Aces High Bulletin Board

General Forums => Aircraft and Vehicles => Topic started by: SectorNine50 on January 25, 2009, 07:45:31 PM

Title: The P-51... And her flaps.
Post by: SectorNine50 on January 25, 2009, 07:45:31 PM
This topic I know has been talked about many times before in various threads, but I've never seen one specifically about it.  I've heard arguments to both sides, and I'm creating this to curb my curiosity more than anything.

So, the question is:  Are the P-51's flap performance in-game true to life?

I have no argument either way, and honestly I don't care much if the plane gets changed in-game.  I think it's a challenging and fun aircraft the way it is now.  However what I will say is that I notice that the last 2 or so notches of flaps don't seem to help the turn radius all that much compared to the other flap settings.  From what I've heard and read makes me believe that perhaps there is an error in the 51's flight model in-game, but not being an expert, I cannot be certain.

Let the debate begin!  I'd like to hear what you guys have to say about it.
Title: Re: The P-51... And her flaps.
Post by: Steve on January 26, 2009, 12:40:25 AM
This topic I know has been talked about many times before in various threads, but I've never seen one specifically about it.  I've heard arguments to both sides, and I'm creating this to curb my curiosity more than anything.

So, the question is:  Are the P-51's flap performance in-game true to life?

I have no argument either way, and honestly I don't care much if the plane gets changed in-game.  I think it's a challenging and fun aircraft the way it is now.  However what I will say is that I notice that the last 2 or so notches of flaps don't seem to help the turn radius all that much compared to the other flap settings.  From what I've heard and read makes me believe that perhaps there is an error in the 51's flight model in-game, but not being an expert, I cannot be certain.

Let the debate begin!  I'd like to hear what you guys have to say about it.

I can't say what how it performs to the real life counterpart but you gain little turn radius improvement after two notches of flaps, relative  to turn RATE performance and drag penalty. JUst my opinion, I fly the pony a bit.
Title: Re: The P-51... And her flaps.
Post by: moot on January 26, 2009, 12:51:03 AM
SectorNine50, you should say what you've read that makes you believe that there could be something wrong with the 51.
Title: Re: The P-51... And her flaps.
Post by: SectorNine50 on January 26, 2009, 02:30:44 AM
Dang, the HTC website is very slow right now...

I can't say what how it performs to the real life counterpart but you gain little turn radius improvement after two notches of flaps, relative  to turn RATE performance and drag penalty. JUst my opinion, I fly the pony a bit.
I agree, the last 3 or so notches on the Pony seem to be trival.

SectorNine50, you should say what you've read that makes you believe that there could be something wrong with the 51.
What I've read makes me believe that there could be something wrong with the modeling on the P-51. :aok
Title: Re: The P-51... And her flaps.
Post by: moot on January 26, 2009, 03:07:05 AM
So you have no references?
Title: Re: The P-51... And her flaps.
Post by: SectorNine50 on January 26, 2009, 03:36:01 AM
So you have no references?
Ohhh!  That's what your asking for, that makes much more sense.  1 AM here, excuse the lapse in intelligence.

I brought up this question out of sheer curiosity as someone had mentioned a "bug" in the flight model of the P-51 in another thread, I made this one so I wouldn't hijack the other one.  What was brought up is that the Jug, which has a much higher wingloading, turns much better when than the P-51.  However, since the P-47 has slotted flaps, I figured that might make the difference.  What has bugged me is how (what seems to be) every other aircraft's flaps seem to make a large difference in lift every notch.  This doesn't seem true with the P-51, it actually feels like after the 2nd or 3rd notch the flaps are just for looks.

I don't know enough about aerodynamics to make an accurate argument, but this topic intrigued me enough that I was hoping someone could enlighten me and perhaps start a discussion to get it fixed if a problem exists.  I'm a sucker for realism so for better or for worse (or maybe neither) I'd like to try to figure it out.
Title: Re: The P-51... And her flaps.
Post by: Bodhi on January 26, 2009, 09:31:27 AM
I think you are misunderstanding the use of flaps.  They are there to allow for continued handling at low speeds that are used during landings.  Not all aircraft were equipped with flaps designed to increase performance.  Some were, some were marginally, and some just weren't.
Title: Re: The P-51... And her flaps.
Post by: Anaxogoras on January 26, 2009, 09:57:13 AM
What has bugged me is how (what seems to be) every other aircraft's flaps seem to make a large difference in lift every notch.

Have you tested this assumption?  There are many aircraft in AH that receive no benefit whatsoever in turn-rate from flaps, some even turn more slowly.
Title: Re: The P-51... And her flaps.
Post by: Cthulhu on January 26, 2009, 10:02:06 AM
Went looking for flap info and found this:
http://www.zenoswarbirdvideos.com/P-51.html

Pretty sure most Pony guru's have already seen this, but it's full of good info. Doesn't really answer the OP's question though.

