Author Topic: F4u flaps  (Read 7322 times)

Offline bozon

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F4u flaps
« Reply #90 on: December 15, 2006, 03:00:16 AM »
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Originally posted by SgtPappy
Lol.. and suddenly I bring up the question... and they all go silent and slowly step away ...  *fetal position, rocking back and forth*.

What was the question?
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Offline hitech

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« Reply #91 on: December 15, 2006, 09:27:03 AM »
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Lastly, I was wondering if flaps could, in real life, only be opened at lower speeds. I.e. the Hog and P-38 can only open up their flaps at 250 mph in the game. Is that some sort of saftey mechanism so that our flaps don't rip off? I'm assuming this was some kind of 'flap regulation' in the real-life manual that advised pilots not to open their flaps over 250 IAS.


Yes they have real life limitations. And when ever we have that info on any plane, thats what we use.

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Offline hogenbor

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« Reply #92 on: December 15, 2006, 10:10:07 AM »
Quote
Originally posted by Widewing

In real life, P-38s were complex fighters, and only the best pilots became masters of the type. Average pilots were constantly struggling with the plane, which is why they had much greater confidence in the P-51. It was just easier to fly.

In Aces High, we have the same issues. P-38s are very capable, but require time to learn and not everyone will be able to exploit the Lightning to its full potential. Those that can and do are quite formidable.

My regards,

Widewing


As a capable, but occasional player I tend to agree. The P-51D is my favourite plane as my style centers around killing without being killed. That's what I like, that's how I play. I strive to always get the tactical advantage, if I can't get it or am losing it I disengage. You may call that running ;)

If I read Widewing's analysis after a patch or an FM change I often wonder how on earth does he tell the difference that a 109F can now own a Spit V in a knife fight? You'll figure that out if you slug it out time & time again in the TA one on one, on the edge of the flight envelope. Fun, no doubt, but I don't have the time & patience to do that. If I reach the edge of the envelope during the sparse hours I play, I usually die.

Coming back to the P-38, I often read comments from Widewing and others like AKAK that the P-38 is so formidable. But when I fly them or fight them (the P-38, not these gentlemen) I can't find those hidden qualities... most of the time.  I never use manual trim, only to get a 109 out of a terminal dive. I never use flaps, using flaps means bleeding E and bleeding E means someone else I don't see yet may get an advantage over me. The only thing I think is remarkable how well it behaves in the vertical.

Offline Bodhi

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« Reply #93 on: December 15, 2006, 10:20:13 AM »
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Originally posted by SgtPappy

Lastly, I was wondering if flaps could, in real life, only be opened at lower speeds. I.e. the Hog and P-38 can only open up their flaps at 250 mph in the game. Is that some sort of saftey mechanism so that our flaps don't rip off? I'm assuming this was some kind of 'flap regulation' in the real-life manual that advised pilots not to open their flaps over 250 IAS.
 


In F4u's, the selector will allow you to deploy the flaps at any speed down to 15 or 20 degrees and no damage will occur.  The beauty of this system is that the flaps will not deploy above 250 kts or so, because there is an unloader valve in the hydraulics as well as a series of heavy duty springs on the actuator ends.  What this does is allow the flaps to be extended, and if you go above 250kts or so, the springs do not have the tension to keep the flaps down, so they retract due to this lack of tension.  As you slow down, they come back out as the force of the airflow does not out weigh the spring tension.  So, in essensce, the flaps come down almost instantly as you need them, making them much more effective than the average birds which must be deployed upon reaching a speed.
If the flaps are deployed down past 40 degrees and you go above 250kts or so, you run the risk of damage as the spring system does not have enough travel.  In reality what ends up happening is either the unloader allows the flaps to retract, and between this and the tensioned springs, they retract enough to prevent damage.  In rare cases, the actuator arms will sometimes kink on the end and not allow the tension springs to work properly, and the flaps get stuck in that position, and will neither  retract or deploy more than a few degrees.  I have dealt with this in two different u birds and felt it to be a pilot error owing to a misindication in the cockpit of the asi.

As for the 38, it does not have the same system as the Corsair, and you run the very real risk of damage of flaps deployed past their operating speed with very real jamming of the system happening.  Keep in mind the flap system on the 38's involves an actuator arm controlled by a steel rod that resides in the flap well.  The actuator has two steel roller bearings in a track that is aluminum.  This track will not take side load of any kind without scoring and jamming the roller bearings.  If this happens, the aluminum where the flaps actuator rod attachs will fold up if high speeds are encountered with the flaps deployed.  

