pro aileron_diff, past_edge_array, clevis_height, linkage_travel, angle=angle, _extra=_extra
	; Past_edge is positive if linkage is attached above the wing,
	; and negative if attached above aileron.
	n_pts = n_elements(past_edge_array)
	;result = fltarr(n_elements(clevis_height), n_pts)
	for i = 0, n_pts-1 do begin
		past_edge = past_edge_array[i]
		radius = sqrt(past_edge^2 + clevis_height^2)
		linkage_angle = atan(clevis_height / past_edge) / (!pi*2/360.)
		if past_edge lt 0 then linkage_angle = 180. + linkage_angle
		for_angle = acos((past_edge + linkage_travel)/radius) / (!pi*2/360.)
		aft_angle = acos((past_edge - linkage_travel)/radius) / (!pi*2/360.)
		f_angle = linkage_angle - for_angle
		b_angle = aft_angle - linkage_angle
		;result[0, i] = b_angle/f_angle*100.
		percent_of_f_angle = b_angle/f_angle*100.
		tvlct, /get, r,g,b
		c = transpose([[r],[g],[b]])
		ci = i*24
		if keyword_set(angle) then $
		display, clevis_height, f_angle, color=c[*,ci], oref=oref, $;, psym=4, linestyle=6, /over;
			xtitle='Clevis height, mm', ytitle='Upward aileron angle, deg.', $
			over=i ne 0, _extra=_extra $
		else display, clevis_height, percent_of_f_angle, color=c[*,ci], oref=oref, $
			xtitle='Clevis height, mm', ytitle='Down is smaller than up by (%)', $
			over=i ne 0, _extra=_extra
	display, /over, oref=oref, title='Linkage travel '+string(linkage_travel, format='(F3.1)')+' mm.'
	endfor
	;print, 'Forward pull angle: ', f_angle
	;print, 'Backward push angle: ', b_angle
	;print, 'Differential: ', b_angle/f_angle*100.
end