How long does it take for a helicopter to start up?

Question

Does a helicopter require a battery to start up?

Answer 1

It really depends on the helicopter. An Apache, for example, takes around 5 - 10 minutes to start with all the checks and such. Under fire or in extreme emergencies, it can start up and be gone in about 2 - 3.

And yes, helicopters use batteries. Pretty big ones too. =)

Answer 2

As said before, it depends on the helicopter, and what you mean by start up? I am asuming you mean from dead stop to lift-off.

In pistion helicopters, so use a centrifugal clutch that engages as soon as the engine begins to spin by the starter. An example of this is a Bell 47. Others use belts which after the engines starts, which is similar to how a car starts, the belts might be engaged immediately as in the Robinsons, or after a breif warm-up like the Schweizer 300 series, or the Enstrom.

Turbines vary in design as well. Most use a free power turbine which begins to turn the rotors as soon as the free power turbine begins to spin. Examples includes most, if not all the Bell turbine helicopters, MD helicopters, AS-350 series, EC-130, EC-120, etc etc. This will happen within a couple seconds of engaging the starter. The whole start process of one engine takes usually between 15 and 20 seconds. Some turbines have warm-up times of 30 seconds, and others as long as two minutes. But it is very easy to have a turbine off the ground and flying in around a minute.

Some twin turbines have a tranmission that can disconnect the engines from the rotor with a manually actuated clutch, so the engines can be started and then the rotor enggaged. They can even stop the rotors and leave the engines running. An example of this are many of the larger twin Eurocopters like the AS-365.

And finally, some turbine helicopters have a fixed shaft turbine engine and a centrifugal clutch. These start spinning immediatly on starter engagement, like the Bell 47, and spin up very quickly. However, they still need time for the clutch to fully engage and engine warm-up which is around a minute. Exampels of this are the Lama and Alouette.

Answer 3

Almost all helicopters use batteries to start except for some of the former Eastern Bloc designs which use compressed air which works better in extremely cold temperatures. A piston engined helicopter requires 5 - 10 minutes to reach and stabilize operating temperature before full throttle can be applied. Most turbines don't have this limitation, so they can be ready to go in 3 - 5 minutes.

It's interesting to note that most helicopters require a cool-down stabilization also, which means running at idle for 3 - 5 minutes prior to shutting them down.

Answer 4

There are several answers for this question.

A helicopter requires electrical power to start, it does not care if the electrical power comes from a battery or a ground power unit. (Because of inertia, it's pretty clear that you aren't going to hand prop a helo.)

If you time from the preflight completion until engine start, a helicopter powered by a reciprocating (piston) engine will usually start with almost the speed of a Toyota Tercel in the hands of a skilled pilot. Turbine, ("jet,") helicopters will start combustion, either off the battery or ground power unit in a matter of seconds.

Helo's powered by recips will need to warm for a minute or two before engaging the rotors where a turbine helicopter can have the rotors at speed in less than a minute from flipping the switch.

Reciprocating engines are usually the same engines that you'd find in an aerobatic fixed wing airplane; they're choke bored, meaning that the cylinder diameter is smaller at the top end than at the bottom end of he piston stroke when "cold." This means that you want to see the temperature needle start to rise before you engage rotors and start pouring fuel to the engine.

Turbine engines don't have that worry and can start producing power as soon as they're on-line and the starter-generator has been switched.

Answer 5

Like some of the previous answers have noted, the question is not clear if you are referring to the electro-mechanical start-up process, or the entire procedure including pre-flight planning (weather, weight and balance, fuel, flight plan, log book prep, pre-flight inspections, securing cargo, passenger briefings, etc).

Another important note is that for a turbine-powered helicopter, the start is actually a start sequence. Unlike a piston engine which has a well defined point where it is running under its own power and the starter can be disengaged, a turbine start is a process that takes 15-30 seconds. If the start sequence is abandoned too early, the engine may continue to run and eventually come up to full RPM on its own, but a "hot start" could be the result, and that could cost hundreds of thousands of dollars.

Assuming the pilot has completed all the pre-flight work, is sitting in the helicopter, and has completed all the cockpit checks prior to pressing the starter button, most commercial helicopters can start the engine, come up to 100% "NR" rotor RPM, and be airborne in 2-3 minutes. The exact time depends on the air temperature, how long it has been since the helicopter was last flown, the type of helicopter, if it has one or two engines, and how thorough the pilot is with his/her cockpit checks prior to "pulling pitch".

Most single-engine light commercial helicopters (eg MD 500, Bell 206B & 206L with Rolls Royce 250 series engines) have a combination starter-generator that needs to be cooled for 30 seconds after the start sequence is complete prior to engaging the generator function. In theory it would be possible to fly without a generator, but taking-off without the generator turned on is prohibited by the flight manual. The AS350 series helicopters with Turbomeca engines do not have this cooling requirement.

Twin-engine helicopters (eg AS355 and Bell 212) take longer to start up because the battery requires a bit of a charge after starting the first engine so there is enough "juice" to get the second engine going.

The electrical starter is normally engaged for only 15-30 seconds, and is dependant on battery condition, engine temperature, outside air temperature, engine type, and various settings including pilot input and fuel control adjustments.

All commercial helicopters require a battery to spin the compressor wheels fast enough and long enough to get the power turbine wheels (hot section) spinning so that the compressor is powered by the hot section and the engine combustion process can sustain itself without internal melt-down. Most of the air produced by the compressor is used for cooling and not for combustion. Electrical power is also required for the igniter - a spark plug that ignites the fuel-air mixture.

Safety and professionalism aside, if you had a race to see how fast you could start a helicopter and get airborne, I'd go with a piston-engine helicopter such as the Robinson R44 which had just been shut down. I suspect a complete start and getting the rotor to 100% RPM could be achieved in less than one minute, but you wouldn't see me in the cockpit!

Most of the 3-5 minutes to get airborne noted by a previous answer is taken up by cockpit checks and not actually starting and warming up the engine. There are many aircraft systems that need to be checked before taking off; its much better to find a problem while you are still on the ground than in the air.

Answer 6

Helicopters require batteries.

How long it takes to start depends on the machine. Most can be ready to fly within 3-5 minutes. FADEC controlled engines can be flyable in as little as 45 seconds. I don't like to start straight to 100 percent, because it makes me feel like I should be in a hurry, and flying is the last place you should feel that.

A good rule of thumb would be the 3-5 minutes. By this time, you have a chance to check systems, get generators and radios on and tuned, have an idea as to local traffic.

Answer 7

When I watch Lifeflight start up and take-off from the local hospital, it usually takes about 3-5 minutes to warm up and get airborne.
Yes, a helicopter requires a battery to turn the starter to turn the engine or turbine.

I hope this helps.

Answer 8

In other words, the question is: If you are being attacked, lets say you spotted an enemy attacking you from a distant and heading towards you, HOW MUCH time is it required for the helicopter to take off "quickly" before the enemy reaches you?