Why is a 777 so high off the ground?

Question

like when taxiing, the distance from the wheels to the body is really high

Answer 1

It has to do with the 777's length. Boeing designed the body to be high off the ground to accomodate for stretched versions. The 777-300/300ER is one of the longest airliners in the world. If the body weren't high enough, the tail might scrape the runway when the aircraft rotates.

The height of the landing gear was one of the reasons the 747 was built. During the late 60s, the new jets had increased demand for air travel. As a result, Boeing decided to build larger jets. However, the 707, unlike the DC-8, couldn't be stretched because its landing gear was too short. Therefore, Boeing came up with an entirely new aircraft family--the 747.

Answer 2

Both Lithoprint and Alexander Yu are correct. If the engine were too close to the ground, it would suck up sand, gravel, and other debris which would damage the compressor blades. Height above ground gives tail and WING TIP clearance on landing. Modern airliners have swept back wings and in a nose high landing configuration, the tips are pretty darn close to the ground. When landing in a cross wind it adds a little more margin for error.
Most jet liners have a tail skid for when they do drag the tail, which is NOT often. In the DC-8, they had a crushable cartridge. When the skid hit the ground, mechanics would remove the cartridge and measure it. If it was longer than a certain dimension, they just replaced the cartridge and went on. But if the cartridge was crushed to a small enough dimension, it required further inspection for damage. I saw a B-757 that a stupid pilot had hit the tail so hard that it was a major structural repair job to make the plane airworthy again. Of course, the pilot claimed that it was on auto land and the autopilot did it. No problem was ever found with the autopilot, he was just lying to protect his job.

Answer 3

Two fold: First, the engines for this plane are massive, larger than a bus. If you were to keep that engine very close to the ground, it would choke because it cannot get air to feed the engine. When it is taking off, this is critical as the engines need the most power at this time. More air=more power. By installing the engine high, it is easier to suck air out of the atmosphere to power the engine.

Also, it is to keep a proper clearance from the ground for FOD purposes. Consider, 747's have four engines with which to operate meaning if you were to pick up some foreign object damage that totaled one of your engines, you're good. However, 777's have only two engines meaning they are more critical. The higher the plane is from the ground, the "safer" the two engines are from foreign object damage.

Answer 4

the 777 is one of the longest airliners in the world, so higher ground clearance makes higher approach and departure angles to further reduce the risk of a tail strike, and plus look at those GE90-115B engines, Have you seen those monsters, They are wider than a 737, and hang lower so those need to be protected from striking the ground too, as they are 3.4 million dollars, plus if the 777 was lower then runways whould litterally crumble because of the thrust causing erosion, as for 777 engines have 115,000 lbs of thrust each. plus since the 777 is a heavy plane it needs higher ground clearances to be less susceptible of ravages caused by poorly paved runways. One othermain reason for the high departure angles from the high ground clearance is since the plane is very heavy, it needs a greater wing area and greater wing areas mean higher angles of attack, so this higher ground clearance will decrease the risk of a tail strike.

Answer 5

From 747s onwards, the wheels of the other boeings are made to be further away from the body for two reasons:
1. To prevent tail scrape as the body of the aircraft is very long ;
2. To make sure the engines do not scrape the ground during landing. Engines this days are huge.

Answer 6

I agree. Primary reasons are tail drag on stretch versions and FOD clearance for the engines. It's easier to imagine the scale of the 777's hieght when you consider that the fuselage of a 737 will physicall fit inside the engine intake on the 777!

Answer 7

The landing gear are so long because the 777 is a very heavy aircraft so when it lands there is a lot of force pushing down on the gear units so they need larger shocks and when not compressed the plane is high off the ground

Answer 8

To keep the engines far enough from the ground. The engines in 777 are really huge.

Answer 9

the higher they fly, the better fuel efficiency. also a 777 flying at low altitudes for the duration of fly, would be very hazordous to general aviation and small prop planes. 777 fly at around 350 - 400 knots. while a small prop plane can usually reach 200 knots at cruising speed.

Answer 10

The main reason why the Triple 7 is so high off the ground, is to accommodate the massive engines.