Buck fifty range profile question

"Dallas" wrote in message
...

Am I reading this graph incorrectly?

http://img.photobucket.com/albums/v1...ofileChart.jpg

At the 45% power setting, the best range for a Cessna 150M would be
achieved by flying anywhere from sea level to a maximum of 1,800 feet?

At 75% power the gain is about 2.5 NM of range by flying at 7,000 feet vs.
1,000 feet.

This pretty much trashes my fundamental belief that higher altitudes give
greater range. What am I missing?



--
Dallas

If you stay at 45%, the climb to altitude takes a looooong time, and you are
moving slowly, so the range suffers.

I think most CAFE folks have figured out the best thing to do is climb at
max power, get to a high altitude quickly, then throttle back at the high
altitude to get the max fuel economy. YMMV.

Regards,
John Severyn
KLVK

On Jun 8, 1:43 pm, "J. Severyn" wrote:
"Dallas" wrote in message

...







Am I reading this graph incorrectly?

http://img.photobucket.com/albums/v1...RangeProfileCh...

At the 45% power setting, the best range for a Cessna 150M would be
achieved by flying anywhere from sea level to a maximum of 1,800 feet?

At 75% power the gain is about 2.5 NM of range by flying at 7,000 feet vs.
1,000 feet.

This pretty much trashes my fundamental belief that higher altitudes give
greater range. What am I missing?

--
Dallas

If you stay at 45%, the climb to altitude takes a looooong time, and you are
moving slowly, so the range suffers.

I think most CAFE folks have figured out the best thing to do is climb at
max power, get to a high altitude quickly, then throttle back at the high
altitude to get the max fuel economy. YMMV.

Regards,
John Severyn
KLVK- Hide quoted text -

- Show quoted text -

Climb time is not built into that chart because there is no assumption
about field elevation. It is simply a cruise performance chart *after*
you have climbed to altitude. The reduction in range comes from
reduced propeller efficiency at higher altitudes for the same output
power.

"Andrew Sarangan" wrote in message
oups.com...
On Jun 8, 1:43 pm, "J. Severyn" wrote:
"Dallas" wrote in message

...







Am I reading this graph incorrectly?

http://img.photobucket.com/albums/v1...RangeProfileCh...

At the 45% power setting, the best range for a Cessna 150M would be
achieved by flying anywhere from sea level to a maximum of 1,800 feet?

At 75% power the gain is about 2.5 NM of range by flying at 7,000 feet
vs.
1,000 feet.

This pretty much trashes my fundamental belief that higher altitudes
give
greater range. What am I missing?

--
Dallas

If you stay at 45%, the climb to altitude takes a looooong time, and you
are
moving slowly, so the range suffers.

I think most CAFE folks have figured out the best thing to do is climb at
max power, get to a high altitude quickly, then throttle back at the high
altitude to get the max fuel economy. YMMV.

Regards,
John Severyn
KLVK- Hide quoted text -

- Show quoted text -

Climb time is not built into that chart because there is no assumption
about field elevation. It is simply a cruise performance chart *after*
you have climbed to altitude. The reduction in range comes from
reduced propeller efficiency at higher altitudes for the same output
power.


Climb time is built into the referenced chart. Note on the referenced photo
of the page from the POH: "This chart allows for the fuel used for engine
start, taxi, takeoff and climb, and the distance during climb as shown in
Figure 5-6."

J. Severyn

On Jun 8, 2:09 pm, "J. Severyn" wrote:
"Andrew Sarangan" wrote in message

oups.com...



On Jun 8, 1:43 pm, "J. Severyn" wrote:
"Dallas" wrote in message

. ..

Am I reading this graph incorrectly?

http://img.photobucket.com/albums/v1...RangeProfileCh...

At the 45% power setting, the best range for a Cessna 150M would be
achieved by flying anywhere from sea level to a maximum of 1,800 feet?

At 75% power the gain is about 2.5 NM of range by flying at 7,000 feet
vs.
1,000 feet.

This pretty much trashes my fundamental belief that higher altitudes
give
greater range. What am I missing?

--
Dallas

If you stay at 45%, the climb to altitude takes a looooong time, and you
are
moving slowly, so the range suffers.

I think most CAFE folks have figured out the best thing to do is climb at
max power, get to a high altitude quickly, then throttle back at the high
altitude to get the max fuel economy. YMMV.

Regards,
John Severyn
KLVK- Hide quoted text -

- Show quoted text -

Climb time is not built into that chart because there is no assumption
about field elevation. It is simply a cruise performance chart *after*
you have climbed to altitude. The reduction in range comes from
reduced propeller efficiency at higher altitudes for the same output
power.

Climb time is built into the referenced chart. Note on the referenced photo
of the page from the POH: "This chart allows for the fuel used for engine
start, taxi, takeoff and climb, and the distance during climb as shown in
Figure 5-6."

J. Severyn- Hide quoted text -

- Show quoted text -

You are correct; I missed that part. Fig 5-6 shows climb performance
for climbing from sealevel to the designated altitude. So how does one
figure out the range when departing from a high elevation airport?