Please help about "CORNER VELOCITY" (CV)

[terracota]

Hello dear pilots, I need some help wiht these concepts:
The other day I read an article about corner velocity, I dont understanded to much
I guest is about the optimal air speed of a plane to maneuver, how I now the CV of determite plane? , what exactly is the CV?
thhis is the link of the article: http://www.simhq.com/simhq3/sims/air_combat/bfm101/bfm101_part2.shtml
can somebody help?
see ya

[Lephturn]

Basically "Corner Velocity" really means "The speed at which the plane has the best turn rate".  This is the speed you want to try to maintain to maximize the turning ability of whatever plane you are flying.  Above or below that speed, the time to turn 360 degrees will be greater.

Basically, we are talking about the speed that allows a particular plane to pull the highest G's in at the lowest speed.  Planes that are "good turning" planes, will tend to have lower best turning speeds than the heavier BnZ oriented planes like the FW-A8.  For example a Spit V has a best corner speed somewhere below 150 Mph, while the F4U-1D's best corner speed is around 220 Mph.  If I'm in a turn fight flying either of these planes, I want to stay close to that speed to maximize my turn rate.

How to test this in a simple manner?  Use your virtual pilot's G tolerance.  Simply put, find the lowest speed the plane will induce the start of black-out in a horizontal sustained turn.  You will have to angle the turn downwards somewhat to maintain a given turn speed while pulling G's.  It's not the most scientific method, but it will give you a good idea of what speed range is best if you are in a turning battle flying a particular plane.

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[Andy Bush]

terracota

Corner velocity is an academic term that has a specific definition...it is simply the lowest speed at which the aircraft can pull its max allowable G. This does not necessarily mean sustained speed...it only means an instantaneous speed in many cases.

Corner velocity will change if the aircraft changes its weight, configuration, or altitude. It is NOT a single value...although in a sim, it may be modeled that way in the sim's AI.

Corner velocity tends to be different in a WW2 fighter as compared to a modern jet. In most cases, this is because of the ability of the piston engine to produce its maximum thrust (power) at its lowest speed. This is not true of jets...most jet engines do not produce their max thrust in the lower speed range...consequently, their corner velocities occur at speeds above the stall. In a prop plane, the corner speed occurs at or very near the stall.

Because of this, many WW2 sim pilots fly a technique known as 'stall fighting'...this means they turn at a speed just above a stall in the knowledge that this will give them their best turn. 'Best' in this sense means smallest turn radius and max turn rate.

Corner velocity has nothing to do with sim AI induced 'blackout'. The sim's AI G value that has been programmed in as the point at which the pilot begins to lose consciousness is an artificial boundary on pitch control. In practice, however, it may well serve as a G limit since you as the sim pilot can no longer see anything if you continue to pull on the pole...just understand that this G limit has nothing to do with aircraft performance...only pilot performance.

As a way to determine corner velocity in AH, try this. Fly in level flight (clean...no flaps) at a slower speed than you anticipate corner velocity to be. Roll into a steep turn as you simultaneously add full power. Maintain level flight and smoothly increase your G until the 'stall' buzzer sounds. Continue to turn on the stall buzzer...add back pressure until you achieve the max G allowed according to the AH aircraft figures...or the G induced blackout begins. Your airspeed should continue to build and its value at the max G point will be your corner velocity for that weight and altitude. If the G blackout occurs first, then that becomes your practical value for max G at the slowest speed...it isn't corner velocity, but it will be a realistic limit.

BTW...if you have questions regarding those SimHQ articles, post your questions on the SimHQ Tiger Talk forum or e-mail the author at alfakilo@doitnow.com.

Good luck,

Andy

[terracota]

well now is clear thanks a lot guys!