Hope that helps you understand their sytems better.
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Offline Bronk

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« Reply #94 on: December 15, 2006, 10:30:27 AM »
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Originally posted by hogenbor
As a capable, but occasional player I tend to agree. The P-51D is my favourite plane as my style centers around killing without being killed. That's what I like, that's how I play. I strive to always get the tactical advantage, if I can't get it or am losing it I disengage. You may call that running ;)

If I read Widewing's analysis after a patch or an FM change I often wonder how on earth does he tell the difference that a 109F can now own a Spit V in a knife fight? You'll figure that out if you slug it out time & time again in the TA one on one, on the edge of the flight envelope. Fun, no doubt, but I don't have the time & patience to do that. If I reach the edge of the envelope during the sparse hours I play, I usually die.

Coming back to the P-38, I often read comments from Widewing and others like AKAK that the P-38 is so formidable. But when I fly them or fight them (the P-38, not these gentlemen) I can't find those hidden qualities... most of the time.  I never use manual trim, only to get a 109 out of a terminal dive. I never use flaps, using flaps means bleeding E and bleeding E means someone else I don't see yet may get an advantage over me. The only thing I think is remarkable how well it behaves in the vertical.




I thinks it because your stuck in one play style. If all you do is fly a 51 and only attack when your holding all the card .. I don't think your pushing yourself . I'm not knocking your idea of fun mind you.  But in order to see the benefit of flap usage  you actually have to slow down enough to deploy them.

I say jump in a slower turn fighter for a tour and not worry about getting shot down . Then you might learn the benefit of flap usage .


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Offline Widewing

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« Reply #95 on: December 15, 2006, 12:51:44 PM »
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Originally posted by hogenbor
If I read Widewing's analysis after a patch or an FM change I often wonder how on earth does he tell the difference that a 109F can now own a Spit V in a knife fight? You'll figure that out if you slug it out time & time again in the TA one on one, on the edge of the flight envelope. Fun, no doubt, but I don't have the time & patience to do that. If I reach the edge of the envelope during the sparse hours I play, I usually die.


When the 109 FM was fixed, we tested them extensively. What we discovered is that the 109F-4 could more than hold its own with the SpitV, provided that the 109 pilot knows how to get the most out of the 109. We flew dozens of duels against everything in the plane set. I flew duel after duel with Timmpa, with him trying about half of the fighter set. Time after time, the 109F-4 prevailed. We proved that the 109F had attained "one of the most dangerous" status.

I flew a little duel with Sonic23. Sonic is a very, very good Spit pilot. I have to fly like mad just to earn a draw when we fight in Spits, and if I make just one mistake, he's all over me. Yet, he could do nothing with the 109F-4, especially when I refused to reverse my turn but kept pounding around to the 109's strong side and by not reversing, I never give up any angles. Eventually, the 109's superior turn rate and vertical performance prevailed. Here's a FILM of that encounter.

To know what a plane can do, you have to explore its limits. Then you have to learn how to quickly find the limits and fly on the edge without pushing too hard. That takes lots of practice and many duels.

My regards,

Widewing
« Last Edit: December 15, 2006, 12:58:36 PM by Widewing »
My regards,

Widewing

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Offline SgtPappy

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« Reply #96 on: December 15, 2006, 08:04:30 PM »
Thanks all for helping. Bohdi, it really does help me understand the systems of the 2 planes. Wow.. the P-38's were more of pains to learn how to fly than I thought, but aren't many of our planes lol.

Good thing you filmed that, Widewing. Seems like the SpitV was struggling indeed. Wondering if that makes a Spit8 or 9 even more vulnerable. The 8 does become faster and faster as alt increases and it climbs better in the same way (of course, the 109 has those few supercharging boosts at some alts), but, of course, I'm often proved wrong if I ever say that these things alone will help the Spit prevail. I personally think that the 2 planes are equal.
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Offline SgtPappy

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« Reply #97 on: December 18, 2006, 04:31:09 PM »
I've come back with some information regarding the F4U's turning ability vs. that of the Spitfire VIII or IX. On www.spitfireperformance.com , you'll find (under the F4U directory) flying charateristics of the F4U-1... the second most maneuverable Corsair in the game. According to those trials (with an F4U-1 loaded to 12,000 lbs.), the F4U-1 turned only slightly tighter than that f the P-38G both with and without flaps.

Now comes the assumptions: The F4U-1A turns slightly tighter than the F4U-1, so assuming that the P-38G turns as well as it does in the game (and assuming that tests have been made with no flaps, 10 degrees of flaps, 20 degrees, 30 etc.), the Spitfire VIII should easily outturn the Corsairs.

