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.
Just trying to be safe.
Thanks,
Jim Scales (almost 1200 hours and very happy)