UH-1H Performance and wind

[xavnl]

Hi,

 

I am looking at the graphs and I do not see any wind input for computing the max IGE weight (same for OGE).

Wind can ease things a lot.

 

Did I missed something?

[Quadg]

wind is unpredictable..

 

if you take off heavy with wind and the wind dies. you will be overweight and crash when you land.

 

so you plan vehicle weight on worst case scenario, which is no wind.

 

yes you need to be aware of the effects of wind on translational lift.

but you dont plan for it because of its unpredictability in real life.

Edited October 8, 2019 by Quadg

[xavnl]

Thanks.

[Jester986]

Some aircraft do have charts that account for wind. I fly a UH-1H with a T53-L-703 engine with the BLR fast fin and strake kit and a van horn tail rotor. My performance charts have an Area A and an Area B where A is with a wind of up to 17 knots from any direction and B is with calm wind or a head wind and B gives you significantly more performance. Generally we can always make our approach and departure into the wind so we can assume area B in most cases. there are one way in one way out situations though where you have to go by area A. And wind is reasonably predictable and checking weather is part of any flight planning. But that doesn't mean it won't be different on the ground due to some geography or just a bad forecast. Also in the military world I'm sure there are other reasons you wouldn't be able to approach or depart into the wind, namely what the enemy is doing.For example though at 6000 feet pressure altitude and 30 degrees C i could out of ground effect hover at 7550 lbs in Area A and about 9250lbs in Area B.

 

That being said ED has modeled The UH-1H with the T53-L-13B engine and none of those after market mods. What I'm seeing in those performance charts says all figures are for a calm wind and they don't offer any adjustments to capacity based on the heading of the wind. They do have a chart for determining controlability based on cross winds and tail winds and available pedal and cyclic authority but nothing about the corresponding reduction in available power if you have the left pedal at the stop.

 

TL/DR Quadg is right in that the charts don't take into account a wind helping you but wrong in that you absolutely plan for an adverse wind and many helicopters have charts that adjust for it.

[xavnl]

Thanks Jester.