the turn fight and why it kills

[crutch]

adding power and causing a climb is a function of lift. moving faster means more air over the wing and increased lift leading to a climb.  but it doesnt induce a turn, if it did the plane would not just climb but increase the angle of attack until the nose was pointed straight up.  that doesnt happen does it?

A turn is simple, sort of, physics.  three things define a turn; velocity, radius and accelleration (Gs).  a turn is a unique combination of all three components.  change one of them and you change one or both of the other components.

changing the Gs does the most to change the radius and the turn rate. it is much more effective than changing velocity.

[Mace2004]

I understand your point and I'm not arguing that. My point is that airplanes typically don't speed up when you add power, they climb. If you consider a turn to be a horizontal climb then you can see where adding power while maintaining G would increase the turn rate not the speed.

You're confusing a specific example for one flight condition with the more complex relationship between power and overall aircraft performance.  The idea that an airplane will climb rather than accelerate when you add power is true but assumes the pilot does nothing but add power and is a bit simplistic.  If you're trimmed for straight and level flight and add power with no adjustment to elevator position or trim the airplane accelerates above its trim speed and climbs.  You reduce power and it will descend.  On the other hand, the airplane will certainly accelerate (or decelerate) rather than climb (or descend) if you simply adjust your trim and elevator position.  In both scenarios, what we're really talking about is specific excess power (P_s) and that's what Crutch is talking about.

P_s describes the relationship of available power to the power required to sustain a given flight condition.  In trimmed, stabilized, level flight (i.e., a constant airspeed and altitude) P_s=0.  Add power and P_s>0 and the aircraft climbs.  Reduce power and P_s<0 and the aircraft descends.  The same relationship is true for a stabilized level turn but you have to consider G (since level flight assumes a constant 1G.)  If an aircraft is stabilized in a level turn and maintaining G, altitude, and airspeed it is at P_s=0.  If you increase power at least one of those three factors will have to increase because P_s will be greater than 0 and that extra power has to go somewhere.  In Crutch's example if you maintain constant G and altitude then airspeed must increase.  If you maintain altitude and airspeed then G must increase.  If you maintain airspeed and G then altitude must increase.

[crutch]

this is where my no being a real life pilot shows

I only know the things I know now because I have been interrested in flight for 25+ years.  only in the last 10 years or so have I truely begun to understand the intracscies of flight. even now just because I understand what is supposed happen doesnt mean I can get out there and fly rings around everyone else, far from that

[FLS]

It seems you both just illustrated my point. If you increase power in a turn while maintaining G load then you increase lift which increases the turn rate.

[crutch]

lets try this:

 C---------------R-----------------P-----A-->

C = center point of the turn
R = Radius
P = the Plane
A = the direction of acceleration (Gs)

if you increase the speed and keep the acceration the same then R stays the same. the formula for this is R=V*V/A
V is feet/sec and A = feet/sec/sec
If R increases, the flight path also increases by this formua = flight path = 2 * R * PI (PI = 3.14159)
generally your speed isnt fast enough to motor around that increased path any faster than the slower speed.
a contradiction but true.

[FLS]

Well now you're talking about speed not power but I see the issue. You can't increase lift in a turn and maintain the G load unless you reduce the AOA which is what increases your speed and turn radius.   

[Badboy]

Hi Crutch,

I would like to point out some aspects of your post which I think could be misleading for anyone trying to learn how to win in the situation you describe in the example of an "actual fight" because the conditions you use are a better description of what to do if you want to lose, and not really representative of an actual fight. Also, the conclusion of your post:

The absolute guaranteed way to win a turn fight is not to get in one.

is even more misleading, because you can't win a fight you aren't in, and overlooks the things that really can be done to ensure success in a turn fight.

Allow me to explain: 

Example:
Two pilots are fighting a duel, each are flying the same aircraft, Spitfire Mk 9s.  Both pilots have the same fuel and ammunition loads.  The determining factor here is pilot skill. Each pilot enters a turn with exactly the same airspeed (250 IAS) and G-load (3 Gs) and they are in full knife edged (90 degree) banks.

In your initial post you mention that "You can see an aircraft's best turning numbers are unique for a sustained turn" however, what may be confusing to some is that the figures you have presented are infact instantaneous values, and that if those conditions are sustained, if that is even possible, it implies that the pilot deliberately holds the given speed and g which in your example, is entirely the wrong thing to do, because staying at 3g in a duel is likely to concede a first shot opportunity to a more aggressive opponent.

More realistically, both pilots would attempt to max perform their aircraft in the turn and that implies higher g and loss of speed, at which point the fight will be determined by how each pilot manages his energy in his effort to gain angles.

Even for similar aircraft and equal starting conditions victory will go to the pilot who does that the best. Just because the fight starts equal, in terms of speed, altitude and position, what we call co-E, doesn't mean that the situation will remain equal for long. Everything a pilot does, every control command and every maneuver will involve an exchange of energy for position, each degree of turn has to be paid for, and the pilot who pays the least wins.

So, the best way to win a turn fight isn't to stay out of it, and it isn't just about a simple concept of instantaneous turn radius and rate.

Winning in a turnfight is about learning how to gain the most angles for the least energy, and how the geometry of the fight and the maneuvers used,  influences that trade, and knowing how everything you do influences the energy balance relative to your opponent. Then how to convert any incremental energy gains you achieve during the fight into angular gains that build into an eventual kill.

The point is that even in the hardest turning fight where energy is being lost rapidly by both pilots, and where it may appear on the surface that they are both oblivious to the cost in energy, the pilot who wins the rate war will be the pilot who gets the most angles for the least energy. So any discussion of how to win in a turn fight that focuses on instantaneous turning examples, and doesn't consider sustained turning ability, energy, Ps and how various maneuvers influence those things, will always be incomplete and potentialy misleading.

