Specifically emphasizing fuel flow (Gallons per hour in aircraft, miles per gallon in automobiles) & comparing, obviously, piston engines producing 100-300Hp.
2006-12-29 05:19:48 · 7 answers · asked by Protowing 2 in Cars & Transportation ➔ Aircraft
You're kind of comparing apples and oranges. Maybe you should think along the lines of power to weight ratio. Say the engine in a mid size car weighs 400 lb and produces 250 horsepower. The GE T700 turboshaft used in helicopters ( Apache, Blackhawk, and others), M-1 tanks, and some turboprop planes, weighs about 450 lbs and produces around 1700 hp at sea level.
On jets, you have a turbofan engine. The GE90 on the 777 is about 134" across, weighs 16,000 lbs, produces 93,000 lbs of thrust. One variant holds a record for around 120,000 lbs of thrust. A loaded 777, different versions have different weights and engines, is around 550,000 lbs. And a light 777 can accellerate to 60 mph faster than many cars. I don't think you can compare fuel economy between cars and planes. Too big of a difference
2007-01-01 02:05:05 · answer #1 · answered by JET_DOC 2 · 0⤊ 0⤋
You need to compare the gph to miles traveled to get the fuel mileage. You will discover that many private light aircraft get comparable mileage. For example: the Cessna 152 is listed in the POH as burning 6 gph. I flight plan for 100 kts which in 2 hours I would travel 230 miles on 12 gallons of fuel in a no wind situation. That is 19.1 mpg.
The particular aircraft I flew had a different propeller and only burned 4.5 gph.
2006-12-29 07:05:40 · answer #2 · answered by eferrell01 7 · 1⤊ 0⤋
They are very old designs (most from the 1940s and 1950) and cannot spin faster than 2700RPM without a heavy and unreliable reduction gear box. Also propeller efficiency is about 66%.
That being said: a Cherokee Six 260 can go cross-country at 150MPH burning 12 gallons per hour for 12.5 miles per gallon.
Tell me a car that can carry six people and baggage that can go as fast while burning less fuel.
2006-12-29 16:25:57 · answer #3 · answered by Anonymous · 0⤊ 0⤋
I don't believe the engines are less effecient but rather the transfer of power to motion is.
You can calculate distance traveled from knowing the cars gear ration and tire size. Your tires on the road don't slip.
You can't in a boat or in an airplain because you are pushing water or air. The prop will not always move the same amount forward for a given number of revolutions. It "slips" in the air and water.
Airplane engines may also be slightly less efficient because of different air pressure up there but I don't think that's the biggest problem.
2006-12-29 05:36:49 · answer #4 · answered by tom 2 · 0⤊ 1⤋
the transfer of energy from engine to motion is less efficient. in a car: engine through gear train through tires in direct connection to the road. in an aircraft the power is transfered to the air and some of the energy is absorbed by the air because the air gives way to the prop or the pressure from the jet or rocket.
2006-12-31 14:52:33 · answer #5 · answered by oreos40 4 · 0⤊ 0⤋
They are not less efficient, aircraft engines are working more than 12hrs per day non stop while car engines are not. Aircraft engines are also maintained and serviced to a much higher standard
2006-12-30 21:51:14 · answer #6 · answered by frigatewren 2 · 0⤊ 0⤋
They probably are. Most aircraft engines are larger and heavier per horsepower than a car. They are also simpler. Aircraft engines are designed with reliability in mind. You don't want the engine to fail while in flight!
2006-12-29 05:45:48 · answer #7 · answered by William S 3 · 0⤊ 0⤋