Weight and Balance Formula, Can one calculate the envelope

Ross, Thanks for your note and your offer to send me a
spreadsheet. Hopefully I'll be able to figure out the
math principles behind the formulas. Based on the number
of responses, there is hope for what is needed. I'll have
a close look at the posts when I get home.

My email to you bounced as well. I guess no one uses real
email addresses anymore. Try this one, it'll be valid for
a couple of days: jwasikusa "@" dublinhills "dot" com.

Thanks.

Ross Richardson wrote in message ...
Send me your correct e-mail address and I will send you the spreadsheet
I developed for my C-172F. It even has the graphic and a "*" to show you
where you are in the envelop. I do not have access to post is anywhere
and I cannot attach to this message. I tried to reply to the address in
your post and it bounced back.

Joe Wasik wrote:

Hello, I put together a quick Excel spreadsheet that calculates total
weight and total moment for a Cessna 172. However, to check the CG, I
still have to take these calculated values and place them onto the
diagram called "Center of Gravity Moment Envelope". Does anyone know
if this lookup can be performed via a calculation? Knowing this
would be very helpful.
Thank you.


Ross
N7905U
180hp

Excel uses only an IF statement. I have used it in an unrelated large
scale water flow situation, but found it messy to use. I was thinking
that a series of them could be used to end up with a yes (OK) or no
answer, but I like your concept better of showing where you are on the
actual CG/GW range.

In addition you could show the effect of burning off fuel as a line.
I don't think any 172s will present a problem in this area, but some
others like Bonanzas can.

My experience is that it is hard to exceed the CG range of a 172, but
easy to exceed the gross weight.

wrote in message
om...
Excel uses only an IF statement. I have used it in an unrelated large
scale water flow situation, but found it messy to use.

Most likely because you are not sufficiently familiar with Excel. The fact
that you think that "Excel uses only an IF statement" supports this
likelihood. It has hundreds of worksheet functions, not counting all of the
add-ins that provide even more functionality.

I don't know what calculations are involved in a "large scale water flow
situation", but I doubt it really required exclusive use of nested IF
statements.

[...]
In addition you could show the effect of burning off fuel as a line.
I don't think any 172s will present a problem in this area, but some
others like Bonanzas can.

You could draw a line, but why bother? All you really need are the two
end-points. I've never seen a W&B graph that had a convex curve, which
would be required to allow the takeoff and landing weights to fall inside
the envelope, while still having an intermediate state outside the envelope.

Pete