Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Krusty on November 13, 2006, 04:56:02 PM
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While checking the AH plane comparison webpage (http://www.gonzoville.com/ahcharts/index.php) to see how the spit14 stacks up to certain other planes, I noticed something odd.
I checked all the US planes, P38s, P47s, P51s, and f4us and f6f.
Most planes have a different turn radius when using no flaps and when using full flaps. The average difference in most planes (I didn't check them all, just a handful from different nations) is about a reduction of 120 feet for turn radius.
The F4Us average a reduction of nearly 300 feet. Over twice that of every other plane I tested, save the F6F, which only got about 200 feet reduction in turn radius.
This can't be right. The flaps on the f4us are just that, flaps. They're not magical lift machines.
Is this a bug in the AH flight model? Or what? On the surface there's nothing special about the F4u flaps, so why do they nearly cut the turn radius in half, when no other plane in the game reaps this benefit?
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This is just a WAG and I'm no corsair expert but the flaps are huge and they span almost 50% of the wing length, so maybe that has something to do with the numbers you are finding.
SIK1
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Meh, all the US flaps span about 50% of the wing, yet the P51s, p47s, P38s all consistently get about 120 yards taken off the turning radius. I'm just wondering why the corsairs. I'm also wondering if this is realistic. I don't think it is, somehow.
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maybee it isn't realistic, but are you gonna tell that to Robert Conrad
(http://upload.wikimedia.org/wikipedia/en/1/1c/Pappy.jpg)
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I'm no expert either which may explain why I find the F4U's handling the least convincing out of the entire planeset. I find it odd that the fabled Ensign Eliminator with all the torque, and yes I know they added the strip to compensate, can virtually hover onto the carrier and land on its rudder.
What intrigues me most is how they dump all flaps and gear and loop at about 40 mph.
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I'm no Luftwhiner. I love all American birds, and the Corsair's one of my favorites. But I agree wholeheartedly. The real F-4U, according to a NACA graph in America's Hundred Thousand, had the very worst sustained turning circle without flaps. It was even wider than the P-47's. I see no reason why the flaps on the Corsair would make such a difference; after all, they were not Fowlers. It's the 38 that should turn like that with full flaps, because of its Fowlers!
Currently, the Corsair is the best turning American airplane in the simulator, and it's pretty close to the Spitfire. That's just not right; though the F-4U was rated the best dogfighter of the war at the 1945 Joint Fighter Conference, it was not because of the turning ability but rather in spite of it. The F-4U, FW-190, and P-47 were all abysmal at turning circles but had great maneuverability in other areas that more than made up for the poor sustained turns.
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the flaps are pretty big compaired to most flaps though....
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Who was it that posted video showing a real Hog doing pretty much all the helicopter stunts the F4U performs in-game?
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I've no doubt it can hang on it's propeller like nothing else. As I said, it was a very maneuverable aircraft. It's the turn radius I'm worried about. I have at least two very good sources that show quite clearly how the F-4U turns compared to other aircraft, and it's quite poor in that regard.
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But as you said above, that's sans flaps.
You also have to remember that the F4U has a wing configuration that was unlike anything else in the air. The root of the main span of each wing is placed at a point BELOW the fuselage by the gull design. I wouldn't find it at all surprising that the effect of the Corsair's flaps was markedly different than it is for other aircraft as a result.
(http://downloads.hitechcreations.com/images/f4u1d/ahss10.jpg)
I wish I knew where, but I remember reading a report somewhere (maybe posted by F4UDOA or Widewing) where it was stated by the test pilot that even one notch of flaps GREATLY improved the F4U's turning ability, and even more as angle increased, although more than one notch of flaps wasn't recommended because of the added drag.
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Benny,
The numbers Dean used in AHT for the Clmax's of alomst all of the aircraft were wrong. If you compare those numbers to the NACA document with the real numbers and then rerun Deans calculation the results are quote different. BTW the Clmax of 1.48 for the F4U with no flap is correct.
I did not realize the F4U gained so much more than other A/C. I can say that the F4U benifits very heavily in the reduction of stall speed by lowering flaps.
Notice the addition of full flaps lowers the stall speed at idle power from 84KIAS to 66KIAS or 22% decrease. Even two notches of flap (The actual maneuver setting) reduced the stall power off from 87KIAS to 79KIAS or 9% . That is a load of lift.
By comparison the P-51D at 9,000lbs no power no flaps stalls at 101MPH IAS. With full flaps power off it stalls at 94MPH IAS a gain of 7%.
So the F4U generates more lift with 2 notches of flap than the P-51D with full flaps. Sorry I don't have the P-51D manual scanned but it isn't hard to find I'm sure.
(http://mywebpages.comcast.net/markw4/F4Ustall.jpg)
Here is the flight envelope of the F4U no flap no power.
(http://mywebpages.comcast.net/markw4/F4UG.jpg)
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Lol. Ask and ye shall receive. :D
When you consider the F4U is as much as a ton and a half heavier than the P-51 that's a pretty impressive difference in flap performance. I guess the question still remains as to WHY they generate so much more lift. Wing configuration? Surface area?
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The gull wing was to shorten the landing gear. It wouldn't really change the lift of a wing much (it was an old design, even Junkers took it from somewhere else to use on their Stuka). It has been around since biplane days.
As for the flaps, I don't believe they're that special. They have drop flaps, just like P47s and P51s. The P38 flaps at least slide BACK as they drop, increasing surface area. F4u flaps do not. They're not full-span. They're not much deeper than P47/P51 flaps. The wingspan isn't notably larger than the P51 wing. It doesn't have 3x the surface area for lift.
So why are they acting like this?
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I know why the Corsair wings were dropped like they were. However the design turned out to have OTHER advantages that WEREN'T intended, such as drag-reduction.
Clearly, whether "plain old" drop flaps or not there's SOMETHING about the F4U's flaps that allow them to provide SIGNIFICANTLY greater lift than similar flaps on other aircraft. The data DOA provides is proof of that.
While the Corsair's overall wingspan may not be much larger than the 51, it DOES have a particularly wide chord from leading to trailing edge without the significant taper at the tip. What's the actual wing area of the F4U compared to some of these other fighters clean and with flaps deployed? Could that help otherwise unremarkable flaps become Wonder Flaps?
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Originally posted by Saxman
Clearly, whether "plain old" drop flaps or not there's SOMETHING about the F4U's flaps that allow them to provide SIGNIFICANTLY greater lift than similar flaps on other aircraft. The data DOA provides is proof of that.
While the Corsair's overall wingspan may not be much larger than the 51, it DOES have a particularly wide chord from leading to trailing edge without the significant taper at the tip. What's the actual wing area of the F4U compared to some of these other fighters clean and with flaps deployed? Could that help otherwise unremarkable flaps become Wonder Flaps?
Hi,
i dont see a that high liftincreasement for the F4U with full flaps!!
Stallspeed drops from 87 to 75knots (power off), the 66 knots is probably a stall flight(hanging on the prop), i guess also the P51 could do this more slow.
The flaps of the F4U in AH miss zero drag and the whole F4U airframe miss induced drag(similar to the Tempest).
Greetings,
Knegel
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sounds like somebody got pawned by a F4U in a turn fight, :D
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The difference in stall speed in the F4U at power off clean and full flaps is 13%, which is STILL nearly DOUBLE the difference as in the P-51. And the Hog is 3000lbs HEAVIER.
There's SOMETHING about the REAL F4U--if the pilot's manual is to be believed, which why wouldn't it be? That's written for the safety of the pilot so if anything would be CONSERVATIVE in its estimates--that makes her flaps much more efficient than in other aircraft.
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They may be more effective, but not more efficient. Lowering the stall speed more doesn't mean they're more efficient. The drag is probably proportional, since the F-4U had conventional flaps. The P-38's Fowler flaps were more efficient; they greatly lowered the stall speed without greatly increasing drag. Even though the F-4U has a much lower stall speed with flaps, that doesn't mean its turn will be better. It will be tighter, but a lot slower because it doesn't have Fowlers. Moreover, the F-4U without flaps in game doesn't have a wide turn at all.
F4UDOA, how do you know that Dean's graph is wrong? And can you post corrections? Aside from that graph, I've seen another NACA graph comparing the F-4U, a few American airplanes, and the Spitfire. Once more the F-4U was on the outside. Unless you can convince me otherwise, I still believe that the F-4U has far too good of turning ability in the simulator.
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Where is Widewing when you need him .
Bronk
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Benny Moore,
Sure no problem, my favorite subject. In fact I can show you exactly where Dean's number came from.
However I am working at the moment so I will post tonight in greater detail.
FYI, I would tend to agree that the F4U flaps are not of a "special design" and did produce proportionate drag to lift. However the drag at that speed would not have very much effect IMHO (engineers jump in). Case and point you add more flap not less to take off quickly. Yes your acceleration is less but the lift generated overcomes the drag. You don't have to turn as fast when you are turning so tightly which is what happens in AH.
Also despite weighing 12,000LBS fully loaded the wingloading of the F4U is low with good power loading for an American A/C and that is without flaps.
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Originally posted by Trikky
I'm no expert either which may explain why I find the F4U's handling the least convincing out of the entire planeset. I find it odd that the fabled Ensign Eliminator with all the torque, and yes I know they added the strip to compensate, can virtually hover onto the carrier and land on its rudder.
What intrigues me most is how they dump all flaps and gear and loop at about 40 mph.
yet the Spit 14, Typhoon, Mosquito and Tempest all suffer horrendously with torque.
auto takeoff cannot even keep the wings level on the hawkers on climbout, and the mosquito snakes around with its tail wagging like a stoned puppy.
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Originally posted by Krusty
The gull wing was to shorten the landing gear. It wouldn't really change the lift of a wing much (it was an old design, even Junkers took it from somewhere else to use on their Stuka). It has been around since biplane days.
The gull wing was indeed added to the Corsair to make the landing gear shorter.
Unintended consequences though of the shortened gear went into decreased drag owing to the perpendicular attach point of the wing root. Increased lift owing to the larger wing area resulting from the extra wing required to form the gull. Lastly, the form and area of the flaps differs greatly from most other American fighters, and I believe this also plays a role in their increased maneuvering effectiveness.
