HLSR—Roll Axis Response Criteria
Bandwidth criterion: The BW criterion of roll axis response (RAR) is similar to the pitch axis response (PAR) BW criterion.
Dynamic stability criterion: The dynamic stability criterion addresses the oscillatory roll modes following a lateral doublet in hover. These oscillations are dominated by DR mode. The limits on the natural frequency and damping of these oscillations are similar to the pitch axis limits.
Altitude quickness criterion: The altitude quickness criterion is for the bank angle changes of moderate amplitude between 10° and 60°.
Large amplitude criterion: This measures the absolute control power in terms of the maximum achievable roll rate (for a rate-command system). It measures the maximum achievable roll altitude change for an altitude command system. A typical limit for moderate agility MTE is ±50°/s for Level 1 HQ.
TABLE 10.10
Possible Handling Qualities Criteria Matrix for Helicopters
HLSR Forward Flight Requirements
Direct Axis/Inter-Axis Coupling (Response Criteria) Direct Axis/Inter-Axis Coupling
Pitch |
Roll |
Yaw |
Heave Yaw due Pitch due |
Roll due |
Pitch |
Roll |
Yaw |
Heave |
Pitch due Pitch due |
Roll due |
to roll to roll |
to pitch |
to roll to roll |
to pitch |
|||||||
BW |
BW |
BW |
HR AA AA |
AA |
BW |
BW |
BW |
Flight path |
||
control |
||||||||||
DySt |
DySt |
DySt |
TR |
DySt |
DySt |
DySt |
||||
AQ |
AQ |
AQ |
Pitch control |
AQ |
||||||
power |
||||||||||
LA |
LA |
LA |
LA |
LA |
||||||
SpSt |
||||||||||
BW = |
Bandwidth |
criteria; |
Dyst = Dynamic stability criteria; |
AQ = Attitude |
quickness |
criteria; LA |
= Large-amplitude criteria; HR — Height response |
criteria; |
AA = Aggressive agility; and SpSt — Spiral stability. |