Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Fri, 07 Jun 2002 12:44:55 -0400
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 originator="Paul Davis <pdavis@pdavis.bmc.com>"
From: "Paul Davis" <pdavis@bmc.com>
Reply-to: "Paul Davis" <pdavis@bmc.com>
Subject: If you're sick of left-throttle just read first paragraph
In-Reply-To: Your message of "Thu, 06 Jun 2002 22:04:48 EDT."
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I hope this is the last post you'll ever need to read about left-hand
throttles.  Please hang in there for just this one last post.  I spent
a fair amount of time thinking (and my lunch time) before posting
and I hope I've managed to write something NEW that might be worth
your time to read.  If I failed, I apologize.  I include a simple
do-it-yourself, no-guesswork test so you can answer the question for
yourself (if you still care).  I've put this test at the front knowing
your patience is probably exhausted.


The argument stopper.  (Hope springs eternal.)

If it's REALLY important to you, for whatever reason, to falsify the
hypothesis that one of YOUR hands flies the airplane better than the
other, I think I can give you an example of a method that is both
"science-based" AND pragmatic.  Just the sort of cheap but hopefully
effective experiment you can do at home.

You'll need a pencil and paper (you're allowed to write with either
hand), a personal computer or other flight simulator with a joystick
that can be manipulated by either hand, and the ability to massage the
environment such as by varying the amount and strength of turbulence
and wind gusts, crosswind component, stall speed, etc.  This will be
tougher if you don't also have rudder pedals as you won't be able
to use slip-to-landing, but for our purposes a crab-and-kick (hard
to imagine even that without rudder pedals) might be even better as
enough crosswind will force you to make a rather radical adjustment
just before touchdown.  JUST the sort of thing we're looking for.  In
any event, you need to figure out some way to use what you have to
make landings difficult but just barely possible (with sufficient
skill).  The main thing you want is something that requires quick and
precise stick inputs with little margin for error.

This isn't a perfect experiment, but until someone designs a better
one, this might be "good enough".

  Set up a reproducible landing scenario on the simulator.

  Fly the scenario with first one hand, then the other.

  Record the results.  All you really need to keep track of is the
  hand used and either "one" (landed) or "zero" (crashed), though it
  would be nice to also note the "settings" used for each pair of data
  points.

  Repeat as needed alternating hands and increasing the difficulty
  (however you choose to do that) until one hand or the other is
  "crashing" at least 25% of the time, or even better till your
  overall smoothed average crash rate for both hands is above 25%.
  You can even carry this out till you crash virtually every time.
  Remember, we need to test right at the limits of our ability to
  control the airplane.

  Now, graph or scatter-plot your results (different color for each
  hand).  The X-axis is either numeric order or degree of difficulty.
  The Y-axis is landed (1) or crashed (0).  If there is a significant
  difference between hands it should be obvious from the graphic.  If
  you can drive the crash rate up to about 25% (this is arbitrary)
  overall and don't see an appreciable difference between hands, then
  congratulations.  You've just falsified the hypothesis.  You're good
  to go fly.  If on the other hand (pun) one hand "flat-lines" before
  the other, you might just have a problem.  Either way, you'll KNOW.

Here are other wrinkles you might add:

  If there is a difference in performance, does it converge over time?
  (In other words, if there is a marked performance disparity, can you
  "train" till this difference disappears?)  If you do this, keep in
  mind that you must continue to test BOTH hands and keep increasing
  the difficulty as necessary to keep the failure rate stable.

  Does it matter if you keep the hand that's off the control stick
  "busy"?  This is to prevent masking by the same sort of phenomenon
  as Brent's mirror image writing trick.

  Same results with a yoke as with a stick?

Just try to keep things simple.

If anyone chooses to actually do this experiment (or one of your own 
design) I'd love to get a copy of your methodology and results -- off 
list PLEASE.


That's the end of the potentially useful stuff.
The rest is me blowing off some steam.
Get back to work!


Whew!
This wasn't THAT big a deal even for me and I think I started this
thread.  I thought about this for about 30 seconds before putting a
deposit down on the kit, decided I could live with being forced to
land left-handed, and signed over a chunk of money.  Been landing
left-handed for years with control yokes so even though it seems
kind of "unnatural" with a stick I figured I could handle it.  I
even asked about it during the demo ride and was assured that it
was something you got used to quickly.  Considering what the demo
pilot (who shall remain nameless -- but WOW what a ride) did with the
airplane, I was convinced that this wasn't a major problem.  Only
later I thought that if I could safely and cheaply have it both ways,
well, why not?  Probably should never have mused (to the list) that
this might POSSIBLY be a safety-of-flight issue.  Even then I wasn't
concerned, just wondered if anyone knew for sure.  Too late.  The game
was afoot.

For the moment, forget about trying to "prove" anything.
Isn't it enough that I'm just more comfortable with my right hand on
the stick when landing?  Why does that so annoy some folks?  Jeez.
Gi'me a break.

>>>>> On Thu, 6 Jun 2002, "Jack Cowel" wrote:

  +> I find it incredible that anyone would consider adding the
  +> complexity,

  Marvin> Finally, a little science-based pragmatism.

I'm sorry, but I just couldn't let this go unchallenged.

Real science is seldom seen in public these days.  Most folks wouldn't
recognize real science if it bit them.  Here's my take on it.  If you
don't have a process that consists of:
    a hypothesis
    that generates falsifiable predictions
    that are then tested according to accepted methodologies
    and that yield reproducible results
    that are subjected to rigorous analysis
    using criteria established before data are collected
    and submitted for peer review
then you don't have science.  All you have is opinion and guesswork.

The referenced post falls into the same seductive trap that misled
so many brilliant minds before the scientific method was developed.
It SOUNDS like science, but it's really the same approach used by
Aristotle (and probably before): make some observations and REASON
your way to a "truth" that agrees with your prejudices.  It simply
doesn't separate truth from falsehood.  What it DOES tend to do is
stamp the imprimatur of science or at least reasoned opinion on
flawed beliefs that then become that much harder to displace when the
real science is done.  Worse yet, it sometimes is so convincing that
the real science doesn't even get a hearing.  Before you jump on me
about this, finish this post, re-read Brent's post and then decide.
I'm not even saying that Brent's belief is necessarily incorrect --
until someone does the REAL science, no one KNOWS -- only that the
foundation of that belief is suspect.

I won't spend much time on the obvious double-think involved in
vilifying twin throttles as dangerous, unnecessary weight and an
unwarranted complication in a design that duplicates all other flight
(and brake) controls.  This is just an example of what can happen when
we BELIEVE something and close our minds.  Happens to us all.

If anyone wants to talk about it, contact me off-list.  I'll be happy
to at least pass on the notes I made while reading Brent's post and
some clever (I think) little experiments you can run at home to
falsify some of what he asserts.


Now, can we please drop this or at least take it off list?

-------------------
Paul Davis
Lancair Legacy builder
pdavis@bmc.com
Phone 713-918-1550
-------------------
Qui desiderat pacem, praeparet bellum (Epitoma rei militaris, Prologue, 3)
If you want peace prepare for war