A Mathematical Model of a Single Main Rotor Helicopter for ... - Read

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Main rotor interference and transformation Tg- The fuselage angles of attack, angle of sideslip, and dynamic pressure include an averaged effect of rotor downwash. The expression for downwash was obtained for typical single rotor helicopters from an empirical fit to data presented in reference 10. The velocities on the fuselage are as follows: wf = WB + wi f .- Where wif is the induced velocity due to the rotor and is defined as: (F) = 1.299 + 0.671~ - 1.172~~ + 0 .351~~ The rotor wake angle x is defined as: The angles of attack and sideslip are then: where Wf af = tan-’ - Uf The dynamic pressure on the fuselage is based on the velocity, including the effect ’- of rotor downwash. Transformation Tlo- The fuselage forces and moments are calculated in the wind system of axes about the fuselage reference point. The transformation must transfer the moment to the center of gravity and express all forces and moments in the body system of axes. 33
The forces and moments in the body-c.g. system of axes are given by the follow- ing equations: Xf = -D cos B cos a - Y sin f3 sin a + L sin a Yf = Y cos B - D sin B Zf = -L cos a - D cos B sin a - Y sin sin a 34
Page 1 and 2: 1 \ 1 i I ! t ... NASA Technical Me
Page 3 and 4: I . I CONTENTS SuMMAEtY ...........
Page 5 and 6: 1 2 3 4 B- 1 B-2 D- 1 FIGURES Block
Page 7 and 8: 0 Q p 0 16 9 2 w a, U & 3 4 t4 0 U
Page 9 and 10: summing the contributions, to each
Page 11 and 12: sideslip that will be encountered a
Page 13 and 14: gust levels. For this representatio
Page 15 and 16: damping matrix in flapping differen
Page 17 and 18: 0 Euler pitch angle, rad 00 et A bl
Page 19 and 20: HU B-BODY AIRCRAFT REFERENCE SYSTEM
Page 21 and 22: 1w II 8 2 + - + w 0 N Nlm I n "w (N
Page 23 and 24: 18 c
Page 25 and 26: (-& Q = nb pacR2 (RR) [l + (1 - - (
Page 27 and 28: (B, is defined as zero if VH = UH =
Page 29 and 30: 1 + jJ KlTRblTR - a blm +-- 4 'TR T
Page 31 and 32: This implicit relationship is solve
Page 33 and 34: APPENDIX E EMPENNAGE FORCES AND MOM
Page 35 and 36: The angle iHs is the incidence of t
Page 37: APPENDIX F CALCULATION OF FUSELAGE
Page 41 and 42: It is important to note that the cu
Page 43 and 44: c, = ‘C, (s) The terms CK1 and CK
Page 45 and 46: a 8 a m a ma a 0 a m 0. a 3" a m a
Page 47 and 48: TABLE J-1.- CONFIGURATION DESCRIPTI
Page 49 and 50: Fus pitch moment, a = B = 0 TABLE J
Page 51 and 52: REFERENCES l . 1 . Sinacori, J. B.;

A Mathematical Model of a Single Main Rotor Helicopter for ... - Read

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