Author Topic: Flaps and the F4U (Read 716 times)

wells · « **Reply #15 on:** July 20, 2001, 11:53:00 AM »

DOA,

I can get off the deck 100% of the time with that load. Here's the film
http://www.iaw.com/~general6/f4u_carrier_takeoff.ahf

Rocket · « **Reply #16 on:** July 20, 2001, 12:31:00 PM »

DOA I agree with you that the flaps do not seem to be generating enough lift and you have data everytime to prove it.

BUT, I can get the hog up with 2 1k bombs 8 rckts and 100% fuel everytime without a problem.

1. Start engine
2. Kick off autotakeoff (YES I AM A LAZY DWEEB!)
3. Apply full flaps
4. Throttle full and hit WEP
5. As soon as she clears the end of the deck gear up.
6. Wallow her almost to water level and start to climb.
7. Bring the flaps up
8. As speed climbs hit auto climb speed

Works for me everytime. I usually can get 100mph +/- as I cross the end of the deck even with full flaps.

My landings aren't as pretty tho

S!

Rocket

batdog · « **Reply #17 on:** July 20, 2001, 12:44:00 PM »

F4UDOA yea I hope it does improve the 38. The question is will it really improve me,LOL. It cant hurt as I am a rabid turner in the 38 to a point of idiocy,

I dont think Pyro and those guys ever even hinted at a date, I think he stated something like it'll be out when its out more or less. They have a huge platter this upcoming version I think so are most likely busy as heck.

xBAT

Zippatuh · « **Reply #18 on:** July 20, 2001, 12:49:00 PM »

Since they are going to change the flap model, are they going to fix the climb and e-retention problems you were also able to identifiy F4UDOA? Still looking for that zoom

Zippatuh

F4UDOA · « **Reply #19 on:** July 20, 2001, 02:41:00 PM »

Batdog and Zip,

I think all our hope are tied together on this one. The climb/acceleration(not really e-retention) on the -1D and the underweight -1C are supposed to be fixed according to Pyro at the same time he does the F4U-1 early and the F4U-4. I swear he said it in the MA. And since part of the problem is the stall as it relates to the flaps I guess you would have to say that all of those issues would be tied together. This will also affect the P-51B/D and possible others including the NIK2. Unless Pyro breaks out the flap/stall issues away from the rest of the FM problems with the -1D.

How nice would it be to be able to accelerate at a respectable level in a D hog when fighting a Yak or a NIK2 on the deck. How nice will it be to see more P-38's in the MA instead of a constant diet of NIK2.

We can only hope

Tac · « **Reply #20 on:** July 20, 2001, 04:49:00 PM »

Hope... yeah.. hope.

Btw, to get off carrier with fully loaded hog just hit brakes till rpm's up, WEP it without flaps till you almost off the carrier, hit 2 flaps just before the jump.. on the jump retract gear and let the plane fall a bit, retract 1 flap before hitting the water.. and level. Works every time.

Remember, the trick is to not look down

Razzor · « **Reply #21 on:** July 20, 2001, 07:10:00 PM »

F4UDOA, the USS Franklin was an Essex class carrier. The Midway class included the FDR and the Coral Sea.

Razor

niklas · « **Reply #22 on:** July 21, 2001, 06:17:00 AM »

hmm 8 Rockets and 2*1000lb bombs would be a total weight of 15320lb

If 15000lb is the maximum weight, then you can assume that they didn´t fly with full tanks.
Furthermore you have on the runway a ground effect for the lift, which is missing immediatly after you left the carrier deck.
There´s a note in you pdf-document about the take-off distance from carriers. The page is labeled "performance comparison of various CV current and future airplane", Note 4. I can´t read it 100%, maybe it is helpful. What does it say exactly?

Climbrate is correct for the FU4 at the moment! But the F4U is 10mph to fast over 3k so enjoy your speed advantage.

niklas

F4UDOA · « **Reply #23 on:** July 21, 2001, 12:01:00 PM »

Niklas,

15,000lbs is the highest weight listed in the Pilots manual not the max takeoff weight. The loading I took from America's Hundred thousand so I know the weight for the rockets is correct. The loaded weight for the A/C varies depending on source. Some are just under 12,000lbs and some are over. 15,000+ a few hundred pounds is good enough for me

As far as the climb goes I have multiple documents that put the initial climb of the F4U in combat condition at 3300FPM+.

Check these docs of the F4U-1 with prop blade design 6443

F4U-1A

Against the F4U-1D with Prop blade design 6501A-0

F4U-1D

I have several docs that confirm a improvement in climb with the use of the latter blade design.

