You may have seen helicopters sitting out on the apron or helipad and thought nothing of it, but then when you see a helicopter sitting in a hanger the thought may have come up as to how they get the helicopter from the hanger to outside so it can take off? Depending on the type of helicopter, moving it around on the ground can be fairly simple or take a little bit more work.

Helicopters without wheels can only move on the ground by use of a dolly, tow-cart, or ground-handling wheels. Helicopters with wheels can be towed using a tow vehicle and towbar and can move by using the thrust produced by its main rotor when running. Helicopters without wheels need to hover taxi.

Having flown both types of helicopters – ones with wheels and ones without I can give you some insider knowledge on how helicopters move around when on the ground. Helicopters that don’t have wheels have landing gear known as ‘Skids’. The helicopters with skids provide the most problems to personnel trying to move them around while they are on the ground.

How Do You Move a Helicopter Out of a Hanger?

For helicopters that have wheels, moving a helicopter in and out of the hanger or around the apron is a simple task. You connect a tractor, tug, or tow vehicle to the aircraft using a tow bar, release its brakes and pull/push it wherever you wish. Pretty simple.

For helicopters with skids, there are three main ways to move a helicopter:

1. Tow-Cart
2. Dolly
3. Ground Handling Wheels

Moving a Helicopter Using a Tow-Cart

Tow-Carts are an electric/hydraulic device that attaches to the helicopter skids, picks it up, and allows the helicopter to be driven around. These are great devices that allow even large helicopters to be moved just by a single person. They come in a range of sizes to suit all helicopters.

Moving a Helicopter Using a Dolly

A helicopter dolly is a large platform mounted on wheels. The helicopter pilot lands the helicopter on the dolly and then it can be moved around using a tow vehicle, or some really fancy dollies are on rails that can move the entire machine in and out of a hanger with just the press of a button!

Dollies are a great way to allow a helicopter to be moved by just a single person but if they are small they can be dangerous to land on for a novice pilot, especially in high winds. Catching a skid on the edge of the dolly leads to Dynamic Rollover with catastrophic results!

In this case, the helicopter was doing maintenance runs, and the dolly was not chocked to prevent it from rolling. It starts to roll and the pilot panics and pulls the helicopter into the air but not high enough. They catch a skid and that’s the beginning of the end for that helicopter! The report from the police department says it was caused by a sudden gust of wind, but in my opinion, that sounds like BS. Someone screwed up by not choking the dolly!

Moving a Helicopter Using Ground Handling Wheels

Every helicopter comes from the factory with a set of ground-handling wheels. These are wheels that temporarily attach to the skids and then use either a hydraulic mechanism to lift each skid up off the ground or in smaller helicopters, a cam mechanism.

Small helicopters like a Robinson R22 or Gumibal Cabri can easily be moved by a single person but once you get into helicopters larger than two seats you either need some kind of tow device or multiple people to help move the helicopter because of its weight.

How Do Helicopters Taxi?

Now that we have seen how a helicopter is pushed/pulled or towed around the hanger how do helicopters get from the hanger to the takeoff and landing locations? At some airports, there are designated areas that helicopters can only operate from or they may be restricted to landing and taking off only from a runway, so how do they get to those locations?

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How Do Helicopters Ground Taxi?

Ground taxiing is used for helicopters with wheels only. When the pilot pushes slightly forward on the cyclic it tilts the rotor disk forward and creates a thrust vector towards the rear of the helicopter, just like they were accelerating away while in flight. The rearward thrust moves the helicopter forward.

Once the pilot releases the brakes the helicopter will begin to roll forward, this is known as ground taxiing. To turn the helicopter the pilot pushes on the foot pedals to make the tail rotor push the rear of the helicopter left or right, thus swinging the nose in the opposite direction:

Ground taxing works great to help keep debris and rotor wash to a minimum. It requires far less blade pitch to ground taxi, thus the amount of rotor wash produced is far less than if the helicopter was hovering. This is great for taxiing around airports with private and corporate jets parked close by and not peppering them with dust and debris!

How Do Helicopters Hover Taxi?

Hover taxiing is primarily used by helicopters that only have skids, although wheeled helicopters can hover taxi too, especially if they are trying to move around a grassed field etc. Hover taxiing is just what it sounds like, it is when the helicopter is in a hover and moves from point A to point B. Most helicopters hover around 5 – 10 feet depending on their size.

This is how I move my Astar around when I need to taxi from my parking spot to the takeoff point. A hover taxi is done at a typical hover height and at a slow speed and is used to cover only small distances, but it does create a lot of rotor wash and dust when lifting off next to the hanger and other aircraft. With skidded helicopters, there is no other option.

How Do Helicopters Air Taxi?

