how did the f4u have such a low CD,0

[F4UDOA]

Wells,

I didn't know that was characteristic of higher manifold pressure?

The strange thing is that the max speed is virtually identical with the two charts except the max speed of 446mph comes at 26,000ft instead of 20,000ft.
Also the top speed at sea level is 380mph even with the lower manifold pressure. The real differance in performance is in the climb. 3850Fpm instead of 4770FPM. I guess the brick wall of drag is the limiting factor more than available HP when it comes to speed.  

[juzz]

Aren't the numbers in AHT calculations?

The USN F4U-4.pdf quotes 383mph @ s/l, and 463mph at 20,600ft with 115/145 octane fuel and no pylons - and it says "Performance is based on flight test of the F4U-4 airplane."

In the .pdf chart the MAP used is so much higher than normal the lowest supercharger gear isn't even used!

[niklas]

Again, i hope for the last time:

You say according to the Naca829 report without flaps the max. Cl value for the F4U is 1.48 , right??

This is NOT true!!

NO chart/figure/sentence in naca829 report says Clmax=1.48 for the F4U

so STOP LYING

There is only one figuere (figure 15) in the naca829 report for the F4U without flaps (and propeller removed) and it says max CL = 1.18 for a wing in service condition!!
All other figures/charts for the F4U in the report are with flaps 50° down!

DO YOU FINALLY UNDERSTAND ME???

niklas

[juzz]

I don't see any 1.48 figure in the NACA report either...

[-lazs-]

It must be distressing to finally realize that for every model/performance level of FW 190.... There is a model of the Corsair that is vastly superior.   To find out that they also have range and be are able to turn must be a shock.  Oh well... That's what you get when you think of WWII as a Euro only war.
lazs

[F4UDOA]

Juzz,

It is a graphed performance chart Juzz. The only calculated numbers I can see are in the back of the book were the author tries to determine the drag, range and turning radius of the aircraft. I hadn't noticed that they didn't use low blower. I guess that would explain the difference in power curves. It's amazing that it was that fast at low alt without using the low blower!

Niklas,

The 1.48 comes from "America's Hundred Thousand". Which is the source document in question. If you would actually read the entire post you would realize that. Why you keep telling me what the value is with no prop I do not know. I didn't ask you, and it has no bearing on this conversation.

BTW, don't reply to me on these boards anymore please, Thank you.

[juzz]

Ahem... perhaps there has been a typo?

 

Also check this NACA doc that list the max Cl of the F6F, F4U, P-51, P-40 and P47.
 http://naca.larc.nasa.gov/reports/1945/naca-report-829/  

look at page 20 that shows the max cl no flaps of the F4U being 1.48

[F4UDOA]

So what?? I just said it didn't come from the NACA doc. It came from AHT.

It doesn't change the stall speed. It doesn't change the calclation for stall speed. And at the end the max Cl no flaps is still the same.

Again.

Cl = Lift * 391 / (V^2 * WingArea)
= 12000 * 391 / (100^2 * 314)
= 1.49

Any questions?

BTW Niklas you said.

 

F4Udoa the Dora was much more powerful. Less drag, more power > faster and tighter turn. The missing cannons in the outer wing section> higher AoA usually possible. Much better aerodynamic in the nose section > better airflow around the fuselage and wing root section
Less frontal area, but longer fuselage can maybe also have an influence ("floor area"), you also need less elevator deflection with a longer tail which reduce your total lift less.
Bigger propeller > bigger propwash effect

Wells said
 

DOA,
If an 8500 lbs 190 stalls at 110 mph, a 9500 lbs 190 stalls at 116 mph

It's 1G level stall is 116MPH, 3G accelerated stall 201MPH.

Sorry Dude. It turns like a truck on ice. And just for fun.

Cl= 9480LBS * 391 / (116^2 * 197)
Cl= 3706680 / 2650832
Cl= 1.398<====Sucks!! IMO

[juzz]

So what?! That quote is the big part of what started the whole mess, is what... I didn't think it was clear that you got the number from AHT, and niklas had to ask where in the NACA report it was 3 times before he got a definite answer.

