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 lbs
h = 10,000 ft
Find: RMAX
T-38
Example
Given: W = 8,000 lbs
Find: RODMIN
h = 10,000 ft
T-37 drag polar example





CD = 0.02 + 0.057 CL2
S = 184 ft2
W = 6,000 lbs
Hr = sea level
Find


(L/D)max
PRmin
T-38
Example
Given:
W = 12,000 lbs
h = Sea Level
Find: gMAX
T-38
Example
Given:
W = 12,000 lbs
h = 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 Summary
Best Case
Relation between
Induced and
Parasite Drag for
best case
Graphical relation for
best case
Max Climb Angle
CDo = kCL2
-
Max Climb Rate
No set relation
-
Breguet (5.28) or
Avg Value (5.27)
Max Jet
Powered Range
CDo = 3kCL2
-
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
VD PR
R.O.D. =
=
W W
Best Glide
Endurance (min
sink)
3CDo = kCL2
- Minimum from the PR curve
Relationship
T D
)
W
V (T  D) Px
R.O.C. =
=
W
W
g = arcsin(
Climbing
Cruise
Glides
Minimum from TR curve
- Tangent point on a line
from origin to PR curve
Draw a line parallel to PA
curve, and move it down till
it is tangent to PR curve
Tangent point on a line
from origin to TR curve
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