Procedure for calculating weight and balance

Mxsmanic wrote:
/snip/ Can someone provide me
with a pointer to an explanation of the procedure on the Web
somewhere?


This site has good information:

http://www.amishrakefight.org/gfy/

Happy Flying!
Scott Skylane

Orval Fairbairn writes:

All W & B calculations result from taking the sum of all moments and
dividing by the sum of the associated weights.

Sum (arm*weight) / sum (weight) = CG

The arms are referenced to the datum -- an arbitrary point -- sometimes
the LE of the wing, sometimes a point ahead of the nose; but nonetheless
it is THE reference point for a given aircraft.

The POH will list the arms for each seat, fuel, oil, baggage, etc.

OK, thanks. That doesn't seem too difficult. Apparently "moment" and
"arm" are synonyms (?).

I guess the manufacturer doesn't say exactly what point constitutes
neutral trim.

I've been experimenting with changing the payload in flight (one of
the advantages of a sim) and that helps a bit with figuring out how to
get the most neutral load distribution possible.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Stubby writes:

also check faa.gov AC-61-238 "Pilots' Handbook of Aeronautical
Knowledge" will answer all your questions (I hope).

Section 12 explains the principles behind it, but it didn't actually
say how to calculate the center of gravity, or how to achieve neutral
trim (which nobody seems to care about except me).

--
Transpose mxsmanic and gmail to reach me by e-mail.

Mxsmanic,

Apparently "moment" and
"arm" are synonyms (?).

Dammit, learn to google and wikipedia, if you don't remember this
elementary stuff from school (you did go?). Moment is arm times weight.


I guess the manufacturer doesn't say exactly what point constitutes
neutral trim.

The manufacturer gives a range of allowed arm.

--
Thomas Borchert (EDDH)

Mxsmanic,

which nobody seems to care about except me)


Ah, time to take a clue, isn't it?

Why would "neutral trim" be important? For that matter, what would it
be?

What you get is a range of allowable CGs, which often depends on total
weight. This all has to do mostly with elevator authority. Trim (as in
the trim wheel) is not really important, trim is just a tool to relieve
the pilot. Trim as in weight distribution, well, see above.

Once you've figured this out, ponder why an aircraft will be faster or
consume less fuel if the CG is as aft as possible.

--
Thomas Borchert (EDDH)

Thomas Borchert writes:

Why would "neutral trim" be important?

It allows for maximum control movement in both directions.

For that matter, what would it be?

Neutral trim in cruise, usually.

What you get is a range of allowable CGs, which often depends on total
weight. This all has to do mostly with elevator authority. Trim (as in
the trim wheel) is not really important, trim is just a tool to relieve
the pilot.

Any trim adjustment has an effect on the remaining elevator authority
beyond the trimmed position.

Once you've figured this out, ponder why an aircraft will be faster or
consume less fuel if the CG is as aft as possible.

I'm not worried about speed or fuel consumption. I'm not in a rush,
and I generally take off with full tanks, at least in the Baron.

--
Transpose mxsmanic and gmail to reach me by e-mail.

Mxsmanic,

It allows for maximum control movement in both directions.

Maximum relative to what? What do you think the CG limits set forth by the
manufacturer are made for? Why would they matter in certification? Why would
a manufacturer and a certification authority consider them sufficient? How
much control movement do you "lose" when fully trimming to one side?

I'm not worried about speed or fuel consumption.

I know. You're playing MSFS, a game.

But if you where truly interested in these questions, then you'd find the
answer very educational. But again you show that you're not. You're an
imposter, bending the limits of your interest to maximize insult to the
pilots here. That's how you derive an "ego increase" from your visits to
this group. Pathetic! But interesting.

--
Thomas Borchert (EDDH)

Mxsmanic wrote in
:

Stubby writes:

also check faa.gov AC-61-238 "Pilots' Handbook of Aeronautical
Knowledge" will answer all your questions (I hope).

Section 12 explains the principles behind it, but it didn't actually
say how to calculate the center of gravity, or how to achieve neutral
trim (which nobody seems to care about except me).


as you burn fuel your CG changes. Your 'neutral trim' wont last. read
about the benifits of forward/aft CG's.

Now if your doing areobatics I believe the placement of the CG becomes even
more importent (all I have done is spins) and my guess is that a 'neutral
cg' is not the best place?

"Orval Fairbairn" wrote

The POH will list the arms for each seat, fuel, oil, baggage, etc.

Are you sure you want to be answering this putz? I beg of you; reconsider.
--
Jim in NC

Thomas Borchert writes:

Maximum relative to what?

Relative to its default position.

How much control movement do you "lose" when fully trimming to one side?

It depends on the aircraft, but you always lose something.

I know. You're playing MSFS, a game.

In the simulation, I have lots of money and time, so speed and fuel
costs are not important.

But if you where truly interested in these questions, then you'd find the
answer very educational.

I will be interested in them if and when they are imposed upon me.
For example, if I were flying an actual aircraft, I would not be able
to buy infinite amounts of fuel or take vast amounts of time to get
somewhere (probably).

--
Transpose mxsmanic and gmail to reach me by e-mail.