How Long Can A Helicopter Hover? First off, if you want to learn how to hover a helicopter, you’re going to have to overcome your urge to commit pilot induced oscillation, which basically means constantly freaking out and over-controlling the vehicle to make the whole thing wobble. You actually have to be super chill to drive a helicopter – slow, delicate movements keep the whole thing stablised. In the video above, you’ll see the helicopter pilots are barely moving a muscle while they fly. So how long can a helicopter stay in the air?
The secret to flying a helicopter, and then figuring out how to keep one hovering in the one spot, is understanding how a bunch of different controls interact with each other. It’s the same concept as those crazy kids who know how to solve a Rubik’s cube in a few seconds flat – they just look at it, and something in their brains just clicks and they know how to solve it, they just have to get their fingers to move quick enough.
“If you think about it, every time you change something on a Rubik’s cube, multiple inputs are changing all over the thing. It’s a whole system,” says Destin. “That’s the way helicopters work – you have to come up with the most efficient and effective solution instantly to arrive at that perfect solution right off the bat.”
how long can a helicopter stay in the air
The first part of understanding how to drive a helicopter is knowing what the three main controls do. You’ve got collective, which is the power you’re applying to the rotor blades; pedals, which help to balance out the torque on the body of the aircraft; and cyclic, which is able to move the rotors independently of each other for more control. Each of these plays a crucial role in how a helicopter can be maneuvred through all the competing airflows around the craft.
Let’s get started
how long can a helicopter hover
The defining characteristic of a helicopter is its ability to hover at any point during a flight. To achieve hovering, a pilot must maintain the aircraft in nearly motionless flight over a reference point at a constant altitude and on a heading (the direction that the front of the helicopter is pointing). This may sound easy, but it requires tremendous experience and skill.
Before we tackle the technique of hovering, let’s take a moment to discuss nap-of-the-earth (NOE) flight, another unique characteristic of helicopters. NOE flight describes a helicopter located just above the ground or any obstacles on the ground. Military pilots perfected the technique during Vietnam as a means to become more elusive to ground-based weapons. In fact, film footage from the era often shows helicopters rapidly skimming the Earth’s surface, machine-gunners firing from open rear doors or hovering with their skids just a few feet off the ground as troops disembark at a target location.
Of course, any helicopter taking off or landing must undertake NOE flight, if only for a few moments. It’s a particularly critical time for a helicopter because a wild attitude adjustment could tip the craft too far and bring the rotor blades in contact with an obstacle. Attitude, for our purposes, refers to the helicopter’s orientation in relation to the helicopter’s direction of motion. You’ll also hear flight-minded folks talk about attitude in reference to an axis, such as the horizon.
With that said, here’s the basic technique to bring a helicopter into a hovering position:
- First, the pilot must cease any directional flying. For example, if flying the helicopter forward, the pilot must ease back on the cyclic until the helicopter’s forward motion stops and the aircraft remains motionless over a point on the ground.
- Next, it’s important that the pilot can detect small changes in the aircraft’s altitude or attitude. He or she accomplishes this by locating a fixed point outside the cockpit and tracking how the helicopter moves relative to that point.
- Finally, the pilot adjusts the collective to maintain a fixed altitude and adjusts the foot pedals to maintain the direction that the helicopter is pointing.
To maintain a stabilized hover, the pilot must make small, smooth, coordinated corrections on all of the controls. In fact, one of the most common errors of novice pilots is to overcompensate while trying to hover. For example, if the helicopter begins to move rearward, the pilot must be careful not to apply too much forward pressure on the cyclic because the aircraft will not just come to a stop but will start drifting forward.
Over the years, innovations in helicopter design have made the machines safer, more reliable and easier to control. The next page presents a few of these innovations to provide a glimpse of how far helicopters have come and where they might go in the future.
If a helicopter hovers in a fixed position for 24 hours will the earth rotate around it?
Perhaps you’re familiar with the idea of inertia: an object in motion tends to stay in motion (unless acted upon by a net external force). In a way, we can also refer to this idea as conservation of momentum. That idea’s going to play a big part in answering your question. When the helicopter starts out, it’s sitting on the ground and the ground (being part of the Earth) is rotating at one revolution per day, as we know. Since the helicopter is also sitting on the ground, it’s also inside this moving reference frame, and has the momentum that goes with it so the helicopter is also moving at one revolution per day.
