Testing your glide. Are people doing this?

Big planes glide much better than small planes. An airliner has about
twice
the glide ration that your Pathfinder does.

Well, the Pathfinder glides like a rock. ;-)

But is that true of all airliners? I guess I would have thought that a
600,000 pound un-powered jetliner wouldn't glide very well.

Of course, the odds of losing all your engines are slim. But then who would
ever believe that they would run the Boeing 307 out of gas?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Trentus" wrote in message
...
OK, this is going to sound really silly, but I'm not a pilot,
If planes glide so well, then how come they crash?
It would seem reasonable, that if they glide, and they have an engine
failure etc. that they'd glide them in, not leave smoking craters like the
news tends to show.
Am I missing something here?

Apart from your naivete about the broadcast news industry, yes. Very big
planes are very heavy have a big potential energy load and land at speeds
over 100 miles an hour. Very, very hard to make it look pretty on anything
but a long flat surface. Little planes are very light and land at speeds
under 60 miles an hour. Very little energy to dissipate. A pilot current
in forced approaches can land them without much risk of injury anywhere with
a few hundred yards of relatively flat surface or something soft to absorb
the impact.

le moo

Careful, Jay. A BA 747 flew into the dust cloud from Mount Pinatubo and all
4 engines flamed out. He glided nicely for about 20 minutes until he got
them all to restart at some ridiculously low altitude.

And remember that glide performance has nothing to do with weight but to do
with wing design. And, if I remember correctly, a 747 or like glides just
about like a 172 does, it just needs a faster airspeed to do it, but does it
at the same kind of angle.

But on the subject of the glide ratios of cars, my Mercedes probably glides
a little better than the Pathfinder cuz it's all sleek and aerodynamic-like.
But the Integra's performance was horrible - it didn't glide worth a damn on
the roof!

Shawn
"Jay Honeck" wrote in message
news:VNwnb.51170$HS4.234123@attbi_s01...
Big planes glide much better than small planes. An airliner has about
twice
the glide ration that your Pathfinder does.

Well, the Pathfinder glides like a rock. ;-)

But is that true of all airliners? I guess I would have thought that a
600,000 pound un-powered jetliner wouldn't glide very well.

Of course, the odds of losing all your engines are slim. But then who
would
ever believe that they would run the Boeing 307 out of gas?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

I suspect that the Pathfinder glides about like any fixed gear single and
would be surprised if its glide ratio differed much from a 152 or Cherokee
6.

Jets have glide ratios of up to 20:1. They have no props, dangling gear,
exposed rivits, large openings for cooling ect. The 600,000lb airliner
comes down fast but it goes forward fast too. Remember weight is potential
energy.

My MU-2 has a glide ratio of about 12:1.

Mike
MU-2


"Jay Honeck" wrote in message
news:VNwnb.51170$HS4.234123@attbi_s01...
Big planes glide much better than small planes. An airliner has about
twice
the glide ration that your Pathfinder does.

Well, the Pathfinder glides like a rock. ;-)

But is that true of all airliners? I guess I would have thought that a
600,000 pound un-powered jetliner wouldn't glide very well.

Of course, the odds of losing all your engines are slim. But then who
would
ever believe that they would run the Boeing 307 out of gas?
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote in message news:VNwnb.51170$HS4.234123@attbi_s01...

But is that true of all airliners? I guess I would have thought that a
600,000 pound un-powered jetliner wouldn't glide very well.

They glide better because they have much less drag. They're slick and don't have
landing gear and other cruft sticking out (and what antennas and stuff they do have
are much smaller in ratio to the overall area).

"ShawnD2112" wrote in message news
And remember that glide performance has nothing to do with weight but to do
with wing design. And, if I remember correctly, a 747 or like glides just
about like a 172 does, it just needs a faster airspeed to do it, but does it
at the same kind of angle.

Actually, it is a function of the lift and drag. While wing design figures into,
the lack of things sticking out of the fuselage like landing gear, big (compared
to the size of the aircraft) antennas, and an overall more streamlined shape
than Jay's Piper yields much less parasitic drag.

"ShawnD2112" wrote

And remember that glide performance has nothing to do with
weight but to do with wing design.

TRUE!!

And, if I remember correctly, a 747 or like glides just about
like a 172 does,

NOT TRUE!! A B-747 has about the same glide ratio as the B-707s
that I flew for 17 years, 20:1 or better. From 35-37,000'(6nm),
we could do 125nm easily.

it just needs a faster airspeed to do it, but does it at the same
kind of angle.

TRUE!! About 250kts plus or minus depending on weight.

Bob Moore
PanAm (retired)

Truer point. That's what I was trying to get at from memory while being too
lazy to pull out my books! :-)

Shawn
"Ron Natalie" wrote in message
m...

"ShawnD2112" wrote in message
news

And remember that glide performance has nothing to do with weight but to
do
with wing design. And, if I remember correctly, a 747 or like glides
just
about like a 172 does, it just needs a faster airspeed to do it, but
does it
at the same kind of angle.

Actually, it is a function of the lift and drag. While wing design
figures into,
the lack of things sticking out of the fuselage like landing gear, big
(compared
to the size of the aircraft) antennas, and an overall more streamlined
shape
than Jay's Piper yields much less parasitic drag.

I stand corrected! Didn't realize the glide ratio was that high. Makes my
point even better.

Shawn
"Robert Moore" wrote in message
. 7...
"ShawnD2112" wrote

And remember that glide performance has nothing to do with
weight but to do with wing design.

TRUE!!

And, if I remember correctly, a 747 or like glides just about
like a 172 does,

NOT TRUE!! A B-747 has about the same glide ratio as the B-707s
that I flew for 17 years, 20:1 or better. From 35-37,000'(6nm),
we could do 125nm easily.

it just needs a faster airspeed to do it, but does it at the same
kind of angle.

TRUE!! About 250kts plus or minus depending on weight.

Bob Moore
PanAm (retired)

Am I missing something here?

Yes, loss of control. This is the key event in most fatal accidents
involving smoking craters - the pilot lost control of the airplane. From
this, springs the adage: Always, ALWAYS, fly the airplane first. Worry
about the other stuff later, but right now, FLY THE AIRPLANE.

- Mark