Leaning at higher altitudes

[Mxsmanic]

Am I correct in assuming that changes to mixture diminish with increasing
altitude? That is, a mixture change is more important and larger when going
from sea level to 5000 feet than when going from 10000 to 15000 feet?

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

[Ron Natalie]

Mxsmanic wrote:
> Am I correct in assuming that changes to mixture diminish with increasing
> altitude? That is, a mixture change is more important and larger when going
> from sea level to 5000 feet than when going from 10000 to 15000 feet?
>
Nope. As a matter of fact, my old engine that had the altitude
adjusting carb had the it's automatic adjustment give up around
10,000 (by definition) and you then had to lean manually.

[[email protected]]

Mxsmanic > wrote:
> Am I correct in assuming that changes to mixture diminish with increasing
> altitude? That is, a mixture change is more important and larger when going
> from sea level to 5000 feet than when going from 10000 to 15000 feet?

No, and from the question it is clear you have no understanding of
why leaning is performed or how it is done in spite of being told.

If you really want to stop sounding like a dumb ass, go buy a copy
of Rod Machado's Private Pilot Handbook and read what it all means
and how you do it in detail.

And, no, I am not going to type in the 5 pages of text and pictures
for you.

--
Jim Pennino

Remove .spam.sux to reply.

[Bertie the Bunyip]

On Apr 15, 5:15 pm, Mxsmanic > wrote:
> Am I correct in assuming that changes to mixture diminish with increasing
> altitude? That is, a mixture change is more important and larger when going
> from sea level to 5000 feet than when going from 10000 to 15000 feet?
> \\Why, you're computer consuming too much juice, wannabe boi?

Bertie

[Andrew Sarangan]

On Apr 15, 10:15 am, Mxsmanic > wrote:
> Am I correct in assuming that changes to mixture diminish with increasing
> altitude? That is, a mixture change is more important and larger when going
> from sea level to 5000 feet than when going from 10000 to 15000 feet?
>
> --
> Transpose mxsmanic and gmail to reach me by e-mail.

The pressure and density change exponentially with altitude. So in
theory you are correct that the changes in mixture would diminish with
altitude. However, pressure is almost linear up to about 20,000ft (ie
1" Hg per 1000ft) so one could consider the mixture to be linear at
these altitudes.

[Tom L.]

On Sun, 15 Apr 2007 16:15:40 +0200, Mxsmanic >
wrote:

>Am I correct in assuming that changes to mixture diminish with increasing
>altitude? That is, a mixture change is more important and larger when going
>from sea level to 5000 feet than when going from 10000 to 15000 feet?

Depends.

If you're talking about the amount of fuel needed for optimal mixture:

Density of dry air in standard atmosphere decreases almost linearly at
the altitudes you mention.
Normalized to density at sea level the numbers are:
S.L. 1.0
5000' 0.86
10000' 0.74
15000' 0.63
20000' 0.53

So the change from 0 to 5000 is marginally larger than 10k - 15k. They
both decrease about 15% *relatively* to the starting point.


But if you're talking about the amount of movement of the mixture
control, you may be right, at least for some aircraft.
182 that I fly requires about 1.5" of movement of the mixture lever
for SL to 5000' climb.
Climbing another 5000' to 10k requires much smaller adjustment.

This may be due to the way the control is implemented and may vary
between aircraft.

- Tom

[Judah]

Mxsmanic > wrote in
:

It depends on whether you lean to the right or lean to the left.

But rudder and aileron trim help.