REFLECTOR: Abstract versus Hands On

[Terry Miles]

Al,

I have watched over the years now as you put your airplane through its
tests and  shared it all with us.  I particularly remember your engine mount
tests.    As a retiree now, I have an interest in High School math
education.  In fact I have an appointment in July with the PA Dept of Ed on
that very subject. One big topic at that meeting will be will be the
difference between abstract math and what I would call visual or sensual
math.  Kids don't take to math often because it is too abstract.  I am
hoping to change that, and you have been an influence to me in refining how
I can best explain this to school officials.    

 

 I flew the B747 for about 5 years and we went in and out of the old Hong
Kong airport.  The abstract math/physics of takeoff were the FAA performance
charts.  Out of HK we were "runway limited."  In other words we were
required "according to the charts" to calculate a speed at which we could
lose an engine and safely takeoff or safely come to a full stop in the
remaining runway.  "Vee one" they called it.  The problem was it presumed
perfect brakes, no delay by the pilot,  tromping whole hog on the binders to
a full stop,  and a dry runway.  There was no correction factor for wet.  At
the end of the runway was sea wall.  If you overran that sucker you were in
the Hong Kong Harbor.  None of the windows in the B-747 opened.   We had 3
guys drown in a DC8 in the 70's in Japan for similar reasons.  

 

Needless to say the FAA legal "abstract learning"  said one thing.  The
saloon talk was something different.  For what it is worth conventional
wisdom was not to go to the very end of the runway, runup the engines and
release the brakes from a dead stop.  820,000 pounds (runway limited often
to the mid 700,000s).   Rather, we would stop well short of the stop line on
the taxiway and when take off clearance was given we would  cut that last
corner all we could and at the loss of a little total runway get as much
speed as was safe during the turn on to the runway  and sort of start the
take off from a 45 degree turn on from the hold short position, and if in
the rain, subtract 10 knots from Vee one on the abort side.   It made for a
shorter lift off point than the dead stop, hold the brakes, run the engines
method.  I can't say for the Velo.  

 

Thank you for sharing all you have with us.  On the immediate topic you
raise, and with regards to landing distance, I can add that I have a lot of
slop in my trottle cable dispite efforts to fix it, and if I just ease the
throttle to idle on landing I still have 1100 RPM  or more.   I have tried
to teach myself not  to accept high final speeds below about 400 AGL and to"
yank"  the throttle closed in the flare to get min idle speeds for the roll
out.  I have an XL with the LY 300 HP and it wants to float too.  I put a
speed brake in mine and I find that it helps limit the float tendency.  

 

Best regards,

Terry

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of vance atkinson
Sent: Friday, May 22, 2009 13:02
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Takeoff roll - fuel burn

 

Al Gietzen wrote: 

A further comment - For me and my plane the limiting factor is landing
distance, not takeoff roll. While doing these tests I found I had to brake
fairly hard to make the exit at 2400'.  Rolling out over the numbers I still
carry quite a way in ground effect before the mains touch.

 

Al

Hey guys,  
If you find yourself with a problem landing distance wise,  GO TO FUEL
CUT-OFF......   The sooner you do that the shorter your roll out will be.
In fact you will be amazed how much shorter.  Try it some time when there is
no traffic in the pattern.  

Also I just switched to Grove brakes,
http://www.groveaircraft.com/wbproducts.html  what a difference! The new
ones have twice the stopping energy as my old clevelands.  Most of the
runways I use are longer but there are occasions where I need to stop or
turn off early and these beauties can do it easily.  You can get them thru
Aircraft spruce a little cheaper than the mfg.

Vance Atkinson
EAA Tech and Flt Advisor
COZY  N43CZ
VEZ  N3LV



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