Blade for high-performance shrouded propeller, multi-blade shrouded propeller provided with such blades and tail rotor arrangement with shrouded propeller for rotary wing aircraft

Claim 2

A blade for shrouded propeller comprising a tunnel and a rotor with multiple blades coaxial to said tunnel, said rotor comprising a rotating hub of which the radius is of the order of 40% that of said tunnel and on which said blades are mounted via blade shanks, wherein: in plan, the aerodynamically active part of said blade presents, beyond the blade shank, a rectangular shape with the result that the successive profiles constituting said aerodynamically active part all have the same chord 1 and that the end section of said aerodynamically active part is straight; and, along the span of the blade counted from the axis of the tunnel, between a first section of which the relative span is close to 45% and the end section of said blade: the maximum relative camber of the successive profiles constituting said aerodynamically active part of the blade is positive and increases from a value close to 0 to a value close to 0.04; the twist of said aerodynamically active part of the blade decreases from a first value close to 12° at said first section to a second value close to 4° at a second section of which the relative span is close to 0.86, then increases from this second section to a third value close to 4.5° at said end section of blade; and the maximum relative thickness of said successive profiles decreases from a value close to 13.5% to a value close to 9.5%.

Claim 3

The shrouded propeller blade of claim 1, wherein said maximum relative camber increases virtually linearly from this value close to 0 to a value equal to 0.036 for a relative span equal to 0.845, passing through values 0.01 and 0.02 respectively for the relative spans 0.53 and 0.66, then increases from this value equal to 0.036 for the relative span equal to 0.845 up to a value equal to 0.038 for the relative span equal to 0.93, and, finally, is constant and equal to 0.038 between the relative spans 0.93 and 1.

Claim 4

The shrouded propeller blade of claim 1, wherein the root of said blade presents evolutive profiles of which the maximum relative camber is negative and increases from a value substantially equal to -0.013 for a relative span equal to 0.40 to said value close to 0 for a relative span equal to 0.45.

Claim 5

The shrouded propeller blade of claim 1, wherein, between the relative spans 0.45 and 1, the evolution of the twist is at least substantially parabolic, with a minimum for the relative span of 0.86.

Claim 6

The shrouded propeller blade of claim 4, wherein the axis of twist of said aerodynamically active part is parallel to the line of leading edge and to the line of trailing edge thereof and is distant from said line of leading edge by a distance approximately equal to 39% of the length of the chord of the profiles.

Claim 7

The shrouded propeller blade of claim 5, wherein the twist of the root of said blade increases from said value close to 8° for a relative span close to 0.38 to said value close to 12° for the relative span equal to 0.45.

Claim 8

The shrouded propeller blade of claim 1, wherein the maximum relative thickness of the profiles decreases linearly from a value close to 13.9% for a relative span equal to 0.40 to a value close to 9.5% for a relative span equal to 0.93, and is constant and equal to said value close to 9.5% between the relative spans respectively equal to 0.93 and 1.

Claim 9

The shrouded propeller blade of claim 7, wherein the portion of the aerodynamically active part included between the relative spans 0.93 and 1 is constituted by a profile (I) having a maximum relative thickness equal to 9.5% and such that, as a function of the reduced abscissa X/1 along the chord, counted from the leading edge, the reduced ordinates of its upper surface line (35) are given between X/1=0 and X/1=0.39433, by the formula Y/1=f1(X/1).sup.1/2 +f2(X/1)+f3(X/1).sup.2 +f4(X/1).sup.3 +f5(X/1).sup.4 +f6(X/1).sup.5 +f7(X/1).sup.6 ( 1) with f1=+0.16227 f2=-0.11704.10 -1 f3=+0.13247 f4=-0.25016.10 f5=+0.10682.10 2 f6=-0.22210.10 2 f7=+0.17726.10 2 between X/1=0.39433 and X/1=1, by the formula Y/1=g0+g1(X/1)+g2(X/1).sup.2 +g3(X/1).sup.3 +g4(X/1).sup.4 +g5(X/1).sup.5 +g6(X/1).sup.6 ( 2) with g0=+0.22968 g1=-0.17493.10 g2=+0.77952.10 g3=-0.17457.10 2 g4=+0.20845.10 2 g5=-0.13004.10 2 g6=+0.33371.10 whilst the reduced ordinates of the lower surface line 36 of the said profile are given between X/1=0 and X/1=0.11862, by the formula Y/1=h1(X/1).sup.1/2 +h2(X/1)+h3(X/1).sup.2 +h4(X/1).sup.3 +h5(X/1).sup.4 +h6(X/1).sup.5 +h7(X/1).sup.6 ( 3) with h1=-0.13971 h2=+0.10480.10 -3 h3=+0.51698.10 h4=-0.11297.10 3 h5=+0.14695.10 4 h6=-0.96403.10 4 h7=+0.24769.10 5 between X/1=0.11862 and X/1=1, by the formula Y/1=i0+i1(X/1)+i2(X/1).sup.2 +i3(X/1).sup.3 +i4(X/1).sup.4 +i5(X/1).sup.5 +i6(X/1).sup.6 ( 4) with i0=-0.25915.10 -1 i1=-0.96597.10 -1 i2=+0.49503 i3=+0.60418.10 -1 i4=-0.17206.10 i5=+0.20619.10 i6=-0.77922.

