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exam1.pdf - Fall 2013 EAS 4105 Flight Mechanics Midterm...

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Unformatted text preview: Fall 2013 EAS 4105- Flight Mechanics Midterm Name Wm %m Score PID 11:30am - 12:20 pm Problem 1 (20) Problem 2 7 (20) Problem 3 (30) Problem 4 (30) —__— l. (20 Points) Conceptual Questions (1.1) Which airplane is statically stable, airplane 1 or airplane 2? (2 Points) 0 Angie of Sideslip (1.2) We have developed the 6 DOF aircraft mot' (model. Here are some questions related to it. (1.2a) In which frame the velocity, roll, pitch, d yaw rate are expressed in? (2 points) (1.2b) What is the rotation sequence from the inertial frame to the body frame? (2 points) (120) Is the Euler angle rate the same as the yaw, pitch/and roll rates or not? (2 points) (1.3) Please list two types of drag. (2 points) (1.4) Which point is stable in the following thrust curve, V; or Y4? (2 points) (1.5) In order to decrease the level turn radius, shonjd’"you lower the A/C speed or increase the A/C speed? (2 points) (1.6) Please explain what the “adverse yaw” is using one sentence. (2 points) (1.7) Will downwash increase or decrease the horizontal tail’s effective angle of attack? (2\points) (1.8) Please write clearly which li'rfifiiwthrfignre below represents the case of stability margin larger than zero (SM>0)? (2 points), 2. (20 Points) A T-37 is at the following condition: the Euler angles are \I’ =10",® = 30°,CI) = 5" , and the Euler angle rates are ‘1’ =0” /s,®=10" /s,(I>=—5° ls. Please calculate the roll, pitch, and yaw rates. 3 (30 Points) The wing-fuselage pitching moment characteristics of a high-wing, single—engine, general aviation airplane follow along with pertinent geometric data of Cm = —0.06—0.0040a ”Ew/ where a is the fuselage reference line angle of attack in degrees and wf means “wing- fuselage”. The data we know are: SW =180fi2, xcg/c=0.1, bw =36ft, ARW =72, 5w =5.0ft, CL" =0.07/deg, wf iw = 2.00, CL“. = 0.26, I, = 14.75 ft , 77 = 1, AR, = 4.85, CL“ = 0.26 Estimate the horizontal tail area and the tail incidence angle it so that the complete airplane has the following desired pitching moment characteristics Cm = 0.16 — 0.024a. 2an Equation may be helpfiJl: Cm0 =VH77CLU (iw +80 —i,), Cm 2— HnCL (1—3—8) , I II a d8 2CL _ ZCIO __ ———“l-, go _ da nARw nARW 4 (30 Points) An F-4 is in level flight at 18,000 ft on a standard day. The a/c weighs 48,000 lbf initially and is cruising at 500 kn true airspeed. . i ‘ ‘ q = 500be / fiz, s = 520 ft2 , AR = 2.77, p = 0.00135 1th /@ CD =0.026+O.115CL2, a“ =00, e=l, C,“ =0.lO/deg I (a) What is the angle of attack? - l (b) What will be the angle of , attack if the pilot slows down to cruise at 400 kn true airspeed at 18,000ft on a standard day? C,“ 57.3C, 1+ “ fleAR Equation may be helpful: C La = ...
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