Reading the corner speed from an EM Diagram

[Bearfoot]

Am I correct in thinking that the max sustained turn rate speed is the point on the PS0 curve that maximizes the turn rate?? If so, how do we decide which point of the curve to pick when there is no peak in the curve? For e.g., in the attached, the PS0 curve "peak" spans ~400 to 500 knts IAS. That's a big range!

 

(Note: corrected confusion between corner speed and Max sustained speed)

Edited September 1, 2019 by Bearfoot

[r4y30n]

That just means you have some flexibility in turn radius at max sustained rate.

[Sandman1330]

Corner speed is misused on these forums,

 

Corner speed is literally the “corner” of the EM diagram where load factor and max AoA meet. Basically it is the point where the aircraft can reach its max load factor without first stalling the wing. Any lower speed and the wing will stall before reaching max G, any faster and you are limited by max G. This is where the aircraft will achieve best turn performance. However, it’s instantaneous turn; the aircraft may not have the power to maintain that speed at that load factor.

 

Best sustained turn rate is usually achieved at a lower speed and much lower load factor, but it is the point where the aircraft achieves best turn rate that it can sustain.

 

At least that’s how I remember it from my military aerodynamics classes many years go...

 

But to answer your question, from trial and error in DCS I find the Tomcats max sustained to be somewhere around 275-325, depending on weight.

 

Edit: seems my memory served me well!

http://navyflightmanuals.tpub.com/P-821/Corner-Speed-200.htm

Edited September 1, 2019 by Sandman1330

[Bearfoot]

That just means you have some flexibility in turn radius at max sustained rate.

 

Corner speed is misused on these forums,

 

Corner speed is literally the “corner” of the EM diagram where load factor and max AoA meet. Basically it is the point where the aircraft can reach its max load factor without first stalling the wing. Any lower speed and the wing will stall before reaching max G, any faster and you are limited by max G. This is where the aircraft will achieve best turn performance. However, it’s instantaneous turn; the aircraft may not have the power to maintain that speed at that load factor.

 

Best sustained turn rate is usually achieved at a lower speed and much lower load factor, but it is the point where the aircraft achieves best turn rate that it can sustain.

 

At least that’s how I remember it from my military aerodynamics classes many years go...

 

But to answer your question, from trial and error in DCS I find the Tomcats max sustained to be somewhere around 275-325, depending on weight.

 

Edit: seems my memory served me well!

http://navyflightmanuals.tpub.com/P-821/Corner-Speed-200.htm

 

Awesome! Thanks for clearing all that up. Now to work on putting it into practice ....

[Hummingbird]

Ps=0 is your max sustainable load factor without losing any altitude, Ps=-100 is the max sustainable load factor when trading 100 ft/s in altitude and so on.

 

The corner speed is as Sandman explained where the max instantanous turn rate is achieved, but not max load factor as the faster you go, the higher the instantanous load factor will also be.

 

Best sustained turn rate in the F-14B is usually around 0.56-0.62 Mach.

[captain_dalan]

Awesome! Thanks for clearing all that up. Now to work on putting it into practice ....

 

It's also known as a cornering and/or turning plateau. It's even more pronounced in the Viper. Instead of a single point on the E-M chart that tops your turning rate, you have an entire range.