If the helicopter has to cover a large amount of ground to get to its takeoff point or from its landing point then a maneuver called an Air Taxi is used. For instance, if air traffic control wants them to take off from a runway, the pilot needs to taxi down the taxiway but at an acceptable pace, or if the pilot wishes to get to the airport’s infield for training.

An air taxi is usually completed under 100ft above the ground and up to 40kts. As the pilot approaches the area they wish to land at they will slow down to a hover taxi and then land or hover in that location before departing.

To Finish

Helicopters are moved on the ground using tow vehicles, ground handling wheels, dollies, or their own power. Wheels make it much easier if they are already attached to the helicopter but these add weight and complexity to the helicopter which is not justifiable on the smaller, cheaper machines.

To move around from point A to B helicopters either have to ground taxi or hover taxi. Both have their own benefits but it all depends on the type of helicopter the pilot is flying and the surface on which the helicopter is moving on.

Further Reading

If you found this article helpful may I suggest these other articles too:

• Why Do Helicopters Takeoff Nose Down?
• Can Twin Engine Helicopters Fly With Only One Engine?
• Helicopter Takeoffs: How Long Does It Take?
• Why Do Helicopters Takeoff & Land On Runways?
• Backward Take Off’s – Why Do Helicopters Do Them?

When a helicopter takes off down a runway it seems to be pointing nose down towards the ground as it accelerates. Why does it do that? Airplanes remain flat and then pitch up when taking off, but helicopters seem to point nose down and then go level as they climb. There must be a specific reason for this.

To accelerate, a helicopter needs to tilt its main rotor system forward to create horizontal thrust. The main rotor system is attached to the fuselage so the whole helicopter also points nose down as it accelerates during takeoff. 5°-15° nose down are typical pitch-down attitudes on takeoff.

When a helicopter’s main rotor is turning it forms a disk and it is this disk that aerodynamically controls how the helicopter moves. Because the rest of the helicopter hangs off the rotor system in flight the fuselage is subjected to longitudinal and lateral attitudes as the helicopter flies.

This article is written in a way to try and leave out much of the tough technical jargon and explain it in a ‘Layman’s Terms’ approach.

How Does a Helicopter Accelerate?

Looking at an airplane it is easy to see what makes it move. It either has a propellor or a jet engine providing thrust to push or pull the aircraft through the air:

On a helicopter, the thrust and lift are created by the rotating disk that is the main rotor system. The downward force of air from the rotor system creates lift to raise the helicopter into the air and in a no-wind hover that is the only force acting on the helicopter as seen on the right:

To move the helicopter in any direction, the rotor disk must tilt and begin pushing air in a lateral direction. This is known as thrust. To accelerate the helicopter forward and gain airspeed the pilot must push forward on the cyclic control which tilts the disk forward. This pushes some air from going straight down to now going towards the rear of the helicopter. This then begins to move the helicopter forward.

The faster forward the pilot wishes to go, the more they have to push on the cyclic, which tilts the disk even more. This then pushes more air rearwards propelling the helicopter forwards.

As the helicopter’s speed increases the amount of nose-down attitude increases as you can see in the picture. The other unwanted side effect of increasing speed is the amount of drag acting on the helicopter increases. These two unwanted attributes are some of the issues helicopter designers fight when they want a helicopter to go faster.

This is why a helicopter takes off nose down. The disk needs to be tilted forwards to create a horizontal thrust component to allow the helicopter to accelerate. Because the main rotor disk is connected to the fuselage this makes the nose drop. It is also the same reason why helicopters look like they are pointing nose up when they are coming into land, except at this point the pilot is decelerating the helicopter by tilting the rotor disk aft.

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Helicopter Flat Floor Concept

On smaller helicopters, the main rotor mast is bolted to the helicopter structure at 90°. This means the faster the pilot wishes to go, the more nose down the helicopter has to be for the duration of the flight. I can still remember flying the Schweizer 269 you see in the diagrams above.

That thing flies so slow because of the drag on the canopy that to get anywhere you really had to push the cyclic forward. This led to you practically hanging off your shoulder straps and feeling like you would fall out the front of the helicopter!

For helicopters where the VIP market is a big focus for the helicopter designers the thought of passengers having the feeling of falling out of their seats for a flight would not make a helicopter sell very well!

To get around this the designers create something known as a ‘Flat Floor’ concept and this means that when the helicopter is in cruise, the floor of the helicopter’s cabin is as parallel to the ground as possible. To do this the designers build in an offset into the mounting of the main rotor system which mechanically tilts the main rotor system forward at all times.

As the helicopter lifts into a hover the fuselage will be pointing nose up as the rotor disk sits horizontal to the ground in a no-wind hover. This makes it harder for the pilot to see, especially when coming into land. The AW129 shown above can sit in a hover with as much as 12-13° nose up. For this reason, most of these types of helicopters are flown in clear environments like helipads and airports.

