Stall Speeds

Twenty-four stall speeds in one table: three flap settings against four bank angles, at two centre of gravity positions. Every figure is quoted at 1670 pounds and power off, and the pattern they form is more useful than any single number.

At a glance

• Conditionpower off, at 1670 pounds
• Most rearward C.G., flaps up, 0 degrees bank36 KIAS / 46 KCAS
• Most rearward C.G., flaps 30 degrees, 0 degrees bank31 KIAS / 41 KCAS
• Most rearward C.G., flaps 30 degrees, 60 degrees bank44 KIAS / 58 KCAS
• Most forward C.G., flaps up, 0 degrees bank40 KIAS / 48 KCAS
• Most forward C.G., flaps 30 degrees, 0 degrees bank35 KIAS / 43 KCAS
• Most forward C.G., flaps up, 60 degrees bank57 KIAS / 68 KCAS

The conditions

The stall speeds are quoted power off, and its note warns that the indicated figures are approximations, worked from calibration data taken with the power off. Every figure is at 1670 pounds — the table gives no lighter-weight row, so none of these speeds may be assumed to apply at a lower weight.

Most rearward centre of gravity

Flaps up

• 0 degrees bank: 36 KIAS / 46 KCAS

• 30 degrees bank: 39 KIAS / 49 KCAS

• 45 degrees bank: 43 KIAS / 55 KCAS

• 60 degrees bank: 51 KIAS / 65 KCAS

Flaps 10 degrees

• 0 degrees bank: 36 KIAS / 43 KCAS

• 30 degrees bank: 39 KIAS / 46 KCAS

• 45 degrees bank: 43 KIAS / 51 KCAS

• 60 degrees bank: 51 KIAS / 61 KCAS

Flaps 30 degrees

• 0 degrees bank: 31 KIAS / 41 KCAS

• 30 degrees bank: 33 KIAS / 44 KCAS

• 45 degrees bank: 37 KIAS / 49 KCAS

• 60 degrees bank: 44 KIAS / 58 KCAS

Most forward centre of gravity

Flaps up

• 0 degrees bank: 40 KIAS / 48 KCAS

• 30 degrees bank: 43 KIAS / 52 KCAS

• 45 degrees bank: 48 KIAS / 57 KCAS

• 60 degrees bank: 57 KIAS / 68 KCAS

Flaps 10 degrees

• 0 degrees bank: 40 KIAS / 46 KCAS

• 30 degrees bank: 43 KIAS / 49 KCAS

• 45 degrees bank: 48 KIAS / 55 KCAS

• 60 degrees bank: 57 KIAS / 65 KCAS

Flaps 30 degrees

• 0 degrees bank: 35 KIAS / 43 KCAS

• 30 degrees bank: 38 KIAS / 46 KCAS

• 45 degrees bank: 42 KIAS / 51 KCAS

• 60 degrees bank: 49 KIAS / 61 KCAS

Reading the pattern

Three regularities run through the whole table, and they are worth more than the individual cells.

What moves the stall speed

• Flap — extending flap lowers the stall speed, and the biggest single step is between 10 degrees and 30 degrees, not between up and 10.

• Bank — the stall speed climbs steeply beyond 45 degrees. At the most forward centre of gravity, flaps up, it rises from 40 knots wings level to 57 knots at 60 degrees of bank.

• Centre of gravity — every forward-C.G. figure is higher than its rearward counterpart. Forward loading gives the higher stall speed.

Notice too that in the flaps-up and flaps-10 columns the indicated speeds at the rearward C.G. are identical — 36, 39, 43 and 51 knots in both — while the calibrated figures differ. Ten degrees of flap is not showing on the indicator at these speeds even though it is doing something.

Check yourself

• At what weight and power setting is the stall speed table quoted?

• Does moving the centre of gravity forward raise or lower the stall speed?

• State the stall speed flaps up, wings level, at the most forward centre of gravity, in both KIAS and KCAS.

• By how much does the stall speed rise between wings level and 60 degrees of bank, flaps up, at the most forward C.G.?

• Why should none of these figures be assumed to apply at a lighter weight?

Study aid — always fly your aircraft's current AFM/POH.