Flap Type and Efficiency

[TequilaChaser]

Don't forget Hammer's graphic.  The F4U only increases turn rate up to the third increment of flaps.  Any more than that and turn rate decreases.

my apologies for chiming in, but could you re-post or link to Hammer's graphic? I have not seen that one yet......

The F4U-1D will start losing turnrate but gain turn radius with any notch of flaps past the 2nd notch

The F4U-1C will start losing turnrate but gain turn radius with any notch of flaps past the 2nd notch

The F4U-1A will start losing turnrate but gain turn radius with any notch of flaps past the 2nd notch

The F4U-4 will start losing turnrate but gain turn radius with any notch of flaps past the 2nd notch ( <--- have to go double check this )

The F4U-1 will continue to gain turnrate/radius all the way to full flaps, or shall I say once the 1st notch of flaps goes out in the F4U-1 it remains constant all the way thru full flaps......

remember to find the best sustained turnrate includes both turn rate & turn radius combined....... you might be turning a tighter circle yet it is taking you longer to complete that turn......... the F4U-1 is the only one that does not get worst past the 2nd notch being deployed............although I am not advocating for people to always go "full flaps" either...

fly your plane to your strengths, and capitalize on your enemy's weaknesses......... going to full flaps in most cases means you got in over your head to begin with and are pulling out all stops to change the tide back to your favor......

YMMV.....

[TequilaChaser]

Raptor's diagram attributes a distinct "nose down pitch" to pretty much all the flap types when deployed.
In AH, all flap types generate a distinct "nose up pitch" when deployed.

So, which is right?
       

In AH, I would have to say that people flying with CT turned on or flying their plane out of trim, is what pitches the nose up when they drop a notch of flaps......... on the other hand, in my experience, I could drop 1, 2, 3, 4 notches and do not see a notable difference of nose-up pitch when dropping the flaps......

so again, I would relate that to how you are flying with no trim / manual trim or in most cases CT ( Combat Trim )

YMMV.......

[FLS]

TC I think Boozeman is referring to the common tendency of low wing monoplanes to pitch down when adding flaps and the fact that it seems this isn't the case in AH. Specifically he asked why certain flap types were noted to have a pitch down moment while AH aircraft all pitch up. If you look at the RAF POH for the Tempest or the Mustang III for example, they specifically state that the flap effect on trim is nose down. The POH for the F4U states that the flap effect on trim is "tail heavy at small flap angles, and nose-heavy at large flap angles." i.e. nose up for small, nose down for large.

Using auto trim of any sort would mask this. If you manually trim for level flight and drop flaps you see the nose go up for all 3 aircraft in AH. This is correct for the F4U for small angles of flaps but it pitches up for all flap settings.

Maybe it's modeled and I just don't see it. I believe that the pitch up is from the flap effect of increasing the AOA and consequently the lift. If the pitch moment of the flaps isn't modeled I don't know that it's worth complicating the flight equations further to add it. This isn't a training simulator for vintage warbirds. Maybe HiTech will chime in and clear it up for us.

[TequilaChaser]

Yes, FLS..... I basically was saying that CT does not take in to account the use of flaps....this is why most people see the nose pitch up ( in all AH planes )........

that is how I understand it being, although my understanding could be completely wrong...( I do not think it is though, and I am stubborn   )

edit: where I said:

on the other hand, in my experience, I could drop 1, 2, 3, 4 notches and do not see a notable difference of nose-up pitch when dropping the flaps......

I trim at a level speed of 325 to 340 IAS, in the F4U series AH planes, and then leave it there........... however right or wrong that is, does not matter to me, that is how /where I myself feel I gain the best performance from the AH F4U........also why I do not see a Nose Pitch-Up when I drop flaps...again my own personal experience.......however right or wrong it is...

got to get up and wing with you ole muskies sometime, would be fun  

[FLS]

I'll look forward to it TC. Look for us on Saturday nights and we'll tune.

I never use CT so I can't comment on it. The pitch up occurs with manual trim for level flight so even if Boozeman uses CT it doesn't change his question. I took it as a flight model question rather than a best performance in AH type question. Now that I'm thinking about it I'm curious. Some of the things that are modeled are very hard to notice since so many forces are working together or in opposition.

[Stoney]

my apologies for chiming in, but could you re-post or link to Hammer's graphic? I have not seen that one yet......

I misspoke...  It was Badboy's graphic.  Its buried in that threadnaught discussion that Gaston started about turning circles...

[Boozeman]

The CT does not have a noticable effect on this. The pitch-up is the same.

There is a very simple test everyone can do:

Take a P-38, take off, trim for level flight, accelerate to just shy of 250 on WEP, and then dial in flaps all the time. one stage will pop after another as the speed goes down and watch the P-38 do a beautiful looping without the slightest control input. With a bit of throttle management on the way down, you can essentially loop a 38 this way until it rus of of fuel, without control input. If that is no indication for a very distinct nose-up pitch, I dont know what is.

You can do the same with an F4U too, you just have to trim out the engine tourqe.

And dont let me start what a distinct advantage the 2 factors (nose-up pitch + high flap deployment speed) have in a stall fight. The question is, is it legitimate?
 

[FLS]

According to the P-38 POH adding flaps makes the control wheel nose heavy (pitch down) and increases lift ( pitch up). Adding flaps has the effect of increasing AOA so why wouldn't your nose go up the same as if you'd pulled your stick back?

[Anaxogoras]

I would be stunned to see a real WW2 era monoplane loop continuously just from dropping flaps.

[FLS]

I would be stunned to see a real WW2 era monoplane loop continuously just from dropping flaps.

So what do you suppose would happen if you were trimmed for level flight within your loop entry speed and dropped flaps? Given that flaps have the effect of increasing AOA and lowering stall speed.

[thorsim]

i thought flaps usually decreased the AOA ...

[FLS]

Since extending flaps increases your lift for the same speed and pitch, you have to trim nose down to continue flying level. You might think this means you decreased your AOA instead of thinking that you effectively increased the incidence of the wing so you adjust for that by lowering your nose.

[Stoney]

According to the P-38 POH adding flaps makes the control wheel nose heavy (pitch down) and increases lift ( pitch up). Adding flaps has the effect of increasing AOA so why wouldn't your nose go up the same as if you'd pulled your stick back?

Increasing lift is not what makes a pitch-up moment on the aircraft.  Dropping flaps on most aircraft in-game does induce a nose-up pitching moment--very important to understand the difference.  HTC has mentioned that flap-induced pitching moments are not necessarily modelled correctly in-game.  I'm not sure what the issue is, but he hinted in another thread that they were looking at a method to correct it.

[FLS]

Please explain the difference. 

[colmbo]

Given that flaps have the effect of increasing AOA and lowering stall speed.

Flaps increase camber, not AOA.