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Best explanation I can think of. Would be nice if someone could dig up tests that confirm that.
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Originally posted by Saxman
Best explanation I can think of. Would be nice if someone could dig up tests that confirm that.
The sad thing is, I spent most of last month working on a new set of flaps for a -4 (no difference between the dashes btw) and I can not remember the data to go along with their form... sad huh! :huh Will be talking to several accomplished F4u pilots tomorrow, and will post their thoughts tomorrow night, or next day... TX day trips are hard on me... usually to fugged up to talk let alone type by the time the cab drops me off at home! :t
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Cool, cool. Although I'll be expecting the whiners to gun their thoughts down as prejudice. ;)
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All I know is that I outturned, in a flat turn of 3 full circles, a Spit IX while flying an F4u-1. The flaps on it are unreal. And it wasn't some nood I was fighting, it was Bronk. I'm sure he was surprised by it as well.
I have seen what Widewing has posted about the F4u-4 outturning the SpitXVI, but I sure didn't expect a U-1 to outurn a better turning spit easily in the Mk IX.
:confused:
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Originally posted by Stang
All I know is that I outturned, in a flat turn of 3 full circles, a Spit IX while flying an F4u-1. The flaps on it are unreal. And it wasn't some nood I was fighting, it was Bronk. I'm sure he was surprised by it as well.
I have seen what Widewing has posted about the F4u-4 outturning the SpitXVI, but I sure didn't expect a U-1 to outurn a better turning spit easily in the Mk IX.
:confused:
Would a had ya to but i forgot to swap back to cannon after dropping my tank.:furious So all i pingged you with were GD 303 :furious
But yup after i blew my oppertunity he just floated away from me in a tight right hand turn.
Nice slow speed control Stang .
Bronk
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Originally posted by F4UDOA
FYI, I would tend to agree that the F4U flaps are not of a "special design" and did produce proportionate drag to lift. However the drag at that speed would not have very much effect IMHO (engineers jump in). Case and point you add more flap not less to take off quickly. Yes your acceleration is less but the lift generated overcomes the drag. You don't have to turn as fast when you are turning so tightly which is what happens in AH.
Flaps, do not "improve" turning where you can sustain a turn without flaps. What they do is extend some of the flight envelope to areas that you can't reach without them due to angle of attack limitation. The price is very much reduced efficiency, meaning for every little extra lift you get, you pay with a much larger amount of drag.
In other words, flaps allow one to convert extra engine power into lift without increasing speed, and where you have passed the normal critical AoA. Yet even this contribution is limited since it has its own new critical AoA, even if you do have the excess power.
I do not buy the "its a gull wing so it works differently" argument. While the gull wing has some interesting properties, it was not such a stellar design. The simple (circumstantial) proof of that is that it hasn't been used since the need of getting the gears low enough to clear the prop has been removed.
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Why don't we just wait until the remodeled versions come out before we get too involved in this discussion? Could be the F4U's benefit from the old flight model--something the updated planes don't benefit from?
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I don't know about that. Since the re-coding of the airflow coad, I think things have settled down a bit. We'll see minor changes, I'm sure, but flaps haven't changed in a while.
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Originally posted by bozon
Flaps, do not "improve" turning where you can sustain a turn without flaps. What they do is extend some of the flight envelope to areas that you can't reach without them due to angle of attack limitation. The price is very much reduced efficiency, meaning for every little extra lift you get, you pay with a much larger amount of drag.
In other words, flaps allow one to convert extra engine power into lift without increasing speed, and where you have passed the normal critical AoA. Yet even this contribution is limited since it has its own new critical AoA, even if you do have the excess power.
You are correct. Fowler flaps are much more efficient than conventional and split flaps, but all flaps are ultimately less efficient (though obviously not always less effective) than not using flaps.
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I also have to say that I feel something is off with flaps in AH in many of the a/c. Its bewildering to see an F4U with full flaps and landing gear lowered doing immelmans in a dogfight.
...I mean, find one real WW2 F4U pilot that wouldnt call that insane, and a ticket to be an oil slick.
Also, wing loading is wing loading, and the F4U had a higher wing loading than many lighter WW2 fighters. Higher wing loading means at a given G, you lose speed faster than a fighter with a lower wing loading. So a Spit IX pulling 5 Gs will say, drop 50mph after one 360 turn, where an F4U would drop 75mph, pulling 5 Gs (assuming same E state and alt). < Just an example, I dont have the data in front of me. The F4U would need to drop to a 4 G turn to remain the same speed, thus the 5 G Spit eventually "out turns" him, thats the mechanics of it.
...and Im not just picking on the F4U, like I say I think the flaps code in AH needs looking at with all of them.
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F4UDOA, how do you know that Dean's graph is wrong? And can you post corrections? Aside from that graph, I've seen another NACA graph comparing the F-4U, a few American airplanes, and the Spitfire. Once more the F-4U was on the outside. Unless you can convince me otherwise, I still believe that the F-4U has far too good of turning ability in the simulator.
Dean uses a wing loading divided by the clmax of each airplane to come up with his lift index.
FYI, Dean's information came from the 1944 JFC which was done over days. He calculated the clmax numbers from the 3G stall speeds. However there was no weight,power or flap condition noted.
I don't want to do every aircraft in his list but I will do two for contrast since the information is available.
From The POH (Pilots Manual)
1. F4U-1D 1G stall speed= 87Knots IAS or 85Knots CAS 97.8MPH at 11,300LBS
391*11,300LBS/ 97.8^2MPH * 314SQ Ft= Clmax
4418300 / 30033597
Clmax = 1.47 Dean's number is 1.48
The F4U is the only aircraft with the correct Clmax
2. P-51D Stall at 101MPH IAS and 106MPH CAS Note-With Wing racks attached
9,000LBS * 391 / 106MPH^2 * 233.19Sq Ft
3519000 / 26201228
1.34
This is a pretty basic calculation but can be done from any POH listing of WW2 aircraft.
Also Check the NACA reports server for report 829 The F4U is also approximately 1.48 and the P-51 is similar although you have to make sure you are looking at Cl numbers with the prop installed and no flap deployed.
I also have a report from a group of modern pilots in 1989 that has simlar results.
Always make sure you are looking at CAS not IAS (especially with the F6F) because many of these aircraft had huge errors to overcome in instrument readings.
I will post more when I can.
Thx
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Originally posted by Squire
Also, wing loading is wing loading, and the F4U had a higher wing loading than many lighter WW2 fighters. Higher wing loading means at a given G, you lose speed faster than a fighter with a lower wing loading. So a Spit IX pulling 5 Gs will say, drop 50mph after one 360 turn, where an F4U would drop 75mph, pulling 5 Gs (assuming same E state and alt). < Just an example, I dont have the data in front of me. The F4U would need to drop to a 4 G turn to remain the same speed, thus the 5 G Spit eventually "out turns" him, thats the mechanics of it.
No, no, no! You are making the terrible mistake which most flight simulator developers and users always make. It is the mistake of thinking that wingloading equals turning ability. Wingloading is a moderately reliable indicator of an airplane's turning and climbing ability, but is far from the only factor or even the only important one. Liftloading, aspect ratio, and a lot of other factors which I don't really understand (chord ratio, taper ratio, et cetera) all are vital in calculating wingloading. They (and the Fowler flaps) are the reasons why the P-38 easily outturned the Me-109 in real life. Ignoring those factors is also why the P-38 doesn't outturn anything in simulators.
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I do not buy the "its a gull wing so it works differently" argument. While the gull wing has some interesting properties, it was not such a stellar design. The simple (circumstantial) proof of that is that it hasn't been used since the need of getting the gears low enough to clear the prop has been removed.
Bozon,
I don't buy the gull wing arguement either.
The flaps provide alot of lift and alot of drag. However the drag at slow speed does not account for nearly as much as the lift.
Just look at takeoffs from short runways with heavy bombs. They don't worry about the drag of the flaps just the weight of the bombs. If the drag from the flaps was equal to the lift then the aircraft could not takeoff.
The downside of the drag really starts about 180 to 200MPH. The power available at low speed is overwhelming.
Remember the F4U-1D could take off with over 4,000lbs of ordinance. The drag from the flaps at high power settings is not nearly enough to prevent acceleration.
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No, no, no! You are making the terrible mistake which most flight simulator developers and users always make. It is the mistake of thinking that wingloading equals turning ability. Wingloading is a moderately reliable indicator of an airplane's turning and climbing ability, but is far from the only factor or even the only important one. Liftloading, aspect ratio, and a lot of other factors which I don't really understand (chord ratio, taper ratio, et cetera) all are vital in calculating wingloading. They (and the Fowler flaps) are the reasons why the P-38 easily outturned the Me-109 in real life. Ignoring those factors is also why the P-38 doesn't outturn anything in simulators.
Benny,
Wingloading is THE primary indicator of turn ability. Everything else is less than second.
Just look at stunt planes. The power loading is less than average, the aspect ratio's are average (Between 5 and 5.5) but the wing loading is key.
BTW, The P-38 wingloading is poor and that is why it cannot turn well. However with flaps it turns very well in sustained turns in one direction.
