On Apr 3, 12:07 pm, Dave Doe wrote:
In article ,
says...

chris writes:

That's a rather negative way to look at it!!!

Better safe than sorry, I say.

In a few days I will be
flying for 2 1/2 hours on a cross country. I will have 4 1/2 hours
fuel. That doesn't sound reckless to me!!!

If you really have the fuel you think you have, and if you really consume it
as slowly as you think you do, perhaps not.

Say 32 litres and hour, plus or minus a few - ain't gonna make much
difference.

Or to rephrase, how can a 32l/hr plane consume say twice that?

We know you're not a real pilot - well let me tell you that in the real
world, the rated value is used, *and checked* over time. And adjusted
as necessary.

I've flown a number of Cessnas and Pipers from different organisations
and they've all consumed the amount the manual tells me +/- sweet FA.

--
Duncan

Same here... I fly a variety of aircraft, all with 180hp engines, and
we flight plan for 40l/hr. And although there is no way to be 100%
positive without a fuel flow gauge, whenever I have checked the amount
of fuel in the tank when I've come back and it's usually got the right
amount of fuel in it. Sometimes it's got more fuel left if we were
crusing around at a lower power setting...


I missed the post you replied too but I want to tell him that I *will*
have 4 1/2 hr fuel on board because that's how much it takes when the
tanks are full. We know at 75% it burns 40L / hr, and I know what 75%
is because it's marked on the tacho!!! For those who don't know,
that's why 172s have marks on the tacho with SL, 5 and 10. That's the
RPM for 75% at those altitudes.

Or so I am led to believe...