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Greg:
OK,
maybe I should clarify a few things.
1. Perhaps I should have said the airspeed indicator
is our ONLY instrument source for AOA and not necessarily a good one.
You are right in that it does not indicate an accurate AOA in many conditions of
flight - especially turning, slipping, skidding, spinning or
pull-outs. Wolfgang devotes a lot of space to AOA in "Stick and
Rudder" and also to relative wind or as he describes it "the wind of
flight." The AI is accurate for AOA if you are wings level and
coordinated at 1G. You can do 70 knots in climbing
flight, descending flight or level flight and your AOA will be the same -
the difference is power. With more than the requisite power to
maintain level flight, you will climb, with less you will descend. Try
this the next time you go flying: Trim the airplane for a level cruise
speed at a reduced power setting - say 2300 RPM. If your straight and
level speed is 90 MPH, add power with out changing trim. You will climb at
90 MPH IAS. The more power you add, the higher your rate of climb but your
airspeed will be the same. The same thing goes for descending, pull the
power back below 2300 rpm and the plane will descend indicating 90
MPH. The more power you pull off, the faster you descend. I've
noticed the coupe does this quite well.
2. The "nervous chef" technique applies more to the yoke and rudders - small constant corrections. I don't make a lot of corrections to the power setting coming down final.
3. I don't believe I'm "dragging in " the coupe at 70
MPH. I'm well above my stall speed. In my airplane, 70MPH
indicated is the best rate of climb and more or less the best glide speed.
That tells me that it is NOT behind the power curve and is actually
the speed of LEAST drag. Significantly slower than 70MPH would require a
greater power setting to maintain the same rate of descent and then yes, I'd be
dragging it in. I fly 70 MPH on approach because if I have
to go-around, I'm already at my VY speed - all I have to do is go full
throttle and pitch to maintain that magic 70 MPH. It is also well
above stall speed, gives me good authority on the elevator in the flare and
allows good cross-wind correction ability.
4. I will always aim to land near the end of the
runway - power on or power off. It has nothing to do with machismo
and everything to do with flying with precision. BUT, I make approaches
steep enough and carry enough residual energy to make the runway if I were ever
to lose the engine on final. You are correct that the carrier landing
is an extreme condition and not the kind of approach we want to make.
In my coupe 1.1 x stall would be about 50-55 MPH. I'd need a lot
more power to do that and be in deep-s*it if the motor gave
out. For that very reason, I don't drag it in, slow, nose-high with
lots of power. 70 MPH gives me plenty of energy to work
with.
5. In my experience, the carrier pilot brings the
power to full at the moment he strikes the deck. Any sooner and a bolter
is guaranteed. I don't know how adding power can raise the stall
speed as you suggest - maybe you meant the airspeed.
Tim
[Timothy J. Briggs]
-----Original
Message-----
From: Greg Bullough [mailto:[EMAIL PROTECTED]
Sent: Monday, July 19, 2004 9:01 PM
To: [email protected]
Subject: RE: [COUPERS-FLYIN] Approach and landing speeds.
From: Greg Bullough [mailto:[EMAIL PROTECTED]
Sent: Monday, July 19, 2004 9:01 PM
To: [email protected]
Subject: RE: [COUPERS-FLYIN] Approach and landing speeds.
Tim, all due respect to your carrier qualified guys, but the carrier landing
is certainly NOT the model of arrival that we'd want to use shore-side.
(I think Lynn Nelsen is probably the only carrier-qualified denizen of this
group, and he made up his mind that test-flying experimental helicopters
was safer, so chime in, Lynn.)
The carrier-landing is executed in a behind-the-power-curve mode, such
that with a fairly constant pitch the airplane can be dropped onto the
surface in a precise location at the lowest possible speed. As such, it
is horribly dependent upon power...the pilot who loses power on approach
to a carrier WILL go into the drink or the fantail, and the only solution for
a crew in that situation is 'eject-eject-eject.'
This is not a desirable condition for a landing that is aiming for the numbers
on terra firma. 'Over the fence' can easily become 'right through the bloody
fence!'
Similarly, the need to constantly play the throttle (i.e. nervous chef) is symptomatic
of a too-low airspeed and/or the failure to establish a normal glide which will terminate
at the threshold. Yes, it is a legitimate short-field technique. However, if on a long
runway this technique is being used, the pilot is trading certainty of making the runway
in event of an engine failure for the machismo of having smacked the numbers with
minimal residual energy in the airplane. It bears re-consideration of the technique
and of the motivation behind it.
Also, an airspeed indicator is not, nor is it a substitute for an angle-of-attack (AOA)
indicator. It is fifty-percent of the information that an AOAI gives. An AOAI allows
the pilot to know fairly precisely when his wing will cease to fly (stall). It makes
an approach at 1.1 Vso (stall speed in landing configuration) possible by synthesizing
the one variable...angle of attack...that governs the onset of stall.
Note also that the carrier pilot brings on full-power at or just after the threshold for
two reasons... 1) To raise the stall speed and cushion the landing a bit (somewhat
offset by the abrupt stop at the wire) and more importantly 2) to ensure that he is
spooled up in the event of a 'bolter' or a landing which misses all of the wires.
Other than an extremely short runway or a spot-landing contest, there is no reason
on god's green earth to be dragging an Ercoupe in at 70MPH behind the power
curve. There are a number of things that can happen as a result, only one of
which is any good.
Greg
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