Nuther SR-22 crash/incident?
"Roger" wrote in message
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Welllll... In the Deb Vso is about 63 MPH at gross. I fly final at 80
minus 1 MPH for each 100# under gross. However if I kill the power
it'll drop like a rock. Pull the nose up and it'll just go down faster
and I have about 17 MPH over stall.
There's no reason to pull the nose up until you're ready to flare, and with
17 mph there's absolutely no reason you should not have the ability to
arrest your descent and land without "dropping like a rock".
My own plane is very "draggy", without power it glides very steeply, and if
you're too slow when flaring power-off, the flare does need to be fairly
rapid. Otherwise, the airspeed drops more quickly than you can increase the
AOA to account for the reduced airspeed.
But that doesn't mean that the lift isn't available. It just means it
requires correct piloting technique to take advantage of the lift, at the
right moment and with the correct control input.
Beyond that, your own anecdote isn't very germane, considering that you're
talking a 5 knot smaller margin, in an airplane with a LOT more drag. With
20 knots or more above stall, the Cirrus has plenty of airspeed to have a
nice comfortable flare, even power off.
What lift curve are you talking about? Lift is proportional to airspeed
and
angle of attack, regardless of the wing. Up to the point of the stall,
you
need more lift, you just increase the angle of attack. It's a linear
change.
I think this idea may be what's getting some SR-22 pilots into
trouble.
What idea?
Stop thinking of the SR-22 as a fast Cherokee or Cessna.
Who's thinking of the SR-22 as a fast Cherokee or Cessna?
Things are not as you think.
What things are not as I think?
It varies from plane to plane but is
quite common for high performance aircraft.
What is quite common for high performance aircraft?
Some where around 20
knots above stall speed (give or take) you reach a point where the
drag is so high that although raising the nose may give more lift it
is more than offset by the increased drag.
Drag counteracts thrust, not lift. How can the lift be "more than offset by
the increased drag"?
So raising the nose results
in a faster rate of descent instead of slowing it.
Not until the airspeed drops. An airplane does not slow immediately when
the AOA is increased. The increase in drag takes time to cause an airplane
to slow, and assuming the pilot is not increasing the AOA at an
inappropriate moment (say, 100' above the touchdown elevation), the primary
effect of increasing AOA is to increase lift and thus reduce the rate of
descent.
This is true for any airplane.
Pulling the power
to idle in this range is likely to put you on the express elevator
down.
All that pulling the power to idle will require is a lowered AOA in order to
compensate for the reduced thrust. Yes, descent rate will increase. But
airspeed can easily be kept the same, and with 20 knots above the stall
speed, there is plenty of energy left for a proper flare and touchdown at
the appropriate moment.
This is why there is a substantial difference in my power off and
power on landing speeds with the power on being the slower of the two.
Actually, the reason there is a substantial difference in your power-off and
power-on landing speeds is the amount of power available. It has nothing to
do with some oddball idea of a "flat lift curve".
Plus I'm flying a plane with relatively low wing loading and low stall
speed. The Bo/Deb is very good at short field landings and take offs
when flown by the numbers.
Um, that statement simply reinforces my point. Even your "drop like a rock"
airplane has no trouble if the pilot does things correctly.
Pete
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