> > A glider is
> > "propelled" by the forward - in the direction
> > of flight - component of
> > the aircraft's WEIGHT only.
And thats why they (gliders) obviously fill also
sometimes their watertanks - to get more load, to
feed gravity and to get speed?
Cheers, Raimo
-----Alkuperinen viesti-----
From: Sidsel & Svein Johnsen
Sent: Monday, July 01, 2013 6:24 PM
Subject: SV: SV: Europa-List: Re: wing lift/drag
pins
Johnsen" <sidsel.svein@oslo.online.no>
Frans,
Our postings are crossing a little, but I think
the below covers also your
last one:
>
> How does an autogyro (autocopter?) work? What is
> causing the blades to
> move forward?
>
See http://en.wikipedia.org/wiki/Autogiro
> > A glider is
> > "propelled" by the forward - in the direction
> > of flight - component of
> > the aircraft's WEIGHT only.
>
> Ok, got it. But without wings (but still with
> the majority of the
> weight) will the glider still be propelled
> forwards? I guess not.
Again: What is meant by "forward"? Without
wings, the glider will still be
propelled forwards, and still by gravitational
force. Unfortunately for the
pilot, however, "forward" now means more or less
vertical towards the ground
..........
> Then what exactly is exercising a forward
> pulling force on the glider's
> fuselage? The fuselage has only drag. So
> something must be pulling it
> forward.
>
I may be stating the obvious, but a glider is
always going down, or rather
gliding down - down relative to the air mass
through which it moves. If the
air mass is moving upwards (thermals) faster than
the glider moves downwards
through that air mass, the glider climbs relative
to the ground even though
it goes down relative to the air mass. All the
time, it is the gravity that
causes it to move, and movement through the air
creates lift (if the wings
are still on), so that the glider does not fall
like a stone through the
surrounding air mass. When the total drag on the
glider equals the
gravity's component in the direction of flight,
the glider does not
accelerate any more, it has reached constant
speed.
Same thing with an airplane with engine, if the
engine quits. As long as
the engine works, though, and we fly level, the
engine gives enough pull to
equal the total drag, so that we don't need any
assistance by the gravity to
create speed. At level flight, the lift and the
down force by the
stabilizer are vertical. Gravity is always
vertical. I.e. no fore-or-aft
force component from any of these three forces.
Only drag, which equals
propeller pull at constant speed.
Regards,
Svein
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