Claim 10

The shrouded propeller blade of claim 7, wherein the profile of the blade section disposed at the relative span of 0.845 has a maximum relative thickness equal to 10.2% and is such that, as a function of the reduced abscissa X/1 along the chord, counted from the leading edge, the reduced ordinates of the upper surface line (35) are given between X/1=0 and X/1=0.39503, by the formula Y/1=j1(X/1).sup.1/2 +j2(X/1)+j3(X/1).sup.2 +j4(X/1).sup.3 +j5(X/1).sup.4 +j6(X/1).sup.5 +j7(X/1).sup.6 ( 5) with j1=+0.14683 j2=-0.67115.10 -2 j3=+0.44720 j4=-0.36828.10 j5=+0.12651.10 2 j6=-0.23835.10 2 j7=+0.18155.10 2 between X/1=0.39503 and X/1=1, by the formula Y/1=k0+k1(X/1)+k2(X/1).sup.2 +k3(X/1).sup.3 +k4(X/1).sup.4 +k5(X/1).sup.5 +k6(X/1).sup.6 ( 6) with k0=+0.45955 k1=-0.39834.10 k2=+0.16726.10 2 k3=-0.35737.10 2 k4=+0.41088.10 2 k5=-0.24557.10 2 k6=+0.60088.10 whilst the reduced ordinates of the lower surface line (36) of said profile are given between X/1=0 and X/1=0.14473, by the formula Y/1=m1(X/1).sup.1/2 +m2(X/1)+m3(X/1).sup.2 +m4(X/1).sup.3 +m5(X/1).sup.4 +m6(X/1).sup.5 +m7(X/1).sup.6 ( 7) with m1=-0.13297 m2=+0.36163.10 -1 m3=+0.17284.10 m4=-0.27664.10 2 m5=+0.30633.10 3 m6=-0.16978.10 4 m7=+0.36477.10 4 between X/1=0.14473 and X/1=1, by the formula Y/1=n0+n1(X/1)+n2(X/1).sup.2 +n3(X/1).sup.3 +n4(X/1).sup.4 +n5(X/1).sup.5 +n6(X/1).sup.6 ( 8) with n0=-0.30824.10 -1 n1=-0.20564.10 -1 n2=-0.21738 n3=+0.24105.10 n4=-0.53752.10 n5=+0.48110.10 n6=-0.15826.10.

Claim 11

The shrouded propeller blade of claim 7, wherein the profile of the blade section disposed at the relative span of 0.66 has a maximum relative thickness equal to 11.7% and is such that, as a function of the reduced abscissa X/1 along the chord, counted from the leading edge, the reduced ordinates of the upper surface line are given between X/1=0 and X/1=0.28515, by the formula Y/1=t1(X/1).sup.1/2 +t2(X/1)+t3(X/1).sup.2 +t4(X/1).sup.3 +t5(X/1).sup.4 +t6(X/1).sup.5 +t7(X/1).sup.6 ( 9) with t1=+0.21599 t2=-0.17294 t3=+0.22044.10 t4=-0.26595.10 2 t5=+0.14642.10 3 t6=-0.39764.10 3 t7=+0.42259.10 3 between X/1=0.28515 and X/1=1, by the formula Y/1=u0+u1(X/1)+u2(X/1).sup.2 +u3(X/1).sup.3 +u4(X/1).sup.4 +u5(X/1).sup.5 +u6(X/1).sup.6 ( 10) with u0=+0.39521.10 -1 u1=+0.26170 u2=-0.47274 u3=-0.40872 u4=+0.15968.10 u5=-0.15222.10 u6=+0.51057 whilst the reduced ordinates of the lower surface line of said profile are given between X/1=0 and X/1=0.17428, by the formula Y/1=v1(X/1).sup.1/2 +v2(X/1)+v3(X/1).sup.2 +v4(X/1).sup.3 +v5(X/1).sup.4 +v6(X/1).sup.5 +v7(X/1).sup.6 ( 11) with v1=-0.16526 v2=-0.31162.10 -1 v3=+0.57567.10 v4=-0.10148.10 3 v5=+0.95843.10 3 v6=-0.44161.10 4 v7=+0.78519.10 4 between X/1=0.17428 and X/1=1, by the formula Y/1=w0+w1(X/1)+w2(X/1).sup.2 +w3(X/1).sup.3 +w4(X/1).sup.4 +w5(X/1).sup.5 +w6(X/1).sup.6 ( 12) with w0=-0.25152.10 -1 w1=-0.22525 w2=+0.89038 w3=-0.10131.10 w4=+0.16240 w5=+0.46968 w6=-0.26400.

