Baggage Capacity
4. Weights
5. Performance
6. Powerplant
7. Wing Airfoil Data
8. Sea Level Conditions
Aerodynamic of the Airplane
1. Lift to Drag Ratio
2. The Aerodynamic Center
3. Lift Coefficient Calculation for High Aspect Ratio with Incompressible Flow
Aircraft Performance
1. The Drag Polar
2. Thrust Required
3. Thrust Required VS. Thrust Available
The Fundamentals Parameters
1. Thrust to Weight Ratio, Wing Loading, Drag Polar, and Lift to Drag Ratio
2. Aerodynamic Characteristics
3. Power Required VS. Power Available: Max Velocity
4. The N-V Diagram
Summary

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[...] Comparing Zero Lift Drag and Drag Due to Lift Analytically We know that: CD=0.033+0.0604CL2 and 𝐶 = 2W/ gho*V2*CD,o It's known that: zero- lift drag 1/2ρ*S*V2*Cd,o drag due to lift 2*K*W2ρ*S*V2 Let's see if this graph matches the theoretical analysis: The total drag at sea level will be: D=1/2ρ*S*V2*Cd,o + 2*K*W2ρ*S*V2 7.11 x 10-3 + 1.31*106V2 For a propeller driven airplane, we will use: ( Cl1.5Cd )max. of the propeller correlation. And we got for V=90.54 ft/s ( Cl1.5Cd )max. = 12.06 @ Cl=1.29 Thus, zero lift drag = 56 lb and drag due to lift =158 lb. [...]

[...] Dimensions 4 B. Cabin Interior 4 C. Baggage Capacity 4 D. Weights 4 E. Performance 5 F. Powerplant 5 G. Wing Airfoil Data 5 H. [...]

[...] the zero − lift drag equals three of the drag due to lift Let's compare using (ClCd )max: And for V=120.6 ft/s, ( ClCd )max = 12.33 Thus, zero-lift drag=101 lb drag due to lift=90.88lb Verifying the comparison gives: zero lift to dragdrag due to lift approximately. the zero lift drag equals to drag due to lift. Conclusion The above result agrees with the graphical Drag analysis Thrust Required VS. Thrust Available For subsonic propeller driven aircraft, the thrust available curve is a horizontal line as sketched in (figure 4). [...]

[...] Thus, a0 = dcld=-0.6-1.08-8-8 = 0.105 From the moment coefficient curve, we can read off: At cmc/4 = -0.045 At =10°, cmc/4 = - 0.035 Thus, m0 = dcmc/4d=-0.045+0.035-8-10=5.56 x 10-4 Finally, Xacc=-AoMo=-0.0053 Lift Coefficient Calculation for High Aspect Ratio with Incompressible Flow AR = 7.52 As we have a high aspect ratio with a straight wing, let's calculate the taper ratio for this wing: e1 = tip chordroot chord=1.121.63=0.6877 Following the Prandtl's lifting line theory: a=ao1+aoPIe1AR Where a0= 0.105 per degree, e1=0.7, AR=7.52 Converting degree into rad a0= 6.01 per radian Thus: Cl=a(α-αL=0) Calculating a gives: a=6.011+6.01PI*0.688*7.2 = 4.40 per rad =0.0769 per deg Angle of Attack CL (read off) CL (calculated) Error -0.6 - -0.4 - -0.2 As expected, the finite aspect ratio reduces the lift coefficient, in this case, AR=7.52, the reduction in total is by For lower aspect ratios, the reduction will be even higher. Aircraft Performance The Drag Polar For NACA 2412, the zero-lift drag is equal to CD, 0.033. We know that: CD=CD,0+ KCL2 With: 1/e x AR x PI = 0.0604 Thus, CD = 0.033 + 0.06CL2 At Steady Flight Level For an airplane in a steady flight level, where there is no acceleration or slowing down. [...]

[...] The maximum lift to drag ratio was found to be 12.06 For the power and rate of climb analysis: The max rate of climb from sea level is about 840 ft/min. Its corresponding velocity is 160 ft/s.max angle of climb is 4.803 degrees, its corresponding velocity is 17 ft/s (less than stall speed) The absolute and service ceiling values were 14200 ft ft respectively. The range and endurance of the aircraft were found to be 900 miles and & 12 hours The limit load factor is about 2.2 The power available at maximum velocity at sea level is 120 hp and the thrust available is 423.69 𝑙𝑏. [...]

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