For
what I have gathered so far the lancair 4p has a glide ratio similar like a
piano LOL In other words if the engine quits then open the door, throw out
your keys because there is where you land LOL
And
I needed to respond to this…
My
IV-P has a glide ratio (at 120 KIAS) of between 5:1 and 20:1, depending on
configuration. The difference is truly amazing/impressive/sobering…
depending on your situation and mind set. With the gear and flaps down and
the RPM at max (prop all the way in), the glide ratio approximates that of a
brick…not really, but you’re coming down so fast relative to forward
progress that it’s difficult to plan and execute a planned touchdown (at
least for me). With the gear and flaps up, AND THE PROP CONTROL ALL THE WAY
OUT, my glide ratio at gross weight is approximately 18:1, increasing to a
bit better than 20:1 at 800# under gross. At this glide ratio, the
performance and “sight picture” approximates that of some gliders. It’s easy
to plan and execute an approach and landing to a pre-planned spot…ideally a
runway. I have practiced this many times from various altitudes/distances
from the airport to a full stop on the runway, using the gear to increase my
descent rate, and then the flaps and/or the prop control to adjust the
touchdown point. Using the prop control is ideal because the drag
effect/descent rate increase almost immediately reversible by pushing it
back in. Not so with the flaps. One feature of my Chelton
EFIS is a wind-adjusted glide range predictor. I have tested this many times
starting at altitudes up to 17,500’ and (set at 18:1)
gives me a very accurate and immediate sight picture of airfields within
glide range. If it’s within the green circle, I can turn toward an airfield
and execute a safe landing there. My MT 4-blade is not full feathering, but
allows the engine to run at approximately 700 RPM when at idle and the RPM
set to min. I believe this is pretty close to 0 thrust, as the engine idles
at approximately 600 RPM on the ground.
So,
in summary, the throw out the keys and follow them down scenario can be
executed if you really want to go down, but a planned glide at 120 KIAS
(very close to best glide for my airplane) in clean configuration yields
approximately the performance of a 2-place sail plane—and you have the
ability to transition easily between these limits as needed. Try it; you’ll
be impressed.
Bob
PS:
I considered and rejected a full feathering prop for what I have.
Wouldn’t trade for any amount of
money…