Claim 12

The shrouded propeller blade of claim 7, wherein the profile of the blade section disposed at the relative span 0.53 R has a maximum relative thickness equal to 13.8% and is such that, as a function of the reduced abscissa X/1 along the chord, counted from the leading edge, the reduced ordinates of the upper surface line are given between X/1=0 and X/1=0.26861, by the formula Y/1=α1(X/1).sup.1/2 +α2(X/1)+α3(X/1).sup.2 +α4(X/1).sup.3 +α5(X/1).sup.4 +α6(X/1).sup.5 +α7(X/1).sup.6 ( 13) with α1=+0.19762 α2=+0.17213

Claim 13

α=- 0. 53137.10 α4=+0.56025.10 2 α5=-0.32319.10 3 α6=+0.92088.10 3 α7=-0.10229.10 4 between X/1=0.26861 and X/1=1, by the formula Y/1=β0+β1(X/1)+β2(X/1).sup.2 +β3(X/1).sup.3 +β4(X/1).sup.4 +β5(X/1).sup.5 +β6(X/1).sup.6( 14) with β0=+0.28999.10 -1 β1=+0.38869 β2=-0.10798.10 β3=+0.80848 β4=+0.45025 β5=-0.10636.10 β6=+0.47182 whilst the reduced ordinates of the lower surface line of said profile are given between X/1=0 and X/1=0.20934, by the formula Y/1=γ1(X/1).sup.1/2 +γ2(X/1)+γ3(X/1).sup.2 +γ4(X/1).sup.3 +γ5(X/1).sup.4 +γ6(X/1).sup.5 +γ7(X/1).sup.6 ( 15) with γ1=-0.25376 γ2=+0.61860 γ3=-0.96212.10 γ4=+0.12843.10 3 γ5=-0.90701.10 3 γ6=+0.32291.10 4 γ7=-0.45418.10 4 between X/1=0.20934 and X/1=1, by the formula Y/1=δ0+δ1(X/1)+δ2(X/1).sup.2 +δ3(X/1).sup.3 +δ4(X/1).sup.4 +δ5(X/1).sup.5 +δ6(X/1).sup.6( 16) with δ0=-0.25234.10 -1 δ1=-0.23995 δ2=+0.10890.10 δ3=-0.10066.10 δ4=-0.32520 δ5=+0.11326.10 δ6=-0.64043.

Claim 14

α=- 0. 53137.10 α4=+0.56025.10 2 α5=-0.32319.10 3 α6=+0.92088.10 3 α7=-0.10229.10 4 between X/1=0.26861 and X/1=1, by the formula Y/1=β0+β1(X/1)+β2(X/1).sup.2 +β3(X/1).sup.3 +β4(X/1).sup.4 +β5(X/1).sup.5 +β6(X/1).sup.6( 14) with β0=+0.28999.10 -1 β1=+0.38869 β2=-0.10798.10 β3=+0.80848 β4=+0.45025 β5=-0.10636.10 β6=+0.47182 whilst the reduced ordinates of the lower surface line of said profile are given between X/1=0 and X/1=0.20934, by the formula Y/1=γ1(X/1).sup.1/2 +γ2(X/1)+γ3(X/1).sup.2 +γ4(X/1).sup.3 +γ5(X/1).sup.4 +γ6(X/1).sup.5 +γ7(X/1).sup.6 ( 15) with γ1=-0.25376 γ2=+0.61860 γ3=-0.96212.10 γ4=+0.12843.10 3 γ5=-0.90701.10 3 γ6=+0.32291.10 4 γ7=-0.45418.10 4 between X/1=0.20934 and X/1=1, by the formula Y/1=δ0+δ1(X/1)+δ2(X/1).sup.2 +δ3(X/1).sup.3 +δ4(X/1).sup.4 +δ5(X/1).sup.5 +δ6(X/1).sup.6( 16) with δ0=-0.25234.10 -1 δ1=-0.23995 δ2=+0.10890.10 δ3=-0.10066.10 δ4=-0.32520 δ5=+0.11326.10 δ6=-0.64043.

