F4U-4 vs YaK-9U

kool kitty89 · 05-07-2008, 04:39 PM

Soren, got it. That sounds about right. (I knew that there was some lost wasn't sure how much)

But according to this The Incomplete Guide to Airfoil Usage the TR at root was 15% tip 9%

(same for the F4F and F6F, except 15.6 for the F6F's root, the F2A had 18% root 9% tip)

Though the Fw 190's would be higher as well as it had a continuous 15% thickness along the span. (15% being very close to maximum CL for the arfoil, as you've shown it drops above 16%)

HoHun · 05-07-2008, 04:48 PM

Hi Koolkitty,

>But according to this The Incomplete Guide to Airfoil Usage the TR at root was 15% tip 9%

If it helps, the BuAer drawing referenced above features a drawing that names the airfoil designations for the F4U ...

Regards,

Henning (HoHun)

Soren · 05-07-2008, 04:54 PM

KK,

According the Vought's own specs it is 18%, so IAU's figure must be a typo.

kool kitty89 · 05-07-2008, 05:24 PM

OK,

And Henning, the F4U (and all WWII US Navy fighters that I know of, along with most Navy a/c used the high lift NACA 23000 series airfoil, so the F4U should be 23018 root 23009 tip)

kool kitty89 · 05-07-2008, 05:38 PM

Did the corsair use an intercooler?

renrich · 05-07-2008, 05:51 PM

Thanks HoHun, interesting info. I have 3 references here, all books, "America's Hundred Thousand," by Dean, which, I believe is the best reference I have ever seen on all fighters used by the US in WW2. It is exhaustively researched with footnotes and references given at the end of each chapter. Dean is a aero engineer, degree from MIT, served USN and worked for Boeing and Curtis Wright in industry for 38 years. "The Great Book of WW2 Airplanes" a compendium of books about various AC of WW2. It has a whole section on the Corsair. "Whistling Death," by Boone Guyton, the test pilot for the Corsair program. He is the one who did a dead stick landing in the prototype on a golf course in 1940. After the plane was rebuilt he flew it over a measured course and clocked a little over 400 MPH. Anyway, all those sources have pretty much the identical same performance numbers for the Corsair. The numbers from your site look good to me as the Corsair is my favorite AC of all time but they look a little suspect. A question you might have the answer to: the inverted gull wing of the Corsair looks like it would have two lift vectors, one for the wing root structure which ties into the fuselage at 90 degrees and one for the rest of the wing. Obviously the other side has the same configuration. What effect do you think this has on flight characteristics of the Corsair?

renrich · 05-07-2008, 05:53 PM

KK, see my post #28 for intercooler question.

claidemore · 05-07-2008, 06:13 PM

Kruska,

My mistake. Yak 9U with NS 37cannon had only ONE 12.7 UB.

Kruska · 05-07-2008, 06:23 PM

Quote:

Originally Posted by claidemore

Kruska,

My mistake. Yak 9U with NS 37cannon had only ONE 12.7 UB.

Hello claidemore,

I wouldn't know of that 9U armament arrangement either

but who knows what "individual" frontline arrangement some aircraft maybe had.

Regards
Kruska

kool kitty89 · 05-08-2008, 01:38 AM

Didn't the inverted Gull wing contribute to the dangerous spin characteristics of some of the early corsairs?

Ant it's interesting that the prototypes of the first 2 US fighter a/c to exceed 400 mph both crash landed dead stick onto golf courses.

Though at leas it didn't delay the Corsair as it did the Lightning, and it wasn't totaled like the lightning. And both the P-38 and F4U have been on topics against the Yak-9.

(I don't think I've heard the whole story of the XF4U's crash though)

Oh, yeah I missed your thing on the intercooler the first time.

renrich · 05-08-2008, 09:47 AM

KK, the crash landing of the XF4U happened when Boone Guyton took the AC out over the Atlantic to run some tests. Because of the speed of the Corsair he went slightly farther than planned and the weather turned bad. He was dodging thundestorms and realised he was running out of gas. He finally decided he was not going to make the field and selected a golf course to land on while he still had power. Boone was a former carrier qualified pilot and executed a full stall to approach landing just in front, if memory serves, of the tee box on a par four. Everything was fine except when he applied the brakes. The grass was wet from the rain and the plane just kept skidding. He finally skidded over the green and into a wooded ravine. The trees ripped the wings off and he wound up upside down hanging from his harness. Was rescued by a passerby. The plane did not catch on fire because the tanks were almost dry. He did not have a par on the hole. I believe it took about 6 months to rebuild the AC. I don't know if the inverted gull wing contributed to the spin characteristics or not. With my limited knowledge of aerodynamics, it seems to me that particular wing design might have an impact on longitudinal stability,(like wing dihedryl.)

renrich · 05-08-2008, 10:03 AM

During the developmental stages of the Corsair, the R2800 engine caused a lot of problems. It was new and the Corsair was one of the first to use it. Among other problems, one of the cylinders (I can't remember which one and the book is packed) kept overheating and causing engine failure. Guyton became proficient at dead stick landings. Once and I believe this was after production had begun, he just failed to make the runway, hit a dike, the plane was totaled and Boone was propelled down the runway still strapped to his seat. He barely survived and spent many months in the hospital. Guyton was 6'4" which explains some of the dimensions of the cockpit. He flew an A6M and could not close the canopy. An interesting point is that Vought spent around 700 flight test hours perfecting the ailerons on the Corsair which showed up in it's roll rate, allegedly perhaps the best of US WW2 fighters. Or course AC which used the R2800 later such as P47 and F6F benefited from Vought's experience.

kool kitty89 · 05-08-2008, 03:24 PM

For Roll it was either the F4U or P-47N, inless you count the P-80.

Too bad he didn't take it in for a belly landing, still ended up better than the XP-38 though.

renrich · 05-08-2008, 04:25 PM

Why would the P47N have a good roll rate? With the extended wing span, I would think that the roll rate would be slower than the P47D. The problem with the F4U and roll rate is concerned is that my reference says that very little data exists which quantifies the roll rate of that AC. All there is to go on basically is testimony by pilots who say that it had a very high roll rate with some claiming a two second 360 degree roll at higher speeds. I rolled an L39 twice at 250 knots and the specs say it will do one second rolls. All I can say is that it rolls plenty fast!

HoHun · 05-08-2008, 05:08 PM

Hi Renrich,

>The numbers from your site look good to me as the Corsair is my favorite AC of all time but they look a little suspect.

Hm, they seem to be official BuAer numbers, and if I were BuAer, I'd have checked them before release. However, I'm not BuAer :-)

You could try to contact F4UDOA over here: http://bbs.hitechcreations.com

He has probably seen most data anyone could dig up by perseverant and inspired internet research, and he'll probably be able to give you an accurate assessment of F4U-4 performance.

He might also be your best hope regarding reports on the Corsair's wings - I have not seen anything relating specifically to the inverted gull shape, I'm afraid.

Regards,

Henning (HoHun)