Author Topic: F4u flaps (Read 7700 times)

Krusty · « **on:** November 13, 2006, 04:56:02 PM »

While checking the AH plane comparison webpage 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?

SIK1 · « **Reply #1 on:** November 13, 2006, 05:01:07 PM »

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

Krusty · « **Reply #2 on:** November 13, 2006, 06:17:30 PM »

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.

FBplmmr · « **Reply #3 on:** November 13, 2006, 06:41:26 PM »

maybee it isn't realistic, but are you gonna tell that to Robert Conrad

Trikky · « **Reply #4 on:** November 13, 2006, 07:07:02 PM »

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.

Benny Moore · « **Reply #5 on:** November 13, 2006, 07:22:55 PM »

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.

Overlag · « **Reply #6 on:** November 13, 2006, 07:55:41 PM »

the flaps are pretty big compaired to most flaps though....

Saxman · « **Reply #7 on:** November 13, 2006, 08:12:27 PM »

Who was it that posted video showing a real Hog doing pretty much all the helicopter stunts the F4U performs in-game?

Benny Moore · « **Reply #8 on:** November 13, 2006, 09:05:52 PM »

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.

Saxman · « **Reply #9 on:** November 13, 2006, 10:11:01 PM »

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.

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.

F4UDOA · « **Reply #10 on:** November 13, 2006, 10:38:18 PM »

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.

Here is the flight envelope of the F4U no flap no power.

Saxman · « **Reply #11 on:** November 14, 2006, 12:50:35 AM »

Lol. Ask and ye shall receive.

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?

Krusty · « **Reply #12 on:** November 14, 2006, 01:25:53 AM »

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?

Saxman · « **Reply #13 on:** November 14, 2006, 01:46:49 AM »

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?

Knegel · « **Reply #14 on:** November 14, 2006, 08:00:09 AM »

Quote

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