In fact, so is the air! Now, when the helicopter takes off, it flies straight up to some height above the Earth’s surface. But though the helicopter has exerted a force (through the use of its rotors) to lift it straight up, it hasn’t exerted a force in the horizontal direction to counter the motion (momentum) it already had that one revolution per minute! So though the helicopter is no longer touching the ground, unless the pilot purposely exerts a force against the helicopter’s initial momentum, the helicopter will continue to move at one revolution per day, and thus remain above the same spot on the Earth’s surface from where it took off. The momentum that the helicopter started with is the same as what it ends with that’s conservation of momentum! The same is true on a smaller scale when you jump in the air if you jump straight up, you’ll land exactly where you started, because in every other direction (except up and down), your momentum is the same (try it out the next time you’re on a plane: the plane acts like a miniature version of the Earth, and when you jump, you land right where you were, even though the plane’s going 500 miles an hour!). On a larger scale, rocket scientists have to account for the motion of the Earth before they launch a satellite. In order to put the satellite into a specific orbit, they can’t just shoot it straight up from the Earth’s surface. They have to apply horizontal forces as well, in order to counter the Earth’s rotation and get the satellite into the correct orbit.
Density Altitude Effects on Military Operations
The capability of helicopters to operate and hover diminishes as the operating altitude increases. This thinning of the air is known as density altitude. At higher altitudes, thin air reduces engine performance known as torque as well as the ability of the rotor blades to grab air and fly or hover.
Density altitude restricts the payload of the helicopter, causing a trade-off between usable payload and fuel. Atmospheric temperature also contributes to the effects of density altitude. Warmer or hot air, especially in the summer, can drastically reduce the payload and capability of helicopters operating at higher altitudes.
Hover-out of ground effect (HOGE) This is the absolute limit of the helicopter’s ability to hover. Factors that contribute to this limit are density altitude, atmospheric temperature, available engine torque, and payload.
Hover-in-ground-effect (HIGE) Helicopters are able to hover anywhere from 5-80 feet above high mountain peaks because of the interaction between the ground and the helicopter’s rotor blades. This means a helicopter can hover within a few feet of a mountain top but if it were to try to hover in mid air, it would not have sufficient lift.
Most helicopters hover within “ground effect”. This is defined as a height above ground equivalent to the rotor diameter, that is, if the span of the tip of one rotor to the other is 100 feet, then the helicopter is capable of hovering in ground effect up to 100 feet. The importance of ground effect is that up to that limit, the air is physically compressed beneath the helicopter, between the helicopter and the ground, and a cushion of the air is created. At altitudes above ground in excess of one rotor diameter the ground effect is lost, with the result is that much more power must be provided by the rotors and more fuel burned as the cushion dissipates, forcing the helicopter to hover, by brute force. This also means there is an altitude limit to hovering, even with ground effect.
The highest helicopter hovering capability, under the most unusual circumstances, has been at altitudes of approximately 15,000 to 18,000 feet. Translational flight, or normal forward flight without hovering, is limited to about 30,000 feet, but rarely do helicopters operate at such altitudes.
In addition, during hover flight, at low altitude, a visual obscuration may occur when flying over ground material that can be blown up into the rotors. This causes a “white out” with snow, or a “brown out” with dust and sand. The result is that the helicopter is engulfed in the cloud of a suspended particulate material and the pilot will lose outside reference and horizon cues. Most helicopters are equipped with radar altimeters that permit them to determine their above-ground height, even at one or two feet above ground level, as well as transitional motion. It is important to avoid sideways motion while landing, as a phenomenon known as dynamic roll over may occur: When drifting sideways, sometimes due to a cross wind, a helicopter may touch down with a wheel while moving sideways. This torque will cause the entire helicopter to rotate around its longitudinal axis until the rotor strikes the ground, and the vehicle rolls up in a ball. Maintaining height above ground and ground position is extremely important and crew coordination can help prevent this, particularly when flying over poor reference surfaces, such as water.
How to Buy a Private Helicopter: 5 Things You Need to Know When You Are Buying a Private Helicopter
There are many benefits of owning a helicopter, including getting to work on time when living 100 miles (ca. 161 km) away from your office. The main advantage of owning a helicopter is freedom. Once you have permission and some space, you can set your course for any destination.
A private owner in the United Kingdom can fly to Devon and back to London without stopping to refuel. A pub in Oxford, the Manson’s Arms, has a helipad. The photographs of helicopters that visit adorn the walls of the pub. It is a thrilling and bizarre place to visit.
