n5lp
fugio ergo sum
Our speedy, high performance airplanes give us capabilities that we don't always use. Sometimes we pick a favorite cross-country altitude without really thinking about it.
I wanted to have lunch in Brenham, Texas, yesterday (4/19/09), for Louise House's birthday. That leg is 424 nautical miles and there was a real good tailwind, increasing with altitude. In this situation, a lot of people would choose to go high, an option we have. I did so, and averaged 185 knots (212 MPH) block to block with a really low fuel burn. That was a really quick and easy leg.
This is the first significant water I have seen in a loong time. Probably more water in this picture than my whole county has received this year.
When I was ready to return home, it was from an airport 500 nautical miles from home, with at least a 30 knot headwind that didn't decrease too much with altitude. There were now decisions to be made. At times I have actually been able to get tailwinds both ways by using radically different altitudes but that wasn't going to work today, and with the wind it wasn't certain I could make it home without a fuel stop.
With a turboprop or turbocharged airplane it is often worth it to go ahead and climb up high. The TAS increases enough to maybe make it worth it anyway. With a normally aspirated piston engine it is normally better to stay as low as possible with a strong headwind, because the wind is almost always less at lower altitudes. So for getting home quickest I should fly low at a high power setting to get a real good speed? No, because the increased fuel burn at low altitude and high power setting would mean I would have to stop for fuel and that takes a really long time.
My decision for this trip was to fly at about 1,000 AGL and power way back. When you do this, you shouldn't look at the GS on the GPS. It is too depressing to see 130 to 135 knots, but it can work out.
The drawbacks are the low speed and bumping around in low level turbulence; the upsides are you get home faster, in this case, and you get a much different and interesting view of the scenery.
If you live on the Edwards Plateau, there is a high likelihood you have a sinkhole in your yard.
I had never had a close look at the Texas Hill Country before and it was fascinating to see all the flooding, hundreds of game ranches and thousands of sink holes. On this day it seemed that much of central Texas was either under water or on fire. You also get a great geography lesson as the trees and green suddenly disappear and sand and creosote appear.
Who knew there were rock hills like this in central Texas?
This trip worked out just right. The lower fuel consumption allowed me to make it home with about 8 gallons left, which is right around my minimum. If I had flown faster I would have had to stop and the trip would have taken much longer.
Aaah, now this is more like it. I'm starting to feel more at home without all that water and humidity
My average speed coming home was still about 139 knots (160 MPH) as the headwind abated near my destination. That may not sound all that slow to folks that aren't privileged to fly such flexible airplanes.
Another drawback of flying low into a headwind is that you have fewer landing options in case of a problem. This is a real trade off, but I felt much safer, even in the hill country, at this altitude, than I did bumping around at low level over flooded country and around 2,000 foot towers, under the Class B at Houston.
I wanted to have lunch in Brenham, Texas, yesterday (4/19/09), for Louise House's birthday. That leg is 424 nautical miles and there was a real good tailwind, increasing with altitude. In this situation, a lot of people would choose to go high, an option we have. I did so, and averaged 185 knots (212 MPH) block to block with a really low fuel burn. That was a really quick and easy leg.
This is the first significant water I have seen in a loong time. Probably more water in this picture than my whole county has received this year.
When I was ready to return home, it was from an airport 500 nautical miles from home, with at least a 30 knot headwind that didn't decrease too much with altitude. There were now decisions to be made. At times I have actually been able to get tailwinds both ways by using radically different altitudes but that wasn't going to work today, and with the wind it wasn't certain I could make it home without a fuel stop.
Leaving Polly Ranch to refuel (Louise Hose photo)
With a turboprop or turbocharged airplane it is often worth it to go ahead and climb up high. The TAS increases enough to maybe make it worth it anyway. With a normally aspirated piston engine it is normally better to stay as low as possible with a strong headwind, because the wind is almost always less at lower altitudes. So for getting home quickest I should fly low at a high power setting to get a real good speed? No, because the increased fuel burn at low altitude and high power setting would mean I would have to stop for fuel and that takes a really long time.
My decision for this trip was to fly at about 1,000 AGL and power way back. When you do this, you shouldn't look at the GS on the GPS. It is too depressing to see 130 to 135 knots, but it can work out.
The drawbacks are the low speed and bumping around in low level turbulence; the upsides are you get home faster, in this case, and you get a much different and interesting view of the scenery.
If you live on the Edwards Plateau, there is a high likelihood you have a sinkhole in your yard.
I had never had a close look at the Texas Hill Country before and it was fascinating to see all the flooding, hundreds of game ranches and thousands of sink holes. On this day it seemed that much of central Texas was either under water or on fire. You also get a great geography lesson as the trees and green suddenly disappear and sand and creosote appear.
Who knew there were rock hills like this in central Texas?
This trip worked out just right. The lower fuel consumption allowed me to make it home with about 8 gallons left, which is right around my minimum. If I had flown faster I would have had to stop and the trip would have taken much longer.
Aaah, now this is more like it. I'm starting to feel more at home without all that water and humidity
My average speed coming home was still about 139 knots (160 MPH) as the headwind abated near my destination. That may not sound all that slow to folks that aren't privileged to fly such flexible airplanes.
Another drawback of flying low into a headwind is that you have fewer landing options in case of a problem. This is a real trade off, but I felt much safer, even in the hill country, at this altitude, than I did bumping around at low level over flooded country and around 2,000 foot towers, under the Class B at Houston.