Trying to land a helicopter like this in a tight confined area, with obstacles and uneven ground always made it tricky. I always had to get the crew to keep their eyes wide open to help ensure I was clear of obstacles.

As the pilot accelerates, the fuselage may pitch from 5-12° nose up to 5-10° nose down for a short while but as the helicopter reaches cruise speed, the mast and rotor system will be tilted forward but the fuselage cabin remains flat. When done smoothly and correctly by a good pilot the passengers will very rarely feel this potential rollercoaster type of maneuver. The flat floor during the majority of the flight is what VIP passengers desire.

Controllable Stabilator

On the UH-60 Black Hawk the rear horizontal stabilizer, known as a ‘Stabilator’ can move up and down like an elevator on an airplane. The Stabilator is controlled by the helicopter’s Automatic Flight Control System (AFCS) and constantly moves the trailing edge up and down in flight to help improve flight handling for the pilot.

One of the benefits of the Stabilator is that in a hover or at low forward airspeed it is angled downwards to allow the main rotor wash flowing over it to create lift which pulls the tail upwards slightly, helping to keep the fuselage more horizontal to allow the pilots to be able to see more.

In forward flight, the Stabilitors’ trailing edge rises allowing the forward airflow over it to help push the nose of the helicopter down and create the flat floor concept.

There is far more to the stabilator than is warranted in this article but that is the Layman’s terms of how it helps keep the helicopter from pointing nose down during flight.

How Do Helicopters Slow Down?

To slow a helicopter the pilot pulls aft on the cyclic which tilts the main rotor disk backwards. The air being moved through the rotor disk now starts to push the helicopter backward as it flies. The longer this position is held, the slower the helicopter becomes until it stops.

It is pretty much the same as accelerating forward. The pilot has to move the cyclic to control the direction in which the helicopters thust points. When in forward flight the thrust vector is pointing forward as the disk is tilted forward.

To slow down the pilot tilts the disk backward and moves the thrust vector to point backward. This coupled with the drag, then begins to slow the helicopter. If the pilot were to hold the cyclic in the aft position the helicopter would slow down, stop and then begin to fly backwards.

To bring the helicopter to a hover the pilot adjusts the cyclic back to the center just as the helicopter comes to a stop. This way there is no horizontal thrust vector moving the helicopter in any direction.

The faster and further the pilot moves the cyclic aft, the faster and more aggressive the helicopter will slow down. One additional function that happens when the pilot moves the cyclic aft is that the rotor disk will catch the airflow like a sail and will cause the helicopter to climb, or balloon up.

To overcome this the pilot must lower the collective to reduce lift so that as the helicopter begins to balloon up the pilot reduces the lift being produced to remain at the desired altitude, or if they are coming into land the pilot manipulates the cyclic to control the airspeed and the collective controls the rate of descent.

To Finish

Helicopters point nose down when taking off because to accelerate from a hover the main rotor disk needs to tilt forward to create a horizontal component of thrust to propel the aircraft forward. The faster the pilot wishes to accelerate, the more the rotor disk needs to tilt forward which means the more nose down the helicopter points.

Offset masts and stabilators help to keep the amount of nose-down attitude to a minimum, but there will always be some degree of nose-down while the helicopter accelerates.

Further Reading

If you found this article helpful you might these ones too:

• Helicopter Tail Rotors – The Different Types Explained
• Backward Take Off’s – Why Do Helicopters Do Them?
• Helicopters Flying In Circles – Why Do They Do That?
• Are Helicopters Faster Than Cars? Well, It Depends…
• Can Helicopters Land On Cruise Ships? Yes & No!

There is a tremendous array of helicopters flying around our planet in every size you can imagine, but how much do helicopters weigh? They need to be as light as possible to fly, but you may be surprised at just how much some of them can weigh!

Helicopters can weigh from 600 lb/275 kg all the way up to 123,400 lb/56,000 kg with every weight and size in between. Helicopters have a Basic Empty Weight and a Maximum Gross Takeoff Weight. The difference in the two is the useful load which includes the crew, passengers, fuel, baggage & cargo.

Helicopters are split into 5 main classes dependent on their weight:-

• Ultra-Lights: Helicopters weighing up to 254 lb / 1,15 kg Empty Weight
• Lights: Helicopters weighing up to 3,500 lb / 1,590 kg Maximum Gross Weight
• Intermediates: Helicopters weighing from 3,500 to 7,000 lb / 1,590 kg to 3,180 kg Maximum Gross Weight
• Mediums: Helicopters weighing from 7,000 to 12,500 lb / 3,1880 kg to 5,670 kg Maximum Gross Weight
• Heavies: Helicopters weighing over 12,500 lb / 5,670 kg Maximum Gross Weight

Helicopters range in size from personal single seat models up to the mighty Mil Mi-26 Russian Troop carrier:

What is Helicopter Empty Weight?

