Testing your glide. Are people doing this?

"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.

"Happy Dog" wrote in message .. .


That's one great thing about owning. Lots of time to fool with mixture and
MP and prop settings. I save about 2 - 3 GPH over common "squared" power
and ROP settings. Also, when you fly a rented plane slower, and more
efficiently, you are penalized. The same style in your own plane costs less
while maximizing your PIC time. Dunno about the CO being a major issue
though.

I'm not sure that MP has much measurable affect on glide, but playing with
the prop control sure does.

"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

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).

I had heard that airliners will generally glide a 3 degree glideslope, clean
and power off. Something that GA airplanes have no hope of doing.

It is a FAST ILS though - less than a minute at 250K.

- Mark

... as was done on my 4th lesson for my PPL with my instructor.
Not only stopped the engine, but made me slow down to actually stop the
prop.

There is always controversy about how realistic to make emergency training.
I think the risk of doing this training outweighs the benefit.

Engine out and windmilling (low pitch if CS) - yes. Stopping the prop - no.

- Mark

"markjen" wrote
I had heard that airliners will generally glide a 3 degree
glideslope, clean and power off. Something that GA airplanes
have no hope of doing.

If we were on the glideslope "way out", and clean power off, our
biggest problem in the B-707 was slowing to the "gear/flap" speed
without using the speedbrakes which shook the Pax too much.
In the 727, because of the T-mounted horizontal stabilizer, we just
yanked the speedbrake.

Bob Moore

I tried this technique in my Bulldog (IO-360, CS prop). It
shuddered and shook so much I went back to the "normal"
method after 2 or 3 seconds!

Paul

"David Megginson" wrote in message
...
Nowadays, in my own Warrior, I
push the throttle to full for takeoff and don't touch it again until
I'm ready to land; in-between, I set power by adjusting the mixture
only, as recommended by the POH for best economy.