REFLECTOR: Glide Ratio and systems knowledge

Fri Dec 16 19:57:23 CST 2005

Within the discussion of glide ratio to a landing point, it might be an
idea to make each glide excise conclude with a configuration change into
a flare target altitude.  It's good also to have a sense of the general
window of time/distance/altitude to drop the wheels in a power off
glide.   

Since I get to enjoy a 40 hour fly-off I am going to accept the 90 knots
as my target best glide, and practice a lot of power off glides until I
can stick the nose right there every time and have VVI and pitch targets
too.  I hope to teach myself the pitch corrections of gear down vs gear
up.   I don't want to be "inside" a lot if I'm are looking for a landing
point.   For me anyway, I plan to keep my auto pilot on the essential
power bus, so to ease work load and clear my thinking in times of high
demand.    I forced myself to do this as a first step, if I feel I have
the flight conditions and reserve battery power to spare.  

I plan also to do an manual gear extension often enough to know what it
sounds and feels like and how long it takes.  This practice will build
confidence in it's operation.   (I would not shut off any engines in the
name of training.)  

In my opinion one big benefit to knowing power-off glide dynamics is the
ability to make more accurate landing point judgements sooner.  That
said, all this is meaningless, if close to the ground, it all goes to
hell.  We've all heard it a hundred times, one's best hope of survival
is to STAY FOCUSED consciously fly the airplane on speed right down to
the flare, with wings level and pointed straight ahead.  .   

Related topic:  Electrical design is still a work in progress on my
airplane, but If I have a load shed routine that removes power from the
gear control when it should have the pump maybe, then I'll also make
some notes on that abnormal checklist so I won't be surprised when the
gear won't go down on the toggle switch.  If I forget to do the load
shed, or become too hesitant to change anything, then I may have to
compensate when Tower asks that I flash my landing lites and the amp
surge blanks-out my PFD screen a few hundred feet in the air.  For me it
will take practice to know where to look for that backup airspeed
indicator and where to put a hand on that pressure dump valve (and which
way it turns!).  

The above were all equivalent mistakes that I made or watched happen
many times over the last 38 years...thank goodness I was in a fancy
flight simulator most of the time.  More hours doesn't mean smarter.  I
commit to myself every time I strap-in, that we pilots take certain
risks.  I am no better than average with a control stick in my hands,
but when my time will comes I hope to be practiced and familiar.  I am
sorry, I know this is private pilot lesson 101 and we all know it
backwards and forwards.  It's just when I hear of preliminary reports
like the one this week:  glide distance absolutes...bounced hard...early
flares?...airspeed?...fear factors to human performance...I have been
taught never to discount any episode no matter how common or bizarre as
if there is nothing in it for me personally.   My heart goes out to
those guys....grateful they got out OK.  It could have been me.  I'm
only a few months away from that point myself.  

Back to work.

Terry

 -----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Scott Baker
Sent: Friday, December 16, 2005 1:39 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Glide Ratio

Another factor to consider is the pitch setting on aircraft with
constant speed propellers.
With the gear "Up", reduce power to idle and establish a glide speed
somewhere near 90 knots (the estimated Best L/D reference speed) -
observe the VSI.  Following this pull the propeller control to "Low
RPM".  The aircraft literally accelerates as if it were in 'overdrive'.
Re-establish V-best glide and make another note of the VSI.  You should
see a 200fpm improvement - or more - in the rate of descent.
Sloooooowly push the propeller pitch control back to the normal position
to avoid damaging the engine.
SB

----- Original Message ----- 
From: Ron Brown <mailto:romott at adelphia.net>  
To: Velocity Aircraft Owners and Builders  <mailto:reflector at tvbf.org>
list 
Sent: Friday, December 16, 2005 9:20 AM
Subject: Re: REFLECTOR: Glide Ratio

Good Morning Dick,

I observed 15 and 16 to 1 in my 173 Elite RG at 90 kts.

It is a fairly easy test to do yourself.

Fly toward an airport.  At 5 miles from the airport, at say 6000' above
the airport elevation.  Get established on your glide speed before the 5
miles to the airport.  Pull the throttle to idle and maintain your glide
speed.  When you reach the airport, note your altitude (AGL).  Then
calculate the ratio between the distance (5 nautical miles or 6076 feet
per mile) divided by the total altitude lost. You can repeat going in
the other direction to compensate for the wind.  

If you want to get brave and pull the mixture to kill the engine, make
sure you have enough elevation upon reaching the airport to do a dead
stick landing in case you can't get the engine refired.  There is a
difference between dead engine and idling, but I didn't try that so I
couldn't tell you the difference.

The Velocity's glide ratio is pretty good - very good compared to a RV
or spam can.

Ronnie

----- Original Message ----- 

From: Richard  <mailto:affenit at charter.net> Affenit 
To: Velocity Aircraft Owners and Builders  <mailto:reflector at tvbf.org>
list 
Sent: Thursday, December 15, 2005 11:39 AM
Subject: REFLECTOR: Glide Ratio

I remember some conversation about the glide ratio for the XLRG in the
past. I wonder if whoever did the testing would mind passing on their
findings.

Thanks...............Dick Affenit N732RA XLRG

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