zero fuel w & b

"Steve Schneider" wrote in message
...
john smith wrote:
d&tm wrote:

Are there any single engine airplanes out there that really can go
outside
the envelope by burning fuel? ( I am only interested in the normal
ategory - not utility). Perhaps the training is just to prepare you
for

Piper PA32's will can also develope this situation.


I'd previously posted links for some weight and balance info for a few
aircraft I've flown over the years. One of them happens to be a PA32.
This link http://www.4-fs.com/new/flying/N3000AWB.xls is to the W&B
spreadsheet for the Piper Lance (PA32-RT300T) which we've been flying
the last few years. I had included variables for fuel at departure and
'low fuel' for landing for just this reason. You can plug in the
following plausible values for a real flight and end up with the CG in
range (though precariously aft) at the start of the flight and have the
CG aft of the limits with 15 gallons remaining at the end of a flight:

Pilot+no front passenger: 180 lb
Center Passengers: 0
Rear Passengers: 360 lb
Fuel: 94 gal
Front Baggage: 0
Rear Baggage: 90

The CG only moves 0.22 inches to the rear after burning 79 gallons of
fuel, but it does take you 0.20 inches past the aft CG limit during the
flight.

Flying this plane with club seating does allow for some interesting
weight shifting when passengers (wife and kids typically) swap seats in
flight. You definitely do feel the change, and as such I always keep in
mind which passengers sit in which seats. Imagine the above loading
with the rear passengers (2x180lb) in the center row of seats and the
rear seats empty. Once airborne they decide they don't like to fly
'backwards' in the club seating and 'help themselves' to the the empty
rear seats. Suddenly we go from a very comfortable CG to a precariously
aft CG. Not a situation one generally needs to worry about in 2 and 4
seat airplanes.

That is part of why I find these spreadsheets so helpful in quickly
looking at a bunch of 'what if' scenarios before we depart.


Steve, thanks for that. I have made up similar spreadsheets for the Warrior
and C172 , but perhaps a little fancier in that they are set up to select
different reg numbers from a drop down menu, with the specific aircraft
data ( useful for paupers like me who dont own their own plane), a clear
button to clear all the input data and a message box to warn if any of the
fuel, baggage or total wt restrictions are exceeded. But I like your idea
of showing the low fuel point ( rather than just deleting the fuel as I do)
I think I will steal this idea :)
As I said in my previous post, it would be very unusual for me to have more
wt in the back than the front, ( which is likely to test the aft cg ) but
I could understand with club seating, the pax might be more inclined to want
to ride in style, instead of up the front.with the driver.

I notice even your 6 seater would struggle to take 4 adults with full fuel.
( the adutls would have to weigh on average less than 180 lbs - counts out
a lot of my friends!
Terry
ppl downunder

d&tm wrote:

Are there any single engine airplanes out there that really can go outside
the envelope by burning fuel?

The Bonanza is the big example that comes to mind.

The moment of the Fuel is forward of the main spar and as you burn your
fuel off, the CG moves aft.

If you have the 5th and 6th seats filled or have lots of aft baggage,
you can end up aft of limits, which can bite when you are low/slow on
approach.

Dave

Only when I fly naked.
tom

Jay Beckman wrote:
"tom" wrote in message
oups.com...
I weigh 170, so the only ballast I carry is around my ass. 8^)
tom

"Does this airplane make me look fat...?"

;O)

Jay B

"john smith" wrote in message
...
d&tm wrote:

snip
At some point, the cg moves out of the envelope (the ability of the
horizontal stabilizer to provide sufficient lift).

Aft c.g. violation makes the aircraft unstable in pitch. Forward c.g.
violation is an ability of the stabilizer to control pitch, i.e. bring the
nose up.

Danny Deger

As the wife and kids move around, I do need to re-trim -- but I haven't
casually noted a significant speed increase. I'll have to recruit some
'hefty' passengers and perform the experiment (our last experiment was
for my son's 5th grade science class when we capped empty water bottles
at various altitudes and he showed the class how much the bottles
collapsed as we returned to the ground).


Morgans wrote:
"Steve Schneider" wrote


Flying this plane with club seating does allow for some interesting weight
shifting when passengers (wife and kids typically) swap seats in flight.
You definitely do feel the change, and as such I always keep in mind which
passengers sit in which seats. Imagine the above loading with the rear
passengers (2x180lb) in the center row of seats and the rear seats empty.
Once airborne they decide they don't like to fly 'backwards' in the club
seating and 'help themselves' to the the empty rear seats. Suddenly we go
from a very comfortable CG to a precariously aft CG. Not a situation one
generally needs to worry about in 2 and 4 seat airplanes.


With the passengers putting the CG at the most aft limits, do you notice any
increase in speed, with the same power and prop settings? I would think the
aft CG would take the downward lift away from the horizontal, and pick up
some speed, but I don't know. It would seem like the ideal experiment; to
be able to quickly change the CG with no changes in air density, power, or
any other type of changes.

d&tm wrote:

Steve, thanks for that. I have made up similar spreadsheets for the Warrior
and C172 , but perhaps a little fancier in that they are set up to select
different reg numbers from a drop down menu, with the specific aircraft
data ( useful for paupers like me who dont own their own plane), a clear
button to clear all the input data and a message box to warn if any of the
fuel, baggage or total wt restrictions are exceeded. But I like your idea
of showing the low fuel point ( rather than just deleting the fuel as I do)
I think I will steal this idea :)
As I said in my previous post, it would be very unusual for me to have more
wt in the back than the front, ( which is likely to test the aft cg ) but
I could understand with club seating, the pax might be more inclined to want
to ride in style, instead of up the front.with the driver.

