Matt Whiting wrote:




That is why I said average height of the Bo wing. Most Bonanzas I've
seen have a fair bit of dihedral and the wing isn't anywhere near 4'2"
at the root. I don't know what the average height is, but is sure isn't
4'2".

Cessna's have dihedral too. May not be exactly the same but it's there.



I don't see how you get a 5 kph difference with 18m altitude difference.


Did I read that wrong? The chart said the wind went from 15 kmh to 20 kmh.





It states that the relationship is to the 1/7th power of the altitude.
Since it takes 1m as the reference altitude for a wind increase factor
of 1.0, an altitude of 18m has an increase factor of 18 to the 1/7th
power. This is 1.51 which indicates that the wind at 18m is 51% faster
than at 1m. Comparing 1m to 2m which is approximately correct to
compare a Bo wing to 182 wing, the increase factor is 2 to the 1/7th
power which is 1.1. Thus the wind velocity at 2m is 10% greater than at
1m. So, if the wind at 1m is 20 MPH then the wind at 2m would be
expected to be 22 MPH. If the wind at 1m is 40 MPH it would be expected
to be 44 at 2m.

That's a lot of words to prove that the difference is irrelevant for the
purpose of this discussion. No way anybody tells the difference from 20
- 22 mph or 40 - 44 mph.