Definitely no the greatest test, but you see my point.
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Offline Widewing

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« Reply #98 on: December 18, 2006, 07:04:41 PM »
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Originally posted by SgtPappy
I've come back with some information regarding the F4U's turning ability vs. that of the Spitfire VIII or IX. On www.spitfireperformance.com , you'll find (under the F4U directory) flying charateristics of the F4U-1... the second most maneuverable Corsair in the game. According to those trials (with an F4U-1 loaded to 12,000 lbs.), the F4U-1 turned only slightly tighter than that f the P-38G both with and without flaps.

Now comes the assumptions: The F4U-1A turns slightly tighter than the F4U-1, so assuming that the P-38G turns as well as it does in the game (and assuming that tests have been made with no flaps, 10 degrees of flaps, 20 degrees, 30 etc.), the Spitfire VIII should easily outturn the Corsairs.

Definitely no the greatest test, but you see my point.


You have to read the Navy test of the F4U vs the P-51B (here) to get an idea of how each service skewed test methods, and likely gundecked the data.

There's no way the AAF was going to state that the F4U was superior to its fighters. Likewise, the Navy isn't going to stipulate that the P-51 was superior to the Corsair. Interservice rivalry certainly extended to testing of fighters.

I have argued for years that the best fighter to see combat in US service was the F4U-4. You could make a very strong argument that the F4U-4 was the best all-around fighter flown by any nation.

A friend of mine, General Ralph Jerome, got his start by going to Canada after being turned down by the USAAC. There he joined the RCAF and flew Hurricanes and Spitfires before transferring to the USAAF, where he flew P-51s. Stateside in early 1950s, he was flying a P-51D and had the opportunity to mix it up with an F4U-4. Despite his vast experience, he was unable to evade that Marine Corsair. General Jerome was convinced that later F4Us were very able fighters. "I was one of those who believed that Mustang was the best fighter of its generation. That experience showed me that the issue was at least open to serious debate."

My regards,

Widewing
My regards,

Widewing

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Offline Widewing

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« Reply #99 on: December 18, 2006, 11:47:10 PM »
I performed some additional max speed testing on the F4U-4, based upon using 26,000 feet as its critical altitude. It was faster at 26k than it was at 25k. I also tested the balance of the faster (at high alt) fighters at 26k as well. Results are as follows, from fastest to slowest of the group.

P-47N: 460 mph (WEP)
F4U-4: 453 mph (WEP)
Spit14: 447 mph (WEP)
109K4: 443 mph (WEP)
Ta 152H: 440 mph (WEP)
P-51D: 439 mph (with or without WEP, no increase in MAP)
P-51B: 434 mph (WEP)

So, this shows that at this height, the P-47N simply runs away from the others. The F4U-4 shows once again why it is the best overall fighter. I did not test any fighters (other than the P-51D) at MIL power. Fuel was 25%, zero burn. Takeoff was from a 30k field on the TA map. Up that high, some aircraft had to horsed off the runway to avoid damaging the landing gear (the 109K-4 was the worst for this). In case someone is curious as to why the Tempest wasn't included in the group, it doesn't measure up. Its speed is well below that of the slowest plane in the test (P-51B) and its acceleration and climb are relatively feeble in comparison. Also, it should be mentioned that the 190D-9 is 8 mph slower than the P-51B at 26k (426 mph). I did notice that at 460 mph @ 26k, the P-47N has a wickedly fast rate of roll. I didn't have time to measure it, but it's on my things to do list.

My regards,

Widewing
My regards,

Widewing

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Offline bozon

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« Reply #100 on: December 19, 2006, 12:27:15 AM »
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Originally posted by Widewing
I did notice that at 460 mph @ 26k, the P-47N has a wickedly fast rate of roll. I didn't have time to measure it, but it's on my things to do list.

Although I'm a jug fan, I barely fly the N. The D jugs are decent rolling planes, but I'm always surprised by the improvement in the N. I don't think that the roll rate is a direct function of alt, but more of IAS.
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Offline SgtPappy

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« Reply #101 on: December 23, 2006, 04:15:38 PM »
Actually Wideeing, though I often run back to the Spitfires (except the 16, i hate flying overmodeled planes), I actually do, whole heartedly believe that the F4U-4 is the greates overall combat fighter of WWII.

