F4U turn performance, flaps, the real plane, etc (discussion)

[nrshida]

When you add flaps you add drag. If lift to drag improved why would you ever have your flaps up?

You're just looking at the difference between full flaps and none.  Fowler flaps can be relatively low drag but likely not after extending more than 50%.  Full flaps are designed for landing slowly, their effect on turn rate is secondary.

Not really sure if you're trying to pick through my posts to illustrate my ignorance  I have no doubt you know a lot more about this than I, I concede that point that's why I'm here asking.

The flaps on the Ki-84 were designed as manoeuvring flaps unlike the Spitfire say which were just for landing. That much I've read in the literature of the development of the Hayate. Further, Fowler flaps improve turn rate I read.

Your first point similarly applies to the Corsair. It's a simple enough question, how can the plain flaps on the Corsair increase it's turn rate with plain flaps while the Ki-84 can only maintain it with Fowlers? Do you know the answer or not?

[FLS]

Not really sure if you're trying to pick through my posts to illustrate my ignorance   I have no doubt you know a lot more about this than I, I concede that point that's why I'm here asking.

The flaps on the Ki-84 were designed as manoeuvring flaps unlike the Spitfire say which were just for landing. That much I've read in the literature of the development of the Hayate. Further, Fowler flaps improve turn rate I read.

Your first point similarly applies to the Corsair. It's a simple enough question, how can the plain flaps on the Corsair increase it's turn rate with plain flaps while the Ki-84 can only maintain it with Fowlers? Do you know the answer or not?

In simpler terms it's because the aircraft are different. You're assuming that Fowler flaps improve turn rate without considering the effect of their degree of extension.

[nrshida]

Can we please get past the condescending obviousness. I know about the extra drag but the F4U has extra drag too, more drag. I'm not comparing the rates of the different aircraft to each other, only the fact that the F4U's rate increases with the same lifting area and the Nakajima does not increase it's rate with MORE lifting area. If the Fowlers (not proper Fowlers in fact, but, nevermind) create so much drag which negates their benefit, then using your own argument why did they fit them at all?

Look I'm just trying to get to the bottom of this because I think it will be informative and I clearly have lacuna in my understanding. If you don't know just say so, that would be more helpful than dancing around.

[FLS]

Can we please get past the condescending obviousness. I know about the extra drag but the F4U has extra drag too, more drag. I'm not comparing the rates of the different aircraft to each other, only the fact that the F4U's rate increases with the same lifting area and the Nakajima does not increase it's rate with MORE lifting area. If the Fowlers (not proper Fowlers in fact, but, nevermind) create so much drag which negates their benefit, then using your own argument why did they fit them at all?

Look I'm just trying to get to the bottom of this because I think it will be informative and I clearly have lacuna in my understanding. If you don't know just say so, that would be more helpful than dancing around.

As the Fowler flaps extend they change their angle and the ratio of lift to drag changes. The same thing happens with the F4U flaps. Because the lift/drag change is different in each aircraft they have different comparative results at each flap extension.

[TequilaChaser]

Just incase it was overlooked in Badboy's "caught in a flap" thread... Only 1 of the F4U series really gains throughout using each flap stage... That is the F4U-1 model.... All others kind of degrade after the second notch when referring to max DPS in sustained turning...

TC

[bustr]

Once the flaps are out isnt this argument a compairison of the relative manuverability and effectiveness at the edge of the stall of both planes "current programing" within very low speed bands?

I am constantly amased at how well the F4U family manuvers with 3 notches of flaps slowly on the deck against rides I assumed without flaps out could saddel up with no problems. A6m, Hurri1\IIC, spit1-9, Ki84, N1K2, Brewster, I16.

I've come to expect spits to be just at stall, with flaps extended, and WEP to hold them in the air at the moment of a shot. While trying to win a lufbry race once everyone has flaps out on the deck. The F4U family with flaps simply appears to be able to hover in the air at slower speeds than spits on WEP with flaps extended. Often I'd rather face a K4 with flaps out. I've been through the same with a Ki84 and N1K2 and full flaps out. I was unable to hover with F4U making slow manuvers that had 3 notches of flaps out. I keep looking for the glowing cyan antigrav feild mod under the F4U's. Just an underappreciated, amasingly manuverable family of 5 ton bumble bees with awsume flaps.

But, when I try the same thing in the F4U family I simply hover flop into the ground, or get overtaken by all the planes I've listed low and slow on the deck.

