From: "Marvin Kaye" <marv@lancaironline.net>
Subject: Re: [LML] Re: Unsafe in any plane - Wake up!
To: lml
Date: Wed, 09 Jun 2004 11:26:44 -0400
Message-ID: <web-145929@logan.com>
In-Reply-To: <104.4886376c.2df8841a@aol.com>
References: <104.4886376c.2df8841a@aol.com>
MIME-Version: 1.0
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 8bit

Posted for Sky2high@aol.com:

  While the discussion of Lancair's aerodynamic warts was of great interest,
  we should all remember that those at the controls of experimental,  amateur
  built heavier-than-air machines are always test pilots.  In any  event, I
found  that:
  
  1. Lee Metcalf's compilation of crash stats,
  2. Mark Ravinski's descriptions of unusual attitudes and
  3. Skip Slater's aft CG discussion
  
  most valuable.
  
  So,
  
  1.  It was amazing to read so many accidents are  loss-of-control.  Always
  remember that we have a small (to some, teeny  even) rudder.
  
  2. These babies demand that you pay attention and understand the craft's
  characteristics even if you aren't capable of (or confident in) testing the
  extremes of the flight envelope.  Geez Mark, any more sky tricks?
  
  
  3. I have included Skip's comments so that I may comment specifically on 
 the
  320/360 Lancairs.
  
  A. It is interesting to note that I have never heard of anyone parachuting
  out of a forward-hinge canopied Lancair (built to plans without a jettison
  ability).  Although I have no direct knowledge, it would seem that the
  canopy
  would open no further than a few inches in flight - perhaps a tail slide
  could
  get it open - perhaps.  I just dont' know and I don't wear a  parachute.
  
  B. Changing CG by lowering Gear. Try this calculation - compute a cruise GC
  and then add 500 (approximate change in nose gear weight moment) to  the
  aircraft moment and re-divide by the weight.  Note that the CG  moves aft by
1/4 to
  1/2 inch.  If you are in a flat spin due to rear CG,  put out the gear
  resulting in added drag and the CG moving forward - of course,  you may have
to make
  new gear doors especially after the nose gear door tries to  act like a
  ventral fin but that is much better than the damage caused by  smacking the
terra
  firma.
  
  C. Using flaps to change the center of lift.  In Jan-Feb 2003, I  performed
  some experiments at 155 KIAS by taking the flaps out of reflex (-7* to  0*).
  
  Besides slowing the aircraft by 12-15 Kts, the Longeron angle came  down
(nose
  down) 2.5* and the AOA indicator changed 17 points (1.7*?).  One  should
  remember that the flap reflex position (if properly built) is  to reduce 
drag
with
  a minimum pitching moment - Hah!  How many of you have  surprised a 
passenger
  with the dramatic pitch change as you lowered the flaps  (or, by raising 
them
  after takeoff)?  I don't know if the 320/360  flaps can take even partial
  deployment in a flat spin, but it may be one way  out.  I understand that 
the
235
  POH says that their flaps must be in the  reflex position above 197 Kts.
  Also, I used the flaperons in my tube &  fabric Challenger to trim the craft
in
  pitch.  Even a "heavily loaded  towards the rear" 320/360 could benefit from
  taking the flaps slightly out of  full reflex.  Also remember that the long
  engine mount moved the CG forward  1.5 inches with no adverse effects.
  Recently, I
  have thought that Lancair  miscalculated the CG limits - maybe because it 
was
  done for the wing  with 0* reflex................
  
  D. P-Factor.  We just don't have enough rudder to compensate for the
  throttle being slammed to the firewall.  Remember that most spam cans are
  underpowered and we are not.
  
  
  Scott Krueger  AKA Grayhawk
  Sky2high@aol.com
  II-P N92EX IO320 Aurora, IL  (KARR)
  
  LML, where ideas collide and you decide!
  
  PS. I am not a military pilot but I read a lot.