shdw

The formula for lift I used in my original post, read that post through and you will see what I mean I think.

Here so others can see the formula:

Re = (qVL/μ)= VL/v = QL/vA

where:
V is the mean fluid velocity (SI units: m/s)
L is a length of the object that the flow is going through or around (m)
μ is the dynamic viscosity of the fluid (Pa·s or N·s/m²)
ν is the kinematic viscosity (ν = μ / ρ) (m²/s)
is the density of the fluid (kg/m³)
Q is the volumetric flow rate (m³/s)
A is the pipe cross-sectional area (m²)

Now I haven't done the calculations for this, but this is what I meant by going over the top. The change in density is only a small amount of what the Reynolds number is made up of and the Reynolds number is only a small a portion of Clmax. That being said the change of a knot or two indicated that would result from such a change as say 0 to 10,000 feet IMO is not worth the time for pilots and will only confuse the crap out of most of them. The intricacies of fluid dynamics is above and beyond what one needs to consider in when discussing the change of indicated airspeed with altitude IMO.

Edit: Here to see the varying changes in air density and how little their values are, http://en.wikipedia.org/wiki/Air_density. The difference from -25 to +25 (25,000 feet of altitude change at standard lapse rate) is 0.239 difference in density. Compare that to velocity being a part of the formula and in m/s 50 knots would be 84 m/s, the wing of a typical aircraft that would stall around 50 knots would be around 10 meters in length, and the viscosity of air at 0.00001827 Pa·s. Hopefully these numbers make it pretty evident that the change in air density has a very little impact on Clmax.

PS If this boring, technical, stuff didn't exist and wasn't discussed we would still be pushing around carts with square tires.