I'll have to dust off an Excel manual and polish up my spreadsheets with
some of your cool features! :-)

I notice even your 6 seater would struggle to take 4 adults with full fuel.
( the adutls would have to weigh on average less than 180 lbs - counts out
a lot of my friends!
Terry
ppl downunder


True, though full tanks would far exceed the typical passenger's bladder
range. Half tanks would still yield over 2 hours of flying time with
reserves (close enough to the upper end of the random passenger's
comfort limit per my experience) and let you carry a 5th person plus a
bit of baggage some 300+nm.

The Lance is by far the most practical aircraft I've ever had the
pleasure to fly. As a coincidental but random trip example, we're
heading off tomorrow to Santa Barbara with a full load of 6 people to
make good on a trip we donated for an event at a local community
college. This will be my wife and I plus 4 people who won the drawing.
Fortunately, the passenger weights are a bit on the low side, so with
partial fuel we can fly the ~300 mile round trip with fuel to spare. It
always seems like our passenger load works out pretty well.

One of the advantages of being a sole owner/operator is that you don't
have to worry about the prior pilot/partner/club member topping off the
tanks when you need to fly with partial fuel. I'd sure hate to drain 40
or 50 gallons before a flight because someone forgot _not_ to top off,
or perhaps the prior scheduled flight didn't occur so the tanks are
still full from the flight before that one.

Steve

I'll have to dust off an Excel manual and polish up my spreadsheets with some of your cool features! :-)

You might also want to take a look at the one I did for our club.

http://www.flying20club.org/planes8237B.html

I did the "new style" spreadsheet a little differently from the others,
take a look at the "how the spreadsheet works" part of the instructions tab.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.

"Jose" wrote in message
et...
I'll have to dust off an Excel manual and polish up my spreadsheets with
some of your cool features! :-)

You might also want to take a look at the one I did for our club.

http://www.flying20club.org/planes8237B.html

I did the "new style" spreadsheet a little differently from the others,
take a look at the "how the spreadsheet works" part of the instructions
tab.

Jose
--
Jose, I like the way yours does flight envelopes for individual aircraft. I
have separate sheets for warrior and C172 with the ability to select
individual aircraft. my understanding was that different planes of the same
type have different wts but the same envelope.
I will post a link to my own spreadsheets, when I work out how to do that.
can you explain how to do it - or point me to some help?
thanks
terry

Jose, I like the way yours does flight envelopes for individual aircraft.

Thank you. I did give it a bit of thought.

my understanding was that different planes of the same
type have different wts but the same envelope.

This generally true; it can be trivially true by defining "planes of the
same type" as requiring the same envelope. Marketers will make a plane
of a different type if it's painted a different color, but company
aircraft designers who deal with the FAA want all their planes to be the
same type so they can piggyback on the old type certficates. Also,
"type" and "name" are not to be confused, and "type" also has a specific
FAA meaning, within which I believe it is possible to have a different
envelope, uncommon though it may be for spam cans. But I don't know
whether you mean "type" colloquially or regulationally.

Confused yet, or should I try harder?

I will post a link to my own spreadsheets, when I work out how to do that.
can you explain how to do it - or point me to some help?

If you go to a web site that has any such link, you can "view source"
and see how they did it. As long as they don't use the mess of scripts
that is becoming popular these days, it will be pretty clear.

Step one: create the spreadsheet, set it up the way you want it to be
seen when it loads (what tab you're on, what cell is active...), and
then upload it to your web server, making note of where you put it.

Step 2: put a link on the page which refers to this file. The format
for such a link is the same as any other link, to wit: an open angle
bracket, the letter 'a', a space, the letters "href", an equal sign, the
target file name (enclosed within double-quotes), including the path if
necesesary, a closing angle bracket, (all the aforementioned "begins"
the anchor tag), the text you want to =be= the link (it will be blue and
underlined by default in the browser), and then to "end" the anchor tag,
an opening angle bracket, a forward slash (usually below the question
mark on a keyboard), the letter 'a', and a closing angle bracket. I'm
being long winded because some newsreaders will grab onto anything that
looks like HTML and try to interpret it instead.

Step III: Upload that page to the web site.

Note that the client computer (the one that clicks on the link) will
need to have an excel-compatible reader to be able to work with the
file, and that some browsers will display the spreadsheet within their
own window, others will simply call Excel to do the work. You can't
control that. Alas, neither can you control whether the user sees your
latest update to the spreadsheet, or their own, old, cached copy (or
even a cached copy along the way). That's why I have the caution to
empty the cache before proceeding. It's the way the web is designed -
no way around it.

Jose

--
He who laughs, lasts.
for Email, make the obvious change in the address.