1. Aero Engineering 315 Lesson 33 GR3 Review

2. General strategy  Prior to class Review reading for lessons 23 – 32 Work / review problems #26 – 42 Review handouts (turbojet performance summary and changes to thrust & power curves) Review slides and other handouts—especially the performance summary handout Know your memory equations (mostly GR2 and q) Be familiar with applicable supplemental data info  In class BRING calculator, straight edge, pencils

4. Performance Summary RelationshipBest Case Relation between Induced and Parasite Drag for best case Graphical relation for best case Max Climb Angle C Do = kC L 2 - Minimum from T R curve - Tangent point on a line from origin to P R curve Max Climb RateNo set relation - Draw a line parallel to P A curve, and move it down till it is tangent to P R curve Breguet (5.28) or Avg Value (5.27) Max Jet Powered Range C Do = 3kC L 2 - Tangent point on a line from origin to T R curve Breguet (5.26) or Avg Value (5.24) Max Jet Powered Endurance C Do = kC L 2 - Minimum from T R curve - Tangent point on a line from origin to P R curve R = h (L/D) Best Glide Range (angle) C Do = kC L 2 - Minimum from T R curve - Tangent point on a line from origin to P R curve Best Glide Endurance (min sink) 3C Do = kC L 2 - Minimum from the P R curve Climbing Cruise Glides

5. Example 5.2 An aircraft with C Do = 0.020 and k = 0.12 is flying at h = 30,000 ft and M = 0.8. If the aircraft has a wing area of 375 ft 2 and it weighs 25,000 lbs, what is its drag coefficient and how much drag is it generating? If the aircraft is in steady, level, unaccelerated flight (SLUF), how much thrust is its engine producing? If its C Lmax = 1.8, what is its stall speed at that altitude?

6. Example 5.4 A sailplane’s drag polar is C D = 0.01 + 0.02 C L 2. It has a mass of 500 kg and a wing area of 20 m 2. What is its maximum glide ratio and minimum sink rate at sea level, and at what speeds are these achieved?

7. Example 5.6 A turbojet-powered trainer aircraft weighs 5,000 lbs and is flying at h = 25,000 ft with 1,000 lb of fuel on board. Its drag polar is C D = 0.018 + 0.095 C L 2, its wing area is 180 ft 2, and the TSFC of its engines is 1.0/hr at sea level. What is its maximum range and endurance to tanks dry at this altitude, and at what speed should the pilot initially fly to achieve each?

8. Example 5.8 The non-afterburning turbojet engines of a Cessna T-37 jet trainer produce approximately 1700 lb of installed thrust for takeoff at sea level, and its takeoff weight is 6575 lb. Its C Lmax =1.6 for takeoff and its drag polar in its takeoff configuration is C Do = 0.03 + 0.057 C L 2. Its reference planform area is 184 ft 2. Normal takeoff procedure requires the pilot to rotate the aircraft to the takeoff attitude just prior to reaching takeoff velocity, so for the majority of the takeoff roll the aircraft’s C L = 0.8. What will be the aircraft’s takeoff distance at sea level with no wind?