Some help with flaps

[mitch22]

I'm really having a tough time getting the knack of flaps during a dogfight. I get that they provide additional lift and will help slow me down when landing with the extra drag they provide. What I can't seem to "get" is the balance between turning in a fight vs the drag. I mean, when I drop flaps and try to turn inside my opponant, the aircraft gets real sluggish which means I usually have to go WEP to maintain control. Doesn't that defeat the whole purpose of turning slow with a tighter radius?  What am I doing wrong?

mitch

[TexMurphy]

One of the best times to deploy flaps is at top of a vertical manouver... helps you swing your nose around faster...

Start training that and move on from there...

Tex

[TequilaChaser]

heya mitch,

somewhere we lost contact, my apologies, I never got to this part of helping you.......

drop me an email, and I will be glad to work with you on differing situations of when it is wise and not wise to use flaps......

look forward to working with you again ~S~

[Target2]

Mitch, just one little clarification.

Flaps are not used to "slow you down". They are used to increase lift WHEN you slow down, thus allowing you to remain airborn at a lower airspeed. This makes landing alot easier.  They do increase drag which will slow you down further. Throttle adjustments are required to maintain minimum airspeed.

Deploying flaps when you are in a slow turn fight will require a throttle adjustment so you don't stall.

[bozon]

Flaps should be used with care. They are aerodynamically inefficient, meaninng they produce more lift but even more drag. This can work for you or against you.

Turn RATE -
Instantanious turn rate (short duration) simply depends on how much lift you can produce. If you can't black out in the turn, deploying flaps will assist you. However, this is not a sustained turn, meaning, you'll be loosing speed fast and your turn rate with it - good for reducing your turn radius and "cutting the corner" but bad for your turn rate after a short while. Sustained turn rate suffers from flaps as you can see in MOSQ's tests.

Turn RADIUS -
Generally speaking, if you want a tight turning circle, you'd want to go as slow as possible (up to a point). With lower airspeed your lift drops till even maximum angle of attack cannot sustain you. Here flaps will add the needed lift at the cost of more drag. If your engine is strong enough to compensate, you will benefit from the flaps in a sustained tight turn. However, if in your specific ride, full flaps generate more drag than your engine can compensate for, it might be better to retract a notch.

Speed management -
Flaps generate drag.  In some cases it is the drag that you want more than the lift. Slowing down quickly allows you to create over shoots and reduce turning radius quickly. In scissors fights, the one that can slow down quicker or, in a prolonged engagement, fly slower, wins.

A good pilot knows hows when to trade speed, radius, and turn rate.  This is not a clear cut case and that is why even a P47 can "out turn" a spitfire sometimes. Always remember that flaps eat your energy, but it is well spent if it gives you that one shot oppertunity you need.

Bozon

[Arcades057]

Speaking of flaps, I usually fly the Zeke (A6M5) and like to turn fight.  Most often I get low with a con, commit to a turn, hit the rudder in the direction of the turn, then when speed gets low I hit flaps a notch or two.  Recently my flaps haven't been deploying until I get to 100MPH I believe.  Is that WAD or a bug?

Also am I doing that right, or should I be engaging somehow differently?  I'll say it usually works, unless the con is a Hurricane, then it out turns me almost immediatley.

[Murdr]

Originally posted by mitch22
I mean, when I drop flaps and try to turn inside my opponant, the aircraft gets real sluggish which means I usually have to go WEP to maintain control. Doesn't that defeat the whole purpose of turning slow with a tighter radius?  

No it isnt defeating the purpose.  You only gain speed when you have excess power.  Conversly if you are losing speed, then you are using more power than your engine is producing.  What you are doing with WEP is adding more thrust to feed the drag you are creating in your maneuvers.  

You can only turn as tight a radius as :  Your airframe is aerodynamically capible of without departing; and the thrust you have availble to overcome the volume of air your displacing.  When you deploy flaps and go to WEP your are maximizing both considerations.

[pellik]

Previous mention of turn radius is a bit off in this thread. The mistake that I believe is being made by Bozon and Murdr has to do with the generally poor quality of most documentation on flight physics on the net, though, so its a pretty common misunderstanding.

The problem is that almost all formulas for turn radius you find are actually formulas for radius in a level turn. Turn radius when altitude loss is ignored is a reasonably static function of the airframe itself. A plane at it's best turn will have the same radius from the point where it has enough speed to fly right up until maximum G loading is reached. Low low speeds change the aerodynamic properties of a plane, which is why stalls are, well, stalls. High speeds increase radius because the G forces experienced when attempting to turn require the plane or pilot increase the radius to reduce stress, which then reduces the radius just as if the pilot let up on the stick a lower speed.

