Questions tagged [ground-effect]

The increase in lift experienced by wings in close proximity to the ground.

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What is the indicated airspeed necessary to exit ground effect on takeoff?

I always thought that a plane needed to be at stall speed or greater to be able to exit ground effect on takeoff. However, after seeing the YouTube video in the link below I am not so sure. ...
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Could we use ground effect (over water) to increase an airliner's range? [duplicate]

Theoretically, would it be possible to increase the range of a modern jetliner in ground effect over the sea?
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Ground effect and Lift coefficient

Is there a correlation between the lift coefficient and the proximity between the wing and the ground? I know that the lift coefficient is dependent on angle of attack; However, based on experiments ...
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Can airspeed in ground effect be used to estimate climb performance?

A very interesting crash video (in which everyone survived) shows a Stinson which takes off but is unable to climb out of ground effect.[*] Watching the video, it ...
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Does a wing produce an appreciable amount of lift during the takeoff roll prior to rotation?

I was hoping for some insight on this, perhaps also from pilots who have used AOA indicators. This because I assume that an AOA indicator is the only means to get at least an idea of how much lift is ...
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Would it be practical that nuclear-powered seaplane (only flying low over the sea) or hovercraft can be an alternative to cargo plane or ship? [duplicate]

Would it be feasible that nuclear-powered seaplane (only flying very low over the sea) or nuclear-powered hovercraft can be an alternative to cargo planes or ships? The aircraft speed can reach 200 mi/...
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Is there ground effect flying below an infinite 2D plane as opposed to above one?

People talk about wing tip vortices and say things like the ground acts as an aerodynamic mirror. What (if any) difference would there be for a wing flying underneath a 2D plane? As in the picture ...
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Why is the critical angle of attack lower in ground effect?

Why is the stalling angle of attack lower in ground effect? Does ground effect more increase pressure on lower side of wing (cushion effect) or more decrease pressure on upper side, or both? So which ...
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What about a Plane-Train?

The Shanghai Maglev Train's max speed is 267 mph. Could a plane be made to follow a rail, surface area provided, if not an existing rail to travel along? How much faster could the heavily modified ...
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What happens when a "ground effect" plane approaches the sound barrier?

Does the shock wave inhibit or contribute to lift? What is the ideal speed to fly near or on the speed of sound while using the ground effect?
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Could a wing be designed to exploit both normal flying and ground effect?

Ground Effect planes' wings are stubby and the height over the ground or water is limited to wing span. Could a wing be designed to exploit both normal flying and ground effect together to give the ...
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Do aircraft obtain better milage by flying high or by using "ground effect?" [duplicate]

It has been said the most fuel efficient way to fly is by flying in thinner air. On the other hand the largest plane in the world was the Russian "Caspian Sea Monster" Ekranoplan, which is ...
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Why do the two different "ground effect"s used by aircraft and automobiles do opposite things in almost the same conditions?

I found How come the ground effect has such a different outcome for wings and cars? and: I am not allowed to comment as a new user because of some weird rule and I do not know enough to answer the ...
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What were the L/D ratio of the A-90 Orlyonok at its different operational atlitudes?

The A-90 Orlyonok was designed to operate in ground effect (altitude significantly lower than its wingspan). If I understand correctly, when in ground effect, the L/D ratio is better due to induced ...
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Is optimal landing flare related to ground effect?

Based on other questions it appears that a "flare" is always part of a healthy airplane landing. This question asked when a flare should be started, and I found it interesting that the accepted ...
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Could an airliner be as efficient lower and slower?

Could an airliner ever be as efficient at 15 or so meters using ground effect as it is at 50,000 km even if it has to go slower and be shaped differently?
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What are the limits of ground effect over water on an airliner plane at cruising speeds? [duplicate]

What height over a fixed plain (such as water) can a plane begin to take advantage of the ground effect or when air is compressed between the wing and ground near cruizing speed? Could an airliner ...
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Is an ekranoplan less efficient than a regular plane? [closed]

This are my conclusions upon researching the matter: Ground effect is the cushion of air that can not escape down because of the ground. The hovercraft creates that cushion using a skirt which ...
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How does the ground effect affects longitudinal stability?

I recently learned that the ground effect increases the effective AoA of the wing and thus increases lift, how does that translates in to the tail plane and it's stabilizing effects? does it reduce/...
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Can ekranoplans (GEV) be more efficient than traditional airliners?

Ekranoplans or Ground Effect Vehicles (GEV) fly low enough to the ground that their wings stay in the ground effect. This increases lift and efficiency. But GEV fly in the lower atmosphere (...
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Does ground effect scale 1:1 with wingpsan?

The rule I have been taught is that ground effect begins within 1 wingspan of the ground. What is the derivation of this measurement? Is it actually true, or just an urban-legend/rule-of-thumb style ...
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Why is ground effect greater over smooth hard surfaces?

Helicopter Flying Handbook: Ground effect is the increased efficiency of the rotor system caused by interference of the airflow when near the ground. The air pressure or density is increased, ...
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Are there any plans, designs, or prototypes for an electric ground effect vehicle?