Including the F4U test against the FW190A-5, P-51B and the pilots manual where it states that the 65501A-0 improves climb and performance. It is the same design as was used on the F4U-4 except in a 4 blade prop. It was three inches shorter and wider ala the paddle blade P-47.

I also have the chart for the F4U-1 with the new prop blade. It is here. Notice the Mil poser climb is much better that the AH charts?

F4U data

As far as the AH F4U being to fast I'm not sure what you mean. It seems to match the AH charts posted pretty closely?

StSanta · « **Reply #24 on:** July 22, 2001, 07:27:00 AM »

Here's the setup:

F4UC, 100% internal fuel, 2*1000lb, full rocket setup.

On the deck, I hit toebrakes, then rev up engine. I hit wep as I release toe brakes.

Lift off, gears up - NO USE OF FLAPS.

Film:
http://stsantas.tripod.com/film89.zip

This is the first time I fly the F4U for - god, many months, since tour 3 - and I get it off even without using flaps.

I make a nice landing too, except the plane starts going backwards and rolls into the sea

.

Minotaur · « **Reply #25 on:** July 22, 2001, 09:32:00 AM »

I have been flying the F4, mostly so I can do carrier ops. What mistifies me is that sometimes you can take off with ease and at other times it is pretty darn hard.

I use the same technique each time!

My technique is:

I notice that it at times it will just not fly at launch, but just sinks into the sea. (An F4 floating is amazing in itself

)

One time it is relatively easy and the next time it is near impossible. Any clues?

niklas · « **Reply #26 on:** July 22, 2001, 01:42:00 PM »

F4UDOA, i have seen all these documents before.

You should slowly begin to have a closer look at the docs.
The clue is in your PDF Document, where you can see that 2250HP is only possible near ground due to the RAM effect. There are several pages (labeld bhp comparison) in you pdf-document where they decide between
- brake horsepower in climb
- brake horsepower in high speed
- rated bhp

If you study them you will can see that the REAL bhp for a slow flight/climb doesn´t exceed ~2050hp near ground, wheras - as already mentioned - due to the RAM effect you can get in a fast flight near sealevel 2250hp. But ONLY in a fast flight.

Ok, your first 2 links lead to pages with a nice hmmm let´s call it "Error". Because they take the rated bhp curve. You can further see a nice contradiction in these docs. Because in ~15k, the critical altitude for topspeed is ~2k higher than for the climb - which is correct, RAM effect. But near 2k, the critical altitudes are the SAME which is wrong. Here they simply neglected in their performance chart the real bhp.
You won´t be able to show me a takeoff power number (slow flight...) with more than 2000hp btw....
BTW those docs and numbers were published in late ´45 after the war, where you can assume that they already had the new propeller.

I hope you understand what i mean, else i will post some pics.

To your P51-F4U test: Sry, but this test was done by the NAVY and the whole style of the test let come up in me the impression (even the first time i read it) that the whole purpose of this test was to have at least on the paper a NAVY fighter which is far better than the best USAAF fighter.
Written for the navy lovers, for someone like you...
Navy and USAAF didn´t like them very much, right ?

niklas

Jekyll · « **Reply #27 on:** July 23, 2001, 04:47:00 AM »

Here's something else you can try F4UDOA ... the patented 'Tom Blackburn' takeoff method.

Engine to full power, hit WEP .. NO FLAPS!

Just as you are about to run out of deck, drop one notch of flaps and rotate, sucking up your gear as quickly as you can.

Flaps may not generate sufficient lift at present, but I seem to recall from my (admittedly limited) F4U flying that the drag from the flaps was enough to prevent sufficient takeoff speed. Starting your roll with no flaps gives you max acceleration down the deck .. dropping one notch on rotation gives you that marginal bit of lift you may need to stay airborne

F4UDOA · « **Reply #28 on:** July 24, 2001, 08:56:00 AM »

Niklas,

The engine was rated at 2250HP. I'm really not sure what it is you are questioning? It is not the only source for that rated HP. And all A/C benifit from the RAM air effect. Especially those with Turbo-charged engines. It certainly doesn't mean that it shouldn't be modeled in AH?

As far as the prop change, I don't have to guess when that took place. It was the end of 1943 into 1944. Just look at the back of the documents for the F4U-1 and -1D. It list the prop blade type. And like I said in the FW190 and P-51 flight test it mentions the benifits of that prop over the previous versions. As well as a note in the pilots manual saying to use the 65501A-0 whenever possible as it "increases performance".

So what is inaccurate about my data?