Question Details

(solution) 1 Exercise 4: Drag and Applications The first part of this


I have attached my file. My aircraft is a PC-12. Thanks 


1 Exercise 4: Drag and Applications

 

The first part of this week?s assignment is to revisit our reciprocating engine powered (i.e.

 

propeller type) aircraft from last week.

 

1. Selected Aircraft (from last week?s module): Make sure to review your data and results from last week and any feedback that you may

 

have received on your work, in order to prevent continuing with faulty data. 2. Main Wing Airfoil type & on-line database designator (from last week?s module):

 

3. Aircraft Maximum Gross Weight [lbs] (from last week?s module):

 

4. Wing Span [ft] (from last week?s module):

 

5. Average Chord Length [ft] (from last week?s module):

 

6. Wing Area ?S? [ft2] (from last week?s module):

 

7. Find the Aspect Ratio ?AR? for your selected aircraft wing. (Use the wing span and average

 

chord length from last week?s module/from above. See also page 63 in your textbook.):

 

8. CLmax for your airfoil (from last week?s module):

 

9. Standard sea level Stall Speed ?Vs? for your aircraft [kts] (from last week?s calculation):

 

Find the appropriate drag polar curve for your airfoil selection (2. above; from last week?s

 

module). You can utilize any officially published airfoil diagram for your selected airfoil or use

 

again the Airfoil Tool at http://airfoiltools.com/search . This document was developed for online learning in ASCI 309.

 

File name: Ex_4_Drag&Applications

 

Updated: 07/11/2015 2 Concentrate for this

 

exercise on the

 

Cl/Cd (coefficient of

 

lift vs coefficient of

 

drag) plot, i.e. the so

 

called drag polar.

 

Use again 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). How to find the

 

minimum Cd

 

10. From the polar plot, find the CDmin value for your airfoil, i.e. the lowest value that the

 

coefficient of drag ?Cd? (bottom scale in the online tool depiction) reaches. (Tip: for a numerical

 

breakdown of the plotted curve, you can again select the ?Details? link and directly read the

 

lowest CD value in the table ? third column, labeled ?CD?):

 

What we?ve just found (?with some degree of simplification?) is the parasite drag coefficient

 

for our airfoil, i.e. the drag that exists due to skin friction and the shape of our airfoil, even when

 

little or no lift is produced. However, this value will only represent the airfoil, i.e. main wing

 

portion of our aircraft; therefore, let us for the remainder of our calculations assume that our

 

aircraft is a Flying Wing type design and the total C DP for the aircraft is the same as the

 

CDmin that we?ve just found.

 

Let us also assume that we are at standard sea level atmospheric conditions and that our

 

wing has an efficiency factor of e = 0.82.

 

A. Prepare and complete the following table for your aircraft (with the data from 1. through 8.

 

above). Start your first row with the Stall Speed ?Vs? (from 7. above) and start the second row

 

from the top with the next higher full twenty knots above that stall speed. Then increase speed

 

with every subsequent row by another 20 knots until reaching 300 kts. You are again

 

encouraged to utilize MS® Excel as shown in the tutorial video and can also increase your table

 

detail. However, the below depicted, and above described, interval is the minimum required for

 

this assignment. This document was developed for online learning in ASCI 309.

 

File name: Ex_4_Drag&Applications

 

Updated: 07/11/2015 3 V

 

(KTAS) q

 

(psf) CL CDP CDI CD C L / CD DP

 

(lb) DI

 

(lb) DT

 

(lb) VS

 

60

 

80

 

100

 

120

 

140

 

160

 

180

 

200

 

220

 

240

 

260

 

280

 

300

 

Equations for Table:

 

q= CL = W CD = CDP + CDi CD = CDP + [1/ ( Di = CDi q S = [1/ ( qS e AR)] CL2 q S CDi =[1/ (?eAR)] CL 2

 

e AR)] CL 2 Dp = CDp q S Dt = Di + Dp = CD q S Answer the following questions from your table.

 

I) Determine the minimum total drag ?Dmin? [lbs] (i.e. the minimum value in the total drag

 

?DT? column):

 

II) Determine the airspeed at which this minimum drag occurs ?VDmin? [kts] (i.e. the speed

 

associated with the row in which ?Dmin? was found):

 

III) Compare parasitic ?DP? and induced ?DI? drag at VDmin. What is special about this point

 

in your table?

 

This document was developed for online learning in ASCI 309.

 

File name: Ex_4_Drag&Applications

 

Updated: 07/11/2015 4 IV) Determine the maximum CL/CD value in your table (i.e. the maximum value in the

 

CL/CD column) and the speed at which it occurs.

 

V) Compare your results in IV) with II) and comment on your findings.

 

VI) Explain which values in your table will directly allow glide performance prediction and

 

how (Tip: Reference again the textbook discussion pp. 61-63).

 

B. If the gross weight of your aircraft is decreased by 10% (e.g. due to fuel burn), how would the

 

stall speed change? Support you answer with calculation as well as written assessment.

 

(Remember, stall speed references and discussions can be found pp. 43-45 in your textbook.) For the second part of this assignment use the given figure below (Figure 1.13 from

 

Aerodynamics for Naval Aviators [1965]) to answer the following questions. (This

 

assignment is designed to review some of the diagram reading skills required for your

 

midterm exam; therefore, please make sure to fully understand all the diagram

 

information and review book, lecture, and/or tutorials if necessary.): Figure 1.13 from Aerodynamics for Naval Aviators (1965).

 

This document was developed for online learning in ASCI 309.

 

File name: Ex_4_Drag&Applications

 

Updated: 07/11/2015 5 C. What is the Angle of Attack at Stall for the aircraft in Figure 1.13?

 

D. What Angle of Attack is associated with Best L/D?

 

E. What would be the best Glide Ratio for this aircraft?

 

F. What is the maximum coefficient of lift (CLmax) value? This document was developed for online learning in ASCI 309.

 

File name: Ex_4_Drag&Applications

 

Updated: 07/11/2015

 


Solution details:
STATUS
Answered
QUALITY
Approved
ANSWER RATING

This question was answered on: Jan 30, 2021

PRICE: $15

Solution~0001000250.zip (25.37 KB)

Buy this answer for only: $15

This attachment is locked

We have a ready expert answer for this paper which you can use for in-depth understanding, research editing or paraphrasing. You can buy it or order for a fresh, original and plagiarism-free solution (Deadline assured. Flexible pricing. TurnItIn Report provided)

Pay using PayPal (No PayPal account Required) or your credit card . All your purchases are securely protected by .
SiteLock

About this Question

STATUS

Answered

QUALITY

Approved

DATE ANSWERED

Jan 30, 2021

EXPERT

Tutor

ANSWER RATING

GET INSTANT HELP/h4>

We have top-notch tutors who can do your essay/homework for you at a reasonable cost and then you can simply use that essay as a template to build your own arguments.

You can also use these solutions:

  • As a reference for in-depth understanding of the subject.
  • As a source of ideas / reasoning for your own research (if properly referenced)
  • For editing and paraphrasing (check your institution's definition of plagiarism and recommended paraphrase).
This we believe is a better way of understanding a problem and makes use of the efficiency of time of the student.

NEW ASSIGNMENT HELP?

Order New Solution. Quick Turnaround

Click on the button below in order to Order for a New, Original and High-Quality Essay Solutions. New orders are original solutions and precise to your writing instruction requirements. Place a New Order using the button below.

WE GUARANTEE, THAT YOUR PAPER WILL BE WRITTEN FROM SCRATCH AND WITHIN A DEADLINE.

Order Now