The empty weight of a helicopter is when the helicopter is weighed with all of its equipment attached. Items that are included in the empty weight are:

• Fuselage, Rotor Systems, Transmissions, Engine/s
• Avionics
• Emergency Floats – If fitted
• Search Lights – If fitted
• Hoist – If fitted
• Baggage Hold Extensions – If fitted
• Auxiliary Fuel Tanks – If fitted

Basically, as the helicopter rolls out of a hanger with no fuel on board is what constitutes its empty weight. It is an important number to know as the rest of the aircraft’s weight and balance builds on this figure.

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What is Helicopter Maximum Gross Weight?

A helicopter’s Maximum Gross Weight is the heaviest a helicopter can be to lift into the air. It is set by the manufacturer during aircraft certification and is usually set to keep the aircraft within structural integrity, and/or maintain control during regular or emergency flight maneuvers.

Some aircraft have two maximum gross weights:

1. Internal Max Gross Weight – This is usually a lower value and is when cargo and passengers are carried inside the aircraft.
   For the Astar AS350 B2 that I fly the Maximum Internal Gross weight is 4,961 lb.
2. External Max Gross Weight – This is a higher weight as the load is carried via a hook on the belly of the helicopter. Because of this, the pilot can jettison this load in an emergency to instantly reduce the weight to the internal maximum gross weight. The external gross weight is usually limited by engine power and/or structural integrity of the aircraft.
   For the Astar AS350 B2 that I fly the Maximum External Gross Weight is 5,512 lb

What is Helicopters Load Carrying Capacity?

A load-carrying capacity is the difference between its maximum gross weight and its empty weight. This is all the ‘Stuff’ that can be put in a helicopter and the more load-carrying capacity it has, the better it can be utilized. The most common items that make up a helicopter’s useful load are:

• Flight Crew – Pilot/s, Engineers, Load Masters
• Fuel
• Passengers
• Baggage
• Cargo

The useful load is what the pilot needs to balance to ensure the helicopter remains under its max gross weight. Many of the smaller helicopters can be limited to how much they can take. For instance, if you put a person in every seat and each person has a 50 lb suitcase there is probably a good chance the pilot will not be able to take full fuel.

This is where the bigger the useful load, the more the helicopter can do.

Pilots usually have to juggle the fuel and passengers to keep the aircraft within limits. If the trip is short enough, the pilot can take less fuel but take all the passengers and baggage in one trip.
If the trip needs more fuel to complete, the pilot may have to elect to do two trips or stop for fuel on the way if it’s available. No matter which option is selected it is always a balancing game of math for the pilot.

How Much Can Helicopters Carry On Their Hook?

When helicopters need to transport bulky, large, or heavy items they are mainly slung under the helicopter. Loads can be attached directly to the belly hook/s or be slung using a length of steel or synthetic rope known as a Shortline or Longline depending on its length.

The load on the hook must still fall into the useful load of the helicopter but when a really heavy load is needed it can be done just using the flight crew and a minimum amount of fuel.

The Astar the I fly can realistically lift around 2000lb on the hook, however, the Boeing CH-54 Chinook can lift over 20,000 lb! The bigger the load that needs to be slung, the bigger and more powerful the helicopter needs to be. In our case, we just break the loads down into more manageable sizes and sling them in multiple trips as we do not have a helicopter bigger than the Astar!

The hook and lifting systems on a helicopter are always oversized to ensure a healthy safety margin is maintained and the pilot will always reach the aircraft’s maximum power available or max gross weight before ever getting close to the capacity of the hook or slinging gear.

To Finish

Helicopters come in every size imaginable with every weight in between. Matching the helicopter to the job is paramount but staying within its weight limitations is a must. When a helicopter’s load exceeds its limitations then either the load must be reduced or a bigger helicopter is required.

The larger the helicopter, the more it weighs, the more it costs, the more parts require maintenance and the more fuel it drinks. I could not imagine the hourly flight costs of the Mil Mi-26 but at a purchase cost over $25M, you can bet you will also need very deep pockets to run it!

Further Reading

If you found this article interesting may I suggest these as well:

• What Is A Helicopter Blade Made of? It Used To Be Wood!
• Can You Land a Helicopter Anywhere? What Will Get You Busted!
• How Much Fuel Does a Helicopter Burn? Get Your Visa Card Out!
• How Much Can a Helicopter Lift? 20 Helicopters Compared!
• Do Helicopter Pilots Wear Parachutes?