Aero Engineering 315

Lesson 27

Gliding and Climbing Flight

Lesson Objectives Write Equations of Motion for power-off glide Calculate glide angle, glide range, sink rate, velocity

for min sink and velocity for max glide range given T-38 charts or a drag polar

Know points where min sink and max glide range occur

State situations appropriate to fly at above speeds Write Equations of Motion for steady climb Calculate climb angle, ROC, Max AOC, and Max ROC

given T-38 chart or drag polar Know points where max AOC and ROC occur Find the velocities for max AOC and ROC

State situations appropriate to fly at above speeds Define absolute, service and combat ceilings

When Max Excess Thrust = 0

Climbs and glides summary

Gliding Flight Glide angle Glide range Sink rate

Climbing Flight Climb angle Climb rate Ceilings

Results in just six separate

parameters to determine

T-38 Example

Given:W = 8,000 lbsh = 10,000 ft

Find: RMAX

T-38 Example

Given: W = 8,000 lbs h = 10,000 ft

Find: RODMIN

T-37 drag polar example

CD = 0.02 + 0.057 CL2

S = 184 ft2

W = 6,000 lbs Hsea level Find

(L/D)max

PRmin

T-38 Example

Given:W = 12,000 lbsh = Sea Level

Find: MAX

T-38 Example

Given:W = 12,000 lbsh = Sea Level

Find: ROCMAX

T-38 Ceiling

What happens to TA - TR as we go higher?

Ceilings

Based on maximum climb rates

Absolute Ceiling = 0 ft/min ROC

Service Ceiling = 100 ft/min ROC

Cruise Ceiling = 300 ft/min ROC

Combat Ceiling = 500 ft/min ROC

Performance Summary(text p. 173)

*for typical non-afterburning turbojet aircraft

Performance SummaryRelationship Best Case Relation between

Induced and Parasite Drag for best case

Graphical relation for best case

Max Climb Angle CDo = kCL2 - Minimum from TR curve

- Tangent point on a line from origin to PR curve

Max Climb Rate No set relation - Draw a line parallel to PA curve, and move it down till it is tangent to PR curve

Breguet (5.28) or Avg Value (5.27)

Max Jet Powered Range

CDo = 3kCL2 - Tangent point on a line

from origin to TR curve

Breguet (5.26) or Avg Value (5.24)

Max Jet Powered Endurance

CDo = kCL2 - Minimum from TR curve

- Tangent point on a line from origin to PR curve

R = h (L/D)Best Glide Range (angle)

CDo = kCL2 - Minimum from TR curve

- Tangent point on a line from origin to PR curve

Best Glide Endurance (min sink)

3CDo = kCL2 - Minimum from the PR curve

)arcsin(W

DT

W

P

W

DTVCOR x

)(...

W

P

W

VDDOR R...

Climbing

Cruise

Glides

Next Lesson (T28)…

Prior to class Read text 5.9.1-5.9.2, 5.9.5-5.9.7 Complete homework problems #31 and 32 Complete FDP parts a, b, i, j, k, l, r

In class Discuss Cruise Range and Endurance

Fighter Design Project