PPRuNe Forums - Corner Speed

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- - Corner Speed (https://www.pprune.org/military-aviation/253362-corner-speed.html)

Can one of you zoomies explain the meaning of this phrase please. Just interested, having seen it referred to a number of times.

Thanks. CG

I was trying to figure out how 747 would answer you so I did a Google .... :p

Quote:

Corner velocity

Corner velocity /also called corner speed or maneuvering speed/ is an important value for each aircraft. It is determined by plotting the structural limitations /in G forces/ against airspeed. The corner velocity is the minimum speed at which an aircraft can pull its maximum rated Gs. An aircraft at corner velocity attains maximum instantaneous turn performance.

The corner velocity for the F-16A in a stock configuration is 450 knots. This means that at 450 knots the F-16 has its best turn performance. At speeds above the corner speed, turn performance drops off.

Corner speed also affects the minimum turn radius. The size of the turn radius of an aircraft depends on the speed it is traveling. A faster aircraft requires a larger circle to turn in than a slower one. However, the turn redius isn't only a function of speed. It also depends on the number of Gs a pilot pulls during the turn. An aircraft at a constant speed will make a relatively wide circle at 1 G but will turn in a very tight circle at 7 or 8 Gs. The corner velocity is the speed that gives the optimum balance between turn rate and turn radius.

It will keep you going till the lads get back from watching the Footy ..... :)

Cheers Hobie, makes sense.

CG

Corner speed is that IAS that you can pull like a randy schoolboy, to the buffet, and reach your maximum allowed G.

Fly faster, pull to the buffet, and you will over-G.
Fly slower, pull to the buffet, and the bad guy will gain angles.

Corner speed equals the Square root of the maximum G multiplied by the 1G straight and Level stall speed for that weight or something..... :zzz:

"An aircraft at a constant speed will make a relatively wide circle at 1 G but will turn in a very tight circle at 7 or 8 Gs. The corner velocity is the speed that gives the optimum balance between turn rate and turn radius"

An ac will fly a HUGE circle at 1 g!!

Author is getting a bit tangled with rate and radius too (with respect to corner speed).

Ray

One could say that an aircraft would fly a "Great Circle" at 1G!

Sorry ;)

........and all along, I thought it was the speed that the Sqn Cdr steppped sideways when I asked for my annual leave.

Normally, a high wing loaded aircraft will generate maximum instantaneous turn rate at corner velocity - that is the minimum speed at which maximum G can be obtained. Instantaneous turn rate is lift limited.

The creation of maximum lift causes a rise in induced drag and it is unlikely that corner velocity will coincide with maximum sustained turn rate unless the aircraft has lots of thrust to balance the drag increase.

Corner velocity is important if the ability to achieve max turn rate is required for defensive manoeuvres - fly below or above corner speed and the ability to achieve max instantaneous turn rate suffers.

'When I were a lad', corner speed ( we ignorantly called it velocity) was the airspeed at which the aeroplane could sustain limiting G. In the F4K it was around 420 knots for the peacetime limit. It would have been a bit higher in grunt puff snap shot this barsteward mode.

Thanks all, I get it. Much appreciated.

CG

Jack raises a valid point. If your aircraft doesn't have the poke then you will be at corner speed only instantaneously, if your engine can push out enough thrust it should be able to keep you there. You can go down the hill aswell to augment a weazy engine, thus sustained performance also relies upon thrust at a given altitude whereas corner speed is purely aerodynamic. That's why people (well - spotters) talk about specific excess power - the measure of stuff thats pushing you.

Lowest indicated airspeed that you can attain max placard G.

The F-111F cornered at 630KIAS.....briefly!.....puts the WSO to sleep though., not a bad thing - really.