Guys,
I am trying to tweak my Super ES performance information
and would like your input on a couple of things.
I want to put together some charts/tables that let me
calculate my plane's performance relative to density altitude. The purpose
of this information gathering exercise is to put together a chart that can use
realistic numbers to help me calculate performance at higher elevations and
density altitudes. I want to do some flying out west and feel my tools
are lacking where performance calculations for my plane are concerned.
I have been able to gather quite a bit of info over the
years of flying my ES concerning climb rate, cruise, percentage of HP, as they
are affected by density altitude. These seem pretty clear.
My gray area is take-off distance. I have never
actually done my own tests in this area other than paying attention at my home
airport about where down the runway I start flying. If any of you have actual
numbers for your ES I would like to see them if you don't mind.
Consensus of information that I found on the internet and
in Lancair publications seems to be about a 700 ft ground roll on a standard
day at sea level for 3400 pound gw. This number appears unrealistic to
me.
The standard procedure that I have seen in a couple of
places seems to require lifting the nose wheel around 55 and climbing at 85.
Doesn't mention holding brakes till full power. Can't seem to find
information that indicates when this method causes the plane to break ground.
(Might be the 700 feet that is mentioned). This strikes me as an
aggressive method (might not be, just seems so to me given my experience in my
plane). I am not a test pilot and have no intention of flying at what
might be the edge of the envelope. I prefer a bit of a conservative
number, whatever it might be.
I have tried this method on a few occasions and I find it
somewhat uncomfortable because the plane tends to settle in a tail low attitude
after becoming airborne and seems quite lazy even while still in ground effect.
I prefer crisp performance and firm response to control inputs. The 55/85
process doesn't seem to fit these preferences.
My method involves 10 degrees of flaps, deliberate, but not
speedy, application of power, slight back pressure on stick beginning about 65,
holding that pressure until plane flies off. Usually flying occurs at
about 85-90 with no "sag" feeling and very positive control response.
Climb out is at 100 till 400 feet then 125-130 to altitude.
On an approximately standard day this results in wheels off
the runway at about 900 feet at about 3200 pounds. At gross of 3400 the
number is about 1100. Again I have done no actual measurements, just
judging by the thousand foot marks on the runway.
I discovered the Koch Chart and found it to be really
useful but it is all based on a fairly accurate standard day gross weight
ground roll.
So is it possible to put together a chart that can help me
figure ground roll and climb rate for various gross weight situations? Is
one already available that I just don't know about? The Koch Chart only
requires ground roll and climb rate for performance calculations relative to
density altitude.
Being a flatlander I have not ever been that concerned
about this subject. Always had plenty of runway and lots of horsepower.
I don't want to be that "loose" in my calculations when I
encounter high density altitude situations. I prefer to know what to
expect as far as airplane performance is concerned.
I am probably not able to adequately explain what it is
that I am searching for. I believe my primary need is a realistic
standard day gross weigh ground roll number that can be safely used to
calculate density altitude take off performance. Hopefully some of you
can gather from what I have written what else you think I need.
I appreciate any input you might have on this subject.
I have not seen this subject on LML so maybe I am not the only one who
could use this information.
Jim Scales (almost 1200 hours and very happy)