Mailing List lml@lancaironline.net Message #48839
From: <Sky2high@aol.com>
Sender: <marv@lancaironline.net>
Subject: Lancair Accidents - Another Perspective
Date: Wed, 10 Sep 2008 21:29:54 -0400
To: <lml@lancaironline.net>

This is the first in a series about how custom-built, single-engine aircraft's unique characteristics might contribute to the accidents that occur in them.  Of course, I can only refer to the characteristics of my own custom pre-fast-build Lancair 320 and how it differs from spam can flight performance concepts taught in flight schools across the country.  I am beginning to understand the importance of accumulating many hours of experience (successful time in type) and the value of investigating simple flight performance attributes (experimentation), especially when some of that results in "aha!" illuminations from uh, minor error$.  Learn about your craft before you use it – if you can’t do that, at least learn about it while you’re using it.

 

Let me point out that I am just your average guy.  No military or commercial flight time is in my resume - 2300 hours with 930 in my Lancair.  201 hours of instruction (1060 total time) got me Pvt SEL, Commercial MEL/CLT and INST Airplane ratings by the time I first flew my Lancair in 1996.  Since then I have added merely 13 hours of dual, including two trips to HPAT.  I first flew my plane after a demo flight with Don Goetz, 2 hours in the right seat of a friend’s Lancair and 1 hour (1 landing) in the left seat of mine.  I do not recommend this scenario to others - training from a CFI with Lancair experience is crucial. I now think of my self as a Group A pilot (cautious good judgment) but otherwise as a Group B person - I ride a motorcycle and use my hand to put stuff down the garbage disposal.  Hmmmm, risk is relative to the engaged activity.............

 

Anyway, while recently at lunch with a group of airport bums, the topic of stall/spin was being actively discussed.  Eventually the conversation moved to flight controls, a part of which was expounded upon by an elderly, highly respected CFII, past aerobatic and air show pilot with beaucoup hours in all types of airplanes.  He said something like, "In the kinds of airplanes we fly (spam cans), I teach students to lead with the rudder and then bank into the turn to keep the ball centered.  After all, the rudder is used for turning......."  

 

After lunch I told him my experience was different and he said that was probably because of the differential movement of the ailerons (more up than down to reduce yaw from the drag of higher lift).  Well, yeah... but don't most airplanes incorporate that old principle in their design?  Later, I went flying:

 

  • Trimmed in level flight at a low cruise speed, strongly depressing the left rudder pedal resulted in a ball out skid with a slight declination of the nose (probably because of the added drag).  Trying this to the right is similar with a slightly different feel.  No turn or bank was induced.

 

  • A 40 degree banked aileron-only (no rudder involvement) turn to the left resulted in a short quarter ball displacement during the on set of the bank and an immediate return to the center throughout the turn.  Back stick pressure was held to keep the turn level.  The same action to the right resulted in the same result with slightly less back pressure.

 

  • If I added any rudder at the start or during the turn, the ball was out of the cage. 

 

I hope that transitioning pilots don’t have the rudder push so deeply ingrained from training that it is automatic.  Of course, this is quite a bit different in the Challenger ultra-light I built, where the rudder was king and was used to start a turn or lift a wing as the differentially moved flaperons were relatively ineffective.  BTW, for a few years I flew both the Lancair and a Skymaster.  The Lancair improved my skills in flying the Skymaster - the reverse was not true.

  

The CFII further said that, “All spins are pilot induced.”  I suppose so, as the AOA increased it is likely that right rudder is used to offset P-factor. If these two forces are not balanced at the stall the plane probably falls off to one side or the other.  Perhaps one of our aerobatic 300 series brethren could comment further (Mark?) as I don’t do stalls or spins.  Having no experience entering a Lancair spin, upon entering one I would simultaneously pull the power and momentarily cover my eyes – this would seem to be correct as both hands would be off the controls for a bit.  I guess I should still await comment from those more experienced (that’s easy, isn’t it?).  The real issue with slick Lancairs is how quick they are at leaving a safe flight regime and then how quick they are at furthering the depth of any abnormal flight regime.

 

Back to something I know about – the value of a good AOA indicator.  Recently I was leaving a friend’s airport where his hangar is off to the side of the departure end of the runway I was using.  Employing Group B behavior, right rudder pre trimmed for climb, liftoff, up went the wheels and flaps and a takeoff-power climbing right turn towards the hangars was begun.  A glance at the AOA had me creeping up along the yellow chevrons and I eased off the turn and climb before hearing “Angle, Angle, Push.”   Group A behavior was reinstated.

 

If you have made it this far through these ramblings, note that there will be more in the future. Such as:

 

  • Is flight control lost in the order of ailerons, elevator and rudder?  Is the rudder the first control to return?  Is this true in a Lancair?

 

  • Does the popular lift over drag chart (parasitic and induced drag vs speed) correctly represent Lancairs?  Does this have decision making implications in emergencies?

 

  • How strong is the nose bob effect when cross controlled at slow speeds? Should crossed controls be used at slow speeds?

 

  • Is a steep approach better than a shallow one?  Does this yield more options and resistance to the vagaries of unpredictable turbulent air?

 

  • Is a steep curved approach better than a squared pattern (like the end of a military low approach but not screwing up everybody else trying to land)?  If so, are more approach options available rather than those available when over tightening a squared turn?

 

  • Is a higher speed, partial flap landing configuration more often result in a successful (pleasant) landing than a slower, full flap setup?  Does “fly it on” mean that one should avoid “full stall” landings as taught in flight school?  Does float result because my wings are closer to the runway than other's wings?

 

And other obscure performance puzzles.

 

Grayhawk

 

Only 70 hours more to safety.

 




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