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Takeoff Flaps Selection

Gulfstream G450 Flight Procedures


 

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Figure: Flap Selection, from Eddie's notes.

Runway Length Required

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Figure: Effective Runway Length Required, from G450 Airplane Flight Manual, §5.2-11, 13

Generally speaking, if the aircraft has a choice of takeoff flap setting, a higher flap angle will reduce runway length required but will also reduce climb gradient. For example, in a G450 using two conditions:

Going from 10° flaps to 20° flaps reduced the effective runway length required by around 10% in our two example cases.

GWT Temp P.A. 10° Flaps 20° Flaps
60,000 30°C 4,000' 5,500' 5,000'
65,000 20°C S.L. 4,750' 4,400'
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Figure: Takeoff Second Segment Climb, 10° flaps, from G450 Airplane Flight Manual, §5.6-15.

Using the same conditions, looking at climb gradient for flaps 10°:

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Figure: Takeoff Second Segment Climb, 20° flaps, from G450 Airplane Flight Manual, §5.6-13.

Using the same conditions, looking at climb gradient for flaps 20°.

Going from 10° flaps to 20° flaps reduced the climb gradient by around 15% in our two example cases.

GWT Temp P.A. 10° Flaps 20° Flaps
60,000 30°C 4,000' 6.6% 5.7%
65,000 20°C S.L. 7.7% 6.4%

References

Gulfstream G450 Airplane Flight Manual, Revision 35, April 18, 2013

Revision: 20131217
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