"Stealth Pilot" wrote in message
...
ok my last post on this.

You should've stopped a long time ago.

I had a think about your thought of different cooling drag being the
reason for the identical fuel burns at the different airspeeds.

I never made any comment about cooling drag.

If you ever get to fly a Tailwind take up the offer. You will experience
an
aircraft with a significantly increased induced drag influence
compared to the higher aspect ratio Cessnas/commercial stuff that you
seem to be basing your comments on.

You are talking gibberish.

It seems to me that induced drag
builds up quicker in the Tailwind at slower speeds than in the
commercial offerings.

"builds up quicker...at slower speeds"? What is that supposed to mean?

It is true that there is more induced drag at slower speeds, for any
aircraft. It is also true that the exact amount of induced drag will vary
from airplane to airplane, and indeed even from weight to weight for the
same aircraft. But the nature of the curves for induced drag and parasitic
drag are always the same, and they always result in a single L/Dmax
airspeed.

FOR ANY AIRPLANE.

I will warn you that you are in for a surprise which may cost you the
aircraft in the right (wrong) conditions.

Doubtful.

This was covered ad nauseum in my commercial pilot studies under
aircraft performance.

Something was covered. You should have paid better attention when it was.

I'll give a brief reiteration here.
If you have a look at the Cessna POH for the 150M you will find your
range profile graph on page 5-15. what you indicate is correct - for
the conditions that the graph was made for, which is for zero wind
conditions.

Yes. So?

two pages over you will find a more useful graph which just gives just
endurance. you use this for calculating range in the more usual
condition of having a wind component.

Endurance and range are two completely different things. You cannot depend
on endurance numbers to provide range numbers, unless you also take into
account the differences in airspeed. Best endurance will NOT be the same
airspeed as best range.

CPL theory (and demonstrated calcs) says that for a tailwind or no
wind you fly slower to increase range.

for a headwind you fly faster!

I'll leave it for you to work out why.

Do you have a point? I said several posts ago this exact thing. Sounds to
me like you're just making my point for me. Or maybe you're just copying my
posts, trying to make it look like you have an original thought. I'm not
really sure which.

However, it also appears that you are misunderstanding the general truth
regarding how to deal with tailwinds and headwinds. For a given no-wind
power setting, it is true that you should fly faster (and with more power)
in a headwind and slower (and with less power) in a tailwind to compensate.
However, you will not achieve the same range as in no-wind conditions.

In a headwind in particular, your best range airspeed most likely will still
be less than the normal cruise airspeed. It all depends on the headwind,
but for typical, light headwinds the change due to wind does not overwhelm
the need to fly closer to the L/Dmax airspeed. Even in a headwind, best
range airspeed is usually found below normal cruise.

It is simply not true that even in a headwind, one needs to fly faster than
normal cruise to achieve best range, nor would that be relevant at all to
this discussion even if it were.

Pete