how to achieve maximum turn rate

[wolle]

Does anyone have a recipe for achieving the maximum turn rate. Throttle open/closed? Ideal airspeed? Ideal g?

[louisv]

Does anyone have a recipe for achieving the maximum turn rate. Throttle open/closed? Ideal airspeed? Ideal g?

 

Cornering speed: 270 mph (not sure if that's how its called, but that's how I remember it...)

 

I'm pretty sure its in the book.

[WildBillKelsoe]

Cornering speed: 270 mph (not sure if that's how its called, but that's how I remember it...)

 

I'm pretty sure its in the book.

 

^ that and

from the manual p. 100-101/183

 

When you lower the flaps, the airplane becomes nose heavy.

When you raise the flaps, the airplane becomes tail heavy.

When you retract the landing gear, the airplane becomes tail heavy.

When you lower the landing gear, the airplane becomes nose heavy.

Similarly, normal flight attitude changes can be expected when raising or lowering the flaps and landing gear. Increased drag causes the aircraft to lower the nose, while decreased drag results in raising the nose.

The P-51 does not hold a sustained side-slip. The aileron control is not sufficient to hold the aircraft in a side-slipping angle. However, side-slip can be maintained for a short duration of time in an effort to evade enemy fire. When any side-slipping is attempted, complete recovery should be achieved above 200 feet to avoid ground collision.

 

Of course, turning with gears down is a nutcase....:smartass:

[Flamin_Squirrel]

Does anyone have a recipe for achieving the maximum turn rate. Throttle open/closed? Ideal airspeed? Ideal g?

 

louisv has given you corner speed of 270mph. This will give you the highest instantanious turn rate. So at that speed, (throttle open/closed - doesn't make much if any difference) you'll get max turn rate.

 

When you pull back hard at 270mph however, you'll bleed off energy and start slowing down. As you slow down below 270mph your turn rate will decrease; to minimise this, you'll want as much power as possible to keep your speed up. However there won't be enough power to maintain 270 mph (even modern fighters can't maintain corner speed in a sustained turn) so your speed will drop off until you've got enough power to maintain a slower speed. At this point you're maintaining your sustained turn rate.

 

Therefore to answer your original question, for max instantanious turn rate you want to be at 270mph but throttle isn't so important, for max sustained turn rate you want full power and your speed will take care of itself (but it will always be less than corner speed) :joystick:.

[tintifaxl]

That's a very good explanation here.

[MACADEMIC]

If I remember correctly, the manual says 270mph is Maneuvering Speed (Va) which it then equals with corner speed. I'm not sure this is correct. Maneuvering speed is a maximum speed at which maximum control forces can be applied to the airplane without the risk of structural damage, since stall will occur earlier than damage (stall preventing the damaging forces). Above maneuvering speed, structural damage would be possible. How this should relate to best turn rate I do not understand.

 

MAC

[MTFDarkEagle]

Yep, cornering airspeed is 270.

[Tailspin45]

...Maneuvering Speed (Va) which it then equals with corner speed...

 

It's all about Q (total energy) in then end, whether it's an angles fight or an energy fight.

 

See Fighter Combat Tactics and Maneuvering By Robert L. Shaw. Page 387-392 covers corner speed

[Flamin_Squirrel]

If I remember correctly, the manual says 270mph is Maneuvering Speed (Va) which it then equals with corner speed. I'm not sure this is correct. Maneuvering speed is a maximum speed at which maximum control forces can be applied to the airplane without the risk of structural damage, since stall will occur earlier than damage (stall preventing the damaging forces). Above maneuvering speed, structural damage would be possible. How this should relate to best turn rate I do not understand.

 

MAC

 

Manouver speed and corner velocity are indeed the same. Here's an article that should explain why: http://www.simhq.com/_air/air_011a.html

[FLS]

Corner speed is the slowest speed that allows max load factor. Max load factor in the P-51 would be pilot blackout instead of airframe limits since we want a conscious pilot for our max turn. Corner speed is approximated by your clean stall speed at your current weight multiplied by the square root of the load factor. So if you have a 7 G load factor the square root is about 2.65. If your clean stall is at 100 mph your corner speed would be 265. Note that you only get your max turn rate at corner speed when pulling max G so you would pull to the sustainable beginning of blackout.

[Yo-Yo]

Corner speed is the slowest speed that allows max load factor. Max load factor in the P-51 would be pilot blackout instead of airframe limits since we want a conscious pilot for our max turn. Corner speed is approximated by your clean stall speed at your current weight multiplied by the square root of the load factor. So if you have a 7 G load factor the square root is about 2.65. If your clean stall is at 100 mph your corner speed would be 265. Note that you only get your max turn rate at corner speed when pulling max G so you would pull to the sustainable beginning of blackout.

 

This rule of thumb must be corrected a little though for 90% of practice cases it does not matter.

The max lift for unswept wing is significantly different for a low Mach 1G stall and accelerated stall at high M (at high altitude for example).

[MACADEMIC]

Thanks all for the replies to my question. Good information.

 

MAC

[Echo38]

Okay, before I go spend a couple of hours doing some laborious flight tests, has anyone done a test to determine our P-51D's best sustained turn speeds?

 

The test in question involves making coordinated turns a few yards above the water, at a set speed, weight, and power setting. If each 360-degree turn is performed at a different speed (e.g. one at 150 MPH, one at 160 MPH, one at 170 MPH, etc.), with all else constant, and how long it takes to complete each turn is recorded, then the speed which produced a 360-deg turn in the shortest time is the best sustained turns speed.

 

Of course, best sustained turn speed changes with mass, altitude, and power settings. Higher weight means higher best climb and best sustained turn speed. Higher power settings also means those two speeds will be higher. Higher altitude, however, means those speeds will be lower.

 

The USAAF pilot training manual for the Lockheed P-38 has a nifty little chart for best climb speed at various weights, power settings, and altitudes. Back in the day, I used that to calculate the power settings and weights for the Lightning I was using in whichever sim-game I was playing at the time. I flew with lighter fuel loads than the Berlin run pilots did, and so the weight was actually lower than the chart went, and the horsepower ratings on the L model were higher than the chart used, but a little bit of mathematics allowed me to extrapolate and complete the chart.

 

In those less-realistic sim-games, best sustained turn speed tended to be pretty close to best climb speed, but here, all bets are off; this sim is much different to those older games in many areas. So, I'm considering doing some test turns, but, before I do: has anyone already done them?

Edited September 25, 2012 by Echo38

[Sepdawg]

Ironhand did a tutorial sometime ago covering the concepts involved with instantaneous turn rate, corner speed, turn radius and the relationship between them. It was geared toward FC2 but the concepts he presents would apply here. It's the BFM 101: Understanding Corner Speed video on his site. http://flankertraining.com/ironhand/a2a.htm :thumbup: