Testing your glide. Are people doing this?

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?

Trentus

"Montblack" wrote in message
...
("Yossarian" wrote in the Catalina Perep thread)
My first trip I was that low too, but now my FBO insists on a continuous
climb to the middle of the channel for better glide distance if your
engine
quits. 4500' in a 172 is only like 7 miles glide.


I wonder how many people have actually glided their planes (rentals or
otherwise) and so know what their real world glide range numbers will be -
from say, 6,000 ft AGL down to 3,000 ft AGL? Into the wind vs tailwind,
etc?

I'm under the impression that 5:1 is a good (safety) number to have in
your
head for an average 172 flying at 3,000 ft AGL, and below. Gives you some
"what the hey?" room and *some* turning room.

Can't quite make a 3 mile target with exactly 5:1 at 3,000 ft
AGL....15,000
ft. Leaves you 840 ft short of 3 miles. Still, (a mile glide per 1,000 ft
of
altitude) seems like a good number to keep in your head for lower
altitudes.
Almost 5:1.

I wonder how much better (than the made up safety number 5:1) people will
see up at 6,000 ft AGL. Are people getting book numbers, in their planes,
when they go up and practice real world glides - from say 6k down to 3k?


Montblack
Happy Birthday Kristen
October 25

"Trentus" writes:

OK, this is going to sound really silly, but I'm not a pilot,
If planes glide so well, then how come they crash?

If cars steer so well, how come *they* crash? In both cases, the
problem is the usually the squishy part sitting on the seat in front
of the controls, not the metal parts.

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.

The news doesn't typically show the ones that glide in, not to mention
the ones that land without incident (i.e. nearly all of them). Here
are some other headlines you don't see:

80M children arrive home from school safely.

Politician not under investigation for corruption.

U.S. doesn't invade Belgium.

Study links weight loss to moderation and exercise.

No bank robberies in state.

Police treat black suspect politely.

Terrorists do not attack museum.

etc. News is the unusual stuff -- it doesn't represent most of what
is going on.


All the best,


David

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?

A few disparate points to help you understand the situation better:

- Little planes tend to glide a lot better than big planes.

- Where you lose your engine is important. A little plane losing its engine
over Iowa might make the local newspaper, but everyone will walk away. The
same engine failure over downtown Chicago is going to make national news.

- Smoking holes are created when planes glide into something -- hard. No
matter how well you can glide, sooner or later Mother Earth reaches up to
smite you. If there is a big building or mountain in the way when you run
out of glide, well...

- Smoking holes happen when a pilot allows the plane to slow to a speed at
which the wing no longer creates lift. This is the "stall" speed. A
wing/plane that is stalled takes on the flight characteristics of a load of
sand, and comes down in a hurry, creating a smoking crater.

Hope this helps.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Jay Honeck" wrote in message
newsLunb.50518$HS4.232034@attbi_s01...

A few disparate points to help you understand the situation better:

- Little planes tend to glide a lot better than big planes.

- Where you lose your engine is important. A little plane losing its
engine
over Iowa might make the local newspaper, but everyone will walk away.
The
same engine failure over downtown Chicago is going to make national news.

- Smoking holes are created when planes glide into something -- hard. No
matter how well you can glide, sooner or later Mother Earth reaches up to
smite you. If there is a big building or mountain in the way when you run
out of glide, well...
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"



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

Mike
MU-2

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"

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).

On Tue, 28 Oct 2003 at 16:27:33 in message
VNwnb.51170$HS4.234123@attbi_s01, Jay Honeck
wrote:

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.

The weight makes a difference to the rate of sink but I see no obvious
reason why it should make a big difference to the glide angle. After
all, airliners need good lift drag ratios to make them economical.

The BOAC 747 that lost all engines due to volcanic ash expected to be
able to glide 141 nm from 37,000 ft taking 23 minutes. That's a glide
ratio of over 20 to 1 and around 1600 ft a minute and 240 knots.

They did worse than that because they did not know the best speed and
they needed to maintain the engine start speed. Not only that but they
had no reliable speed measurement either. One pilot had 320knots and the
other had 270 knots on their ASIs - 50 knot difference!. Then they had
to sacrifice height because of loss of pressurization. Of course when
they passed out of the ash they were able to restart.

Ref: Air Disaster Volume 2 by Macarthur Job
--
Francis E-Mail reply to

Wow, sure did not realize this, thanks
Mike and all.

Pat Thronson PP

"Mike Rapoport" wrote in message
ink.net...

"Jay Honeck" wrote in message
newsLunb.50518$HS4.232034@attbi_s01...

A few disparate points to help you understand the situation better:

- Little planes tend to glide a lot better than big planes.

- Where you lose your engine is important. A little plane losing its
engine
over Iowa might make the local newspaper, but everyone will walk away.
The
same engine failure over downtown Chicago is going to make national
news.

- Smoking holes are created when planes glide into something -- hard.
No
matter how well you can glide, sooner or later Mother Earth reaches up
to
smite you. If there is a big building or mountain in the way when you
run
out of glide, well...
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"



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

Mike
MU-2