newbie flaps only angle downwards ?
leslie chard
generate lift ?
or can flaps be angled up as well ?
1 other question with 2 fuel tanks do you pump from both at same time or
empty 1 and change to the other
thinking bout it if tanks are in the wings then you would need to pump from
both at same time otherwise plane would become unbalanced over time i guess
Alan Wood
the best lift:drag raio (glide angle) at a higher airspeed.
"leslie chard" <lo...@one.net.au.invalid> wrote in message
news:vu_Pc.32275$K53....@news-server.bigpond.net.au...
Ron Garret
"leslie chard" <lo...@one.net.au.invalid> wrote:
> i am correct in assuming that you only use flaps for landing or taking of to
> generate lift ?
I powered airplanes, yes.
> or can flaps be angled up as well ?
As another poster noted, on gliders the flaps can sometimes be angled up.
> 1 other question with 2 fuel tanks do you pump from both at same time or
> empty 1 and change to the other
Neither. Again, it depends on the type of airplane. On a high-wing
plane you can typically draw fuel from both tanks at once, or from one
or the other, depending on the setting of the fuel selector valve. When
drawing from both tanks at once, fuel can cross-flow between the tanks.
If the plane is level then this will tend to keep the fuel balanced
between the tanks.
In a low-wing plane you typically have to draw from one tank or the
other, and you have to keep switching back and forth in order to keep
the tanks in balance. This is typically done every 30 minutes or so.
> thinking bout it if tanks are in the wings then you would need to pump from
> both at same time otherwise plane would become unbalanced over time i guess
Yes, indeed. Keeping the fuel in the tanks balanced is an important
part of the pilot's job.
RG
Kirk Stant
Gliders use negative flap settings for flatter glide at high speed.
Some power planes do the same (I thing the Maule does) for the same
reason; by reflexing the training edge there is less drag at high
speed (mainly useful on a high lift wing).
Modern jets such as the F-16 set their trailing edge surfaces to the
optimum position for the current flight condition, which may include
negative settings for minimum drag at high speeds.
As far as fuel is concerned, it depends on the plane. Some require
switching tanks, some do it automatically, some feed both wings into a
collector tank, some (multi-engine) feed engines with their own tank,
etc. It's surprising how much of an imbalance a plane can have before
it really makes a difference; normally you feel a trim change and have
to trim out the aileron force or hold a little aileron, but until you
get slow (and stall or spin!) it isn't a big deal. If you think about
the ratio of the weight of the fuel imbalance, vs the amount of lift
the wing is making, you can see why.
Again, in gliders, we may carry up to several hundred pounds of water,
divided (hopefully) equally in each wing. This is usually dumped
before landing, and it can happen that one wing doesn't dump
correctly. This will not be a problem if the pilot realizes it and is
prepared for the ground loop that is going to happen when the glider
slows down after landing and the heavy wing drops. Likewise, trying
to takeoff with a wing that is significantly heavier than the other
usually results in a ground loop and aborted takeoff in front of all
your friends!(spoken from experience...).
Kirk
LS6-b
leslie chard
lance smith
[snip]
> correctly. This will not be a problem if the pilot realizes it and is
> prepared for the ground loop that is going to happen when the glider
> slows down after landing and the heavy wing drops.
So a ground loop in a glider isn't a problem if the pilot realizes it
is going to happen? Is this because the loop will happen at low speed,
there is no 'real' landing gear to rip off, and the wings have skids
on them?
-lance smith
Kirk Stant
Well, any ground loop is potentially a problem, but if you are not
expecting it, it will definitely be a problem! On the other hand, if
you know you will groundloop, then you can plan your approach and
touchdown to minimize the effects.
Think of it like landing a skittish taildragger (a T-6, perhaps, or a
Stearman?) with a flat tire on one side. If you aren't expecting it,
it's going to water your eyes; but if you know before landing that you
have a problem, you can plan and prepare for it.
A glider ground loop caused by a heavy wing is usually a lot less
violent than a classic taildragger groundloop; probably since the
glider pivots around the centerline wheel as the wingtip skid drags on
the ground. Most gliders have a fixed tailwheel or skid that slows
the groundloop somewhat. So what happens (if you have picked a good
place to drop your wing) is that you end up with quick (for a glider!)
turn off the runway as the tip hits the ground and slides along. So
as long as you are not heading for something hard and/or expensive,
it's not too bad. Groundlooping on takeoff into a full hangar would
definitely not be fun, but it sure would be noisy! But at least you
don't have to worry about catching fire...although I do know of a
glider pilot who was killed by a falling Saguaro cactus that they hit
with the wing of their two-seat glider during a landing at an airport,
causing the pissed-off one-ton cactus to fall on the cockpit!
Not the same as a glider groundloop caused by snagging a wingtip - say
by landing in tall grass or crops. Those can break the tail off or
rip the gear off!
Oh, and my glider (an LS6-b) has a fully suspended and retractable
gear, full gear doors, brake, gear warning horn ... more "real",
perhaps, than the average spam can's landing gear? As long as it
keeps the belly from getting scratched, it's a real gear, after all,
whatever it's attached to!
Kirk
Doug
airspeed. I'm not sure they actually do much. But, yeah, flaps are for
flying slow. They reduce your stall speed and allow you take off and
land at a slower speed. Planes have "flap extension speed" that is
usually well below cruising speeds, so they only work when going slow.
Also, in turbulence you don't want your flaps down as it increases the
load on the wings and can cause problems. Basically, flaps, on most
planes are for landing and sometimes for takeoffs.
The surfaces that stick UP on airliners are spoilers, not flaps. They
act as air brakes. Different concept, and ONLY for landing or steep
decents. They actually reduced climb performance. Never used for
climb or takeoff.
"leslie chard" <lo...@one.net.au.invalid> wrote in message news:<vu_Pc.32275$K53....@news-server.bigpond.net.au>...