John Newton
Well-Known Member
I have been toying with the idea of trying to create a formula that will give a good approximation for the neutral point of a linearly tapered and swept wing allowing for sweep effects.
I have based it on the C-point calculation used by Dr. Panknin, the Hortens, K. Nickel etc. (this assumes the lift is centred on the quater chord point for the entire wing). The C-point is simply the quater chord point of the Mean Aerodynamic Chord of the wing.
I would be very grateful if anyone has any data they can point me toward concerning true neutral points of sweptback wings so I can see how accurate my formula is for varying sweep, taper and apect ratios. Also if anyone has an existing design with a known neutral point if they could pass on the wing data and I will again compare it against the neutral point my formula predicts.
My idea is to produce an equation that is more accurate than the C-point for moderately swept and tapered wings. It is based on figure 2.7.5 on page 84 of Tailless aircraft in theory and practice. This is data for a wing with an apect ratio of 10 and a sweep angle of 15 degrees but I am hoping it will still provide a good approximation for other values.
The equation is as follows:
Yn/semispan = (Yc/semispan)-(((Zx2)-1)x0.04) approximately
Where:
Yn = Spanwise distance from wing root to Neutral point
Yc = Spanwise distance from wing root to C-point
Z = taper ratio
Thankyou to all the people that have helped me so far, particularly Norman, Topaz and Autoreply, any help or suggestions on the above would be very much appreciated.
I have based it on the C-point calculation used by Dr. Panknin, the Hortens, K. Nickel etc. (this assumes the lift is centred on the quater chord point for the entire wing). The C-point is simply the quater chord point of the Mean Aerodynamic Chord of the wing.
I would be very grateful if anyone has any data they can point me toward concerning true neutral points of sweptback wings so I can see how accurate my formula is for varying sweep, taper and apect ratios. Also if anyone has an existing design with a known neutral point if they could pass on the wing data and I will again compare it against the neutral point my formula predicts.
My idea is to produce an equation that is more accurate than the C-point for moderately swept and tapered wings. It is based on figure 2.7.5 on page 84 of Tailless aircraft in theory and practice. This is data for a wing with an apect ratio of 10 and a sweep angle of 15 degrees but I am hoping it will still provide a good approximation for other values.
The equation is as follows:
Yn/semispan = (Yc/semispan)-(((Zx2)-1)x0.04) approximately
Where:
Yn = Spanwise distance from wing root to Neutral point
Yc = Spanwise distance from wing root to C-point
Z = taper ratio
Thankyou to all the people that have helped me so far, particularly Norman, Topaz and Autoreply, any help or suggestions on the above would be very much appreciated.
