Question about Flaps Deployed at High Speeds..

[F4UDOA]

Ageed,

However even the page 59 chart should be compared to the existing FM. As well as the fact that the AH F6F has multi position flaps contrary to the manual.

I have run several test today. The question I have about the FM is what do you consider a stall? The AH FM tends to mush forward and loose altitude before stalling or wing break. I believe the stall begins when you can no longer hold the horizon. Correct?

[hitech]

When you can no longer maintain 0 decent.

HiTech

[Kweassa]

Now this is way over my league...
 
 Carry on!

[Pongo]

Something I have gathered from years of watching these threads..
Pilot manuals and engagment anecdotes and after action reports were not written to develop a sim from where they.

[F4UDOA]

Actually Pongo the pilots manuals are probably the single best source of data because it was written for the pilot. Not to sell warbonds or for the propaganda department. Just to keep some poor dudes powder dry.

HT,

If that is correct then the stalls definitely need some adjustment. Especially with flaps. I know that flap lift has already been changed in 1.04 I believe.

Kweassa,

It's all your fault!!

Actually it's been a great thread. Especially the part about the P-47 flaps extending like fowlers. I learned allot about flaps in this thread.

[dtango]

So what are the figures on page 59 of the F6F-5 Pilots Manual?

Regarding NACA Report 824 - disregard the data for the models shown as a report of CLmax figures for actual a/c.  The tests were models and airfoils of different configurations in the 19 foot tunnel at Langley.  After reading through it they were used as a way to do an estimation and compare of differences between the 2-D airfoil data they were deriving and 3-D wings to see if there was general agreement between the data.  The models weren't specifically a given a/c but just different models with different wings, types of flaps and flap configs.

Tango, XO
412th FS Braunco Mustangs

[F4UDOA]

Dtango,

On the previous page in the same manual it listed the stall speeds for the F6F clean at approx 64Knots and with flaps down at 50knots.

Then page 59 has a graph of stall speeds which is a much higher range. Totally contradicting data in the same manual. Very strange.

However even the pg 59 data is significantly different than AH with flaps.

Remember the stall in HT words begins when you can no longer maintain a 0 rate of decent which is what I was testing to begin with.

[hitech]

Btw I would have described is slowest speed that you can maintain level flight. But F4UDOA was talking about keeping is nose on the horizon and thats not how the test is normaly done.

Btw make sure the ball is right in the center when testing. Normal procedure is watch the VSI as the plane slows down , maitaining level flight, Then when it departs i.e. stalls check the speed.

HiTech

[dtango]

F4UDOA:

Can you provide the speeds listed?  I'm interested in just having the data.  Or if you can scan the page in question and post it.  That would be great.  Thanks!

Tango, XO
412th FS Braunco Mustangs

[Vermillion]

Nice thread guys!

Its SOOOO nice to see an intelligent discussion without, all the rest of the normal crap.

[F4UDOA]

Heya Verm long time!!

Dtango,

I have a scanner but I can't jam my manual into it. I will make a run to a copy machine a copy the chart for you.

The listed speeds on page 44 under stalls are

Pilots Flight operations manual for the F6F page 44.

Section 18 paragraph B. Stalling

Clean Power on- 62Knots
Clean Power off- 64 Knots

LG&Flaps down- power on- 50Knots
LG&Flaps down- power off- 53Knots

And the CAS correction chart for the F6F-5

Flaps retracted

100Knots subtract 5 knots
120Knots subtract 6.5 knots
140Knots subtract 7 Knots

Flaps extended

80 Knots Add 6.5 Knots
100 Knots Add 4.5 Knots
120 Knots Add 2 Knots


This data is completely contradicted by the chart on page 59. It is bizzarre.

HT, I will film and post my test.

[Vermillion]

Hey F4UDOA !  I'm still around, just been busy.  I haven't flown in months and months, but I still try and catch the interesting threads on the BBS, which are few and far between it seems.  Just been teaching myself a new and interesting hobby !

[dtango]

F4UDOA:

I'm interested in the data on page 59 too.  Thanks!

Tango, XO
412th FS Braunco Mustangs

[F4UDOA]

Hitech,

Here are my test results for stalls as follows.

Method of test
1. Hold A/C level until it can no longer maintain 0 rate of decent.

Conditions
1. 25% fuel
2. No ordinance
3. Full Ammo

F6F-5
Full weight 12,483LBS
Adjusted Weight 11,358LBS

Measured clean stall 101MPH
Measured Full flap stall 85MPH

No flap Calculated Clmax 1.30
Film  F6Fstall

F4U-1D
Max weight 12,175LBS
Adjusted weight 11,108.5LBS

Measured stall no flap 103MPH
Measured stall full flap 91MPH

No flap Calculated Clmax= 1.30 Same as F6F, is this a coincedence? Should be 1.49 according to NACA post spoiler strip.

Film F4U1Dstall

F4U-1
Max Weight 12,835LBS
Adjusted Weight 11,210.5lbs

Measured stall no flap 103MPH
Measured stall full flap 89MPH

No flap calculated Clmax= 1.32  This should be higher than 1.49 as it is pre spoiler strip F4U with harsher stall.

Film  F4U1Stall

[F4UDOA]

Hitech,

Are you calculating your Clmax for these birds assuming that slotted flaps do no extend to incease wing area??

If you are I think that is part of the issue because I can absolutely prove otherwise on the F4U.