- Joined
- Oct 30, 2003
- Messages
- 18,373
- Location
- Santa Maria, California
- Aircraft
- Givens Predator
- Total Flight Time
- 2600+ in rotorcraft
The following is my opinion based on my experience flying and instructing at airports where the density altitude is over 5,000 feet to as high as 9,800 feet density altitude.
I don’t change approach or climb out indicated air speeds despite having a higher true air speed at 5,000 feet density altitude for a given indicated air speed.
I keep this ground speed difference in mind that is roughly 2% per 1,000 feet of density altitude because it changes the sight picture so at 5,000 feet density altitude the ground speed is ten percent faster at the same indicated air speed.
What this means to me is; if a client has the nose too high during the takeoff roll and we lift off early we may have trouble getting away from the ground. If they don’t have full power in on lift off it exacerbates the challenge.
Based on most gyroplane performance charts my takeoff distance to clear a 50 foot obstacle is typically increased by 60% at 5,000 feet density altitude in most of the gyroplanes I fly.
My rule of thumb from the Mountain Flying Bible is 12% increased takeoff distance per thousand feet of density altitude.
In other words to takeoff and climb over a fifty foot obstacle at 8,333 feet density altitude will require double the distance it does at sea level and standard temperatures.
My impression is my cyclic control inputs are larger and more aggressive. I have no data to quantify that and it may be my response to the sight picture of the faster ground speed.
I don’t change approach or climb out indicated air speeds despite having a higher true air speed at 5,000 feet density altitude for a given indicated air speed.
I keep this ground speed difference in mind that is roughly 2% per 1,000 feet of density altitude because it changes the sight picture so at 5,000 feet density altitude the ground speed is ten percent faster at the same indicated air speed.
What this means to me is; if a client has the nose too high during the takeoff roll and we lift off early we may have trouble getting away from the ground. If they don’t have full power in on lift off it exacerbates the challenge.
Based on most gyroplane performance charts my takeoff distance to clear a 50 foot obstacle is typically increased by 60% at 5,000 feet density altitude in most of the gyroplanes I fly.
My rule of thumb from the Mountain Flying Bible is 12% increased takeoff distance per thousand feet of density altitude.
In other words to takeoff and climb over a fifty foot obstacle at 8,333 feet density altitude will require double the distance it does at sea level and standard temperatures.
My impression is my cyclic control inputs are larger and more aggressive. I have no data to quantify that and it may be my response to the sight picture of the faster ground speed.