Hope that helps...

Badboy

[crutch]

Badman, my point about the best way to win a turn fight is not get in one is this;
once a pilot is commited to a turn fight he is more/less fixed in place on the map.  if he is in friendly territory he is more likely to recieve aid than the enemy. if the fight is in enemy territory then his foe is more likely to get aid.  either way is bad. if the former, someone else is probably going to get the kill of the bandit. if the latter, he is going to be outnumbered while he is low and slow.

the other little nasty secret of turn fights is this, if you are losing a turn fight they are damn hard to get out of.  most of the time you are down low and cant dive away to gain speed. the bandit is already in your rear. very not good.

I am NOT saying never turn, you cant do any real BFM without some turns, but be smart about it.  fight out of his plane of motion and use your roll rate against his turn rate. hight and lo Yo-yos, barrel rolls to offset your turn center and so on.

[Badboy]

Badman, my point about the best way to win a turn fight is not get in one is this;
once a pilot is commited to a turn fight he is more/less fixed in place on the map.  if he is in friendly territory he is more likely to recieve aid than the enemy. if the fight is in enemy territory then his foe is more likely to get aid.  either way is bad. if the former, someone else is probably going to get the kill of the bandit. if the latter, he is going to be outnumbered while he is low and slow.

If that was the point you were trying to make, it may have been better if you had said that in your original post, instead of presenting some unrealistic situations in a simplistic and misleading way.

Badboy

[papjohns]

If that was the point you were trying to make, it may have been better if you had said that in your original post, instead of presenting some unrealistic situations in a simplistic and misleading way.

Badboy

I for one appreciate the simple fact that you took the time to do the writeup, thank you crutch. There are few that will take the time to lay out information as you have. Of course I am new, so I have no clue if it is misleading or not, but to me it seemed like a sincere attempt provide informative data...

[TequilaChaser]

Of course I am new, so I have no clue if it is misleading or not, but to me it seemed like a sincere attempt provide informative data...

This is why when something is posted on these boards ( especially here in the Help & Training Forum), it is our duty to follow up on them and present an accurate reason of how or why it is misleading and then offer a more accurate methodology with maybe even examples to correct any misleading information or theorys....

your post is a perfect example of why this is needed..... you yourself posted you did not know if it was misleading or not, and if it is infact misleading then the data is not imformative at all and sends a new player down the wrong road....

The Aces high Community appreciates all Help & Training posts made, that people offer to try and help other community players... and this particular thread is not being scorned for being inaccurate, It is just being corrected so people like you, are not mislead or lead down the wrong path...

with just a bit of re-wording, crutch could have explained the difference between Instantaneous turn rate/turn radius & Sustained Turn Rate / Turn Radius...... and used a little more detail and all would have been possibly ok..... it is all in the wording & the example used.....


my thoughts on the matter anyhow, and I too appreciate any write-ups , Information people post here in the Help & Training Forum, just as long it is the correct information being posted... this is not a arguement / complaint / Flame by any means.......

hope this helps....

[crutch]

this was not an attempt to explain sustained turns or instantaneous turns, I do that in another section of my book. it was an attempt to explain the physics of a simple flat turn.   the example I gave was overly simplified, intentionally to make the physics easy to understand.

if I have opened any discusion at all I have accomplished my goal.

[FLS]

I thought you had some helpful information there crutch, I mainly wanted to point out that simply adding power doesn't increase speed like it does in a car since this isn't generally understood by newbies.

I need to remember that it's ok to read in the middle of the night but I shouldn't post when I'm sleepy.   

[Badboy]

this was not an attempt to explain sustained turns or instantaneous turns, I do that in another section of my book. it was an attempt to explain the physics of a simple flat turn.

That's commendable, but unfortunately the the physics you have presented is not the physics of a flat turn, not even a simple one, as you state above. The physics of a flat turn requires that an aircraft maintain at least one G vertically upwards to prevent it from falling out of the sky.

So anyone trying to learn from your calculations might also be misled. To illustrate that point, consider the aircraft in your first example which is doing 250mph IAS at 3g, and lets say it is at 5000ft ASL, based on the way you have done your calculations, the turn would never be completed because the aircraft would hit the ground well before they made it all the way around the first circle. It's actually worse than that, because you have used IAS in your calculations and so your figures would only be correct for sea level, but for the same reason, the type of turn that your calculations describe would be over the moment it began at sea level.

if I have opened any discusion at all I have accomplished my goal

Indeed, I'm sure this discussion may prove helpful. There are also a number of other potentially misleading issues in various messages in this thread that remain unchallenged, and I would simply advise anyone trying to learn from this discussion to seek further clarification before accepting any points that don't seem to fit your current understanding of the topic.     

Badboy

[FLS]

Let me restate these so I don't mislead anyone.

I understand your point and I'm not arguing that. My point is that airplanes typically don't speed up when you add power, they climb. If you consider a turn to be a horizontal climb then you can see where adding power while maintaining G would increase the turn rate not the speed.

My point is that airplanes typically don't speed up when you just add power, they climb. If you consider a turn to be a horizontal climb then you can see where adding power while maintaining angle of attack would increase the turn rate not the speed. Of course this would increase the G load so your example of maintaining G means you'd have to reduce the AOA which would increase your speed.

It seems you both just illustrated my point. If you increase power in a turn while maintaining G load then you increase lift which increases the turn rate.

If you increase power in a turn while maintaining angle of attack then you increase lift and G load which increases the turn rate as Mace so helpfully pointed out.