On Oct 26, 2:04*am, John Smith wrote:

The vertical angle is all you need to know. Gliders tend to glide at an
angle.

It helps when you are in the pattern, but the issue here is what to do
when you are away from the pattern. Also, I wouldn't necessarily
recommend that a student focus solely on the angle. I would not
consider it equally good piloting to enter the pattern at 3,000' AGL a
mile abeam of the runway as at 1,000' 1/3 mile abeam of the runway.

For the circling over the airport problem you can get some indication
of altitude by looking at the path the wingtip traces on the ground
from a known bank angle. Above a certain height the path will be
counter to the turning direction, below that height it will be in the
same direction. Do the math to convince yourself. (Note: This is one
cue that creates problems as it tends to make skidding turns down low
seem "normal". A pilot will over-rudder to make the wingtip move
backward -- don't do this). You also get altitude cues from the rate
that objects on the ground change angle in straight ahead flight at a
known airspeed. The least precise cue except at very low altitudes (or
for very big objects) is the included angle from one end of a ground
object to another. Use the length of the ramp, not the length of a
car.

Another big issue is gaining the experience to know when you need to
"head for home" from 10-20 miles away to hit a point that's 1,000' AGL
for pattern entry. The angle for most gliders is very flat but looks
flatter and flatter the farther away you get because the glide
terminates well above the ground. For instance, if your glider can go
7 miles for every 1,000' (L/D= 37) the angle will "look" roughly half
as steep from 20 miles as from 5 miles away. Fortunately this builds
in some conservatism in the pilot's judgement rather than the other
way around.

Try some of these techniques from different altitudes the next few
times you fly. Eventually it becomes (almost) second nature. Also read
Tom Knauff's fine text or one of the many others on the subject. They
are written by professionals.

9B