Claim 15

The shrouded propeller blade of claim 7, wherein the profile of the section of blade root disposed at the relative span of 0.40 has a maximum relative thickness equal to 13.9% and is such that, as a function of the reduced abscissa X/1 along the chord, counted from the leading edge, the reduced ordinates of the upper surface line are given between X/1=0 and X/1=0.19606, by the formula Y/1=ε1(X/1).sup.1/2 +ε2(X/1)+ε3(X/1).sup.2 +ε4(X/1).sup.3 +ε5(X/1).sup.4 +ε6(X/1).sup.5 +ε7(X/1).sup.6 ( 17) with ε1=+0.22917 ε2=-0.22972 ε3=+0.21262.10 ε4=-0.39557.10 2 ε5=+0.32628.10 3 ε6=-0.13077.10 4 ε7=+0.20370.10 4 between X/1=0.19606 and X/1=1, by the formula Y/1=λ0+λ1(X/1)+λ2(X/1).sup.2 +λ3(X/1).sup.3 +λ4(X/1).sup.4 +λ5(X/1).sup.5 +λ6(X/1).sup.6( 18) with λ0=+0.32500.10 -1

Claim 16

λ=+ 0. 29684 λ2=-0.99723 λ3=+0.82973 λ4=+0.40616 λ5=-0.10053.10 λ6=+0.44222 whilst the reduced ordinates of the lower surface line of said profile are given between X/1=0 and X/1=0.26478, by the formula Y/1=μ1(X/1).sup.1/2 +μ2(X/1)+μ3(X/1).sup.2 +μ4(X/1).sup.3 +μ5(X/1).sup.4 +μ6(X/1).sup.5 +μ7(X/1).sup.6 ( 19) with μ1=-0.19314 μ2=-0.22031 μ3=+0.44399.10 μ4=-0.41389.10 2 μ5=+0.23230.10 3 μ6=-0.66179.10 3 μ7=+0.74216.10 3 between X/1=0.26478 and X/1=1, by the formula Y/1=ν0+ν1(X/1)+ν2(X/1).sup.2 +ν3(X/1).sup.3 +ν4(X/1).sup.4 +ν5(X/1).sup.5 +ν6(X/1).sup.6 ( 20) with ν0=-0.42417.10 -1 ν1=-0.29161 ν2=+0.57883 ν3=+0.41309 ν4=-0.19045.10 ν5=+0.18776.10 ν6=-0.63583.

Claim 17

λ=+ 0. 29684 λ2=-0.99723 λ3=+0.82973 λ4=+0.40616 λ5=-0.10053.10 λ6=+0.44222 whilst the reduced ordinates of the lower surface line of said profile are given between X/1=0 and X/1=0.26478, by the formula Y/1=μ1(X/1).sup.1/2 +μ2(X/1)+μ3(X/1).sup.2 +μ4(X/1).sup.3 +μ5(X/1).sup.4 +μ6(X/1).sup.5 +μ7(X/1).sup.6 ( 19) with μ1=-0.19314 μ2=-0.22031 μ3=+0.44399.10 μ4=-0.41389.10 2 μ5=+0.23230.10 3 μ6=-0.66179.10 3 μ7=+0.74216.10 3 between X/1=0.26478 and X/1=1, by the formula Y/1=ν0+ν1(X/1)+ν2(X/1).sup.2 +ν3(X/1).sup.3 +ν4(X/1).sup.4 +ν5(X/1).sup.5 +ν6(X/1).sup.6 ( 20) with ν0=-0.42417.10 -1 ν1=-0.29161 ν2=+0.57883 ν3=+0.41309 ν4=-0.19045.10 ν5=+0.18776.10 ν6=-0.63583.