The attached file is the questions for the assignment.1

Exercise 3: Lift and Airfoils

The first part of this week’s assignment is to choose and research a reciprocating engine

powered (i.e. propeller type) aircraft. You will further use your selected aircraft in subsequent

assignments, so be specific and make sure to stay relatively conventional with your choice in

order to prevent having trouble finding the required data during your later research. Also, if you

find multiple numbers (e.g. for different aircraft series, different configurations, and/or different

operating conditions), please pick only one for your further work, but make sure to detail your

choice in your answer (i.e. comment on the condition) and stay consistent with that choice

throughout subsequent work.

In contrast to formal research for other work in your academic program at ERAU,

Wikipedia may be used as a starting point for this assignment. However, DO NOT USE

PROPRIETARY OR CLASSIFIED INFORMATION even if you happen to have access in

your line of work.

1. Selected Aircraft:

For the following part of your research, you can utilize David Lednicer’s (2010) Incomplete

Guide to Airfoil Usage at http://m-selig.ae.illinois.edu/ads/aircraft.html or any other reliable

source for research on your aircraft.

2. Main Wing Airfoil (if more than one airfoil is used in the wing design, e.g. different between

root and tip, pick the predominant profile and, as always, stay consistent):

Please note also the database designator in the following on-line tool (see picture below):

Find the appropriate lift curve for your Airfoil from 4. You can utilize any officially published airfoil

diagram for your selected airfoil or use the Airfoil Tool at http://airfoiltools.com/search and text

search for NACA or other designations, search your aircraft, or use the library links to the left of

the screen. Once the proper airfoil is displayed and identified, select the “Airfoil details” link to

the right, which will bring up detailed plots for your airfoil similar to the ones in your textbook.

Text search input

Library links

Search result display

Airfoil details tab

This document was developed for online learning in ASCI 309.

File name: Ex_3_Lift&Airfoils

Updated: 06/23/2015

Please note the airfoil

database designator (in

parenthesis) in your

answer to 2 above.

2

Concentrate for this exercise on the Cl/alpha (coefficient of lift vs angle of attack) plot. Start by

de-cluttering the plot and leaving only the curve for the highest Reynolds-number (Re) selected

(i.e. remove all checkmarks, except the second to last, and press the “Update plots” tab).

Details Link

“Update plots”

tab

3. From the plot, find the CLmax for your airfoil (Tip: for a numerical breakdown of the plotted

curve, you can select the “Details” link and directly read the highest CL value, i.e. the highest

number within the second column, and associated AOA in the table, i.e. the associated number

in the first column):

4. Find the Stall AOA of your airfoil (i.e. the AOA associated with CLmax in 3.):

5. Find the CL value for an AOA of 5 for your selected airfoil:

6. Find the Zero-Lift AOA for your airfoil (again, the numerical table values can be used to more

precisely interpolate Zero-Lift AOA, i.e. the AOA value for which CL in the second column

becomes exactly 0):

This document was developed for online learning in ASCI 309.

File name: Ex_3_Lift&Airfoils

Updated: 06/23/2015

3

7. Compare your researched airfoil plot to the given plot of NACA 4412

(http://airfoiltools.com/airfoil/details?airfoil=naca4412-il).

a) How do the two CLmax compare to each other? Describe the differences in airfoil

characteristics (i.e. camber & thickness) between your airfoil and the given NACA 4412,

and how those differences affect CLmax. (Use your knowledge about airfoil designation

together with the airfoil drawings and details in the on-line tool to make conclusions

about characteristics.)

b) How do the two Stall AOA compare to each other? Explain how the differences in

airfoil characteristics (i.e. camber & thickness) between your airfoil and the given NACA

4412 affect Stall AOA.

in

c) How do the two Zero-Lift AOA compare to each other? Evaluate how the differences

airfoil characteristics between your airfoil and the given NACA 4412 affect Zero-Lift AOA.

8. Compare your researched airfoil plot to the NACA 0012 plot.

in

a) How do the two Zero-Lift AOA compare to each other? Evaluate how the differences

airfoil characteristics between your airfoil and the given NACA 0012 affect Zero-Lift AOA.

b) What is special about the design characteristics of NACA 0012? How and where

could this airfoil design type be utilized on your selected aircraft? Describe possible additional

uses of such airfoil in aviation.

For the second part of this assignment use your knowledge of the atmosphere and the

Density Ratio, (sigma), together with Table 2.1 and the Lift Equation, Equation 4.1, in

your textbook (remember that the presented equation already contains a conversion

factor, the 295, and speeds should be directly entered in knots; results for lift will be in

lbs):

L = CL *

* S * V2 / 295

Additionally, for your selected aircraft use the following data when applying Equation 4.1:

9. Research the Wing Span [ft]:

Use 36’ (Cessna 180k) Given

in Class

This document was developed for online learning in ASCI 309.

