Cheers! and Happy New Year!
I know this topic has been breached several times but, having noted
the penchant for losing lift due to loss of airspeed control, am bent on
pronouncing for a further study of Angle of Attack instruments.
This is not for the ex-Naval test pilots or 100-series fighter
types but a short topic for the 500-hour private drivers among us.
The airspeed indicator has been with us all along as the prime tool
for lift control. Some have been very effective over the years. However
the primary sensor should really be a lift/drag comparator because IT is
the basic guide to what the wing is doing. Having come once or twice to
shaving the stall region too closely at airshows or on tests, I can say
that nothing raises the hair on the back of the neck (nor promotes hot
sticky nightmares)better than realising you've used up your lifetime
ration of slow lift hours! Amother thing this does is to promote many
hours of contemplation.
In the course of those hours, and having had the experience of
"alpha-flying" - that is flying by reference to the angle of attack
indicator instead of the airspeed - I am convinced that more of us need
to do this. It has saved my buns twice now.
Instead of memorising the 30,45 and 60deg bank factors on 'stall
speed' (and density altitude and all those other factors), one need only
consult the alpha angle to know how to control the lift/drag ratio and
thus the proper approach attitude under ALL conditions. This holds true
for best endurance, best rate of climb, best CofG, best this, best that.
The alpha indicator is to lift control as GPS is to the alidade or
octant.
There are a number of alpha systems out there and each should be
evaluated before choosing. The airspeed indicator is fine for cruise
control but is IMHO a secondary needle on final approach and landing.
Else why would Lockheed have chosen alpha as the prime parameter for the
TriStar Direct Lift Control system and landing variable? Looking at all
those heavy=lift accidents in recent years, I cannot help but wonder why
other makers haven't addopted the same principle.
If you're at the wing-building stage, please consider the
implications of installing this great device.
Happy Landings for 1999,
Ferg (#A064)
P.S: No, I'm not involved in ANY way with providing them!
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