corner speed

[df54]

 


 
  can anyone give me a rough estimate of the corner speed for a yak9u.

[DoNKeY]

In the mean time until more knowledgeable people drop by, I'd say that depending on weight (fuel mainly) that it's going to be somewhere around 250ish, give or take a little.

donkey

[Mace2004]

I did a quick check with a windup turn and Donkey has it right.  It's about 250 with half gas, about 3k ft alt and stall limiter off.  It's tough to nail it precisely without a full range of data points to generate a full maneuvering diagram.

[df54]

   

   many thanks mace. not to much info on yaks cept at sodas or doc gonzo. wish i could locate e-m for yak.

[Badboy]

many thanks mace. not to much info on yaks cept at sodas or doc gonzo. wish i could locate e-m for yak.

[DoNKeY]

How do I interpret the (almost) horizontal bottom blue line that seems to cut threw the rest of the blue functions graph?

Thanks

donkey

[Mace2004]

Thanks for the diagram Badboy.

Donkey, the line you mention is the Ps = 0.  In simple terms, the airplane is neither losing or gaining energy.  This gives you the maximum sustained level turn for the aircraft.  In this case the 9u with 25% fuel at sea level.  Per the diagram, the 9U should be able to sustain a max continuous level turn at 160mph with full power giving you about 2.8G, slightly more than 20deg/sec and a turn radius of about 680 ft.  Corner velocity is 235mph.

[DoNKeY]

That's where Ps equals 0.  In simpler terms, the airplane is neither losing or gaining energy.  This gives you the maximum sustained level turn for the aircraft.  In this case the 9u with 25% fuel at sea level.  Per the diagram, the 9U should be able to sustain a max continuous level turn at 160mph with full power giving you about 2.8G, slightly more than 20deg/sec and a turn radius of about 680 ft.  Corner velocity is 235mph.

Got it.  Thanks.

donkey

[df54]

   therefore judgeing by the em diagram the yak is an energy fighter and should avoid angle fighting.

[Soulyss]

   therefore judgeing by the em diagram the yak is an energy fighter and should avoid angle fighting.

Not necessarily, sticking to one or the other merely handicaps your thinking.  Most successful dog fighters will switch back and forth depending on the situation at hand.  The trick is to know when to give up angles and go for creating an Energy gap and when to convert to angles and back.

For instance, if I engage a plane with a smaller turning radius but I set up the angles in my favor on the first merge, even if I don't get a shot I can force the other guy to burn his E to try and get those angles back on me, while conserving my own E. 

I'm not sure how long you've been flying, and I'm no hotshot myself, however there is a tendency to think either E or Angles when people start out, I know I used to think in those terms and in the end I think it just limits your options and growth.  Think in both worlds and instead focus on when to use one strategy or the other, or both.

[df54]

   


    im not a noob been flying ah for a few years and flying the yak excluisively for a year. Although the yak has some major drawbacks
such as low ammo, low speed handling and e-retention i just like the little bugger. I'm just not makeing  good use of its assets like speed and maneuverabilty. Everybody seems to think its small size makes it difficult to shoot down but i don't find that to be true. Does anyone know of a trainer i could spend some some time with so i can get the
best out of this plane. As already stated i'mnot makeing good
use of the transition from e-fighting to angles fighting.
buy the way i would like to thank bad boy for his e-m diagram.

















   

[Yossarian]

This is probably a bit of a lazy/noob question, but what exactly is meant by "corner speed"?

Thanks,
Yossarian

[Mace2004]

This is probably a bit of a lazy/noob question, but what exactly is meant by "corner speed"?

Look at the diagram Badboy posted.  Follow the blue line on the left that goes up and curves to the right.  That line is called the "Lift Limit", anytime you're to the left of that line your stalled.  At the peak the lift limit line intersects another line.  That line is your maximum G limit.  Anything above that and you'll overstress the airplane.  The intersection of the lift limit line and g limit line is the "corner velocity".  Corner is that point at which you have maximum instantaneous turn rate and minimum turn radius 

[Badboy]

   therefore judgeing by the em diagram the yak is an energy fighter and should avoid angle fighting.

That depends on what adversary aircraft you are referring to. A fighter only becomes the Angles or Energy fighter in comparison to a specific enemy aircraft and for specific aircraft configuration. This is easier to see if you overlay EM diagrams. Here are two overlays for the Yak9U one with the Spit16 and the other with the P-51D. In the first case, against the Spitfire you would be right, the Yak would need to keep the fight fast, employ energy tactics. Also, looking at that diagram it can be seen that the Spitfire has a Ps advantage at all speeds below 300mph so as the Yak driver I would want to engage with a significant energy advantage, use energy tactics, and break off the engagement before the advantage was gone, and use my small speed advantage to bug out. 




Against the P-51D though, the situation is different. Inspection of the diagram below shows that the Yak9U is the Angles Fighter. If you can force the P-51D to engage you will have a significant sustained and instantaneous turning advantage.




However, that is configuration and altitude specific, so a heavy Yak v a light P-51D can make a difference. For example, the diagram below shows what would happen if a Yak9U with 100% internal fuel met a P-51D that was down to 10% internal fuel.



Here you can see the situation is very different, a slight instantaneous advantage to the Yak9U, but a clear sustained advantage to the P-51D. In this situation the the higher Ps for the P-51D would mean that the Yak would slow down more quickly, which combined with its slightly better instantaneous values would give it an advantage in the one circle fight, say a scissors, while the P-51D would have an advantage in a two circle fight, say a protracted Lufbery. However, with the margins as close as this, the outcome is more likely to be determined by other factors, such as pilot skill.

Lastly, you will notice how the corner velocity is dependant on aircraft weight, for example in the last EM diagram the heavy Yak9U has a corner velocity much closer to the 250mph value suggested earlier.   

Hope that helps.

Badboy 

[BnZ]

Also, looking at that diagram it can be seen that the Spitfire has a Ps advantage at all speeds below 300mph so as the Yak driver I would want to engage with a significant energy advantage, use energy tactics, and break off the engagement before the advantage was gone, and use my small speed advantage to bug out. 


Badboy 

Cherry-picker! Run-Tard!

Seriously though, <S> to you and your plethora of informative posts on this board.