Here is a Sukhoi SU-29 Stunt plane
Dimensions, External
Wing span 8.20 m (26 ft 10½ in)
Wing chord: at root 1.985 m (6 ft 6¼ in)
at tip 1.04 m (3 ft 4½ in)
Wing aspect ratio 5.5
Length overall 7.285 m (23 ft 10½ in)
Height overall 2.885 m (9 ft 5½ in)
Tailplane span 2.90 m (9 ft 6¼ in)
Wheel track 2.40 m (7 ft 10½ in)
Wheelbase 5.08 m (16 ft 8 in)
Propeller diameter 2.50 m (8 ft 2½ in)
Propeller ground clearance 0.425 m (1 ft 4½ in)
Dimensions, Internal
Cockpit: Length 2.60 m (8 ft 6¼ in)
Max width 0.82 m (2 ft 8¼ in)
Max height 1.05 m (3 ft 5¼ in)
Areas
Wings, gross 12.20 m2 (131.4 sq ft)
Ailerons (total) 2.32 m2 (24.97 sq ft)
Fin 0.28 m2 (3.01 sq ft)
Rudder 0.90 m2 (9.69 sq ft)
Tailplane 0.98 m2 (10.55 sq ft)
Elevators (total) 1.56 m2 (16.79 sq ft)
Weights and Loadings (two persons)
Weight: empty 735 kg (1,620 lb)
empty, equipped 780 kg (1,720 lb)
Max fuel 207 kg (456 lb)
Max T-O weight: pilot only 860 kg (1,896 lb)
two persons 1,204 kg (2,654 lb)
Max wing loading 98.7 kg/m2 (20.21 lb/sq ft)
Max power loading: M-14PT 4.55 kg/kW (7.48 lb/hp)
M-14PF 4.01 kg/kW (6.73 lb/hp)
M-9F 4.78 kg/kW (6.41 lb/hp)
Performance (M-14PT engine)
Never-exceed speed (VNE) 242 kt (450 km/h; 279 mph)
Max level speed 175 kt (325 km/h; 202 mph)
Stalling speed 62 kt (115 km/h; 72 mph)
Max rate of climb at S/L 960 m (3,150 ft)/min
Service ceiling 4,000 m (13,120 ft)
Max rate of roll 345º/s
*T-O run 120 m (395 ft)
*Landing run 380 m (1,250 ft)
Range with max fuel 647 n miles (1,200 km; 745 miles)
g limits +12/-10
*at 914 kg (2,015 lb) AUW
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Originally posted by F4UDOA
Wingloading is THE primary indicator of turn ability. Everything else is less than second.
No. By that argument, the F-15 (weighing about four times your average World War Two fighter) shouldn't be able to turn well at all. But it does! In fact, it turns much better than aircraft with far, far lower wingloading. The reason is powerloading.
Powerloading and liftloading cannot be dismissed as easily as you do. Dismiss aspect ratio and the others if you must as "less than secondary," but powerloading is easily the most important factor in turning ability. After all, missiles don't need wings. Liftloading, a good indicator of climbing ability, also greatly impacts turning ability.
I'm no aeronautical engineer. I don't know much about aerodynamics. But I do know enough to know that you're making a big mistake when you calculate turning ability based soley or even just mostly on wingloading.
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Originally posted by Ball
yet the Spit 14, Typhoon, Mosquito and Tempest all suffer horrendously with torque.
auto takeoff cannot even keep the wings level on the hawkers on climbout, and the mosquito snakes around with its tail wagging like a stoned puppy.
The hog, both IRL and in this sim have exceptional control surface authority. So even though the plane has significant torque the control surfaces all offer exceptional force at both high and low speed. No other plane has anywhere near the "ground loop" potential of the hog. It is the most difficult plane to control on takeoff and landing in the game when control authority is lost due to insufficient air flow.
What seperates the hog from other planes is its exceptional docility in "unusual attitude" situations (as long as the pilot stays withing the flight envelope). It does in fact remind me of the unusual attitude training I had in a T-28. The hogs "seperation" is remarkably like that described in the manual BTW....
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I think a lot of people seem to expect the F4U wants to depart under any significant AoA or Gs. I agree that she may be a LITTLE more forgiving in the game than the historical aircraft, but get too heavy under the wrong conditions and she'll REALLY quickly bite you on the bellybutton (and yes, I HAVE frequently spun in during low-alt, low-speed fights pushing things just a bit too hard).
In particular, too much rudder and elevator at the same time seems to be the magic combination. The Hog snap rolls like MAD (oddly, every time I do it--intentionally for not--I always seem to end up inverted when I recover).
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AH models powerloading (weight/hp) as well as wing loading, as well as drag and lift.
The F-15 btw, has a 73lb/ft wing loading, the MiG-21, 77lb/ft and the MiG-23 78lb/ft.
The F-104 Starfighter, which is not known for having a great turn ability, has 105lbs/ft.
So it will out turn them with its wing loading rating.
The P-38 isnt an F-15 as you well know, and it doesnt have anywhere near the advantage in powerloading over its contemporaries as the F-15 had. In fact its powerloading is no greater than its contemporaries. You can crunch the #s yourself if you like, its a simple combined hp vs weight rating.
Regards.
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No. By that argument, the F-15 (weighing about four times your average World War Two fighter) shouldn't be able to turn well at all. But it does! In fact, it turns much better than aircraft with far, far lower wingloading. The reason is powerloading.
It depends on what you are comparing it too.
Can an La-7 out turn an A6M2?
All things being equal or close power loading, apect ratio or Clmax might affect the outcome but as long as one aircraft has a clear wingloading advantage I believe it be superior in turn radius.
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Benny,
There is one other type of turn that can be executed where wing loading is not the final answer but then either is power loading.
Instantainous turning.
That is a limitation of the airframe that can be improved with powerloading and wingloading but ultimately it is the limits of the aircraft design (not just the wing or wingloading).
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Flap up ,flap down in rapid motion give to the F4U the "flapping" hability.
This hability autorise the Corsair to float over the CV desk and some skilled pilot even can take off using this trick.
Now where did I put my Jack Daniels bottle ?
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I had a discussion yesterday with an experienced Corsair pilot (modern day) and his answer to the the reason that the Corsair turns (in a circle as krusty brought up) so much better than the spit and mustang was that the Corsair's wing is of a high lift design as opposed to the laminar flow wings of the mustang and spit. The spit was still a good turning airplane, but he said an experienced Corsair driver should be able to keep up or win in a turn competition. The other thing he mentioned was that Corsair pilots rarely tried to turn their birds to extremes in combat, because if they ended up in a high speed stall, or any stall, the chances of spinning it were so great. Most spins in a Corsair quickly become unrecoverable. As for the Mustang, he said that basically it hated slow turns, and it's departure is so nasty that slow mustangs generally meant dead mustangs. ie the spin. Did not have much bad to say about the spit, actually he rather enjoyed flying the ones he had.
I am not an engineer, but this does make sense
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Originally posted by F4UDOA
BTW, The P-38 wingloading is poor and that is why it cannot turn well. However with flaps it turns very well in sustained turns in one direction.
:rofl :rofl :rofl
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Originally posted by Squire
Also, wing loading is wing loading, and the F4U had a higher wing loading than many lighter WW2 fighters. Higher wing loading means at a given G, you lose speed faster than a fighter with a lower wing loading. So a Spit IX pulling 5 Gs will say, drop 50mph after one 360 turn, where an F4U would drop 75mph, pulling 5 Gs (assuming same E state and alt). < Just an example, I dont have the data in front of me. The F4U would need to drop to a 4 G turn to remain the same speed, thus the 5 G Spit eventually "out turns" him, thats the mechanics of it.
...and Im not just picking on the F4U, like I say I think the flaps code in AH needs looking at with all of them.
Hi,
actually its the other way around at same G´s!!
If lets say a 109F4 and a SpitVb turn both with 5G´s, it depends to the inertia(spanload), propeller thrust and other wing design factors(wing aspect ratio, airfoil ), which of both decelerate faster.
The reason why many people get confused is the fact that the more heavy wingloaded plane tend ot need a more big AoA to gain the same G load or tunrradius than the more light wingloaded plane. What most people dont see is the fact that the more heavy wingloaded plane have a smaler relative wingarea. As result, while turning, planes with similar weight(109F4/SpitVb) show a very similar wingarea into flightdirention. The big wing of the Spit need a smaler AoA, while the smal wing of the 109F4 need a more big AoA.
In general planes with heavy wingload tent to keep more energy as faster the planes fly and and/or a smaler the AoA is, while planes with a low wingload tend to be able to turn more tight.
But this depends much to the wingdesign. A wing with a high aspect ratio tend to produce more lift and smaler drag at high AOA than a wing with smal aspectratio. As result the wingarea of a high aspectratio wing can be smaler to arcive the same lift like a more big wing with smal aspectratio.
In your example the F4U for sure will get faster out of the 5G 360° turn than the Spit(only a Spit14 probably could keep up).
Why?? Cause the F4U had MUCH more inertia and MUCH more power.
Same count for the FW190A vs a SpitV and P38 vs A6M2.
The more light wingloaded planes(lets assume they are also more light liftloaded) can turn more tight where the heavy liftloaded planes already stall, and they also have advantages while a sustained turn(but this depends much to the powerload), as faster the planes fly, as less advantage the relative big wings bring and as more disadvantage they offer. The faster deceleration of the more light wingloaded plane is the reason for a more tight turn while a turn with a constant G load.
Imho in Ah the inertia isnt modeled always right, but it got better with the last patches! Heavy planes mainly suffer by their weight, while the advantage of the inertia dont count much.
For example the A6M´s keep energy at highspeed(+300mph IAS) like mad, while this relative big but light and powerless planes should bleed speed like mad, same count for the Hurri II. At highspeed planes like the P47 and FW190 should very easy get rid of this lightweights by flying a highspeed smooth turn, where the high inertia and power keep should keep the speed much better up. Unfortunately its the other way around. Even the smalest turn slow the FW190 down, like dont have any weight, as result it only can run strait to gain distance, a upzoom at 350mph in low level with 2k distance is suecide(and that vs so outdated planes like the Zero and HurriII). While a upzoom with initially 400mph a Spit16 close in to the FW190A8 from 3k distance, althought the the Spit was intially more slow. Looks like the inertia of 850kg at 400mph dont count much, while the P51D and even the FW190A5 zoom pretty good or at least better at 400mph.
Greetings,
-
Knegel:
Imho in Ah the inertia isnt modeled always right, but it got better with the last patches! Heavy planes mainly suffer by their weight, while the advantage of the inertia dont count much.
For example the A6M´s keep energy at highspeed(+300mph IAS) like mad, while this relative big but light and powerless planes should bleed speed like mad, same count for the Hurri II. At highspeed planes like the P47 and FW190 should very easy get rid of this lightweights by flying a highspeed smooth turn
What you are missing is it takes much more lift & hence more drag to turn a heavy wing load plane at the same g load. Therefore for a given G load and speed the heavy plane will be expending more kinetic energy (yes it also has more to spend), than the light wing loaded plane (which has less to spend).
And it is impossible for inertia (i.e. simply the mass of the airplane) to be wrong in AH.
