Why are airplane engines so powerful?

Question

Why are airplane engines so powerful?

Answer 1

Pretty simple, really.  Take a basic airplane with 4 people and a full tank of gas.  2500 lbs.  Now, accelerate it to 90 mph in 1000 feet and then lift that 2500 lbs at 1000 feet per minute while pushing the craft along at 100 mph.  It just takes a lot of HP and a proportionate amount of fuel.   It's about like climbing a 20% grade in your car, fully loaded, at 100 mph... Not gonna happen without maybe 200 HP.

That kind of performance is just what's needed to have a reasonable safety margin.  

That's for older planes, though.  The new crop of efficient, modern, "light sport" airplanes do well for 2 people on around 100 HP.

Answer 2

Airplane engines, specifically the smaller general aviation engines, are not that powerful for their displacement.   For example, a Lycoming 360 CID engine usually only puts out between 180 and 200 horsepower.   Most decently tuned car engines with that much displacement put out closer to 300-350 horsepower.  Aircraft engines are rated for 100% power output at 100% duty cycle, thus they are de-tuned for reliability purposes.  

Like a previous answerer said...why is water wet?  

Answer 3

Becase they need to be ???

Answer 4

Because airplanes are heavy.  And they need to overcome the force of gravity, which is pretty strong.  Engines help them do that.

Answer 5

The more powerful the engines, the faster the airplane can fly, and the whole point of traveling by air is to get somewhere quickly.  Most airliners have engines that are much more powerful than they really need to be just to get into the air.  The excess power provides greater speed.

Some airliners have to have powerful engines for other reasons.  Twin-engine aircraft flying over water must be able to fly on just one engine for an extended period in case the other engine fails.  For this reason, their engines are far more powerful than they need to be for normal flights.  This also means that twin-engine airliners often climb extremely fast after take-off, if the pilots take off at full power.

Answer 6

That's like asking "Why is water so wet?"

Engineers have spent more than 100 years developing more and more powerful engines so that airplanes could be made larger and faster.  How could there be any question about that in a person's mind?

Sounds like a talk with your science teacher might be called for.

Answer 7

first consider the mass of any aircraft, lets pick a piper cub for instance. this aircraft has a maximum take off weight around 1500lbs as i recall. you need an engine with enough power to not only get this aircraft moving, but you need enough power to take off, and to reach a high enough speed and altitude to maintain flight, even in a headwind. for the piper it takes about 100hp to reach a top speed of about 85kts. remember that the bigger and heavier the aircraft, the more power you need to reach and maintain altitude and speed.  

Answer 8

if they weren't it wouldn't take off!

Simple

Answer 9

Believe it or not, the secret to overall aircraft performance is not how powerful the engines are, it's how efficient they are.

  This is measured by a value called the specific fuel consumption, which is based on the amount of power derived from a pound (or kilo in metric) of fuel. If a more powerful engine burns more fuel for each horsepower of work performed, all of that extra power is wasted by having to carry all of the extra fuel.

   An example of that in light planes is the Diamond Twinstar. It was designed with a pair of very efficient 135HP turbo diesel engines, but the engine manufacturer went bankrupt. To get close to the same performance they are going to have to use 180 HP conventional engines that burn twice the fuel per hour.  That means that the plane will not be able to fly as far or carry as much payload.