Wow, that’s a hilarious stat. How is that even… possible?
The Piper Cherokee PA-28-140 weighs a petite 2150 pounds (max loaded weight) and burns 10 gallons an hour and would do about 115 KIAS, which translated to roughly 130 miles per hour ground speed, which is 13 miles per gallon.
It would do even better if you flew for efficiency, but since rental was by hours of engine time wet (I didn't pay for fuel and would be reimbursed for fuel purchased), there was really no reason to not throttle that baby up to full rental power.
The reason is to reduce pollution, but that's obviously no concern at all for most GA pilots and passengers.
There's nothing magical about flight. Take-off takes a bunch of energy. Maintaining that energy, not so much. Planes are pretty aerodynamic, imagine that :) Some are much lighter than cars since every pound counts. To the point that people often opt to not have AC (if it's even an option) to save a few pounds.
They will cover a lot of ground in the same amount of time. That helps even more.
Not all planes are that economical, of course. But some are indeed hilarious. Check ultralights (or microlights as they are known in Europe).
Yep, take-off and ascent burns a lot of fuel, much more for the time duration than cruising. It's too bad there isn't a way of recovering some of that energy when descending, similar to how electric cars recover energy when braking.
A descent is a pretty efficient conversion between potential energy (altitude) and kinetic energy (speed/horizontal distance) so you get it back. Your RPM difference between cruise and descent is a proxy for your recovered energy. An engine out glide/landing is the extreme demonstration of this.
But that's exactly what happens already. Point the aircraft down and it will pick up speed.
Nearer the airport, I’ll make a power reduction and continue to convert that potential energy to forward travel, eventually putting out gear and flaps.
There’s more than enough drag for any reasonable descent profile to allow the potential energy to be used to move forward without gathering excessive speed.
Power off, I can glide around 1.5 nautical mile for every 1000’ of elevation I have to use.
Additionally, planes tend to fly at constant and pretty high speed for most of their operation, while a car has a lot of acceleration and deceleration going on. Planes can also use wind thermals to change altitude (sail planes can only use that!) or can stay at the same altitude while a car driving below it is stuck with the geography (i.e. it has to follow and climb hills).
I never checked mpg while taxiing but the motor would be almost idle.
I said GALLONS PER HOUR. If you're taxiing for hours, you're doing it wrong.