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Originally posted by hitech
Knegel:
What you are missing is it takes much more lift & hence more drag to turn a heavy wing load plane at the same g load. Therefore for a given G load and speed the heavy plane will be expending more kinetic energy (yes it also has more to spend), than the light wing loaded plane (which has less to spend).
And it is impossible for inertia (i.e. simply the mass of the airplane) to be wrong in AH.
Hi,
thats wrong!!!
A more heavy plane need more lift to turn at given G, a more heavy wingloaded plane can be more light and would need less lift to turn at given G.
Therefor the more heavy wingloaded plane dont will expending more kinetic energy, but the more heavy plane will do, but this is in relation to its wings(lift) and therefor isnt a handycap while a decelerated turn.
Thats why i took the SpitVb and 109F4 as eaxample, they are both similar heavy and also had similar power(combat power). Both planes need a similar lift to gain a given G. Afaik both wings did produce a very similar ammount of lift at max AoA, with a smal advantage for the big Spit wing, for the price of a high induced drag + high zero drag. As result the SpitV did decelerate faster, resulting in a more tight turn, particular for the price of Speed.
The main handycap of a heavy liftloaded plane is the limited turnradius until a speed where the blackout limit the turn, a higher stall speed and as result also a not that good sustained turn, regarding the E-bleed at highspeed its not not necessarily handycapped, this depends much more to the spanload AND specialy power. 1800HP in the 190A8 + the inertia out of 1400kg vs 1130HP of the A6M5 in low level should do the job while a upzoom out of 350mph.
Ok, if the inertia(somewhat thrust out of moving mass) cant be wrong, its to much induced drag, maybe the calculation dont take the influence of the wing aspect ratio into account??
The Japanese HQ also did need quiet a time to get aware that low wingload(liftload) isnt a advantage at highspeed and specialy hinder the planes to get to highspeed and to keep it.
Btw, i think the relation betwen F4U, P51D and A6M5 is good(only the US flaps are strange), but the P47(it miss the super flaps) and FW190 dont fit. Once the AH P51 also was such a energy killer.
Greetings,
-
Originally posted by Knegel
Hi,
thats wrong!!!
A more heavy plane need more lift to turn at given G, a more heavy wingloaded plane can be more light and would need less lift to turn at given G.
Therefor the more heavy wingloaded plane dont will expending more kinetic energy, but the more heavy plane will do, but this is in relation to its wings(lift) and therefor isnt a handycap while a decelerated turn.
Thats why i took the SpitVb and 109F4 as eaxample, they are both similar heavy and also had similar power(combat power). Both planes need a similar lift to gain a given G. Afaik both wings did produce a very similar ammount of lift at max AoA, with a smal advantage for the big Spit wing, for the price of a high induced drag + high zero drag. As result the SpitV did decelerate faster, resulting in a more tight turn, particular for the price of Speed.
The main handycap of a heavy liftloaded plane is the limited turnradius until a speed where the blackout limit the turn, a higher stall speed and as result also a not that good sustained turn, regarding the E-bleed at highspeed its not not necessarily handycapped, this depends much more to the spanload AND specialy power. 1800HP in the 190A8 + the inertia out of 1400kg vs 1130HP of the A6M5 in low level should do the job while a upzoom out of 350mph.
Ok, if the inertia(somewhat thrust out of moving mass) cant be wrong, its to much induced drag, maybe the calculation dont take the influence of the wing aspect ratio into account?? Or maybe the FW and P47 have to few drag and also to few power at highspeed, resulting in missing power to keep speed while turning?? Sooooo many possibilitys. ;)
The Japanese HQ also did need quiet a time to get aware that low wingload(liftload) isnt a advantage at highspeed and specialy hinder the planes to get to highspeed and to keep it.
Btw, i think the relation betwen F4U, P51D and A6M5 is good(only the US flaps are strange), but the P47(it miss the super flaps) and FW190 dont fit. Once the AH P51 also was such a energy killer.
Greetings,
-
"Thats why i took the SpitVb and 109F4 as eaxample, they are both similar heavy and also had similar power(combat power). Both planes need a similar lift to gain a given G. Afaik both wings did produce a very similar ammount of lift at max AoA, with a smal advantage for the big Spit wing, for the price of a high induced drag + high zero drag. As result the SpitV did decelerate faster, resulting in a more tight turn, particular for the price of Speed."
While I agree with the general idea that these two planes area a close match I have yet to see a thorough analysis of their true relative turn perfomance. The 109 uses the slats to extend its max allowable AoA while at max allowable AoA only the wing tips of the Spit provide lift and the root section is a huge drag. I have always thought that since the basic airfoil the Spit has rather limited AoA the proble of Spit is that it cannot effectively decelerate where as the 109 can, and have to if it wishes to create lift to compete with a larger wing. Dunno...
On topic: Due to the big propellor and huge HP the Corsair is probably able to energize the lift of its wing's root section in slow flight -and that is why it is so prone to spin with torque. Due to this same factor I'd expect its departure to be very sudden and uncontrollable in a slow stall fight. Also remember that the lift the flaps produce is not free but comes with a drag penalty. Notice that the full flaps extend to 50 deg and with max AoA the flap angle to airflow is somewhere around 65 deg. The effect of gull wing is stabilizing but I doubt it produces any magical qualities (like the elliptic wing) but it hides the actual wingspan the wing has.
-C+
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The design of the Spitfire wing was such that when the stall occured, the stall happened 1st at the wingtips, to give the pilot some warning, and it made the stall more gentle.
Source-
"A feature of the final Spitfire design that has often been singled out by pilots is its washout feature, which was unusual at the time. The incidence of the wing is +2° at its root and −½° at its tip. This twist means that the wing roots will stall before the tips, reducing the potentially dangerous rolling moment in the stall known as a spin.
Many pilots have benefited from this feature in combat when doing tight turns close to the aircraft's limits, because when the wing root stalled it made the control column shake, giving the pilot a warning that he was about to reach the limit of the aircraft's performance."
...Im not sure what to make of some of the other comments, Spit not being able to decelerate ect, I really have no idea what you guys are talking about there.
...A low wing loading means you decelerate more slowly at the same G as an a/c with a higher wing loading, ie. it retains energy more efficiently, thats how a/c out turn each other, by retaining better E. At a certain point the high wing loading a/c has to drop to a gentler G, or stall out.
Regards.
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No biggie, but a slight correction:
"The design of the Spitfire wing was such that when the stall occured, the stall happened 1st at the wingtips, to give the pilot some warning, and it made the stall more gentle."
"This twist means that the wing roots will stall before the tips"
-C+
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Originally posted by Charge
[B
While I agree with the general idea that these two planes area a close match I have yet to see a thorough analysis of their true relative turn perfomance. The 109 uses the slats to extend its max allowable AoA while at max allowable AoA only the wing tips of the Spit provide lift and the root section is a huge drag. I have always thought that since the basic airfoil the Spit has rather limited AoA the proble of Spit is that it cannot effectively decelerate where as the 109 can, and have to if it wishes to create lift to compete with a larger wing. Dunno...
On topic: Due to the big propellor and huge HP the Corsair is probably able to energize the lift of its wing's root section in slow flight -and that is why it is so prone to spin with torque. Due to this same factor I'd expect its departure to be very sudden and uncontrollable in a slow stall fight. Also remember that the lift the flaps produce is not free but comes with a drag penalty. Notice that the full flaps extend to 50 deg and with max AoA the flap angle to airflow is somewhere around 65 deg. The effect of gull wing is stabilizing but I doubt it produces any magical qualities (like the elliptic wing) but it hides the actual wingspan the wing has.
-C+ [/B]
Hi,
if you wanna get a idea of the lift relation with max AoA, simply compare the stallspeeds. Regarding this the Spit and 109 was pretty close.
The flat airfoil and probably also the "twisted" wing and also the smal wing aspect ratio of the Spit are ptobably the reason for its smal lift factor, which lead to a unexpected "bad" liftload in relation to its wingload.
How much drag the open slats of the 109 did produce we only can guess, same like the we only can guess what induced drag the stalled part of the Spitwing did produce.
But anyway, i dont was up to start a Spit/109 discussion, i only was up to try to explain that a high wingload isnt a indicator for a high e-bleed!
In generally its not good for any plane to make hard manouvers with full flaps, cause extracted flaps decrease the aspectratio and make the planes more unstable. In general flaps was made to drop the nose and to reduce speed(drag). The max AoA normaly also get minimized with full flaps, as result of all this the turn performence of a plane with full flaps decrease. Flying with a high bank angle at slow speed lead to extreme altitude losts, but this i cant see regarding the AH F4U.
The AH F4U can extract the flaps at very high speed(in relation to most other AH planes) and it still keep energy like mad. The Spit flaps are same strange. To use the flaps in the SpitV is a real bringer, while the real flaps was mainly made to create drag and to lower the nose(the spit only had full flaps or nothing).
Greetings,
Knegel
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Twisting the wing reduces its efficiency in significant parts of the envelope. What it does allow are two main things:
1. It allows the stall to develop progressively giving the pilot ample warning.
2. It reduces AoA at the aileron section. This is extremely important at high AoA as deflecting the aileron may push the wing beyond the stall on one wing (the one that is supposed to go up in the roll). When only one wing stalls, the plane flips over instantly. So when stall fighting, an attempt to roll hard right may result in a snap roll to the left. The twist of the wing delays this effect - at the cost of efficiency, mainly in high speeds.
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The wing twist or the slots/slats were generally just solutions to the same tip stalling problem in the WWII fighters. Both solutions have good and bad points; at low AoA twist causes some additional (form and induced) drag while the slots/slats also ad some drag (even if closed).
gripen
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Knegel: Not really Disagreeing with you that much. But notice in the piece of your post I disagreed with, you were refereeing to inertia. I.E. heavier plane.
In my posted case, I was analyzing same wing & area different plane weights.
HiTech
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So the bottom line is that if you play your cards right while flying the 1A, there's a good chance you'll get inside a Spit 16 or an lgay while turning?
If this is true then that has made my day!:aok
Only downside to that is more than likely you will die quickly after as you would be a sitting duck, worth it though isn't it?
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Of the american planes, the F4U series does have more low speed maneuverability and can fly at 110 ias, but a spit 16 will make a sustained turn faster than the F4U at nearly the same speed. Turn radius is one parameter, like the size of a womans foot. It doesn't say much about acceleration performance, turn rate, roll rate, or control response for an airplane. Not that it's bad data, it's just not so useful by itself.
