Flaps on take-off and landing

Flap extension does cause an immediate (manual flaps)
increase in lift, rotating the aircraft also increases lift
but the flaps seem to work better in the case of just
"jumping" a few feet because they also lower the stall speed
giving a slightly greater margin at the same energy level.



"Bob Moore" wrote in message
. 122...
| Jim Macklin wrote
| Flap extension reduces the stalling speed, often only a
few
| knots, but lift increases as does drag. The airplane
will
| balloon and slow very fast, the extra distance and
altitude
| gained is only a few feet, but if all you need is to
clear a
| 5 foot cattle fence or a 10 foot wide ditch, that is a
| technique that is useful.
|
| Can't create energy out of thin air Jim. You would clear
the
| same 5 foot fence just by increasing the angle of attack
and
| in both cases, glide a shorter distance if you were at
best
| L/D to start with.
|
| Bob Moore

Nope.

As long as you are flying in the green arc, the wing alone will ALWAYS give
you better lift.


Karl
"Curator" N185KG
screw bottom feeders


"Jim Macklin" wrote in message
news:2njOg.22663$SZ3.21477@dukeread04...
Flap extension does cause an immediate (manual flaps)
increase in lift, rotating the aircraft also increases lift
but the flaps seem to work better in the case of just
"jumping" a few feet because they also lower the stall speed
giving a slightly greater margin at the same energy level.

Try it. It is not a long term effect, just a quick change
to get over the short fence or narrow ditch.


"karl gruber" wrote in message
...
| Nope.
|
| As long as you are flying in the green arc, the wing alone
will ALWAYS give
| you better lift.
|
|
| Karl
| "Curator" N185KG
| screw bottom feeders
|
|
| "Jim Macklin" wrote
in message
| news:2njOg.22663$SZ3.21477@dukeread04...
| Flap extension does cause an immediate (manual flaps)
| increase in lift, rotating the aircraft also increases
lift
| but the flaps seem to work better in the case of just
| "jumping" a few feet because they also lower the stall
speed
| giving a slightly greater margin at the same energy
level.
|
|
|

"Jim Macklin" writes:

Try it. It is not a long term effect, just a quick change
to get over the short fence or narrow ditch.

So it's like ground effect, right?

--
Transpose mxsmanic and gmail to reach me by e-mail.

On Fri, 15 Sep 2006 16:49:12 +0200, Mxsmanic
wrote in :

So it's like ground effect, right?

No. It's like increasing the angle of attack on a thicker wing
section which stalls at a lower speed.

Ground effect is completely different:

http://en.wikipedia.org/wiki/Ground_effect
The term Ground effect (or Wing In Ground effect) refers to the
increase in lift experienced by an aircraft as it approaches
within roughly 1/4 of a wingpspan's length of the ground or other
level surface (such as the sea)

http://www.avweb.com/news/airman/185905-1.html

Larry Dighera writes:

No. It's like increasing the angle of attack on a thicker wing
section which stalls at a lower speed.

Ground effect is completely different:

http://en.wikipedia.org/wiki/Ground_effect
The term Ground effect (or Wing In Ground effect) refers to the
increase in lift experienced by an aircraft as it approaches
within roughly 1/4 of a wingpspan's length of the ground or other
level surface (such as the sea)

http://www.avweb.com/news/airman/185905-1.html

But if you are hopping over small obstacles near the runway, you're
probably very close to being within the distance influenced by ground
effect, aren't you?

--
Transpose mxsmanic and gmail to reach me by e-mail.

On Sat, 16 Sep 2006 08:53:53 +0200, Mxsmanic
wrote in :

Larry Dighera writes:

No. It's like increasing the angle of attack on a thicker wing
section which stalls at a lower speed.

Ground effect is completely different:

http://en.wikipedia.org/wiki/Ground_effect
The term Ground effect (or Wing In Ground effect) refers to the
increase in lift experienced by an aircraft as it approaches
within roughly 1/4 of a wingpspan's length of the ground or other
level surface (such as the sea)

http://www.avweb.com/news/airman/185905-1.html

But if you are hopping over small obstacles near the runway, you're
probably very close to being within the distance influenced by ground
effect, aren't you?

That's a reasonable assumption, but I believe you'll find that the
technique described will work at altitude as well, so it's not
dependent on ground effect.