Weight and descend speed

Hi,
Last weekend I flew the heaviest airplane I ever flew, I had two not
so light passengers and my Cessna 172 took a long time to climb to my
desired altitude. Every thing was going as planned but when I was
landing I did not think too much about the weight factor and as soon
as I was on final I noticed my speed decreasing considerably after I
put the last notch of flap down and I had to use more than the normal
power I use to keep the speed up . The landing was smooth but after
landing when thinking about the decreased speed I am a bit unsure
about the cause. So here are my questions:

1. Is weight a factor in slowing the plane down while descending? -
it could be that I might have brought the nose up without noticing ,
but I want to be conclusive about how the weight would effect my
speed while descending.
2. Did I do the right thing by using full flaps and then use power to
keep the speed up or a better strategy would have been to use one
degree lesser flap than I normally do and maintain my required speed?

Any feedback is appreciated, and here is a non-technical question, one
of the awkward things for me in my pre-flight is to ask passengers
about their weight, so does anyone have any tips on how to ask for
the weight of my passengers, without feeling awkward and making them
uncomfortable? Usually I assume the weight of my passengers and do
the weight and balance and then add another ten pounds to the numbers
I assumed and do the weight and balance again to see if we are ok, but
after my last experience I want to stop assuming things and get the
real numbers : )

Thanks,
-Raj

<nybiker13@> wrote in message
news:1177793243.501352.55320@l77g2000hsb. ...
> Hi,
> Last weekend I flew the heaviest airplane I ever flew, I had two not
> so light passengers and my Cessna 172 took a long time to climb to my
> desired altitude. Every thing was going as planned but when I was
> landing I did not think too much about the weight factor and as soon
> as I was on final I noticed my speed decreasing considerably after I
> put the last notch of flap down and I had to use more than the normal
> power I use to keep the speed up . The landing was smooth but after
> landing when thinking about the decreased speed I am a bit unsure
> about the cause. So here are my questions:
>
> 1. Is weight a factor in slowing the plane down while descending? -
> it could be that I might have brought the nose up without noticing ,
> but I want to be conclusive about how the weight would effect my
> speed while descending.
> 2. Did I do the right thing by using full flaps and then use power to
> keep the speed up or a better strategy would have been to use one
> degree lesser flap than I normally do and maintain my required speed?
>
> Any feedback is appreciated, and here is a non-technical question, one
> of the awkward things for me in my pre-flight is to ask passengers
> about their weight, so does anyone have any tips on how to ask for
> the weight of my passengers, without feeling awkward and making them
> uncomfortable? Usually I assume the weight of my passengers and do
> the weight and balance and then add another ten pounds to the numbers
> I assumed and do the weight and balance again to see if we are ok, but
> after my last experience I want to stop assuming things and get the
> real numbers : )
>
Attitude for Speed
Power for Altitude.

you would have a greater rate of descent at a higher weight and perhaps you
were subconsiously raising the nose to compensate. If your attitude is
right your speed will be right, and then you adjust rate of descent with
power. If struggling to make the field or to clear obstacles then less flap
can be used.

If I thought I was anywhere near max wt I would not just ask my pax , I
would use the scales at the airport and be sure. I am sure the pax would
would understand and appreciate your professionalism in doing so.
terry

Did you use 40 degree of flap? what i've found from flying C172's and
Station Air with more weight than normal is to use only 30 degrees of
flap. Hell, in a case like yours i'd go flap less. We do that in the
Station Airs with a full load 9 times out of 10.

nybiker13@ wrote:
> Hi,

>
> Any feedback is appreciated, and here is a non-technical question, one
> of the awkward things for me in my pre-flight is to ask passengers
> about their weight, so does anyone have any tips on how to ask for
> the weight of my passengers, without feeling awkward and making them
> uncomfortable? Usually I assume the weight of my passengers and do
> the weight and balance and then add another ten pounds to the numbers
> I assumed and do the weight and balance again to see if we are ok, but
> after my last experience I want to stop assuming things and get the
> real numbers : )
>
> Thanks,
> -Raj
>

If taking a couple flying I always ask "how much do you and your husband
weigh together"? I have also been know to say "I have 250 lbs, will
that work?". When it looks real close I just ask. You get used to it
after a while.

Margy

Thanks a bunch for all your feeback, and I will keep that in mind on
my next flight and try to figure out the exact reason - and to answer
VH-UNR's question: I used 40 degrees of flap.
Thanks again,
-Raj

<nybiker13@> wrote in message
news:1177793243.501352.55320@l77g2000hsb. ...
>.....I had to use more than the normal
> power I use to keep the speed up .

Attitude controls speed.
Throttle controls altitude.
Oz Lander

Having the CG aft would require more control deflection though, since
there is a shorter arm from the CG to the elevator, correct?

On Apr 30, 9:45 am, Brian <brianfc...@msn.com> wrote:
> Having the CG aft will lighten the control forces so if you are used
> to holding some back pressure on final, it will be less with a more
> aft CG. Also the Trim will probably be positioned in a different spot
> than with a more forward CG.

"kevmor" <kevmor@> wrote in message
news:1178069817.885752.182540@o5g2000hsb. ...
> Having the CG aft would require more control deflection though, since
> there is a shorter arm from the CG to the elevator, correct?

Only the distance of the arm is not the important factor, in this case.

With the CG to the most rear point, the CG is at virtually the same location
as the center of lift. Think of the airplane as though it is balanced on a
pin. It only takes a very small push to send it tilting one way or the
other.

With a forward CG, the plane will go into a dive very easily; more easily
than with the CG aft. It takes a whole lot of movement to get it to climb,
though. That is why on most plans, the elevator throw is something like
3/4" up, and 1/2" down.
--
Jim in NC

On Tue, 1 May 2007 22:20:48 -0400, "Morgans"
<jsmorgan@charterJUNK.net> wrote:

>
>"kevmor" <kevmor@> wrote in message
>news:1178069817.885752.182540@o5g2000hsb. o...
>> Having the CG aft would require more control deflection though, since
>> there is a shorter arm from the CG to the elevator, correct?
>
>Only the distance of the arm is not the important factor, in this case.
>
>With the CG to the most rear point, the CG is at virtually the same location
>as the center of lift. Think of the airplane as though it is balanced on a
>pin. It only takes a very small push to send it tilting one way or the
>other.
>
>With a forward CG, the plane will go into a dive very easily; more easily
>than with the CG aft. It takes a whole lot of movement to get it to climb,
>though. That is why on most plans, the elevator throw is something like
>3/4" up, and 1/2" down.

I once had a passenger in the Cherokee 180 who li...er wasn't very
accurate on his weight. Actually the number he gave me was FAR more
than optimistic and must have been what he was wishing he weighed.

At any rate the flight had well and we were lined up on final coming
to set down on the touch down zone. I pulled the power over the
numbers and the nose dropped (not a stall). I firewalled it and
arrested the sink rate just in time, but we richoceted off the runway.
Working with the throttle I managed to reduce the oscilation and made
a good landing AFTER the spectacular part that happened to be right in
front of a 210 waiting at the hold line.

"Morgans" > wrote

> That is why on most plans, the elevator throw is something like 3/4" up,
> and 1/2" down.

. Even though what I posted about CG's is conceptually correct, the bit
about 3/4" and 1/2" control throws was intended for (where I thought I was)
the model airplane group. Sorry! <g>
--
Jim in NC