One idea I started on, but didn't get too far, was constructing energy-maneuverability graphs for the AH plane set. I figured out how to make them, and I think there's some web resources describing them as well. A concerted (or just group) effort to collect data for E-M charts would go a long way to explaining aircraft relative performance. E-M charts are a concept thought up after the jet age and so there's no real WW2 historical charts of that type.
Badboy has described at various times how a p51 can out turn a spitfire by using E-M diagrams. The same can be said for F4U's vs spits, La's, or even Hurricanes. The general notion is to exploit the strengths of the aircraft you are in and not the aircraft you are fighting.
Shaw talks about them as turn rate versus speed diagrams with velocity (Energy) on the x-axis and turn rate (maneuverability) on the y-axis for a series of g-load curves (on pg 391). The maximum instantaneous turn rate can be easily found from this type of curve set at the 5g (or 6g) load speed. Of course, that type of diagram is good for only one set of conditions including flap settings. However, depending upon the variations in the curves they can be generalized over a range of altitudes, fuel loads, and flap settings.
So, my point is that while minimum turn radius data point is a good start, it is only near the minimum speed. That speed is generally much less than the maximum turn rate speed. While I apprecate the data for turn radius, turn rate data at various g's is more useful for an energy-maneuverabilty diagram.
Regards,
Malta
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Malta,
EM charts are great but they are typically made at no power or idle power and no flaps.
The addition of power changes things but at least you get a baseline idea of what the maneuvering envelope should be. In reality these aircraft could pull pretty high instantanious G's at low speeds than in AH but I think people would feel like it was gamey if it were modeled that way.
I have a few EM diagrams if your interested.
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Actually, the ones I've seen have been made at WEP power. Mil power adds yet another change to the curves. It has to do with a small change in specific power. Nothing like a jet engine in afterburner, but there is a difference.
Sure, I'm always interested in more performance information but I've never heard they were made at idle before. Maybe we aren't talking about the same thing?
Here is a thread describing the E-M diagrams:
http://www.hitechcreations.com/forums/showthread.php?threadid=164617&referrerid=4629
Regards,
Malta
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Originally posted by hitech
Knegel: Not really Disagreeing with you that much. But notice in the piece of your post I disagreed with, you were refereeing to inertia. I.E. heavier plane.
In my posted case, I was analyzing same wing & area different plane weights.
HiTech
Actually i was refering to the influence of inertia at highspeed(speeds around and above Vmax) . In the case of two planes with same engine and wing and different weights the more heavy plane dont will have a disadvantage in a smooth turn, as long as its a decelerated turn.
In this case the more heavy plane of course suffer badly by the more bad powerload, so the real disadvanatge start when the turn get to be sustained. Inertia while turning still work into flightdirection, not only outside the turnradius.
In case of the 190A8 or P47D vs a Zero or HurriII the Power + weight(inertia) should easyly be enough to outzoom the light/powerless planes, at least when the zoom climb start above the Vmax of the heavy planes and so MUCH above the Vmax of the light planes(where the propeller is more a anydycap than a help).
Regarding AH i dont understand that my thoughts work regarding the F4U airframe, but the P47 and FW190 airframe dont follow this rule.
Greetings,
-
There's something else that bothers me about flaps in AH - especially the full flaps.
I tested a few planes in AH at full flaps. At full flaps, full power and auto-speed set to 100 mph (minimum of .speed command), planes climb 1.5-2 kfps. I suspect that the rate of climb may be even higher at lower speeds which I will have to test manually. It would be interesting to check climb rate at the no-flaps stall speed. It would give some indication to efficiency by comparing the increase of throttle (MAN or fuel burn in E6B) with the potential energy increase rate (ROC). Or climb rate at full power with different flap settings but constant speed.
I would very much like to know from people who are familiar with real planes how much sense does this makes to them. I was under the impression that at full flaps planes can barely climb. Of course the excess power of F4U is far more than what you get in cessna 172, but sill...
The other thing is that in planes like 190A5 and P47D25, auto trim reaches the limit and can't keep the plane steady at 100 MPH full flaps and a turn left develops due to the torque. On other planes like the F6F and F4U, trim is enough to counter it even at 100 mph. So some planes can't benefit from flaps at very low speeds simply because they can't handle the torque.
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The F4U-1, F3A-1, and FG-1 pilots manual AN-01-45HA-1 dated 1 March 1944 describes full flap use in the F4U for short distance take off, also there is an exerpt that I will quote:
"FLAP SETTINGS- For normal operation it is recommended that a setting of 20 deg be used for take-off. Actually, any setting from 20deg to 50deg ("FULL DOWN") may be used, the higher settings giving shorter ground distance. Take-offs with flaps up are easily accomplished with a small increase in run, dispensing with the inconvenience of retracting the flaps after take-off. In addition, the rate of climb immediately after take-off with flaps deflected is inferior to that with flaps "UP". Take-offs at high flap settings and at full flap should be made only when it is necessary to obtain the shortest possible ground run, and after more experience with settings increased gradually from the recommended setting of 20 deg. When a high flap setting is used, the elevator tab should be slightly more tail heavy (about 1 deg).
NOTE
It has been found with the flaps down, the tail cannot be held on the ground with the stick full back, at manifold pressures greater than 44 inches Hg. Also, when operating a wooden platform, the wheels will start slipping on the deck at about the same manifold pressure. As a result, when making carrier take off it is necessary to advance the throttle through the final portion of its travel as the airplane starts to roll. No difficulty should be encountered in this operation.
(11) Open the throttle gradually and smoothly.
CAUTION
Do not retract the flaps too soon or too rapidly if the speed is very low; otherwise the airplane may settle due to the loss in lift. It should be remembered that the higher the control speed, the better the control. "
Regards,
Malta
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Stantond,
Is there a performance index in you F4U manual? I don't think I have that one.
The POH is an awesome source of information.
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Originally posted by bozon
I would very much like to know from people who are familiar with real planes how much sense does this makes to them. I was under the impression that at full flaps planes can barely climb. Of course the excess power of F4U is far more than what you get in cessna 172, but sill...
I'm not even sure we can make the comparison. One of the things I'm still trying to figure out about AH is why lowering the flaps makes the nose pitch up. In real life, its the exact opposite.
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Originally posted by stantond
NOTE
It has been found with the flaps down, the tail cannot be held on the ground with the stick full back, at manifold pressures greater than 44 inches Hg.
Malta
This is imho the biggest discrepancy to AH and cause the great turn and climb of the AH F4U with flaps.
In AH i need to push the stick rather down to keep the F4U nose down, while full flaps in general lower the nose, this at least count for high flap angles.
The missing need to pull the stick probably also explain why the F4U with flaps have a so smal induced drag.
Greetings,
-
Originally posted by bozon
There's something else that bothers me about flaps in AH - especially the full flaps.
I tested a few planes in AH at full flaps. At full flaps, full power and auto-speed set to 100 mph (minimum of .speed command), planes climb 1.5-2 kfps. I suspect that the rate of climb may be even higher at lower speeds which I will have to test manually. It would be interesting to check climb rate at the no-flaps stall speed. It would give some indication to efficiency by comparing the increase of throttle (MAN or fuel burn in E6B) with the potential energy increase rate (ROC). Or climb rate at full power with different flap settings but constant speed.
I would very much like to know from people who are familiar with real planes how much sense does this makes to them. I was under the impression that at full flaps planes can barely climb. Of course the excess power of F4U is far more than what you get in cessna 172, but sill...
The other thing is that in planes like 190A5 and P47D25, auto trim reaches the limit and can't keep the plane steady at 100 MPH full flaps and a turn left develops due to the torque. On other planes like the F6F and F4U, trim is enough to counter it even at 100 mph. So some planes can't benefit from flaps at very low speeds simply because they can't handle the torque.
flaps are a real drag, but i've never been in a plane (including many different versions of the 172, even a real dog of a 160hp 172 with a "cruise" prop) that wont climb with them full out, probably some sorta FAA regulation on that
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"The missing need to pull the stick probably also explain why the F4U with flaps have a so smal induced drag."
What do you mean with stick pulling? I think it is logical that for level flight you need to push the stick forward because the profile and thus angle of the wing incidence has changed so radically because of full flaps. Especially in planes with full flaps, not split flaps.
"One of the things I'm still trying to figure out about AH is why lowering the flaps makes the nose pitch up. In real life, its the exact opposite."
I think some planes wanted to pitch down with flaps and some up. I think they generally pitched down.
-C+
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Err, got a brainfart -sry.
Because the flaps try to wrench you nose down you need to pull back the stick some to compensate until the speed has dropped sufficiently.
-C+
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The Spitfire did not have a laminar flow wing, that is why they made a prototype Spiteful.
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Charge: Pitching moment do to flaps can go either direction.
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Where's Widewing in this , he's the only person i'll believe in this discussion, save for GOD. :D
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Flying around with flaps out is certainly not a standard condition. The best rate of climb I could get was 1500 fpm with mil power using full flaps at 100 ias. I have no idea whether this is correct, but it seems plausable. The stall speed is considerably less than this speed with the vne about 140 mph for full flaps.
Certainly the wing provides more lift with flaps out at very low speeds, per the POH. How that affects climb rate can be debated, but with full ordinance take off from a carrier requires full flaps on a -1D. Full flaps on the other aircraft are used to create drag and produce no lift so they are only used on landing. The flaps on the F4U are unique, but I don't have any specific data on their performance.
Regards,
Malta
F4UDOA: there are some performance charts, describing ROC at various weights and ranges along with aircraft weights based on ordinance loadout. Is that the sort of thing you are talking about? I can post a link to jpg's of charts or tables if that helps.
As an aside:
An interesting option in AH would be the 'light' fighter configuration which has 3/4 tank of fuel and 200 rpg. Of course, an itchy trigger finger can add that configuration.
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Malta,
That would be great. I think I know the chart you are refering to but I would like to see if it is anything new.
I have mentioned to HTC that the "Interceptor Loadout" would be a nice option. There are no points for getting shot down with 750lbs of ammo on board.
