Hi all. On a wing with a straight taper (or a constant chord too ) if the root chord thickness is 15% and the tip chord thickness is 10%, then in a wing with 11 evenly spaced ribs, each rib would have its %thickness reduced by 0.5% to produce a wing with a straight upper and lower surface in the spanwise direction. i.e. curved in a single plain.
So my question is, What happens on an eliptical planform wing. If the evenly spaced ribs still reduce in thickness in a linear fashion then the upper and lower surface of the wings will also be curved in a spanwise direction producing a surface with a compound curve. So do you reduce the % thickness in a non linear fahion to produce a wing surface without a compound curve. What happens in full size practice and is it possible to sheet built-up model wings at say 1/5 scale with a compound curve.
Any thoughts? Cheers, Rob.

possible
Of course
You can also do it with a foam cut core and get extremely accurate results

It is necessary tho, to buildup a sheeting with some grain orientation which permits a compound bend
In foam- you have the luxury of a shell and a underlying shape which traps the balsa sheet into a compound bend
using ribs n spars you have the transition from point to point which can easily producee some waves and dips you really did not want.
But give it a go - at least you won't be bored
frusterated perhaps but not bored.

Wizardprang,
I am building a model of the Japanese Val dive bomber which has an eliptical wing. The documentation drawings I have show a straight taper of the wing thickness and I designed my wing to reproduce that. I have built other models with eliptical planforms (Skyshark Val and Direct Connection Sea Fury) and they did have the curved spars. I have completely sheeted the left outer panel and the right one has the top sheeting on. The panels are 28" long and sheeted with 3/32 balsa. I did not have any problem with the compound curve. I did all my rib calculations as follows: I used actual numbers rather than percentages. There are 11 ribs. First I came up with the equation for the depth of each rib. Then from the plan view of the wing I measured the length of each rib in front of the spar and behind the spar. ( the proportions vary) I used a NACA 2315 airfoil becasue the high and low points are both at 30%-this makes it easy to build the spar system. I had the root airfoil in the CAD system I use at work-Vectorworks. For each front and back half of the rib I did a "scale object" with the height (y value) and length (x value) based on the proportions of calculated from the lengths(they were not the same). Seems to have worked out very well. Full-scale Val has either a 15.5% or 16% root airfoil (references vary) I used !5% becasue I had the coordinates. Turns out the tip is also very close to 15% thick. The ribs in between will be somewhat thinner as a percentage.
Chuck

Thanks for the input guys. I am not going to attempt a compound curve wing (not on this build anyway). So I will try drawing up individual ribs with the thickness and chord taken from the drawing.
All the best, Rob.