Aviation: average engine load curve of an airplane

[Christophe]

Taken from a materials course and found on my pc, this curve will interest more than one aeronautical lover.

Legend: Propellant power for a civil jet aircraft according to the flight phase. The curve is similar for piston thrusters. The braking peak by reverse thrust is not systematic and the dotted lines correspond to momentary accelerations (taxiing phases, landing waiting phase)



ps: the time scale is obviously not regular.

[Chatham]

Indeed, that gives a good idea, although the cruising speed seems high, but it is undoubtedly because of the high altitude (the thrust decreases with the altitude), it is true that I am interested in advantage to small airplanes with piston engines than to "flying whales" with jet engines and other turboprop ...
The thrust reset plateau during the landing procedure corresponds to the approach stop at constant altitude before the "final" descent, but in certain northern countries we tend to eliminate this plateau as much as possible by optimizing a descent. constant to reduce fuel consumption, but this is only possible in a clear sky ...
For transport aircraft with piston engines, the cruising speed was around 55%, but could rise to ~ 110% on takeoff (on engines equipped: methanol water injection + boost by temporary pressure increase overeating)
On light airplanes, the fast cruising power varies according to the engines between 70 and 95%, but in general we are rather at an economic speed around 50-60% to consume less ...
Note that the load is much higher for an airplane engine than for a car engine which is most often around 30% of cruising power ... except of course if you are in 2cv on the highway where you is 100% (the engine is designed to support it), but most car engines are unable to sustain the maximum power ...

[Christophe]

Yes 75% on average in cruise it seems important to me too, I would have thought more, like you at 50 to 60% but hey it's an average ...

What I especially wanted to show by diffusing this curve was the curve at the level of the approach and landing since you yourself said that it was almost gliding the approach ... which seems to be contradicted by this curve . Now it's a curve for a "big" airline carrier ... it must be different in light aviation.

For the average hourly load of a car for me it is even lower: less than 20% especially with the race to the current power.

I learned during my motor lessons that the average load of a formula 1 on a medium circuit (so not Hockenheim for example) was 35%... This figure has already been disputed on this forum but do not confuse: engine load and accelerator position. The second is obviously much higher.

Anyway it would be easy to get the real average load with the average speed of an F1 which is around 200km / h ...

[Chatham]

What I especially wanted to show by diffusing this curve was the curve at the level of the approach and landing since you yourself said that it was almost gliding the approach ... which seems to be contradicted by this curve . Now it's a curve for a "big" airline carrier ... it must be different in light aviation.

The "fineness" of a large aircraft is of the order of 18, that is to say that an airplane flying at 10m can theoretically do 000km in glide with the engines switched off, this incidentally happened one day on a 180 of the Japan airlines whose 747 engines suddenly cut off (it had entered a cloud of dust particles from the explosion of Mount St Helens), the engines could not be re-ignited (by nose-down the plane , "top-top" engines) only ~ 4m after 3000km of glide ...
The power level downhill seems high indeed, but it depends on the slope: if it is low, which is most often the case, it is necessary to apply power to maintain the speed, because when gliding (engines at idle, the best smoothness is around 450-500km / h.
On light planes, it depends: the pilots "airplane" (of which I was but while piloting with the old CàD with strong rate of fall in final while regulating the slope with the flaps) often adopt a weak slope (5%) while remaining " Hanging from the engine ", which I personally consider particularly dangerous because there is no defense in the event of an engine shutdown (planes regularly break their mouths before the runway due to an engine failure in final).
Of course there is also a reason: if you put the engine at idle in the final, even with the warm up (which is also ineffective in this case because the engine produces no effort), the risk of icing is high ... those who have driven in 2cv know: when going downhill it does not heat anything at all, while when going up or at high speed you sweat
However in ULM, the idle final is the norm (despite a finesse generally less than 12, (sometimes only 4 on old machines!) Because here we estimate the engine as likely to break down at any time , which happens quite often in the case of 2-stroke engines ... but if we respect the rules, in ulm only the engine failure in initial climb (just after takeoff) is really dangerous, especially if we react bad: I also have 2 friends who killed themselves like that while trying to do a 1/2 turn when they would probably have gotten away without big sores, but broken device if they had landed straight ahead at speed minimum (60km / h on their device) ...

[Christophe]

Ay I put our report online: Aviation, aviation piston engines

It is quite light but allows to have some bases.

Obviously to you and André it will probably learn nothing ...

[Capt_Maloche]

75% is a current continuous load, airplane loaded, which an aviation classified engine must be able to hold

example of a Rotax 912: http://www.piecesrotax.com/moteurs_rotax/rotax_912.htm

Performance
Maximum power (5 minutes) 81CV / 59.6KW at 5800 RPM
Maximum power (sustained) 79CV / 58.9KW at 5500 RPM
Maximum torque 75.9ft-lbs / 103NM at 4800 RPM

On light airplanes, the fast cruising power varies according to the engines between 70 and 95%, but in general we are rather at an economic speed around 50-60% to consume less ...
Note that the load is much higher for an airplane engine than for a car engine which is most often around 30% of cruising power ... except of course if you are in 2cv on the highway where you is 100% (the engine is designed to support it), but most car engines are unable to sustain the maximum power ...

Totally agree, the maximum speed in aviation is only used for takeoff and maximum speed, the cruising speed also depends on the load of the aircraft

Sure it is better not to turn around at takeoff at the end of the runway !! thin, 2 dead? on what type of device?

[Chatham]

75% is a current continuous load, airplane loaded, which an aviation classified engine must be able to hold

Sure it is better not to turn around at takeoff at the end of the runway !! thin, 2 dead? on what type of device?

There is an exemption for certain special engines like certain diesel (Thielert), whose recommended continuous speed is 72% ... but indeed the standard is 75% of continuous power.
The ulm in question was a Skyranger with slit flaps to reduce the minimum speed: this device is considered very safe and solid, but the engine (2 stroke) cut at the wrong time ... if you leave the field even a safe aircraft is no better than any other plane ... in this case it was stall in too slow turn, spin at low height so no time to recover = it does not forgive. ..another ulm pilot had more luck in this configuration: the aircraft fell like a shit of ~ 30m on a wing which absorbed all the energy of the shock: aircraft in mush, pilot unscathed not even one scratch! The guy in question had to have a very effective guardian angel because he cumulated bullshit on bullshit and always got away with it, a sudden awareness (a threat from his wife I think ...) made him stop driving the day at next day

[Capt_Maloche]

Here, do you want to see a guy who shouldn't be living too old?

http://www.youtube.com/watch?v=EmFgN1D2D10

[Flytox]

Bonjour à tous

A crazy man who thinks he's clever because he tries to make an autogyro wheel touch the ground without touching a rotor blade ...
A breeze and he died ...
A+

[Christophe]

A breeze and he died ...
A+

Yeah lol ... but it's not filmed in the desert for nothing I think ...

Speaking of crazy, here is another one in another genre: http://www.dailymotion.com/video/x4p24f_motard-fou_auto