I have been searching around for any plans, designs, or prototypes for a small GEV. All I have found is a ground effect gas powered like this link: or an all ...
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How do ground effect vehicles perform turns?

Considering that Wing-In-Ground-Effect (WIGE) vehicles fly with a rather low ground clearance, there is not much room for banking. How do WIGE vehicles turn? Do they turn just very slow with a low ...
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Would formation of the three planes benefit from increased distance of the ground effect?

I know that the ground effect quickly diminishes as altitude above the ground increases, and it is roughly half of the wing span. Hence it can be used to fly more economically over water, but over ...
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Would ground effect and FOD ingestion be factors at high speeds close to the ground?

How could flight 77 into the pentagon overcome the compression lift of the ground effect at 460 KIAS that close to the ground? Also wouldn't the engines ingest FOD at that power setting that close to ...
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Human-powered flight in vs. out of ground effect?

There is an impressive flight (figure-of-eight) with a human-powered aircraft shown here: Given the long wings of the Aerocycle 3, can it be considered to fly in ...
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Is flying in ground effect dangerous?

The stall angle of a wing in ground effect reduces in comparison to the stall angle of a wing flying outside of ground effect. Doesn't this make soft field takeoff dangerous?
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What are the airflow patterns of a helicopter when operating in ground effect?

When operating in the air cushion region of approximately 8 inches and below to the ground what pattern does the downward flow of air flow?
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What is the difference between ground effect for an infinite wing and for a finite wing?

A question about ground effect has just reappeared. I think one needs to differentiate between ground effect for a finite wing (3D flow) and ground effect for an infinite wing (2D flow). What are ...
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How to keep a helicopter steady when close to the ground?

I understand the ground effect and the air cushion of approximately 3-6 inches when the helicopter is close to the ground. With that in mind, my questions are: Why does the helicopter become ...
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Why did America not build its own ekranoplan?

The Lun-class ekranoplan (NATO name: "Duck") is a ground effect vehicle designed by Rostislav Evgenievich Alexeyev and used by the Soviet and Russian navies from 1987 until sometime in the ...
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Is it practical to use ground effect to extend range in an emergency?

Imagine a piston engine airplane (let's say a DC-3) flying at cruise speed and altitude over a calm sea, trying to reach an unreachable airstrip straight ahead, just above sea level. Fuel is very low ...
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How high does the ground effect last?

Up to which height is the ground effect still significant enough to be taken into account? Would this height be sufficient to actually fly above the ground, overcoming at least trivial obstacles like ...
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Were stub wings on early flying boats designed or able to exploit ground-effect lift?

I came across a link to the Dornier Do X, and the Boeing 314 Clipper in another question, both aircraft have similar short wings/floats low on the fuselage, described in one wikipedia article as "stub ...
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Can a low flying jet fighter lift water?

Can a low flying but super fast jet spray water from the surface of the ocean? I've seen this visual effect done many times in movies. It's often done to highlight supersonic speed just a few feet ...
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8 votes
3 answers
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When leaving ground effect, why is there a nose-up change in moment?

The Airplane Flight Handbook states: The aircraft leaving ground effect will Require an increase in AOA to maintain the same CL Experience an increase in induced drag and thrust required ...
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Can we borrow Formula One's ground effect for airplanes?

(Source) Inspired by the now banned late 70's F1 ground effect, I wondered if it can be adopted by airplanes. So, I came up with this: (Own work) The system A belly door that opens at slow speeds ...
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5 votes
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948 views

How much effect does the ground have on flight control when flying low?

In this awesome video, shot at the "Mach Loop" in Wales, F-15Cs fly down the valley, then cross a ridge very low to the ground. While it's difficult to tell from the video just how low they really are,...
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Why are almost all STOL aircraft high-wing?

Isn't ground effect a big factor in STOL operations? Don't low wings produce greater ground effect than high wings? Or is it a practical concern, that most real-world STOL operations are in ...
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What is the effect of uneven ground on ground effect vehicles?

I understand ground effect as far as Wikipedia explains it. There are two ways to ask my question; A ground effect vehicle flies along and encounters an obstacle (say a big wave) that's maybe about ...
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Why the ground effect has such a different outcome for wings and cars?

I have some confusion concerning the ground effect. If we take two applications: Aircraft and Cars, they seem to have completely opposite effects. Aircraft From Ground effect (aerodynamics), we can ...
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Why is there a plateau in helicopter H/V diagrams?

The "dead-man's curve" in a typical helicopter height/velocity (H/V) diagram is commonly referenced to indicate that "towering flight" is dangerous and avoided in general practice. (Simon explained, "...
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33 votes
2 answers
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Why don't helicopters always takeoff from a hover out of ground-effect?

I've read enough crash reports to see that helicopters discovering too late in takeoff that they lack the power to fly out of ground-effect is a serious problem. I am wondering why the following isn'...
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28 votes
10 answers
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What is ground effect?

We've all heard the "acts like a cushion of air" explanation tossed casually around by CFIs. There's also plenty of books and reference materials that give a detailed, accurate, and complete ...
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