D-9 stall speed of 116mph: I believe wells calculated that speed assuming that the D-9 is simply a heavier A-5. It isn't though: the nose, prop, etc.. are different -> the stall speed just might not be what wells has predicted.

[F4UDOA]

Uhh, the whole point of my post was to tell Bolillo_loco that the chart in the back of AHT showing Max Cl for various A/C were all including flaps.

 

Here is a list of the max Cl's in the chart.

1. FM-2= 2.38
2. P-63A= 2.38
3. P-61= 2.54
4. F6F-5= 2.27
5. P-51D= 1.89
6. P-38L= 2.17
7. P-47D= 1.93
8. F4U-1D=1.48

The only one that is no flap is the F4U. I have said before that most WW2 fighters were between 1.4 and 1.5. My mistake was quoting the wrong source for a no flap Max Cl. It is still 1.48. It still doesn't change anything other than the point of arguing semantics.

And on the D9 the wing area is still the same as an A model and wing loading is still the greatest factor in determining turning ability.

I don't think Wells assumed that the D9 was a heavier A8. It's fairly obvious that the two are different. But the wing of the D9 is not at all similar to the Ta-152 as Niklas would have you believe. The fact is that nobody has produced any 1G stall data for the FW190D9. Until then I will stick with the 116MPH.

[Zigrat]

fyi a 8500 lb 190 doesnt stall at 110, more like 100

[bolillo_loco]

then can somebody explain why in ath that it points to the spoiler of being the cause for the corsairs poor turing performance. also how do you know it was done with flaps and what are the lift coefficients of all planes with full flaps? I think the point I was trying to make was the 38 doesnt even make its lowest performance figures and when I questioned it, many were quick to say "it should spin when stalled"

question why the spoiler is said to have spoiled the turn performance of a corsair and many are quick to come up with some mathmatical calculation that it was wrong. didnt somebody come up with a mathmatical calculation that bumble bees should not fly?

[F4UDOA]

bolillo_loco,

You have to learn on yur own. I tried to explain this to you but you don't want to listen. WW2 fighters had a max Cl of between 1.4 to 1.5 with no flaps. They vary a little of of that at times but not much. The chart in the back of AHT is calculated by the author based on max cl data that he had. You need to understand that everything you read isn't true. The F4U with it's spoiler could still out turn many of it's contemporaries.

Read these flgith test vs the P-51, FW190A5 and F6F.

 http://members.home.net/markw4/FW190_F4U.html
 http://members.home.net/markw4/index2.html

Zigrat,

I know 110MPH is a high number. But this is where it comes from. Do you have any other docs with stall charts??

 http://members.nbci.com/mikewaltz/F-TR-1102-ND.htm

 

Information from Technical Report No. F-TR-1102-ND "Handbook for FW-190 Airplane" By. Lt. F. D. Van Wart, 1946.
Aircraft in question was a Fw 190G-3.  Bomb racks were removed making the aircraft equivalent to a Fw 190A-5.  The G-3 also had a directional autopilot and other equipment not found on the A-5, but the MG 17 in the cowl were deleted (354 lb with ammo).  A-5 airframe differs from A-1 through A-4 in that the engine mounts were extended 15cm forward, increasing aircraft length by that amount.  Aircraft weight was 6940 lb empty and 8538 with pilot, ballast (ammunition), and maximum fuel load.  Stalling speeds were 110 mph clean, 105 mph dirty.

[Citabria]

ahah the emperor has no clothes.

turn performance of the p38 and f4u have been accidentally switched!!!!!!!!!!!!!!
   

heh I bet f4udoa would have a cow if the f4u turned like the p38 does in 1.04.
i also find it curious that the f4u1c has such a large turn performance edge over the f4u1d.

yes very curious.



[This message has been edited by Citabria (edited 12-14-2000).]

[wells]

I highly doubt the spoiler had much effect on overall performance of the F4u.  It's 6" long in a 41' wingspan.  At the time, the Corsair was having problems qualifying for carrier ops and it needed all the help it could get.  A significant increase in stall speed would not have been desirable in helping it's case.