Of course radius is only a very small part of maneuverability. If it takes you 5 minutes to fly in a small circle you're not going to beat anybody.

[bozon]

We were refering to level turning.

Of course radius is only a very small part of maneuverability. If it takes you 5 minutes to fly in a small circle you're not going to beat anybody.

That is not entirely correct. If you position yourself inside the other plane's circle and keep a tighter circle, he may turn 5 revolutions a second and not get guns on you. At the same time he'll be manuvering himself into your gun.
In such a scenario, the other plane, with the better turn rate, needs to displace his circle from yours by doing oblique turns or adding vertical components - not keeping his sustained turn.

Bozon

[pellik]

Originally posted by bozon
We were refering to level turning.
 
That is not entirely correct. If you position yourself inside the other plane's circle and keep a tighter circle, he may turn 5 revolutions a second and not get guns on you. At the same time he'll be manuvering himself into your gun.
In such a scenario, the other plane, with the better turn rate, needs to displace his circle from yours by doing oblique turns or adding vertical components - not keeping his sustained turn.

Bozon

I didn't say that turn rate is everything, but rather that if your turn rate is too rediculously slow radius is moot. Consider actually spending 5 full minutes to turn 360 degrees. Thats only a little bit over 1 degree per second. Maybe you could do alright with that rate if you had some sort of turret mounted gun, perhaps.

I don't see where in any of the previous posts the turn is defined as level.

[Murdr]

Originally posted by pellik
Previous mention of turn radius is a bit off in this thread. The mistake that I believe is being made by Bozon and Murdr has to do with the generally poor quality of most documentation on flight physics on the net, though, so its a pretty common misunderstanding.  

Oh??  Show me the alledged quote.  I only pointed out that adding power does not nessacerly mean adding speed.

[pellik]

Originally posted by Murdr
Oh??  Show me the alledged quote.  I only pointed out that adding power does not nessacerly mean adding speed.

You can only turn as tight a radius as : Your airframe is aerodynamically capible of without departing; and the thrust you have availble to overcome the volume of air your displacing.

So thrust to overcome volume of air determines radius?

I didn't want to pick fights with this post. Sorry if I seemed rude. I don't doubt that you guys know what you're talking about. I was in a strange mood, normally I don't knit-pick or correct people on forums.

[Murdr]

Originally posted by pellik
So thrust to overcome volume of air determines radius?
 

Well, it wasn't a stand alone comment, but, eventually, and inevitablely, in the context of best sustained turn radius, yes.  "Sustained" by definition assumes that additional energy kinetic (speed), or potential (altitude) is eventually not going to be avalible.  Say that your planes wing can carry the angle of attack required to make a 250 foot radius turn, but it cannot produce enough thrust to overcome the drag induced by that AoA.  Your radius is being determined by the aerodynamics of your airframe until your power deficit brings you to stall speed.  At that point, your airframes max AoA is irrelevent.  Now you have to adjust either your AoA, or bank angle, or both so that your total drag is not greater than your availble thrust to stay above stall speed.  

Whatever combination of actions you took to balance out your thrust/drag/lift, your radius is now larger, and being limited by the thrust you have availible.  

The reason I answered the way I did in my first post, is because the original posters scenerio indicated that he was he was pulling instantanious turn rates until his E state hit bottom.  At that point the only energy he has avalible is the power (thrust) being produced.  I wanted to hilight the thrust/drag considerations of the scenerio.  Obviously if you have potential energy avalible in the way of altitude then you can supplement your thrust by adding a vertical component to your turn, but if you sustain that long enough, eventually you will run out of altitude, and enter the level turning realm that krusty and I were refering to.

If you want to call me on the way I worded that quote, it would have been much better of me to specify total energy instead of thrust.  But it was in the context of "...the aircraft gets real sluggish which means I usually have to go WEP to maintain control", which says to me we only have thrust to work with at that point.  I really try not to get into technical walls of text when replying in this forum because there is a wide range of people browsing here, and I want to make things as understandable as possible to the most people.  Maybe to a fault sometimes.  Heck, I never even touched on the effect weight is going to have on excess power avalilble, which is very important factor when looking at lift, thrust, and drag.  But that really isn't a nessacity to explain that adding wep, helps, not hurts turning perfomance when near speeds.

Hope that spells out all the qulifiers for my previous post.  Sorry if I got too simplistic the first time.

[pellik]

Yeah, the consideration of thrust is for radius in a level turn where the pilot maintains alt. My point was mostly that the turn discussed was not defined as a level turn. If you let the plane fall a bit you can keep your wings at 90 degrees and maintain a minimum radius. The radius doesn't suffer from low thrust until you reduce the bank of your turn to maintain altitude.