All my primary students get a couple of lessons on how to fly without an ASI.
When they do, they are quite surprised and pleased with the outcome.
Personally, I rarely ever look at the ASI. The only times I use it is during
max-performance takeoffs and landings. However, since we don't always know the
exact weight of the airplane, I can only imagine that those Vx and Vy's we fly
must be quite a bit off from the optimal. During cruise, I don't care what the
ASI reads (except when ATC asks me). The MP and RPM tell me everything I need
to know. If I hit rough air, I just need to know that I am below Va. I don't
care what the actual number is. All of the above numbers can be more
accurately measured with an AOA indicator than an ASI.
As you point out, there are a few other speeds which are not directly measured
by the AOA. Vfe and Vle, for example, are actual ASI limits, not AOA limits.
However, how many of us extend flaps or open gear doors while doing high-G
maneuvers? It would be quite acceptable to calibrate these speeds in terms of
AOA for 1G at gross weight. As for Vne, that also is an actual ASI limit.
However, if you are skirting the Vne limit, the difference between AOA and ASI
becomes simply academic.
It is true that a 'good pilot' should be able to feel his speed and stall
conditions. However, every year we continue to witness numerous stall/spin
accidents. The ASI does a poor job of preventing them.
My point: The ASI is not a particularly useful instrument anyway. An AOA could
be slightly more useful. Perhaps the ASI could be indispensable in special
cases like acrobatics. I can't speak for that since I am not an acro-pilot.
BCLERX@aol.com wrote:
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I agree that AOA info is useful, but not at the expense of an airspeed
indicator. Since the government desk jockeys require as ASI, its not even
worth wasting bandwidth here talking about it. Keep in mind that trying to
calibrate an AOA in terms of aispeed limits (Vne, maneuvering speed, flap
limits) only works at a fixed weight and 1G flight. It does give wing
"performance" (stall, Clmax,Vx, Vy) info regardless of weight and G loading,
which is why its a great instrument. You still need an ASI to give you the
amount of energy available (with varying weight and G loading, AOA won't give
you this info).
ASI and AOA give you different information. ASI can give you AOA info at 1G
and corrected for weight variations. AOA can be interpolated to give speed
info (at 1G and a fixed weight). You can fly the wing at max efficiency by
using AOA, but if you're going to push the envelope, I'd rather know how much
energy (airspeed) I have available. Any fighter pilot will tell you that AOA
is great, but not at the expense of an ASI. A good pilot can "feel" if he's
at the correct AOA, and certainly can feel where the stall begins.
Bottom line: Keep the ASI (you need it to know how fast you're going and for
energy management). Add AOA if you want to fly the plane efficiently (but you
can get the same info from the ASI). Tape a piece of string to the wingtip
trailing edge for a cheap AOA indicator. If you want to avoid stalling, go
out and practice stalls till you get a good feel for your machine (you need
to do this even with an AOA indicator). Get a book (about the size of a
magazine. Easy and quick to read) by Bob Wander called "Glider Polars and
Speed To Fly". You'll learn more about how a wing works in an evening of
reading than any instructor can teach you. I highly recommend it for all
pilots.
I'm ex- Air Force (supersonic and heavy jets) and now fly a B-777. In my
spare time I also fly sailplanes (cross country racing), bizjets, and teach
air combat and aerobatics in a SF-260 and Extra 300L (where I find an AOA
indicator would be of little use since I can feel where I need to be). The
Europa is my first kit plane.
Ben Clerx #A144
Southern California
CFII
Europa #A178
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