Author Topic: Another F4U carrier launch post(JAB/Redtail) (Read 440 times)

F4UDOA · « **on:** October 10, 2002, 08:04:11 PM »

Ok Gents,

Riddle me this.

At a gross weight of 12175LBS the F4U-1D should lift off at 52" of MAP(Mil power) in a 29MPH headwind(25Knots) in 282FT with full flap.

The length of the flight deck from the spawn point is 556FT. So the F4U-1D should lift off the deck in roughly half of the deck space available for liftoff without rollback.

I have tried it many times and it seems impossible to me.

Any takers?? Film it post it.

I don't think it can be done.

Why?

Because in order to acheive this the F4U-1D must be able to achieve a speed above the stall for the F4U's gross weight. That speed is 87.5MPH full flap no power. Roughly 82MPH full flap power on. And it must be able to reach this speed in half of the availble deck space and in AH it cannot.

To me it says two things.

A. The low end accelleration is not sufficient to reach the correct speed in the distance specified in the manual and historic specs. which is 82MPH in 282FT with full flaps deployed. It currently cannot reach that speed in that distance no flaps deployed.

B. Not enough lift from flaps. The stall speed no flaps is roughly correct in AH for the F4U-1D. But with flaps the stall goes down as low as almost 80MPH with power. At that speed in AH(on the digital viewer) you cannot fly even close to 80MPH. In fact you can't get below 90MPH. This shows me that flaps do not create enough lift.

1. Not enough acceleration.
2. Flaps not enough lift.

Here are the stats.

Moloch · « **Reply #1 on:** October 10, 2002, 08:12:34 PM »

no wep
2 notches of flaps
one notch before rolling and second notch by island

F4UDOA · « **Reply #2 on:** October 10, 2002, 08:40:28 PM »

You bastard!!

Actually I haven't had time to look at it.

Standbye.....

F4UDOA · « **Reply #3 on:** October 10, 2002, 08:54:53 PM »

Errr,

Dude, that is a film of you taking off with bombs at rockets.

I want film of a takeoff full fuel and bullets NO bombs NO rockets.

Lift off in half of the deck (280FT). This should be with full flaps but if you can do it otherwise I would luv to see it.

Your speed at liftoff should be about 83MPH on the film viewer.

Try again??

Moloch · « **Reply #4 on:** October 10, 2002, 09:20:39 PM »

my reading comprehension is bad at night...

best i can do is taking off right before the elevator..

J_A_B · « **Reply #5 on:** October 10, 2002, 09:52:50 PM »

Actually, far from trying to dispute you, I also wish the F4U in AH was somewhat better. I think it's rather under-represented in AH.

How did the late-model -1A's compare to the -1D?

J_A_B

J_A_B · « **Reply #6 on:** October 10, 2002, 10:17:41 PM »

Unfortunately right now I can't do any really good takeoff trials as my rudder control has problems. Just playing around I can get the thing airborne before the elevator, but with no real rudder control it's very sloppy. I'll see what I can do once I have rudder control again.

How large is the elevator and how far is it from the end of the flightdeck? And do we have a long hull or short hull Essex-class ship (this affects flightdeck length before the elevator)?

There are two possible ways to take off in short distances...you can either hold the elevator back until the plane flies off (careful not to stall it), or actually push forward as the plane gains speed to get the tail up, THEN pull back to fly it off. Which method is recommended in your F4U takeoff protocols? I prefer to simply hold the elevator back and keep the tail on the ground until the plane flies itself off.

It lifts off at around 83-85 MPH (hard to tell exactly) somewhat before the foreward elevator, as noted. I am cofident I could do slightly better if I actually had direct rudder control, as the constant yawing from using keyboard rudder doubtlessly bleeds some speed. I'm not posting this film because it's very sloppy and not really representative of a proper takeoff.

J_A_B

F4UDOA · « **Reply #7 on:** October 11, 2002, 03:15:13 PM »

JAB,

The reason I am harping on this so hard goes back to the AH Beta. I have been argueing with HT specifically about the F4U climb and acceleration. I have always felt it was off and for various reasons I have always been argued off of my point by various engineer types.

Well this one is pretty cut an dry.

It is a straight line acceleration test meased at the correct weight, Altitude and power setting. By the book in full flap condition the F4U should be able to reach speed X in 286FT. and lift off. It covers both parts of my arguement.

1. Since the F4U cannot reach its minimum flying speed (approx 82MPH) in the 286FT specified in the manual it then can't liftoff.
Not enough acceleration.

2. Since even at 82MPH the F4U cannot liftoff it shows that the flaps do not provide enough lift.

Both of these issues go back to late 1999. Frankly I it is more of a crusade to prove I'm right as much as to get the FM fixed.

J_A_B · « **Reply #8 on:** October 11, 2002, 03:25:21 PM »

Please post me a pic showing the location of the 280 foot mark in front of the spawn point.

J_A_B

Reschke · « **Reply #9 on:** December 23, 2002, 03:12:05 PM »

Very curious about this and I would love to see an official answer if possible. I believe the same thing about it that F4UDOA does also.

F4UDOA · « **Reply #10 on:** December 23, 2002, 03:40:54 PM »

Reschke,

The final outcome of the testing was this.

You have to manually trin the aircraft almost as in the flight manual.

Right aileron down slightly. Right rudder about the same amount as the aileron. Slight nose up trim.

If you do this you can albeit difficult take off mil power from the carrier deck with 100% bombs and rockets.

I am sure that our F4U is slightly underpowered as I have never seen film of any carrier plane fall off the end of the deck like our F4U. Even Dolittles B-25's were actually climbing not falling at the end of the carrier deck.

Something in the low end accleration of the F4U is off. Unfortunately despite many attempts I have never been able to prove my point conclusively because I do not have the math or engineering backround to do so.

HTC has never responded officially.

Reschke · « **Reply #11 on:** December 23, 2002, 03:47:59 PM »

Well after trying about 15 straight launches last night in an F4U-1D with anything from 100% fuel and full ammo (no rockets and bombs) to 25% fuel and full bomb load, rockets and ammo. I could not get any flight to continue past about 300 feet off the carrier. I tried trimming the aircraft in all manner of situations with no success.

Now on the other hand the F4U-1 is literally jumping off the deck for me with any loadout and the F4U-4 is similar. To me the 1C and 1D are automatic tower poppers for me.

I will start working on setting the trim as you mentioned and hoping for the best.

F4UDOA · « **Reply #12 on:** December 24, 2002, 08:02:22 AM »

One other tip for getting off the deck.

The F4U wants to stall and roll left, so manual trim is set right.
When you hit the end of the runway bank slightly right. It helps offset the stall.

Reschke · « **Reply #13 on:** December 25, 2002, 10:01:13 PM »

After using the trim as you stated a couple of posts ago I was able to bring the F4U-1D off the deck 3 out of 5 times with 100% fuel and full ammo and heavy ord load.

Thanks guys for working on this.

troxel · « **Reply #14 on:** December 26, 2002, 12:20:49 AM »

I agree with F4UDOA completely. His numbers seem to back up his assertions. Why is HTC so quiet on this? Throw us a bone!