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55 votes

Can all helicopters hover, and how long does it take to "stop"?

As noted in another answer, all helicopters can hover, but a so-called "high hover" (out of ground effect or especially at operational altitude) is a more difficult maneuver, requiring more power than ...
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  • 14.6k
48 votes

What is it exactly about flying a Flyboard across the English channel that made Zapata's thighs burn?

He's using the angle of his legs to control the attitude of the platform (and as a result, the direction he's flying in). So he can't take a relaxed pose, he's standing with his knees slightly bent ...
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  • 10.1k
41 votes
Accepted

What is it exactly about flying a Flyboard across the English channel that made Zapata's thighs burn?

This is what he said after the 1st attempt "When you fly with your body, even your hands affect the direction you want to go in. You feel the turbulence and the air through your fingers," Zapata ...
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  • 8,699
32 votes

Can all helicopters hover, and how long does it take to "stop"?

Yes all helicopters can hover, but it requires: More concentration to hover than to fly, because helicopters are unstable in the hover in pitch and roll. Forward airspeed provides stability and ...
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  • 58.8k
24 votes

What is it exactly about flying a Flyboard across the English channel that made Zapata's thighs burn?

There is another bit of information worth mentioning in the CNN link in CrossRoads' answer The flyboard looks like a chunky skateboard and is powered by five small engines. It is fueled by ...
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  • 909
11 votes

Can all helicopters hover, and how long does it take to "stop"?

When navigating WX in a helicopter, it is often less workload to fly orbits. It gives additional perspective and permits easy lateral movement during the course of the orbit. It also reduces ...
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  • 17.4k
10 votes
Accepted

Can a F-35 shoot while hovering?

No, it cannot, at least there is no reason for it to do so... A) The stick while in "hover mode" does not control the pitch/roll of the aircraft, but the forward/lateral position of the aircraft. ...
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  • 35.2k
10 votes

Why would a helicopter hold a 'nose-up' in hover?

1) The 60 has a natural nose up, left wing down hover attitude. I want to say 3, and 1.5 degrees, but I'm going off memory. Given the angle of the shot, I would venture to say that it's more optical ...
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  • 101
10 votes

Does the ARCA hoverboard violate known limits on small-diameter electric fans?

The key is that the Arca board only works in ground effect. Therefore, the pressure difference over the area of the board is the key for calculating its power needs. From the video I would estimate ...
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8 votes
Accepted

Should helicopters fly when they the lack power for vertical climb out of ground effect?

Up to a certain speed, which will be in the POH, the greatest power requirement is when hovering out of ground effect. Next is hovering in ground effect and power required in forward flight is the ...
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  • 30.9k
7 votes

Why does a hovercraft lift blade look one way, but a propeller another?

Because lift propellors need to provide static pressure to inflate the airbag and hover. This means more fan blades to stop backflow. The thrust propellors need to provide force which is a ...
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7 votes
Accepted

Why is tethered hover testing performed on helicopters?

The cable is attached to the helicopter with a tensionometer. This can be used to vary the effective weight of the helicopter by varying the tension applied to the cable. The cable length can also ...
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  • 30.9k
7 votes

Can all helicopters hover, and how long does it take to "stop"?

When a helicopter hovers, it's basically is sitting in its own wash. By pushing air down, it creates a low pressure region above itself, and a high pressure area below it. To stay hovering, it has to ...
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6 votes

Can all helicopters hover, and how long does it take to "stop"?

Question 1: No, an S-76 can hover, but it's more energy intensive than economy cruise. It made more sense to circle and hold in an area as opposed to hovering. In addition, hovering at altitude can be ...
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6 votes

Why is ground effect greater over smooth hard surfaces?

From a conservation of energy perspective, the rotor is transferring energy to the air, which then moves down and is deflected by the ground. A soft or drag-inducing surface will absorb more of that ...
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  • 2,159
6 votes

Why does the Zapata Flyboard Air UL consume so much more fuel/hr than the Mosquito Air?

It's the difference between jet engines and propellers. It is a lot more efficient to accelerate more air to a low velocity, than it is to accelerate less air to a higher velocity. For fixed wings, ...
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  • 58.8k
5 votes
Accepted

Can the V-22 carryout vertical takeoffs with shorter blades?

The rotor size helicopter (or a tiltrotor, in this case) is determined by its aerodynamic requirements, most importantly, its hover characteristics. The main constraint is the weight that has to be ...
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  • 98.7k
5 votes

Why does a hovercraft lift blade look one way, but a propeller another?

There are two parts to this: number of blades and squared off tips. 1. Number of blades. A propeller blade is actually just a wing. This is true regardless of weather you are talking about a piston ...
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  • 2,376
4 votes

Can all helicopters hover, and how long does it take to "stop"?

Not all can hover indefinitely. A fully loaded Soviet era MI-24 Hind attack helicopter could only hover for 15-20 seconds, before the engines are damaged from the overload. US intelligence agencies ...
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  • 8,577
4 votes
Accepted

How does the Bell V-280 (a tiltrotor) rotate, bank, and fly sideways?

The yaw would be accomplished by angling one rotor a little forward, and the other a little backwards. The shifting move to the side is accomplished by generating more thrust on one side. Either by ...
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  • 1,017
3 votes

Can all helicopters hover, and how long does it take to "stop"?

As many of the other commenters here mentioned, it is much easier and lower work load for the pilot to fly forward than hover. It also takes more power from the engine to hover than it does to fly ...
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  • 611
3 votes

Why does the Zapata Flyboard Air UL consume so much more fuel/hr than the Mosquito Air?

First, let's compare apples to apples, and compare the Flyboard to the Mosquito XET, the gas turbine powered version. The Mosquito XET with it's 90hp Solar turboshaft engine consumes around 8.5 gph, ...
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  • 8,577
2 votes

Does the ARCA hoverboard violate known limits on small-diameter electric fans?

Does the ARCA hoverboard violate known limits on small-diameter electric fans? 1) The max theoretical static thrust that can be obtained with an Electric Ducted Fan characterized by: Diameter = 120 ...
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2 votes

Would this hovercraft be stable?

Yes - it can work. Colin Furze (UK inventor & TV personality) built an essentially similar device. Skip to about 1:40 to see some of the problems he had.
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1 vote

Is it hard to hover a coaxial rotor helicopter?

The difficulty in hovering a helicopter lies in the fact that hover is unstable. Any tiny divergence will increase over time, so you have to keep adjusting the controls all the time. And this does not ...
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  • 54.2k
1 vote

Can all helicopters hover, and how long does it take to "stop"?

All helicopters can hover. That's the key advantage of that type of aircraft over the autogyro. Almost all rotating-wing aircraft are today helicopters, with only a relatively small number of ...
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  • 10.4k
1 vote

Why is ground effect greater over smooth hard surfaces?

I think it's based mostly on perception of altitude above ground level. If you're hovering over trees, or over a rough sea, what you care about first and foremost is your clearance from the tops of ...
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