Technical Notes: Comment on the “Minimum Weight Design of Helicopter Rotor Blades with Frequency Constraints,” Journal of the American Helicopter Society, October, 1989

1990 ◽  
Vol 35 (2) ◽  
pp. 69-69
Author(s):  
Kenneth B. Amer
Keyword(s):  
Minimum Weight ◽  
Rotor Blades ◽  
Helicopter Rotor ◽  
Minimum Weight Design ◽  
Frequency Constraints ◽  
Helicopter Rotor Blades ◽  
Weight Design

Technical Notes: Comment on the “Minimum Weight Design of Helicopter Rotor Blades with Frequency Constraints,” Journal of the American Helicopter Society, October, 1989

1990 ◽  
Vol 35 (2) ◽  
pp. 69-69
Author(s):  
Kenneth B. Amer
Keyword(s):  
Minimum Weight ◽  
Rotor Blades ◽  
Helicopter Rotor ◽  
Minimum Weight Design ◽  
Bending Fatigue ◽  
Weight Saving ◽  
Blade Root ◽  
Helicopter Rotor Blades ◽  
Weight Design ◽  
Fatigue Loads

It appears that most of the weight saving from the reference blade to the minimum‐weight blade is in the region of the blade root. Undoubtedly, the reference blade requires this weight increase to accommodate the usual bending fatigue loads at the root. The authors do not address the question of how their minimum‐weight blade would handle blade‐root fatigue loads.

Minimum Weight Design of a Rotor Bearing System With Multiple Frequency Constraints

1988 ◽  
Vol 110 (4) ◽  
pp. 592-599 ◽  
Author(s):  
Ting Nung Shiau ◽  
Jon Li Hwang
Keyword(s):  
Minimum Weight ◽  
Optimization Techniques ◽  
Multiple Frequency ◽  
Minimum Weight Design ◽  
Feasible Directions ◽  
Frequency Constraints ◽  
Design Algorithm ◽  
Rotor Bearing ◽  
Weight Design ◽  
Bearing System

The objective of the present study is to develop an efficient design algorithm for minimum weight design of a rotor bearing system under the requirements of operational speed range, i.e., multiple frequency constraints, to increase the performance of an existent rotor system. The system is modeled as an assemblage of rigid disks, shaft elements with distributed mass and stiffness, and discrete bearings. The system design variables are the inner radius of shaft elements and the stiffnesses of bearings. The optimization techniques employed to compare the results are method of exterior penalty function, method of feasible directions, and method of modified feasible directions. The parameter sensitivity analysis of the system is also presented. Three examples are used to demonstrate the merits of the design algorithm. The results indicate that the weight of the rotor bearing system can be significantly reduced at the optimum stage.

Circulation Control Span-Wise Blowing Location Optimization for a Helicopter Rotor Blade

2010 ◽  
Author(s):  
Alan M. Didion ◽  
Jonathan Kweder ◽  
Mary Ann Clarke ◽  
James E. Smith
Keyword(s):  
Stress Reduction ◽  
Rotor Blades ◽  
Helicopter Rotor ◽  
Base Line ◽  
Control Technology ◽  
Circulation Control ◽  
High Lift ◽  
Location Optimization ◽  
Helicopter Rotor Blades ◽  
Length Reduction

Circulation control technology has proven itself useful in the area of short take-off and landing (STOL) fixed wing aircraft by decreasing landing and takeoff distances, increasing maneuverability and lift at lower speeds. The application of circulation control technology to vertical take-off and landing (VTOL) rotorcraft could also prove quite beneficial. Successful adaptation to helicopter rotor blades is currently believed to yield benefits such as increased lift, increased payload capacity, increased maneuverability, reduction in rotor diameter and a reduction in noise. Above all, the addition of circulation control to rotorcraft as controlled by an on-board computer could provide the helicopter with pitch control as well as compensate for asymmetrical lift profiles from forward flight without need for a swashplate. There are an infinite number of blowing slot configurations, each with separate benefits and drawbacks. This study has identified three specific types of these configurations. The high lift configuration would be beneficial in instances where such power is needed for crew and cargo, little stress reduction is offered over the base line configuration. The stress reduction configuration on the other hand, however, offers little extra lift but much in the way of increased rotor lifespan and shorter rotor length. Finally, the middle balanced configuration offers a middle ground between the two extremes. With this configuration, the helicopter benefits in all categories of lift, stress reduction and blade length reduction.

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