BTW, You did a good job explaining the differance between F4U and land based flaps. The AAF fighter flaps for the most part where to be used to assist in reducing speed to land not to generate lift to takeoff from a carrier with a heavy load or to assist in low speed handling around a ship. Of course the P-38 and P-51 had Combat flaps of their own but not for the same design purpose.
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F4UDOA,
Do you have some drag polars for the F4U, preferably with and without flaps?
It would be fairly easy to calculate at which speed or Cl the drag with flaps exceed the clean situation. There is a NACA report (WR-L-440) on wind tunnel tests of the 1/2,75 scale F4U model but the problem with that report is that the flaps configuration appear to be not standard (full span flaps).
gripen
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Drag polars??
I have some detailed drag listing for the F4U and I have initial climb rates with various flap stages deployed although I believe it is the -4 and I need to scan it.
Is the a way to calculate the additional list provided by measuring the reduction in takeoff length required?
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Originally posted by hitech
Charge: Pitching moment do to flaps can go either direction.
Has it got something to do with CG then? In my admittedly limited experience in the cockpit, the plane always pitches down when flaps are lowered. Seems that way on airliners as well.
The POH for the P-51/47 says that flaps will make the nose pitch down. Its not a huge deal--I've always just wondered why--but I have wondered if the pitch change affected the turning numbers the community comes up with. If someone says its a nuance of the flight model, like the auto takeoff trim, I'll just push the "I believe" button and carry on.
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Originally posted by Stoney74
Has it got something to do with CG then? In my admittedly limited experience in the cockpit, the plane always pitches down when flaps are lowered. Seems that way on airliners as well.
The POH for the P-51/47 says that flaps will make the nose pitch down. Its not a huge deal--I've always just wondered why--but I have wondered if the pitch change affected the turning numbers the community comes up with. If someone says its a nuance of the flight model, like the auto takeoff trim, I'll just push the "I believe" button and carry on.
Most light aircraft nose up when flaps are lowered. The reason, from what I have read, is because of prop wash and the location of the horizontal stabilizer relative to the propeller. This effect isn't seen in jet engine airliners because of the engine locations and they nose down when flaps are lowered.
Now you have made me curious. Does the P51 pilots manual talk about flap limitations during takeoff and landing? Does it talk about combat flap operations? I have to wonder about the P47 as well regarding flap use limitations. Do the pilot manuals for either plane recommend full flap take offs?
Regards,
Malta
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Originally posted by F4UDOA
Malta,
That would be great. I think I know the chart you are refering to but I would like to see if it is anything new.
I have mentioned to HTC that the "Interceptor Loadout" would be a nice option. There are no points for getting shot down with 750lbs of ammo on board.
clip..
Here are the last five charts from the F4U1 pilots manual in compressed tiff format:
Page 70: (http://members.cox.net/~stantond/f4u1_pg_70.tif)
Page 71: (http://members.cox.net/~stantond/f4u1_pg_71.tif)
Page 72: (http://members.cox.net/~stantond/f4u1_pg_72.tif)
Page 73: (http://members.cox.net/~stantond/f4u1_pg_73.tif)
Page 74: (http://members.cox.net/~stantond/f4u1_pg_74.tif)
Regards,
Malta
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Originally posted by F4UDOA
Drag polars??
It's basicly a way to chart the Cd/Cl relation in the same presentation. Below is a simple example; the blue line is Cd/Cl relation at clean condition and the red line is with full flaps. The use of the flaps change the lift/drag relation of the plane and at high Cl, the flaps might decrease drag at this given Cl (roughly above Cl 1 in the example case). Partial flaps would give yet another kind of curve.
gripen
(http://www.onpoi.net/ah/pics/users/852_1164274110_polars.jpg)
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Originally posted by stantond
Does it talk about combat flap operations? I have to wonder about the P47 as well regarding flap use limitations. Do the pilot manuals for either plane recommend full flap take offs?
Malta
Yeah, they're are speeds recommended for full flaps, expressed as a never exceed speed for full flaps. For example, in the jug, its 195 max for full flaps. I don't have them with me as I'm on vacation right now, but I do remember that they recommend 20-30 degrees for heavy takeoffs / obstacle clearing. I can look them up when I get home if you like.
Going back to the pitch moment, I'm not sure that propwash could have anything to do with it since it would affect one side of the plane more than the other, right? Like p-factor? Do the flaps, once they are extended into the air beneath the wing, act a lever on the wing? Enough to make the nose pitch down? Or, what causes the nose to pitch up when flaps are lowered?
Perhaps I should make this another thread...
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BLARG! this is definitely getting nowhere without Widewing - the Silencer. I always have wondered why the P-38's Fowler flaps never could help the large bird outturn the F4U.
The increase in wing chord due to the opening Fowler flaps SHOULD increase a large decrease in the wing loading of the aircraft, causing it to outturn the F4U. Sure, the Hog's flaps could help the a/c turn very well, but the fact that they seem to only direct thrusy downward and out along the wing should give a gentle lift property but NOT such a significant turn radius length reduction since the chord continues to actually shorten when seen from above the wing.
The Fowler flaps, however, would stretch the wing chord out, causing the prop wash to directly move under the 'lengthened' wing chord producing more lift. Why, then do our P-38's, turn sooo poorly when compared to the Spitfire or Mustang - both of which should be completely outturned by the Lightning?
Maybe I'm missing something, but this is what I have learned so far.
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SgtPappy, assumptions as to how different flaps would affect flight seem very logical but are based on practically nothing.
Aero-engineers of WWII knew a lot about aerodynamics but understood very little of it. Surprisingly, todays Aero-engineers know a lot more about aerodynamics, but understand very little more than they WWII ancestors. The only thing they can really do better is use powerful computers. The hydrodynamics equations are annoyingly simple yet difficult. From engineering to astrophysics scientists are still boggled by it.
Intuition like - "the flaps extend so I get more area therefore more lift" or "lets make a slot in the wing so flow from below delay turbulence" hold very well sometimes - and sometimes not at all. Eventually, it all comes down to trial and error, unless you have some rare good physical argument.
My intuition says that lowering flaps would pitch the nose down if we don't trim. More lift means more vorticity behind the wing. The natural direction of a system would be to reduce it by applying torque on the wing to move it to zero AoA. That's why in order to increase AoA you need more downward force from the elevators to twist the wing against the flow. That may hold only when you are far from the stall and maintain smooth flow with a nice big vortex behind the trailing edge. But then again, that's only an idiots intuition. If experience says it can work both ways, I believe it. If numerical simulations says it can work both ways, I accept it for lack of other options.
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Originally posted by SgtPappy
BLARG! this is definitely getting nowhere without Widewing - the Silencer. I always have wondered why the P-38's Fowler flaps never could help the large bird outturn the F4U.
The increase in wing chord due to the opening Fowler flaps SHOULD increase a large decrease in the wing loading of the aircraft, causing it to outturn the F4U. Sure, the Hog's flaps could help the a/c turn very well, but the fact that they seem to only direct thrusy downward and out along the wing should give a gentle lift property but NOT such a significant turn radius length reduction since the chord continues to actually shorten when seen from above the wing.
The Fowler flaps, however, would stretch the wing chord out, causing the prop wash to directly move under the 'lengthened' wing chord producing more lift. Why, then do our P-38's, turn sooo poorly when compared to the Spitfire or Mustang - both of which should be completely outturned by the Lightning?
Maybe I'm missing something, but this is what I have learned so far.
There's several reasons why I haven't pitched in here previously. We have some engineers who post here who have solid aeronautical background. I'm a mechanical engineer, and aerodynamics is not my field. A second reason is that there is almost no test data available that defines how good or bad the P-38 turns with flap use. There is a great deal of combat records, but this type of evidence is often laced with perception and not completely reliable as a basis for modeling virtual aircraft. You can see what I mean by just reviewing the discussions on this BBS. We see films posted where a fighter out-turns another and the pilot involved points to this as evidence that his plane is better. More often that not, this only reflects the pilot of the other aircraft and not what he was flying.
We can look at some basic aircraft characteristics and draw some equally basic conclusions.
Roll rate is important because the quicker a fighter rolls, the faster it can change lift vectors. The P-38s have a low rate of roll at low speeds... Too much mass off of the centerline.
Wing loading is a good place to begin when it comes to turn radius. P-38s have a relatively high wing loading when clean. General Kelsey once estimated that the Lockheed type Fowler flaps increased wing area by 11% and effective area by about 15% (due to slipstream effect). In the game, the normal takeoff weight is 17,500 lb. Dividing that by 327.5 sq/ft provides 53.4 lb per sq/ft. Let's increase the wing area by 15%. 17,500/376.6=46.46 lb per sq/ft. Let's compare that to the basic F6F-5. Our Hellcat weighs 12,483 lb. 12,482/334=37.37 lb per sq/ft. So, a P-38J with full tanks has no chance at out-turning a fully gassed up F6F-5.
Let's do another example. A fully fueled Bf 109G-6 weighs 6,940 lb. So, 6,940/173.2=40.07 lb per sq/ft. Once again, the P-38J should not be able to out-turn this fighter. To have any chance, the P-38 must shed a lot of weight. If it loses 2/3 of its internal fuel, its weight drops to 15,860 lb. 15,860/376.6=42.11 lb per sq/ft. Therefore, the P-38J can compete reasonably with fully fueled 109G-6, to the point that pilot skill is a dominant factor. This assumes that the 109G-6 pilot DOES NOT use his own flaps or his plane is in a low-fuel state as well. If either or both cases exist, he gains the advantage again.
Personally, I believe that both the P-38s and P-51s took a major hit when the drag model was revised. I think both types need some FM tweeking, but I feel the P-51 suffered more than the P-38 did (excluding the initial and now corrected P-38 flap bug).
In real life, P-38s were complex fighters, and only the best pilots became masters of the type. Average pilots were constantly struggling with the plane, which is why they had much greater confidence in the P-51. It was just easier to fly.
In Aces High, we have the same issues. P-38s are very capable, but require time to learn and not everyone will be able to exploit the Lightning to its full potential. Those that can and do are quite formidable.
My regards,
Widewing
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Originally posted by stantond
E-M charts are a concept thought up after the jet age and so there's no real WW2 historical charts of that type.
