Valin,
I like the rule of thumb for altitude: “1,000' more runway than field elevation.”
I have a fairly heavy Legacy and frequently fly it heavy; me, my wife, luggage and full fuel. That is pretty close to my max gross of 2500. I won’t go into a field of less than 3000 ft at sea level.
I have been in and out of several fields in the Denver area including Centennial (KAPA) Rocky Mountain (KBJC). The runway length is OK, but the climb rate is not breathtaking – especially at higher temps.
Suggestions:
· Try to fly when it is cooler
· Leave your takeoff flaps in until you are at least 1,000 AGL
· Don’t “fill up” your tanks unless you need to.
I think you will be fine if you use good judgement.
As for “turbo-normalizing” or “super charging” your engine. I have been interested in that as well. Not so much for takeoff, but to get better speed and climb rate in the teens. But it is not so simple to “cram” a TSIO-550 into a Legacy cowling. There are non-intercooled turbo systems out there, but George Braly (engine guru) strongly advised me against that approach. There are also supercharger systems out there, but again George was not impressed.
Try flying it without turbos and see how you like it.
D. Brunner
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Dennis Johnson
Sent: Thursday, January 02, 2014 12:38 PM
To: lml@lancaironline.net
Subject: [LML] Re: Legacy Takeoff Performance at High Elevation Airports?
I fly my naturally aspirated IO-550 Legacy out of an airport with a field elevation of 4,400'. I've seen density altitude as high as 8,000' in the summer. I've never measured it precisely, but my sense is that my takeoff roll can be up to about 3,000' long if I'm heavy and the density altitude is high. I don't think I've ever needed more than 4,000' of runway for landing. I wouldn't worry about operating out of your 9,000' long runway with its field elevation of 5,700'.
My rules of thumb are mimimum 3,000' runway at sea level and at higher altitudes, I like to have 1,000' more runway than field elevation. I think runway length is controlled by landing distance, not takeoff roll. Of course, runway slope, winds, density altitude, airplane weight, etc. make each situation different.