(Check out a "fat & balding" Lee J. Cobb)
Title: Re: The P-51... And her flaps.
Post by: CAP1 on January 26, 2009, 10:16:34 AM
i think that most any aircraft, be it military, commercial, or civilian, you'll find that once you go past 20 degrees of flaps, you're only increasing drag.


 one of our cfi's should chime in shortly though.....
Title: Re: The P-51... And her flaps.
Post by: BnZs on January 26, 2009, 10:24:31 AM
i think that most any aircraft, be it military, commercial, or civilian, you'll find that once you go past 20 degrees of flaps, you're only increasing drag.


 one of our cfi's should chime in shortly though.....

Lift continues to increase, but yes, the lift to drag ratio gets much worse
Title: Re: The P-51... And her flaps.
Post by: Cthulhu on January 26, 2009, 11:02:08 AM
Lift continues to increase, but yes, the lift to drag ratio gets much worse
CL increases, but Lift may or may not.
In other words, CL does increase with increased flaps, but like BnZ said, drag increases disproportionately, so unless you have huge additional power at your disposal (or can lower flaps at higher speeds), the increase in drag lowers your speed to the point where there is negligible to no increase in actual lift. And as Anaxogoras said, there may even be a reduction in lift. Also consider that to overcome the nose-down pitching moment generated by large flap deflections, you need higher elevator down-force as well. This will generate extra induced drag on the horizontal tail, so the drag just piles up.
Title: Re: The P-51... And her flaps.
Post by: BnZs on January 26, 2009, 11:04:48 AM
CL increases, but Lift may or may not.
 Also consider that to overcome the nose-down pitching moment generated by large flap deflections,

I'm glad you brought that up...I'd give my eye teeth for large flap deflections in AHII to cause nose-down pitching, instead of having to reach over the keyboard and input full nose-down trim once I get into a slow fight w/flaps.... :devil
Title: Re: The P-51... And her flaps.
Post by: Cthulhu on January 26, 2009, 11:20:58 AM
I'm glad you brought that up...I'd give my eye teeth for large flap deflections in AHII to cause nose-down pitching, instead of having to reach over the keyboard and input full nose-down trim once I get into a slow fight w/flaps.... :devil
I think you've already got him wrapped up there Chief. Ease off the stick a bit and the "Red" guy should magically appear. Unless of course you're using full down-elevator to keep that 6g turn from becoming a 9g turn. If so, then the rest of us are doomed. :D
Title: Re: The P-51... And her flaps.
Post by: BnZs on January 26, 2009, 11:24:55 AM
I think you've already got him wrapped up there Chief. Ease off the stick a bit and the "Red" guy should magically appear. Unless of course you're using full down-elevator to keep that 6g turn from becoming a 9g turn. If so, then the rest of us are doomed. :D

The nose up thing is kind of annoying if you are constantly dropping and dumping several notches of flaps...I dunno about you, but having to apply back-pressure on the stick is fairly natural, if I have to push forward on the stick to keep the nose from rising, all sorts of bounce and the gunnery goes to hell. Trim input takes time and finding the right key. I need more buttons so I can map one to trim I suppose.
Title: Re: The P-51... And her flaps.
Post by: Cthulhu on January 26, 2009, 11:32:40 AM
The nose up thing is kind of annoying if you are constantly dropping and dumping several notches of flaps...I dunno about you, but having to apply back-pressure on the stick is fairly natural, if I have to push forward on the stick to keep the nose from rising, all sorts of bounce and the gunnery goes to hell. Trim input takes time and finding the right key. I need more buttons so I can map one to trim I suppose.
Hey, I fly a Dora. The only time I drop flaps is to hopefully slow down below 200 before belly-flopping dead stick on to the runway.

But I know what you're talking about. You have scaled your stick to minimize nose bounce haven't you?
Title: Re: The P-51... And her flaps.
Post by: BnZs on January 26, 2009, 11:50:58 AM
Hey, I fly a Dora. The only time I drop flaps is to hopefully slow down below 200 before belly-flopping dead stick on to the runway.

But I know what you're talking about. You have scaled your stick to minimize nose bounce haven't you?

I tried having it scaled for a long time, but it actually seems to work better for me unscaled. Except for GVing, I click the scaling back on to have smooth movement on the turret.

No, the bouncing difficulties I'm talking about come purely from fighting the nose pitching up tendency when I either don't have time or neglect to reach over and input alot of nosedown trim.
Title: Re: The P-51... And her flaps.
Post by: RTHolmes on January 26, 2009, 12:48:25 PM
arent only the first notch or 2 supposed to be for manouvering on US birds and the rest for landing? the max speed you can deploy them should give an indication of what theyre for, any more than 2 in a jug or corsair feels more like an airbrake to me.
Title: Re: The P-51... And her flaps.
Post by: Cthulhu on January 26, 2009, 01:07:24 PM
arent only the first notch or 2 supposed to be for manouvering on US birds and the rest for landing? the max speed you can deploy them should give an indication of what theyre for, any more than 2 in a jug or corsair feels more like an airbrake to me.
You know, that's probably a good rule of thumb for all aircraft.
Title: Re: The P-51... And her flaps.
Post by: BnZs on January 26, 2009, 02:18:47 PM
arent only the first notch or 2 supposed to be for manouvering on US birds and the rest for landing? the max speed you can deploy them should give an indication of what theyre for, any more than 2 in a jug or corsair feels more like an airbrake to me.