File name: Ex_3_Lift&Airfoils

Updated: 06/23/2015

4

10. Find the Average Chord Length [ft]:

Note: Average Chord = (Root Chord + Tip Chord) / 2

found

Use 6 ft; Given in Class

(if no Average Chord is directly

in your research)

2800 lbs; Given in Class

11. Find the Maximum Gross Weight [lbs] for your selected aircraft:

A. Calculate the Wing Area ‘S’ [ft2] based on your aircraft’s Wing Span (from 9.) and Average

Chord Length (from 10.):

S=216 sqft; Given in Class

12. Use the CL value for an AOA of 5 for your airfoil found in 5. above to simulate cruise

conditions in the following exercise B. (Note it here for easier reference):

CL=.75; Given in Class

B. Prepare and complete a table of Lift vs. Airspeed at different Pressure Altitudes utilizing the

given Lift Equation and your previous data. (For the calculation of Density Ratio ‘ ’ you can

assume standard temperatures and neglect humidity.)

You can utilize MS® Excel (ideal for repetitive application of the same formula) to populate table

fields and examine additional speeds and altitudes, but as a minimum, include six speeds (0,

40, 80, 120, 160, & 200 KTAS) at three different altitudes (Sea Level, 10000, 40000 ft), as

shown below:

Calculate LIFT (lb)

Airspeed:

0 KTAS

40 KTAS

80 KTAS

120 KTAS

160 KTAS

200 KTAS

0

Pressure Altitude (PA) ft

10,000

Example Excel Chart, version 2

in Canvas. Sigma from Table 2.1

40,000

= 1, .7385,

.2462; and using EQ

4.1

I) What is the relationship between Airspeed and Lift at a constant Pressure Altitude?

Evaluate each Altitude column of your table individually and describe how changes in

Airspeed affect the resulting Lift. Be specific and mathematically precise, and support

your answer with the relationships expressed in the Lift Equation.

II) What is the relationship between Altitude and Lift at a constant Airspeed?

Evaluate each Airspeed row of your table individually and describe how changes in

Altitude affect the resulting Lift. Be specific and mathematically precise, and support

your answer with the relationships expressed in the Lift Equation.

III) Estimate the Airspeed required to support the Maximum Gross Weight of your

selected airplane (from 11. above) at an Altitude of 10000 ft and flying at the given AOA

of 5. (As initially indicated, a more detailed table/Excel worksheet is beneficial to

precision for this task. To support the Weight of any aircraft in level flight, an equal

amount of Lift has to be generated – therefore, you can also algebraically develop the lift

This document was developed for online learning in ASCI 309.

File name: Ex_3_Lift&Airfoils

Updated: 06/23/2015

5

equation to yield a precise Airspeed result, i.e. substituting L=W and solving for V in the

lift equation. Remember that conditions in this question are not at sea level.)

C. Fill in the Example spreadsheet using the CL and AOA values from the previously used

NACA 2412 (an example is listed below).

Airspeed (KTAS)

Required Lift = Weight

Required CL

Corresponding AOA

for your airfoil

0

40

80

120

160

200

Finally, use your researched airfoil Cl/alpha plot (from 3. through 8.) to find corresponding AOA

to your calculated CL values (enter the plot in the left scale with each calculated CL value, trace

horizontally to intercept the graph for that CL value, then move down vertically to find the

corresponding AOA and note it in your table (alternatively, you can also look up values in the

detailed table):

THIS PLOT IS AN

EXAMPLE ONLY

AND NOT

APPLICABLE FOR

YOUR AIRFOIL –

PLEASE USE YOUR

RESEARCHED LIFT

CURVE FROM 3.

THROUGH 8.

ABOVE.

Enter

with CL

in the

vertical,

left

scale

Read corresponding AOA on the bottom scale

I) What is the Takeoff speed at 2800 lbs?

II) What is the stall speed at 17 degrees AOA?

(change the A/S in the 17 AOA row until L is >2800 lbs)

This document was developed for online learning in ASCI 309.

File name: Ex_3_Lift&Airfoils

Updated: 06/23/2015

Purchase answer to see full

attachment

#### Why Choose Us

- 100% non-plagiarized Papers
- 24/7 /365 Service Available
- Affordable Prices
- Any Paper, Urgency, and Subject
- Will complete your papers in 6 hours
- On-time Delivery
- Money-back and Privacy guarantees
- Unlimited Amendments upon request
- Satisfaction guarantee

#### How it Works

- Click on the “Place Order” tab at the top menu or “Order Now” icon at the bottom and a new page will appear with an order form to be filled.
- Fill in your paper’s requirements in the "
**PAPER DETAILS**" section. - Fill in your paper’s academic level, deadline, and the required number of pages from the drop-down menus.
- Click “
**CREATE ACCOUNT & SIGN IN**” to enter your registration details and get an account with us for record-keeping and then, click on “PROCEED TO CHECKOUT” at the bottom of the page. - From there, the payment sections will show, follow the guided payment process and your order will be available for our writing team to work on it.