Yet, the Corsairs aren't really supposed to turn that tight. Their power loadings and wing loadings just don't support it. Those flaps and possibly the gull wings shove some extra cornering power, but by the time the fight slows down to medium speeds (250 IAS, so forth) the F4U's flaps should not enable it to turn any tighter than the Spitfires 9,8,16,14 (all of which turn tighter than the Hogs - they are listed from tightest turning to widest turning). A Hog will, very likely be able to almost turn with the Spit 16/14 - so much so that it really comes down to pilot experience rather than the plane, but a Hog turning tighter than the Spit9? Unlikely. Maybe the F4U had some crazy turning b/c of it's wing aspect ratio or something. If so, I'd like to learn why... but the Spitfire 14 seems to have the same aspect ratio, and taper ratio (well slightly smaller but still lol) and so the only thing that give the Hog such nice turning must be those gull wings - that is if they REALLY did help it turn that tight.

Remember, it's not just wing loading that determines turning. There's power loading and a bunch of other factors. I'm not trying to sound smart, b/c I'm not, but this is what I know.

I always get confused over matters like this. I once started in the Spit5, but that was outclasses by the A6M5. Then I tried the Later spits which were outturned by the Hogs. So i tried the Hog, which got mauled by the La-7 (except the F4U-4, but that got killed by the older F4U's), so now I'm back to my Spitty, hoping DESPERATELY like the whiner I am, to fix that crazy Hog turning. Yes, I know, pretty much every plane has at least one enemy that can seriuosly destroy it, but the Spit14 is just a little less susceptible to that. Thanks, though, Widewing for all the advice you've ever given me.. I feel 10 times smarter thanks to you.
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Offline mtnman

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« Reply #102 on: December 24, 2006, 11:55:36 PM »
I have a few tidbits to throw in here, because I haven't seen them discussed yet, and they MAY have application in this discussion.

I don't have the necessary knowledge to really apply them, but hopefully some of you do, and can let me/us know the why's...

1- Regarding pitching motion when flaps are deployed.  The nose generally seems to pitch up for me in the hog as flaps are deployed.  However, I generally attribute that to the auto combat trim.  The trim is trying to support a "hands-off level" condition from what I understand.  From my observatios, the trim ends up going full "up".  In doing so, wouldn't it be compensating for a "nosing down" effect?  In my head, if flaps had no effect on pitch, the trim would stay centered, so the fact that it moves is saying something...

2- According to my copy of the F4U pilots manual, the F4U has an incredibly low stall speed (at least in my mind) for such a large/heavy plane.  Power off, 50 degrees of flaps, the stall speed is listed as 75 knots.  However, with power on (23" Hg, 2400 RPM) and 50 degrees of flaps the stall is listed as 66 knots LEVEL FLIGHT.  Does this explain at all the fact that the plane still is able to manuever at very low alts/speeds, especially considering we are operating with WEP, etc?

How do these stall speeds compare to the spits etc, which most people think should out-turn the F4U in the low/slow fights?

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Offline F4UDOA

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« Reply #103 on: December 25, 2006, 09:18:23 AM »
Gents,

Just my 2 cents and I am not going to get on my F4U soapbox on this one.

The F4U does have a very low stall speed for an aircraft of it's size however the wingloading of the Spit is even more remarkable. I have several Spit Manuals with indicated stall speeds and CAS charts. The Spit IX manual shows as follows.

Power Off 7150LBS

Clean Condition no flaps

78knots (90MPH)

Flaps and undercarrage down

65-69Knots 75-79MPH

The same relative numbers for the F4U

11,300LBS Power off

Clean condition no Flaps

87Knots

Flaps and Gear down

75 knots


At these loading conditions the Spit is certainly superior to the F4U. The F4U speeds are a couple of Knots high according to the CAS chart but not enough to make a difference. The relative loadings are without ammo but full fuel on both. You could adjust the weights for similar range but again the results will be about the same.

The only thing that is not in the manual for the Spit is stalls with power on (idle power). This helps give you an idea on how much wing area is affected by propwash. The F4U goes from 75knots to 66 knots by applying 23" of MAP which is a fairly significant reduction. I am not sure how the SPit is affected.

All that needs to really be done now is to test what speeds the Spit IX in AH stalls at power off at 7150LBS to see if it matches the manual or is close.

FYI, Instantanious turning is another story.

Offline Saxman

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« Reply #104 on: December 25, 2006, 09:53:55 PM »
However given that the F4U is just over 4000lbs heavier a "mere" 10kt difference doesn't appear to be a tremendous difference. Noticeable, certainly, but not overwhelming.

How does the Corsair's stall speeds measure up to the F6F?
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