High Altitude Take Off and Landing

[lv2plyguitar 172]

Wondering if I could get input from any of you regarding take off and landing performances at different altitudes with the rotax 582.  I noticed that when I take off at 2500 msl the take roll is almost double it seems like. 

 

I have a ground adjustable prop and still don't have it in my head what difference it makes to take off at 6100 rpm (cruise pitch) and 6400 to 6800 (climb).  It would seem that if I am grabbing more air on take off that would help me to get off the ground quicker.

 

In summary:

 

What differences should I expect in take off performance from 200 msl to 3000 msl.

 

At high altitude what do I gain my decreasing my pitch.

[C5Engineer 1170]

I wouldn't consider 3000 ft high altitude by any means but yes the higher you go the less performance you get. This is true in any airplane. If you want what seems like a long takeoff and slow climb take off at 6500ft on a 85 degree day with 28 gallons and 100lbs of camp gear on board. This is the scenario on the last fuel stop when I go into the Idaho backcountry. Immediately after takeoff I have to climb to 9500ft to get over a mountain. Luckily it's only about 30 miles once over that mountain to the camping strip but the poor ol throttle doesn't come off the firewall for that flight most of the time.

As far as pitch you will see some increase at 6400-6500 rpm but you are going to lose 5-10 mph cruise. It's always a compromise. With my warp I would tweak it down to half degree increments and 6200 on takeoff had the best compromise between cruise and climb. I always re pitched in the spring and fall as hot weather effects this as well. If you want to forget about all this above paragraph and always have the best prop for a given situation get an IVO inflight adjustable

[akflyer 1427]

The prop turns faster.. and it dont take much.  A cruise prop on a super cub would be say a 76X58.. The climb prop (sea plane prop) would be an 82X41 or X42.  The difference in take off performance of these two props, is literally the difference in drag racing your lawn mower versus a top fuel dragster.

 

The cruise prop your lucky to turn 2100 on take off.  The climb prop your looking at 26-2700 on take off.  The prop turns faster, the engine actually is allowed to make full HP rating because your letting it get to the happy RPM and the plane climbs much better.