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Message
Gents,
Went out and shock
cooled the engine again for the sake of making aviation safer for the rest of
you. My highly inaccurate and unscientific analysis of my 360 glide goes
as follows. BTW, I'm quoting myself here in light of T-34C NATOPS Manual
so don't look for the Lancair stamp of approval. I would like to hear
what parameters Charlie Kohler teaches.
Remember, the beauty
of the High Key technique is in the ability to intercept the circle from
virtually any point. Assess current altitude and aim to get on the
circle. If low, hold the gear. If high get more drag out and
intercept at the 180, or 90 as required. Practice. Practice.
Practice.
Engine Out Descent
rates with 68" Hartzel Prop feathered at 105 kts. 750 fpm -
Prop not feathered (ie. oil loss or gov failure) 1100 fpm. AOA guys could
tell us the precise indicated airspeed but I'm not sure about partial flap
extension differences in simulated versus actual engine out.
Using these numbers
one can simulate engine loss. In my plane using throttle almost idle
(10" MAP) with prop 2700 RPM and 15 deg of flaps yields 105 kts at 750 fpm
ROD. Of note is that this flap game is slightly unrealistic in that extra
decelerating energy would be available during a real engine failure (as the
flaps would be up for most of the procedure).
Regarding the shock
cooling fears, my engine CHT's drop about 50 deg C (180-130). Depending on
how realistic a scenario you are looking for will balance how fast you pull the
throttle. Once a year, I go ahead and do a whole bunch of these to
maintain proficiency.
In review, ideally the descending 360 deg spiral starts at
2500 agl about 1/3 down the runway. In recollection it is also slightly
offset opposite the direction of intended turn. Roughly 1/2 the flap span
works. Gear comes down if you meet this check point. Else, hold the
gear until appropriate. Target bank angle is 15 deg. ROD roughly
doubles (but I wasn't looking at it).
Target altitude at
the 180 is 1200 AGL. Abeam distance of wingtip on the runway worked
well tonight. You have to momentarily roll out to assess the abeam
distance. At the 90, I target 600 AGL and begin to feel high and
fast. Hand moves to flap switch.
At the 45, when
landing is assured, I need to add full flaps to start getting the plane to slow
down.
Two other uniqueness
worth considering.
First, I lean during
this practice. Therefore, my hand rests on the mixture knob (when not
tweaking flaps) to remind me to go rich before attempting a missed
approach.
Second,
the simulated and real engine failure flare both have substantially
less deceleration than I'm used to during a powered landing.. Read huge
floater! Thus, when in the flare during a simulated engine failure,
throttle could be retarded. By contrast, during an actual engine failure,
prop could possibly be advanced to assist in additional drag. This issue
may be irrelevant considering the extra 15 deg of flap travel available during
the actual engine out landing.
After the sight
picture sinks in you'll be comfortable with a few small flap tweaks and get a
nice touch down point routinely. Thereafter, one can work on the lower
altitude and more interesting (stressful) scenarios. Have fun and fly a
little safer.
Larry
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