Modern helicopters have engines that are quieter and more efficient with advanced glass cockpits that offer fewer distractions for pilots. Airbus Helicopters’ Ed Sale responded to GQ at the Elite London event giving insight into what to consider when buying a private helicopter.
1. Will You Be the Pilot or the Passenger?
The majority of helicopter owners are pilots so they can fly themselves. Private pilots and those who own a helicopter and fly themselves prefer hands-on, less bulky designs.
Bigger helicopters are usually reserved for professional pilots while the owners sit in the back. The big shots use this as their executive means of transport. Midrange helicopters have administrative abilities too but are fun to handle.
The bigger the aircraft, the more experience a pilot requires. A well-trained amateur can fly any of the Robinson chopper models. The same applies to the B3 and B4 Eurocopter Ecureuil, AgustaWestland Koala and Bell 407. If you are looking at bigger models, like the AgustaWestland A109 with more sophisticated instrumentation, you will need a professional pilot.
If planning to become a pilot, next choose a flying school. Lots of flying schools will issue Private Pilot Licenses PPLs(H). Ask friends with helicopters to recommend a good flying school.
It helps if the flying school is local to you as you need a minimum of 45 hours of training over 12 months. Training costs vary from school to school but expect it to cost around $26,200 (around £20,000). This covers your tests, exams, flying hours, medicals, equipment, and airfield fees.
Training at Heli Air, one of the UK’s largest Robinson helicopter distributors, will cost you $10,500 (around £8,000). This covers theory in subjects like meteorology, air law, and flight planning. A Class 2 medical is compulsory.
After qualifying, you need an annual review to renew your license. You can opt to expand your qualification to include formation flying and night flying. The choice is yours.
2. Predetermine Your Budget
Design, capacity, and the manufacturer determines a helicopter’s price. Set your budget right from the start. It helps narrow your search.
Just like cars, you will have a range of options. Sloane Helicopters marketing director, Giorgio Bendoni, says first-time buyers can choose from the two-seater, single-piston Robinson R22 to the twin-turbine, eight-seater AgustaWestland Grand. It depends on budget flexibility.
While helicopters are expensive, some are cheaper than a Lamborghini. The Robinson R44, the world’s most famous helicopter, costs only $350,000 (around £313,500) and half that second-hand.
When setting your budget, add maintenance costs too. Some helicopter’s cost more to maintain than others. Lower priced helicopters can cost more in maintenance over the long run.
The AgustaWestland Grand and the AgustaWestland A109 are great in sophistication and space, but with an annual depreciation of five to 10 percent, you may want to weigh your options.
You should also consider the cost of insurance, capital investment, and depreciation.
3. How Far Will You Travel?
Aircraft manufacturers offer similar models with a small tweak in design and performance. Cheaper helicopters are smaller. And this limits the number of people it can carry, fuel capacity, and distance it can travel.
So, you need to decide how many people need to travel in your helicopter regularly. Also look at the distance it can travel before needing to refuel. The H125 is a midrange helicopter that guarantees 300 to 350 miles (ca. 563 km) or 2½ hours without refueling.
4. Other Considerations
The Airbus H160 is a new sleek design marketed to business and private customers, while the H125 has strong competition from the Bell 407. The cabin is separate from the cockpit and is luxurious. It has two seats facing each other and is a great option if you have a pilot. In contrast, an Airbus is a better option with you as the pilot as there is no separation from your passengers.
The choice of interior should reflect the helicopter’s purpose. Some people ignore carpets as it is a lot of work to keep clean. Leather seats are an attractive option as are seats with twin leather stitching which are currently in vogue.
Landing Space is Limited
Landing spaces in London are limited due to their tight restrictions on noise control, which limits helicopter paths. Battersea Heliport is the best place to land and continue your journey using other means. Places you can land outside London include Elstree, Denham, Biggin Hill, and Northolt.
Grab a helicopter landing guide to find somewhere to land in London. It has a list of landing sites around the UK and their phone numbers. This allows you to request landing permission before leaving for your destination. They may let you land for free or for a small fee (around $50).
Terms You Should Know
There are terms you should know if you intend to own a helicopter:
- VFR (Visual Flying Rules) means you have to keep sight of the ground.
- IFR (Instrument Flight Rules) means you can fly above or in the clouds.
- A two-seat piston engine VFR is a basic helicopter.
- ILS (Instrument Landing System) is what you dial into to get to the ground.
- You use a noise-canceling headset for communication.
- Autopilot allows you to control the aircraft without moving the controls and is not available in all helicopters.