Best Glide / Rate of Descent

[Nathan Young]

With the throttle at idle, and plane trimmed for best glide, what is
your plane's descent rate (in fpm)?

I tried this with my Cherokee 180 and found the resulting descent to
be somewhere between 900 and 1000fpm. (This was measured on the VSI,
not via altimeter plus stopwatch, so it is prone to error).

Varying the glide airspeed 5 or 10 mile an hour did not make a big
change in the descent rat, probably 50fpm or so.

Anyone tried the same?

[Darrell S]

With an MD-80 use Gross Weight plus 100 kts. If you weighed 120,000#, fly
220 knots for best glide ratio.

--

Darrell R. Schmidt
B-58 Hustler History: (see below)
http://members.cox.net/dschmidt1/


"Nathan Young" > wrote in message
...
> With the throttle at idle, and plane trimmed for best glide, what is
> your plane's descent rate (in fpm)?
>
> I tried this with my Cherokee 180 and found the resulting descent to
> be somewhere between 900 and 1000fpm. (This was measured on the VSI,
> not via altimeter plus stopwatch, so it is prone to error).
>
> Varying the glide airspeed 5 or 10 mile an hour did not make a big
> change in the descent rat, probably 50fpm or so.
>
> Anyone tried the same?

[Mortimer Schnerd, RN]

Nathan Young wrote:
> With the throttle at idle, and plane trimmed for best glide, what is
> your plane's descent rate (in fpm)?
>
> Anyone tried the same?


Having crashed both, I can definitively state that a C-210 sinks at roughly 700
fpm cleaned up and a Piper Lance comes down at 1100 fpm in the same situation.
While the extra cabin space is nice, the Cherokees are definitely lead sleds
when it comes to power off descents.



--
Mortimer Schnerd, RN

[Bob Gardner]

Did you read Barry Schiff's article on this subject in the May AOPA PILOT?

Bob Gardner

"Nathan Young" > wrote in message
...
> With the throttle at idle, and plane trimmed for best glide, what is
> your plane's descent rate (in fpm)?
>
> I tried this with my Cherokee 180 and found the resulting descent to
> be somewhere between 900 and 1000fpm. (This was measured on the VSI,
> not via altimeter plus stopwatch, so it is prone to error).
>
> Varying the glide airspeed 5 or 10 mile an hour did not make a big
> change in the descent rat, probably 50fpm or so.
>
> Anyone tried the same?

[Sylvain]

Nathan Young wrote:

> With the throttle at idle, and plane trimmed for best glide, what is
> your plane's descent rate (in fpm)?

note that: i) the best glide *speed* as indicated in your POH is
given at gross weight; i.e., sticking to this *speed* all alone
with less than full tanks, etc., i.e., lighter, will not work
as well as advertised; and ii) best glide speed does NOT give you
minimum sink.

--Sylvain

[Ash Wyllie]

Nathan Young opined

>With the throttle at idle, and plane trimmed for best glide, what is
>your plane's descent rate (in fpm)?

>I tried this with my Cherokee 180 and found the resulting descent to
>be somewhere between 900 and 1000fpm. (This was measured on the VSI,
>not via altimeter plus stopwatch, so it is prone to error).

>Varying the glide airspeed 5 or 10 mile an hour did not make a big
>change in the descent rat, probably 50fpm or so.

>Anyone tried the same?

I got about the same results with a 172.


-ash
Cthulhu in 2005!
Why wait for nature?

[Nathan Young]

On Tue, 9 May 2006 14:23:16 -0700, "Bob Gardner" >
wrote:

>Did you read Barry Schiff's article on this subject in the May AOPA PILOT?

Yep, that's what reminded me that I wanted to post my findings. ( I
had flown the test descents about two weeks ago).

-Nathan

[Marc J. Zeitlin]

Nathan Young wrote:

> With the throttle at idle, and plane trimmed for best glide, what is
> your plane's descent rate (in fpm)?

COZY MKIV, gross weight (2155 lb), about 115 mph (100 Kts), I'll get
about 650 fpm. At min. sink (maybe 95 mph), it'll be about 550 - 600
fpm. At lower weights (maybe 1800 lb), BG will be at 100 mph and 550
fpm, with min sink (around 90 mph) about 450 fpm.

IOW, BG gives an L/D of about 16 with the engine at idle. If the engine
was off (and the prop stopped), the L/D is about 13 - 14. There's a lot
of idle thrust, even at 1000 RPM.

--
Marc J. Zeitlin
http://www.cozybuilders.org/
Copyright (c) 2006

[Brian]

Best Glide 50 kts, Sink Rate 133 ft/min, Glide Ratio 38:1

http://www.soaridaho.com/Schreder/HP-16/N16VP.html

Brian

[Jim Macklin]

best glide 60 KIAS, wind 60 on the nose, sink rate 700 fpm.
Path is nearly vertical in this extreme example. If you
have to glide to a landing spot, pick some place downwind,
if you have to glide into the wind, you need to increase
speed, even if it increases sink rate. Your numbers will
vary, but keep the principle in mind.



--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"Brian" > wrote in message
oups.com...
| Best Glide 50 kts, Sink Rate 133 ft/min, Glide Ratio 38:1
|
| http://www.soaridaho.com/Schreder/HP-16/N16VP.html
|
| Brian
|

[Greg Farris]

In article >, says...
>
>
>Did you read Barry Schiff's article on this subject in the May AOPA PILOT?
>
>Bob Gardner
>


Yep - I was going to mention that when I saw this thread.
The article was a bit smug (he should have just trimmed to 70Kt, and he
would have gotten his Skyhawk without getting in a row with the CFI) but the
content was very good. In my opinion it would have been even better if he
had talked us through his complete approach to his selected landing area,
directly beneath, including his management of speed, when and how he changes
from best rate to best glide for better control etc. I say this because many
of us do these simulations during checkrides, but not much in between. The
last time I had to do it in a 182, I was a bit surprised how rusty I was on
it, and I'm guessing I'm not the only one.

GF

[Dylan Smith]

On 2006-05-09, Nathan Young > wrote:
> With the throttle at idle, and plane trimmed for best glide, what is
> your plane's descent rate (in fpm)?

Schleicher Ka8-B : 35 knots, approx 150 fpm :-)

(Approximate, because any air current will affect the rate. Indeed, in
some air currents I get to climb. But I'm sure you worked out by now the
Ka-8 is a glider)

--
Yes, the Reply-To email address is valid.
Oolite-Linux: an Elite tribute: http://oolite-linux.berlios.de

[B A R R Y]

Mortimer Schnerd, RN wrote:
>
> Having crashed both, I can definitively state that a C-210 sinks at roughly 700
> fpm cleaned up and a Piper Lance comes down at 1100 fpm in the same situation.
> While the extra cabin space is nice, the Cherokees are definitely lead sleds
> when it comes to power off descents.
>

My Beech 23 is easily out glided with the power off by a comparable
PA-28, so that must make the Beech a super lead sled. <G>

[Jim Macklin]

The short winged Cherokee and Musketeers don't glide as well
as the newer -151 Piper versions.


"B A R R Y" > wrote in message
om...
| Mortimer Schnerd, RN wrote:
| >
| > Having crashed both, I can definitively state that a
C-210 sinks at roughly 700
| > fpm cleaned up and a Piper Lance comes down at 1100 fpm
in the same situation.
| > While the extra cabin space is nice, the Cherokees are
definitely lead sleds
| > when it comes to power off descents.
| >
|
| My Beech 23 is easily out glided with the power off by a
comparable
| PA-28, so that must make the Beech a super lead sled. <G>