Flaps continue to minimize turn radius and lower the speed at which you can still hang into the air out to full...the thing about AHII vs. real life is that we have auto-retracting flaps and never have to worry about jamming/tearing them off at high IAS.
Title: Re: The P-51... And her flaps.
Post by: Cthulhu on January 26, 2009, 02:41:29 PM
the thing about AHII vs. real life is that we have auto-retracting flaps and never have to worry about jamming/tearing them off at high IAS.
Same can be said for the F4U's gear.

Data says:
Max deployment speed:
Limit speed with gear down & locked:
250 kts
350 kts

But if I understand correctly, the F4U's gear can be deployed in-game at practically any speed. :huh But that's another matter.
Title: Re: The P-51... And her flaps.
Post by: SectorNine50 on January 26, 2009, 03:09:11 PM
Same can be said for the F4U's gear.

Data says:
Max deployment speed:
Limit speed with gear down & locked:
250 kts
350 kts

But if I understand correctly, the F4U's gear can be deployed in-game at practically any speed. :huh But that's another matter.
That is because the F4U's had a dive brake setting on their landing gear that would only drop the front gear and would keep the tail wheel up.  You can drop the front gear at very high speeds but the tail wheel was a little more flimsy.  This is just an easy way to execute it in-game.
Title: Re: The P-51... And her flaps.
Post by: Cthulhu on January 26, 2009, 03:44:49 PM
That is because the F4U's had a dive brake setting on their landing gear that would only drop the front gear and would keep the tail wheel up.  You can drop the front gear at very high speeds but the tail wheel was a little more flimsy.  This is just an easy way to execute it in-game.
You're correct that the mains only (and not the tail wheel) were lowered as dive brakes. That wasn't my concern. The gear could be lowered at relatively high speeds compared to other aircraft. I'm just wondering if it's not a bit excessive in AHII.

The following is from: http://homepage.eircom.net/~frontacs/WBStored/F4UGearAsDivebrakes.html

**************************************
"Got some more about F4U gear for you. All of the following is taken from the Air Ministry Pilot's notes for the Corsair I-IV for RAF and Royal Navy pilots."

Para 44 Flying Limitations

(iii) Dive Bombing

Maximum speed (u/c up)... ... ... ... 375 Knots IAS

Maximum speed for lowering u/c (dive brakes)... 250 KIAS

Maximum speed u/c down ... ... ... ... ... 350 KIAS

**************************************
It's obvious that the gear was incredibly strong once down and locked, but the max deployment speed is 100kts less. I know there are F4U Manuals out there for sale. Hopefully someone has one and can provide some clarification.
Title: Re: The P-51... And her flaps.
Post by: Bronk on January 26, 2009, 04:02:01 PM
Dean's AHT
"The gear was not to be extended over 300 mph IAS or retracted over 400mph IAS."
Title: Re: The P-51... And her flaps.
Post by: Chalenge on January 26, 2009, 05:02:22 PM
Quoting Widewing:
Quote
It has nothing to do with E bleed in the Jug.

With full flaps, a P-47D-25 sustains a turning radius over 50 feet smaller than a P-51D with full flaps, as well as a faster rate of turn.

We've tested these individually and head to head. I've said it many times; the drag model update absolutely killed the P-51s and their ability to maneuver at speeds below corner velocity with flaps deployed. Anything more than 3 notches of flaps is virtually worthless. All you do is trade a small decease in radius for a big hit in turn rate.

http://bbs.hitechcreations.com/smf/index.php/topic,212053.105.html

page 8
Title: Re: The P-51... And her flaps.
Post by: SectorNine50 on January 26, 2009, 09:34:16 PM
Is widewing saying there is an error?  Or it was modified and corrected an error?
Title: Re: The P-51... And her flaps.
Post by: Demetrious on January 26, 2009, 11:44:29 PM
CL increases, but Lift may or may not.
In other words, CL does increase with increased flaps, but like BnZ said, drag increases disproportionately, so unless you have huge additional power at your disposal

That'd explain why the Jug(s) seem to get so much mileage out of full flaps. That 2,000 HP Double Wasp has firepower to spare. I think. The Jug is underpowered as is.
Title: Re: The P-51... And her flaps.
Post by: Stoney on January 29, 2009, 12:30:45 AM
I'd give my eye teeth for large flap deflections in AHII to cause nose-down pitching, instead of having to reach over the keyboard and input full nose-down trim once I get into a slow fight w/flaps.... :devil

http://bbs.hitechcreations.com/smf/index.php/topic,193021.0.html

I brought this up a couple of years ago.  Pyro said they were going to make a change, but nothing has happened...