Besides HTC's programatical offering of the F4U family, there probably is an optimal series of steps to reach hover mode in this game that a number of players execute more effectively than most within the "programed parameters" available to them at their finger tips. I remember years ago in the game when F4U low and slow were fodder except in the hands of a "few very talented experts" like MtnMan. Now days I'm a bit more wary of an F4U than an A6m or K4 in the hands of average players once the flaps are out and I'm slow with it.

Something has changed in 11 years. The F4U family seems to be more user freindly and manuverable than it used to be for the novice. A number of my squadmates have started using F4U as their easy mode ride to gain the center line bomb load, better gunnery from the P51, better rear view then the F6, and manuverability.

[nrshida]

As the Fowler flaps extend they change their angle and the ratio of lift to drag changes. The same thing happens with the F4U flaps. Because the lift/drag change is different in each aircraft they have different comparative results at each flap extension.

You don't know do you?

[FLS]

You don't know do you?

I just answered the same question 3 times. 


I won't waste any more of your time.

[nrshida]

I just answered the same question 3 times. 

No you didn't, you just made vague generalisations which were already obvious. You haven't contributed to this question at all, just sort of wafted the issue away while implying you understood it all completely. Fantastic, thanks for your input 


Can anybody else explain this specific technical question:-

How come the F4U can increase its turn rate with deployed plain flaps when the Nakajima can only maintain the same rate with deployed Fowler flaps? This doesn't make sense to me. Does it make sense to anyone else?

[Saxman]

Corsairs don't HAVE plain flaps. I think they're slotted, but I'm not sure.

[nrshida]

Corsairs don't HAVE plain flaps. I think they're slotted, but I'm not sure.

I'll take your word for it. They still don't increase the lifting surface though I think.

[mtnman]

They still don't increase the lifting surface though I think.

No, the F4U flaps do not increase the lifting surface. 

They are however of the slotted type, which have a gap between the flap and the wing.  This gap allows/forces high pressure air from under the wing to pass over the top edge of the flap.  This helps the air to remain attached to the top surface of the flap rather than separating from it (which would cause extra drag).  In addition, this design raises the velocity of the airflow over the trailing edge, which greatly increases the lift over the entire airfoil.

So, different from plain or slotted flaps, which generally add more drag than lift, the flaps of the F4U are changing the camber of the wing, redirecting the airflow, and using the redirected airflow to increase lift.  Of course, beyond a certain point the flaps produce more drag while not producing more lift.  There's a point of diminished returns.

The flaps on the KI84 are of the fowler type, which is essentially a split flap that slides backwards.  As a result of sliding backwards it increases the area of the wing which serves the purpose of decreasing wing loading.  Increasing the area of the wing isn't as beneficial as adjusting the camber of the wing though, in a discussion on flaps.  Raising the lifting area of the wing adds some parasitic drag, and does not increase the lift coefficient.  Changing the camber of the wing (which fowler flaps also do) does change the lift coefficient.

So, which is better?  Got me.  Although both designs are beneficial, the lesser flap design could actually equate to a more efficient wing if it adjusted the camber of that particular airfoil in a more beneficial manner than the "better" flap on the worse wing...  This part of the discussion is beyond my knowledge....

[nrshida]

No, the F4U flaps do not increase the lifting surface...

The Ki-84 flaps also increase camber and additionally the chord (unlike the Corsair). They are also slotted and not true Fowler flaps because the part closer to the fuselage extends further. Have a look:-



Did you test the angle of bank in a sustained turn Mtnman. I already posted mine above. That will make an interesting comparison.

[mtnman]

I don't think the flow is actually as you indicated. The relative wind is still the relative wind.

If a surface hinged horizontally can be expected to deflect air vertically (i.e. elevators, ailerons, flaps), and a surface hinged vertically can be expected to deflect air horizontally (i.e. rudder), and if the orientation of those surfaces is rotated and the deflection of the airflow changes/rotates predictably (i.e if the plane is banked 90 degrees the rudder will deflect air vertically while the elevators will deflect air horizontally) does it not logically follow that a surface hinged (or rotated) at a 45/135 degree angle would deflect air at a 45/135 degree angle?

And of course the relative wind behaves accordingly regardless of the control surface in question, right?

I have heard also that the gull wing design prevented the blanketing of the tail during nose high slow flight conditions...

I've heard the same.  The wing-to-fuselage arrangement is also reported to be less "draggy" than other arrangements.

...but during sustained low-speed flight...   ...I am not sure if that the case, especially with more than two notches of flaps.

Would it make sense that the airflow would change based on whether the slow speed was sustained or not?  At what point might we expect to see the change?  10 seconds of sustained flight?  20 seconds?  100 seconds?  This seems like an odd direction to argue, but if you can explain it further I'm all ears.