Hi stantond,
The concept dates back before WWII and there are EM diagrams dated back before 1939. The original EM diagrams are slightly different but every bit as informative as the modern ones. If you would like to see some "real WW2 historical charts of that type." then scroll to the end of the second page of this thread for examples of Me109, Spitfire and F2A EM diagrams.
http://www.hitechcreations.com/forums/showthread.php?threadid=137751&referrerid=2314
Hope that helps...
Badboy
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Wow. Great stuff, Bozon and Widewing. You just unfogged my glasses, so cheers to you! Well, we are in a discussion about the F4U, after all, and so, lastly, I'd like to say that, even now that I know the P-38 doesn't turn as well as I thought, I still wonder as to why the F4U turns sooo well.
True, the flaps do direct the propellor wash differently, but does this actually mean that the F4U will turn WITH or actually outturn a Spitfire altogether? Slapshot said that he heard from a Hog driver that a good F4U pilot could outturn the Spitfire. At the same time, pilots of the P-38's also said that they'd 'outturn' Spitfires, though they weren't literally meaning that. When that legendary battle between the Spitfire and P-38 took place, the P-38 may have stayed with the Spit, but it was doing so by riding its stall... not literally outturning it. Was the Corsair's flaps somehow enabling it to execute some odd manipulation of the propellor wash that allowed it to maneuver as it did, just as the P-38's twin engines and design allowed it to ride a stall?
Lastly, I was wondering if flaps could, in real life, only be opened at lower speeds. I.e. the Hog and P-38 can only open up their flaps at 250 mph in the game. Is that some sort of saftey mechanism so that our flaps don't rip off? I'm assuming this was some kind of 'flap regulation' in the real-life manual that advised pilots not to open their flaps over 250 IAS.
*phew* that's it... lots of stuff buzzing around in my 14yr old head! Thanks again all.
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The F4U has the tighter turning circle with flaps deployed. However the Spit will make its turn faster, so unless the F4 can get a shot in within the first couple circles he'll be in trouble.
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O yea, I remember when you taught me about that, Sax. However, the odd thing is, I just wish to learn the physics of those wonder flaps. I've flown the Hog with your great advice and that Hog really kicks butt. If i learn the physics, I believe I could improve a bit. The only reason why I have any success at all in this game is b/c I research a lot about WWII a/c - most notably the P-38, Spit and Hog... ha.. one of my friends thinks I'm such a freak; so much so that she says my very first sight as an infant was the Spitfire.
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Lol.. and suddenly I bring up the question... and they all go silent and slowly step away ... *fetal position, rocking back and forth*.
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Physics isn't my strong suit. It works, and that's all that I want to know.
Otherwise, my brain might explode. :D
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Originally posted by SgtPappy
Lol.. and suddenly I bring up the question... and they all go silent and slowly step away ... *fetal position, rocking back and forth*.
What was the question?
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Lastly, I was wondering if flaps could, in real life, only be opened at lower speeds. I.e. the Hog and P-38 can only open up their flaps at 250 mph in the game. Is that some sort of saftey mechanism so that our flaps don't rip off? I'm assuming this was some kind of 'flap regulation' in the real-life manual that advised pilots not to open their flaps over 250 IAS.
Yes they have real life limitations. And when ever we have that info on any plane, thats what we use.
HiTech
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Originally posted by Widewing
In real life, P-38s were complex fighters, and only the best pilots became masters of the type. Average pilots were constantly struggling with the plane, which is why they had much greater confidence in the P-51. It was just easier to fly.
In Aces High, we have the same issues. P-38s are very capable, but require time to learn and not everyone will be able to exploit the Lightning to its full potential. Those that can and do are quite formidable.
My regards,
Widewing
As a capable, but occasional player I tend to agree. The P-51D is my favourite plane as my style centers around killing without being killed. That's what I like, that's how I play. I strive to always get the tactical advantage, if I can't get it or am losing it I disengage. You may call that running ;)
If I read Widewing's analysis after a patch or an FM change I often wonder how on earth does he tell the difference that a 109F can now own a Spit V in a knife fight? You'll figure that out if you slug it out time & time again in the TA one on one, on the edge of the flight envelope. Fun, no doubt, but I don't have the time & patience to do that. If I reach the edge of the envelope during the sparse hours I play, I usually die.
Coming back to the P-38, I often read comments from Widewing and others like AKAK that the P-38 is so formidable. But when I fly them or fight them (the P-38, not these gentlemen) I can't find those hidden qualities... most of the time. I never use manual trim, only to get a 109 out of a terminal dive. I never use flaps, using flaps means bleeding E and bleeding E means someone else I don't see yet may get an advantage over me. The only thing I think is remarkable how well it behaves in the vertical.
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Originally posted by SgtPappy
Lastly, I was wondering if flaps could, in real life, only be opened at lower speeds. I.e. the Hog and P-38 can only open up their flaps at 250 mph in the game. Is that some sort of saftey mechanism so that our flaps don't rip off? I'm assuming this was some kind of 'flap regulation' in the real-life manual that advised pilots not to open their flaps over 250 IAS.
In F4u's, the selector will allow you to deploy the flaps at any speed down to 15 or 20 degrees and no damage will occur. The beauty of this system is that the flaps will not deploy above 250 kts or so, because there is an unloader valve in the hydraulics as well as a series of heavy duty springs on the actuator ends. What this does is allow the flaps to be extended, and if you go above 250kts or so, the springs do not have the tension to keep the flaps down, so they retract due to this lack of tension. As you slow down, they come back out as the force of the airflow does not out weigh the spring tension. So, in essensce, the flaps come down almost instantly as you need them, making them much more effective than the average birds which must be deployed upon reaching a speed.
If the flaps are deployed down past 40 degrees and you go above 250kts or so, you run the risk of damage as the spring system does not have enough travel. In reality what ends up happening is either the unloader allows the flaps to retract, and between this and the tensioned springs, they retract enough to prevent damage. In rare cases, the actuator arms will sometimes kink on the end and not allow the tension springs to work properly, and the flaps get stuck in that position, and will neither retract or deploy more than a few degrees. I have dealt with this in two different u birds and felt it to be a pilot error owing to a misindication in the cockpit of the asi.
As for the 38, it does not have the same system as the Corsair, and you run the very real risk of damage of flaps deployed past their operating speed with very real jamming of the system happening. Keep in mind the flap system on the 38's involves an actuator arm controlled by a steel rod that resides in the flap well. The actuator has two steel roller bearings in a track that is aluminum. This track will not take side load of any kind without scoring and jamming the roller bearings. If this happens, the aluminum where the flaps actuator rod attachs will fold up if high speeds are encountered with the flaps deployed.
Hope that helps you understand their sytems better.
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Originally posted by hogenbor
As a capable, but occasional player I tend to agree. The P-51D is my favourite plane as my style centers around killing without being killed. That's what I like, that's how I play. I strive to always get the tactical advantage, if I can't get it or am losing it I disengage. You may call that running ;)
If I read Widewing's analysis after a patch or an FM change I often wonder how on earth does he tell the difference that a 109F can now own a Spit V in a knife fight? You'll figure that out if you slug it out time & time again in the TA one on one, on the edge of the flight envelope. Fun, no doubt, but I don't have the time & patience to do that. If I reach the edge of the envelope during the sparse hours I play, I usually die.
Coming back to the P-38, I often read comments from Widewing and others like AKAK that the P-38 is so formidable. But when I fly them or fight them (the P-38, not these gentlemen) I can't find those hidden qualities... most of the time. I never use manual trim, only to get a 109 out of a terminal dive. I never use flaps, using flaps means bleeding E and bleeding E means someone else I don't see yet may get an advantage over me. The only thing I think is remarkable how well it behaves in the vertical.
I thinks it because your stuck in one play style. If all you do is fly a 51 and only attack when your holding all the card .. I don't think your pushing yourself . I'm not knocking your idea of fun mind you. But in order to see the benefit of flap usage you actually have to slow down enough to deploy them.
I say jump in a slower turn fighter for a tour and not worry about getting shot down . Then you might learn the benefit of flap usage .
Bronk
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Originally posted by hogenbor
If I read Widewing's analysis after a patch or an FM change I often wonder how on earth does he tell the difference that a 109F can now own a Spit V in a knife fight? You'll figure that out if you slug it out time & time again in the TA one on one, on the edge of the flight envelope. Fun, no doubt, but I don't have the time & patience to do that. If I reach the edge of the envelope during the sparse hours I play, I usually die.
When the 109 FM was fixed, we tested them extensively. What we discovered is that the 109F-4 could more than hold its own with the SpitV, provided that the 109 pilot knows how to get the most out of the 109. We flew dozens of duels against everything in the plane set. I flew duel after duel with Timmpa, with him trying about half of the fighter set. Time after time, the 109F-4 prevailed. We proved that the 109F had attained "one of the most dangerous" status.
I flew a little duel with Sonic23. Sonic is a very, very good Spit pilot. I have to fly like mad just to earn a draw when we fight in Spits, and if I make just one mistake, he's all over me. Yet, he could do nothing with the 109F-4, especially when I refused to reverse my turn but kept pounding around to the 109's strong side and by not reversing, I never give up any angles. Eventually, the 109's superior turn rate and vertical performance prevailed. Here's a FILM (http://home.att.net/~ww2aviation/film190_SpitV-109F4.ahf) of that encounter.
To know what a plane can do, you have to explore its limits. Then you have to learn how to quickly find the limits and fly on the edge without pushing too hard. That takes lots of practice and many duels.
My regards,
Widewing
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Thanks all for helping. Bohdi, it really does help me understand the systems of the 2 planes. Wow.. the P-38's were more of pains to learn how to fly than I thought, but aren't many of our planes lol.
Good thing you filmed that, Widewing. Seems like the SpitV was struggling indeed. Wondering if that makes a Spit8 or 9 even more vulnerable. The 8 does become faster and faster as alt increases and it climbs better in the same way (of course, the 109 has those few supercharging boosts at some alts), but, of course, I'm often proved wrong if I ever say that these things alone will help the Spit prevail. I personally think that the 2 planes are equal.
