Does glide ratio change with altitude?

Jim Carter wrote:
During a recent discussion about calculating glide ratio, I began to wonder
what the effects of pressure altitude were on the glide ratio of an
aircraft. Since air is 50% as dense at FL180 as at sea level, would the
glide ratio increase (glide further) as altitude decreases? AND if there is
a difference in glide ratio as altitude changes, then what values do most
manufacturers use when they publish their numbers (if they do)?

Oh yeah, I do understand that glide ratio changes to 0:0 upon impact, so the
wags can skip that part of the reply...


Ratio math is good only if terrain is perfectly flat in a
perfect world. You got to figure in the geography to get the
actual ratio. Or...... splat

A little calculus anyone???

"FredGarvinMaleProstitute" wrote in message
...
Jim Carter wrote:
During a recent discussion about calculating glide ratio, I began to
wonder what the effects of pressure altitude were on the glide ratio of
an aircraft. Since air is 50% as dense at FL180 as at sea level, would
the glide ratio increase (glide further) as altitude decreases? AND if
there is a difference in glide ratio as altitude changes, then what
values do most manufacturers use when they publish their numbers (if they
do)?

Oh yeah, I do understand that glide ratio changes to 0:0 upon impact, so
the wags can skip that part of the reply...


Ratio math is good only if terrain is perfectly flat in a perfect world.
You got to figure in the geography to get the actual ratio. Or...... splat

A little calculus anyone???

Ok Fred - that's a new one. What does terrain have to do with glide ratio? I
already noted that impact has an impact on the ratio, but only at point of
impact. Other than that one point on the continuum, what effect could
terrain have on glide ratio? And don't get started on turbulence, or wind
shear, or any number of other weather anomalies, because I'm asking about
glide ratio, not glide distance.


--
Jim Carter
Rogers, Arkansas

"FredGarvinMaleProstitute" wrote:


Ratio math is good only if terrain is perfectly flat in a perfect world.
You got to figure in the geography to get the actual ratio. Or...... splat

LOL. Still got a way to go to catch Mxsmanic, though.


--
Dan

"Did you just have a stroke and not tell me?"
- Jiminy Glick