Beyond two notches of flaps...  The stabilizer is mounted above the wing.  The flaps drop below the wing.  The flaps direct the airflow down, relative to the stabilizer.  If the tail is lowered, the angle of air deflection off the flaps is also lowered.  It's relative.  I'm having trouble visualizing why sustained slow flight with more flaps dropped would change things?

My problem with the flap fights has always been that the people that do that sort of thing can even use full flaps. I don't believe that is relative to any reality. The problem being, as someone else pointed out (Badboy I think) that the nose rate has actually dropped below what would be the optimum with only two notches. So dropping flaps should be detrimental to angle fighting, but it seems to be everyones passion.

In the F4U, dropping more than 2 notches of flaps can definitely be considered detrimental.  I'll not argue that.  

However, "detrimental" is also relative...  I'll quite willingly drop more flaps than that and willingly accept the detrimental side effects, if I see that my opponent is ALSO flying or controlling his plane in a manner that's "detrimental" to him (or even more commonly, if he's using 3D space in a detrimental manner).  The sum of all those detrimental effects may still leave me in a more favorable position than my opponent...  I'm crafty and arrogant and always assume I'm going to win, so I'm willing to take things to the edge.  I'm usually right, too  

My entire point being (the problem I see in it) is that your entire idea of flap fighting is to get out of the way of attackers and yet you are not flying in an optimal manner at all. The reward of course is that once you finally get killed you can laugh and claim you had all of your flaps out for so long and no one got you, but you're still dead. Admitting to it. . . your call.

Honestly, I don't know how to take this.  If this section of your post is aimed at me, you have no idea what you're talking about.  

My idea of "flap fighting" is not to get out of the way of attackers.  Actually, I ALWAYS consider myself to be the attacker/aggressor; the poor fella who thinks I'm defensive just hasn't figured that out yet.  He will though, and very soon at that, lol!

Flying optimally?  I'm out to have a good time, and to kill the other guys, and make it home to land safely.  I think I fly the F4U pretty gol' dang optimally.  I think the vast majority of the guys that get near me in the MA would agree.  If not, I'm not so sure that bothers me?  I guess I haven't thought about it enough to have an opinion on that yet...  Gimme time, I just started playing...

That whole reward part about laughing at myself and claiming I had my flaps out for so long and all that is pure silliness.  If that's directed at me, you're clueless.  Admitting to that is just how you put it though...  Your call...

Now, I'm not attacking the way you choose to fly...

On the one hand, I couldn't care less what you want to do, or how.  On another, I'm excited about the chance to kill you while you're flying in a manner that you think optimizes your chances of survival while minimizing mine.  I'm also excited about the opportunity to trick you into or capitalize on a mistake you make (just as you're hoping to do with me, right?).  Just as I like to fight the hordes and multiple opponents "lone wolf" style.  I like the challenge!

I'm simply pointing out that you do not appear to have the first clue about what motivates me, or how I feel in the event that I get shot down.

[mtnman]

The Ki-84 flaps also increase camber and additionally the chord (unlike the Corsair). They are also slotted and not true Fowler flaps because the part closer to the fuselage extends further. Have a look:-

I spoke to the chord (referring to its effect on wing area).

Some fowler flaps are also "slotted" to a certain extent, but that's not the goal behind that design, and it isn't necessarily as effective as true "slotted" flaps.

When it come to the KI84 flaps, I'm nowhere near an expert.  Honestly, the F4U is the only fighter in WWII I care enough about to do any research on...

However, looking at the picture you posted, and a few more I just saw in a google search, and this video-  http://www.youtube.com/watch?v=NiqBOIVLRig  I see a few things that make me skeptical that they would be as efficient as the slotted flaps on the F4U (but of course I could easily be wrong...)  The section at the fuselage looks aerodynamically "dirty" to me.  Like a mix between fowler and split flaps, which is draggy.  Not only that, it's draggy at a draggy part of the plane (wing-fuselage joint).  The shape of the flap leading edge- is it shaped for optimal slotted flap effect?  Is the gap (and the gap shape) optimal?  What about the leading edge of the flap bay, on the lower surface of the wing?  This looks dirty to me too?

Again, I don't know, just pointing out what I see as potential deterrents to optimal airflow.  Maybe I'm wrong, and the KI84 flaps should outperform the F4U?  Got me, we need an expert.

Did you test the angle of bank in a sustained turn Mtnman. I already posted mine above. That will make an interesting comparison.

No, and unfortunately I don't expect to get into the game for the next few days at least.  I was actually hoping someone might be interested enough to try it in a few planes and post the results...