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I've come back with some information regarding the F4U's turning ability vs. that of the Spitfire VIII or IX. On www.spitfireperformance.com (http://www.spitfireperformance.com) , you'll find (under the F4U directory) flying charateristics of the F4U-1... the second most maneuverable Corsair in the game. According to those trials (with an F4U-1 loaded to 12,000 lbs.), the F4U-1 turned only slightly tighter than that f the P-38G both with and without flaps.
Now comes the assumptions: The F4U-1A turns slightly tighter than the F4U-1, so assuming that the P-38G turns as well as it does in the game (and assuming that tests have been made with no flaps, 10 degrees of flaps, 20 degrees, 30 etc.), the Spitfire VIII should easily outturn the Corsairs.
Definitely no the greatest test, but you see my point.
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Originally posted by SgtPappy
I've come back with some information regarding the F4U's turning ability vs. that of the Spitfire VIII or IX. On www.spitfireperformance.com (http://www.spitfireperformance.com) , you'll find (under the F4U directory) flying charateristics of the F4U-1... the second most maneuverable Corsair in the game. According to those trials (with an F4U-1 loaded to 12,000 lbs.), the F4U-1 turned only slightly tighter than that f the P-38G both with and without flaps.
Now comes the assumptions: The F4U-1A turns slightly tighter than the F4U-1, so assuming that the P-38G turns as well as it does in the game (and assuming that tests have been made with no flaps, 10 degrees of flaps, 20 degrees, 30 etc.), the Spitfire VIII should easily outturn the Corsairs.
Definitely no the greatest test, but you see my point.
You have to read the Navy test of the F4U vs the P-51B (here) (http://www.wwiiaircraftperformance.org/f4u/p-51b-f4u-1-navycomp.pdf) to get an idea of how each service skewed test methods, and likely gundecked the data.
There's no way the AAF was going to state that the F4U was superior to its fighters. Likewise, the Navy isn't going to stipulate that the P-51 was superior to the Corsair. Interservice rivalry certainly extended to testing of fighters.
I have argued for years that the best fighter to see combat in US service was the F4U-4. You could make a very strong argument that the F4U-4 was the best all-around fighter flown by any nation.
A friend of mine, General Ralph Jerome, got his start by going to Canada after being turned down by the USAAC. There he joined the RCAF and flew Hurricanes and Spitfires before transferring to the USAAF, where he flew P-51s. Stateside in early 1950s, he was flying a P-51D and had the opportunity to mix it up with an F4U-4. Despite his vast experience, he was unable to evade that Marine Corsair. General Jerome was convinced that later F4Us were very able fighters. "I was one of those who believed that Mustang was the best fighter of its generation. That experience showed me that the issue was at least open to serious debate."
My regards,
Widewing
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I performed some additional max speed testing on the F4U-4, based upon using 26,000 feet as its critical altitude. It was faster at 26k than it was at 25k. I also tested the balance of the faster (at high alt) fighters at 26k as well. Results are as follows, from fastest to slowest of the group.
P-47N: 460 mph (WEP)
F4U-4: 453 mph (WEP)
Spit14: 447 mph (WEP)
109K4: 443 mph (WEP)
Ta 152H: 440 mph (WEP)
P-51D: 439 mph (with or without WEP, no increase in MAP)
P-51B: 434 mph (WEP)
So, this shows that at this height, the P-47N simply runs away from the others. The F4U-4 shows once again why it is the best overall fighter. I did not test any fighters (other than the P-51D) at MIL power. Fuel was 25%, zero burn. Takeoff was from a 30k field on the TA map. Up that high, some aircraft had to horsed off the runway to avoid damaging the landing gear (the 109K-4 was the worst for this). In case someone is curious as to why the Tempest wasn't included in the group, it doesn't measure up. Its speed is well below that of the slowest plane in the test (P-51B) and its acceleration and climb are relatively feeble in comparison. Also, it should be mentioned that the 190D-9 is 8 mph slower than the P-51B at 26k (426 mph). I did notice that at 460 mph @ 26k, the P-47N has a wickedly fast rate of roll. I didn't have time to measure it, but it's on my things to do list.
My regards,
Widewing
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Originally posted by Widewing
I did notice that at 460 mph @ 26k, the P-47N has a wickedly fast rate of roll. I didn't have time to measure it, but it's on my things to do list.
Although I'm a jug fan, I barely fly the N. The D jugs are decent rolling planes, but I'm always surprised by the improvement in the N. I don't think that the roll rate is a direct function of alt, but more of IAS.
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Actually Wideeing, though I often run back to the Spitfires (except the 16, i hate flying overmodeled planes), I actually do, whole heartedly believe that the F4U-4 is the greates overall combat fighter of WWII.
Yet, the Corsairs aren't really supposed to turn that tight. Their power loadings and wing loadings just don't support it. Those flaps and possibly the gull wings shove some extra cornering power, but by the time the fight slows down to medium speeds (250 IAS, so forth) the F4U's flaps should not enable it to turn any tighter than the Spitfires 9,8,16,14 (all of which turn tighter than the Hogs - they are listed from tightest turning to widest turning). A Hog will, very likely be able to almost turn with the Spit 16/14 - so much so that it really comes down to pilot experience rather than the plane, but a Hog turning tighter than the Spit9? Unlikely. Maybe the F4U had some crazy turning b/c of it's wing aspect ratio or something. If so, I'd like to learn why... but the Spitfire 14 seems to have the same aspect ratio, and taper ratio (well slightly smaller but still lol) and so the only thing that give the Hog such nice turning must be those gull wings - that is if they REALLY did help it turn that tight.
Remember, it's not just wing loading that determines turning. There's power loading and a bunch of other factors. I'm not trying to sound smart, b/c I'm not, but this is what I know.
I always get confused over matters like this. I once started in the Spit5, but that was outclasses by the A6M5. Then I tried the Later spits which were outturned by the Hogs. So i tried the Hog, which got mauled by the La-7 (except the F4U-4, but that got killed by the older F4U's), so now I'm back to my Spitty, hoping DESPERATELY like the whiner I am, to fix that crazy Hog turning. Yes, I know, pretty much every plane has at least one enemy that can seriuosly destroy it, but the Spit14 is just a little less susceptible to that. Thanks, though, Widewing for all the advice you've ever given me.. I feel 10 times smarter thanks to you.
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I have a few tidbits to throw in here, because I haven't seen them discussed yet, and they MAY have application in this discussion.
I don't have the necessary knowledge to really apply them, but hopefully some of you do, and can let me/us know the why's...
1- Regarding pitching motion when flaps are deployed. The nose generally seems to pitch up for me in the hog as flaps are deployed. However, I generally attribute that to the auto combat trim. The trim is trying to support a "hands-off level" condition from what I understand. From my observatios, the trim ends up going full "up". In doing so, wouldn't it be compensating for a "nosing down" effect? In my head, if flaps had no effect on pitch, the trim would stay centered, so the fact that it moves is saying something...
2- According to my copy of the F4U pilots manual, the F4U has an incredibly low stall speed (at least in my mind) for such a large/heavy plane. Power off, 50 degrees of flaps, the stall speed is listed as 75 knots. However, with power on (23" Hg, 2400 RPM) and 50 degrees of flaps the stall is listed as 66 knots LEVEL FLIGHT. Does this explain at all the fact that the plane still is able to manuever at very low alts/speeds, especially considering we are operating with WEP, etc?
How do these stall speeds compare to the spits etc, which most people think should out-turn the F4U in the low/slow fights?
MtnMan
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Gents,
Just my 2 cents and I am not going to get on my F4U soapbox on this one.
The F4U does have a very low stall speed for an aircraft of it's size however the wingloading of the Spit is even more remarkable. I have several Spit Manuals with indicated stall speeds and CAS charts. The Spit IX manual shows as follows.
Power Off 7150LBS
Clean Condition no flaps
78knots (90MPH)
Flaps and undercarrage down
65-69Knots 75-79MPH
The same relative numbers for the F4U
11,300LBS Power off
Clean condition no Flaps
87Knots
Flaps and Gear down
75 knots
At these loading conditions the Spit is certainly superior to the F4U. The F4U speeds are a couple of Knots high according to the CAS chart but not enough to make a difference. The relative loadings are without ammo but full fuel on both. You could adjust the weights for similar range but again the results will be about the same.
The only thing that is not in the manual for the Spit is stalls with power on (idle power). This helps give you an idea on how much wing area is affected by propwash. The F4U goes from 75knots to 66 knots by applying 23" of MAP which is a fairly significant reduction. I am not sure how the SPit is affected.
All that needs to really be done now is to test what speeds the Spit IX in AH stalls at power off at 7150LBS to see if it matches the manual or is close.
FYI, Instantanious turning is another story.
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However given that the F4U is just over 4000lbs heavier a "mere" 10kt difference doesn't appear to be a tremendous difference. Noticeable, certainly, but not overwhelming.
How does the Corsair's stall speeds measure up to the F6F?
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Saxman that is a great question,
Unfortunately Grumman had so many problems with the airspeed indicator in the F6F I don't think there is anyway anyone can know how fast the F6F was actually flying.
Even in later models and in test run by modern pilots the results are so scattered there is no way to know for sure. I have copies of Vought test where they used radio towers to calibrate the airspeed and they could say with little doubt how fast or slow their aircraft was flying. Then I have no less than 4 seperate CAS charts for the F6F some of which having as much as 18knots of error on the high and low end of the speed range.
I believe the F6F would have been marginally better with no flaps and not as good with flaps in terms of turning circle.
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Originally posted by F4UDOA
The only thing that is not in the manual for the Spit is stalls with power on (idle power). This helps give you an idea on how much wing area is affected by propwash. The F4U goes from 75knots to 66 knots by applying 23" of MAP which is a fairly significant reduction. I am not sure how the SPit is affected.
All that needs to really be done now is to test what speeds the Spit IX in AH stalls at power off at 7150LBS to see if it matches the manual or is close.
It is likely that there are some Spitfire training films out there. I've yet to find one, but it may have the info you're looking for - the F4U training vids on www.zenoswarbirdvideos.com (http://www.zenoswarbirdvideos.com) were very useful in telling different stalls under various situations. If you can find a video like that (not sure if there's a USAAF one, but they did use Spits), you may find your info.
If not, look to Widewing! :aok