UH-1 Rules of Thumb

[Sundowner.pl]

Taken from one of the official Bell documents, true for all long body, single engine (dash 11 and dash 13) Hueys:

 

1. One PSI torque equals about 200 pounds of weight lift capacity.
    
   
2. Approximately ¾ PSI of torque is lost for every 1000 foot gain in altitude.
    
   
3. For every 3 degree C rise in OAT, about 1 to 1.5 PSI torque is lost.
    
   
4. Approximately 5 PSI more torque is required for OGE hovering as compared to IGE hovering.
    
   
5. About 17.5 pounds per hour, per PSI of torque is normal cruise power fuel consumption.
    
   
6. Do not attempt a battery start if the static voltage is 21 VDC or lower.
    
   
7. At a given power there is about 1000 pound load difference in OGE versus IGE hovering ability.
    
   
8. With about a 15 degree decrease in Oat, the following will happen:
   
   • Auto revs will decrease about 1 turn (10rpm)
     
   • Flight idle can decrease about 1 – 1.5 % N1.
     
   • The beep range will lower on both ends
     
   • The RPM warning box settings can change
     
   • DC voltage will change slightly
     
   • Maximum N1 available changes
     
   • The bleed band range can change
     

 

[*]In high wind conditions, land with the right side of the helicopter into

wind to keep the low flapping blade away from the tail boom at low

rotor RPM.