"Dave S" wrote in message
.net...
Wonderful.. Thankyou Blanche... I only have to tweak the name of the
variable A6 to plug this in..

This was exactly what I was lookin for.
Dave

Dave, please forgive me for saying so, but if you found the statement "the
speed is
proportionate to the square root of gross weight" to be unhelpful, but
Blanche's "full_va*SQRT(A6/full_weight)" is "exactly what you were looking
for", then with all due respect, you do not understand the calculation well
enough to base a life-or-death piloting decision on it. If you use the
Excel expression without understanding how to derive it yourself or why it's
correct, you're essentially choosing a speed to keep your plane intact by
delegating the decision to someone on Usenet whom you don't even know. And
since you were also uninterested in a very close approximation (within 2%)
that lets you do the same calculation in your head, how are you going to
check whether your implementation of the formula contains a typo or other
problem that results in the wrong answer?

I don't mean to be critical, but I implore you to be sure you understand
exactly why and how some of the V-speeds (Vs, Vs1, Vx, Vy, Va, Vl/d) vary
with weight, and why others (Vfe, Vle, Vlo, Vno, Vne) do not, and how the
relation translates into a mathematical expression. (The reference I
pointed to earlier contains a full explanation using nothing more advanced
than high-school physics.)

Fly safely,
Gary


Blanche wrote:
For the type of aircraft your club will be flying, the formula in
Kershner will be adequate.

The formula in Excel is

full_va*SQRT(A6/full_weight)

where

full_va printed weight in the POH (usually at gross weight)
full_weight gross weight for aircraft (again, most recent W&B)
A6 column with weight for calculation

I fly a cherokee, so I have weights from 1800 (lightest load with
fuel and me and gear) to 2400 (gross weight) in column A.

And while you're calculating Va, the Glide speed can be done at
the same time since it's also weight-based:

full_glide*SQRT(A6/full_weight)

have fun!