6
$\begingroup$

What are the normal climbing angles against ground on a SEP (single engine piston) plane and an airliner?

(no wing-air angles in here, but the climb angle when watched from the side of the plane)

OwnWorkAngle (Source: user11961 - Own Work)

$\endgroup$
  • 1
    $\begingroup$ There is no "normal" angle: it's different for different types of airplane, and even for one airplane it depends on the desired rate of climb. $\endgroup$ – Dan Hulme Oct 23 '15 at 7:33
  • $\begingroup$ Okay i see that is true. Then what is like a "normal typical average" climb angle for an airliner? 10-15degrees maybe? $\endgroup$ – user11961 Oct 23 '15 at 7:39
  • 1
    $\begingroup$ Between 0 and 20 degrees, anything goes. This depends on desired rate of climb, center of gravity, take-off weight/mass, FLEX settings, pilot mood and the how Jupiter is aligned to Venus.... too many factors. ;) $\endgroup$ – SentryRaven Oct 23 '15 at 7:54
  • $\begingroup$ @Simon :D - credit where credit's due... $\endgroup$ – SentryRaven Oct 23 '15 at 11:12
  • $\begingroup$ +1 for incredibly crudely hand-drawn airplane! Makes the non-artist in me giggle with glee. $\endgroup$ – FreeMan Oct 23 '15 at 13:14
5
$\begingroup$

The climb angle depends on a number of factors like the airspeed, desired rate of climb, ToW, T/W ratio, airfield location (density altitude) etc.

For most commercial airliners, the typical climb angles are in the range of 15-20$^{\circ}$, while a few aircraft exceed these limits. (Added in response to @Jon Story's Comment)

The following figure shows the potential climb angles of Boeing airliners:

Boeing climb angle

Image from Boeing AERO magazine

Note that the actual values will be different depending on various conditions as already noted.

As for GA aircraft, the typical climb angles will be in the range of 5-6$^{\circ}$ at sea level and decreasing with altitude, with other conditions being equal.

$\endgroup$
  • 1
    $\begingroup$ Although the chart is nice, a quick description would be nice for searchability/readability: something like this, placed above or below the "As for GA aircraft" section: "For most commercial airliners, roughly 5-10 degrees on takeoff and around 15-20 degrees on climbout would be typical, with a few specific aircraft being closer to 10 or 25 degrees." $\endgroup$ – Jon Story Oct 23 '15 at 14:10
  • $\begingroup$ @JonStory just make that the description for the image ;) $\endgroup$ – flyingfisch Oct 23 '15 at 16:23
  • $\begingroup$ It can be the description, but I meant for people as well as accessibility - the image is good but requires some deciphering while a simple sentence could do the same job $\endgroup$ – Jon Story Oct 23 '15 at 16:59
4
$\begingroup$

That depends on wind speed and the aircraft's thrust-to-weight ratio.

Here are some values, all valid for sea level

  • GA aircraft: 4 m/s climb speed, 36 m/s airspeed. In calm air, this becomes a climb angle of 6.3°. If the wind blows with 36 m/s, the aircraft will climb vertically relative to earth if it flies straight into the wind.
  • Airliner: 20 m/s climb speed, 120 m/s. In calm air this becomes a climb angle of 9.5°.
  • Empty airliner: 30 m/s at 100 m/s. In calm air this becomes a climb angle of 16.7°. At airshows this is used to dramatic effect.

Note that the spectacular angles at airshows involve the conversion of airspeed to altitude, so these maneuvers are instationary.

If you want to know more on computing the optimum climb angle, consider reading this answer.

The main influence on climb speed is the thrust-to-weight ratio of the airplane. Since thrust depends on flight speed, ambient temperature and air density, those factors control the attainable climb speed in combination with the aircraft's weight.

For an observer, the next important influence is wind speed, since the aircraft climbs relative to the air mass it is flying through. If this air mass makes the aircraft appear to fly more slowly, a steeper climb angle can be observed.

Climb performance over airspeed and thrust-to-weight ratio

Climb performance over airspeed and thrust-to-weight ratio for an idealized turbofan engine. The blue lines show thrust (right Y-axis) and the green lines the resulting climb speed. The two black lines show how the optimum flight speed for best climb speed and best climb angle (steepest climb) vary over thrust loadings. They are easy to find graphically: Just measure the angle of a line from the origin to the point on a green line at the desired flight speed and the right thrust loading (thrust-to-weight ratio). If the scales of the two speeds on the X- and Y-axis would be the same, you could directly take the angle from the plot.

With lots of excess thrust, the optimum is limited by the stall speed (the black line bends into a vertical trend), while with no excess thrust both optimum speeds vx and vy converge. This makes sense: If thrust is just sufficient to keep the airplane from descending at one speed, this speed will both give the best flight path angle and the best vertical speed (unfortunately, both will be 0 at this point). It also helps to reduce induced drag, so aircraft with a high aspect ratio wing will climb steepest at a higher lift coefficient (= lower speed).

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.