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It is almost intolerable that so much good information regarding emergency
procedures must come on the heels of the loss of one of us.
The current discussion of the importance of characterizing *YOUR* Lancair
(or any homebuilt, for that matter) for best glide performance following
catastrophic engine failure should have been an ongoing theme from day one -
for this list and any other forum for such matters - and I'm to blame as
much as anyone else since I've done this exercise a number of times
(following changes that affected weight and balance) and never thought to
broach the subject on the list. I wish now that I had at least started the
thread at the time.
I don't know whether Shannon ever did these tests though it will probably be
determined by the NTSB investigation. From what I've heard of him, and
judging from the quality of his Lancair, it is quite likely that he did.
Hard to know now.
An interesting sidelight to the discussion is Hal Woodruff's musing about
best glide performance vs. A/S for best climb rate. Early on in my test
program, I too thought that they were probably the same until I actually did
the tests. On my early 235, I noted that once I accellerated to a certain
A/S, my ROC would always maximize - sometimes a bit higher or lower
depending on weight and ambient conditions. Until I got around to doing
actual tests for minimum altitude loss vs time and minimum altitude loss vs
distance traveled I would have used that A/S. Big surprise! Both of those
numbers ocurred at nearly 25 - 30 MPH IAS less than the speed for best ROC.
(I don't have an AOA sensor in N235SP, the tests were done with stop-watch,
the altimeter and GPS).
Granted, each of our aircraft are different - even ones of the same type so
I'm not advocationg anything here - only that you must do the tests and
determine the numbers for YOUR airplane. Hopefully, you'll never need to use
that knowlege but, since the FAA data says that engine related accidents are
the long pole in the tent for problems with amatuer built aircraft, you need
it.
Note that I've refrained from putting down any numbers that relate to my
235 - for one thing, there's probably not many 235's out there by now that
haven't been properly characterized (and my numbers certainly mean nothing
to later models) - and for another, you need to derive the data for your
airplane without being biased by mine.
If you haven't done the tests, make up some test cards so you know exactly
what you're going to do (plans are always better when made on the ground
where you can verify their accuracy when not having to fly the airplane).
Stick to the old saw "Plan your flight, fly your plan" - test cards with the
data filed in can be used to make emergency check-lists so you'll at least
be able to set things up to a known and tested configuration should the need
arise.
Besides, if you're flying your Lancair out of your restriction area and do
not have these numbers for YOUR Lancair, you haven't explored the entire
flight envelope as required by the Friendly Aviation Administration.
Dan Schaefer
LNC2 N235SP
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