P-51 full-flaps still broken

[TDeacon]

The jump in radius has moved back up from 5/5 flaps to 4/5 flaps, with data very similar to that which first appeared in 2.07.2.  I am becoming frustrated by this, as there was no mention of any change in the release notes, and why would it be changed back to the original worse state??  Spot checking on the F4U-1 indicates that this bug is probably still unique to the P51.  

Testing by same procedure as usual:  http://www.hitechcreations.com/forums/showthread.php?s=&threadid=176856

Note that data labeled "P" is previous data, but was spot checked, and
is still believed to be valid (this test is very time consuming...).  Data labeled "N" is new data.  The overall values in the table are still
believed to be correct for the new software release 2.08-2.  

FLAPS : v(mph) : t(s) : r(yds) : rate(dps) : comment
*******************************************
P-51b (50% fuel = 123 gal)
0/5 159 150 371 12.0 P
1/5 156 152 369 11.8 P
2/5 150 151 352 11.9 P
3/5 137 156 333 11.5 N
4/5 129 200 401 09.0 N; bug = jump in radius, r
5/5 121 203 382 08.8 N;

FLAPS : v(mph) : t(s) : r(yds) : rate(dps) : comment
*******************************************
F4U-1 (50% fuel = 180 gal)
0/5 141 158 346 11.4 P
1/5 138 153 329 11.8 P
2/5 126 150 294 12.0 P
3/5 116 148 267 12.2 P
4/5 106 147 242 12.3 P
5/5 099 145 223 12.4 N

[Widewing]

Originally posted by TDeacon
The jump in radius has moved back up from 5/5 flaps to 4/5 flaps, with data very similar to that which first appeared in 2.07.2.  I am becoming frustrated by this, as there was no mention of any change in the release notes, and why would it be changed back to the original worse state??  Spot checking on the F4U-1 indicates that this bug is probably still unique to the P51.  

Testing by same procedure as usual:  http://www.hitechcreations.com/forums/showthread.php?s=&threadid=176856

Note that data labeled "P" is previous data, but was spot checked, and
is still believed to be valid (this test is very time consuming...).  Data labeled "N" is new data.  The overall values in the table are still
believed to be correct for the new software release 2.08-2.  

FLAPS : v(mph) : t(s) : r(yds) : rate(dps) : comment
*******************************************
P-51b (50% fuel = 123 gal)
0/5 159 150 371 12.0 P
1/5 156 152 369 11.8 P
2/5 150 151 352 11.9 P
3/5 137 156 333 11.5 N
4/5 129 200 401 09.0 N; bug = jump in radius, r
5/5 121 203 382 08.8 N;

FLAPS : v(mph) : t(s) : r(yds) : rate(dps) : comment
*******************************************
F4U-1 (50% fuel = 180 gal)
0/5 141 158 346 11.4 P
1/5 138 153 329 11.8 P
2/5 126 150 294 12.0 P
3/5 116 148 267 12.2 P
4/5 106 147 242 12.3 P
5/5 099 145 223 12.4 N

Here's your problem.... with 4/5 and 5/5 flaps, you have increased drag so much that you do not have enough power to maintain angle of bank. Use of WEP overcomes the drag and the turn radius will tighten as desired.

My testing the other day at 25% using WEP, shows the following:

Flap position (0,1,2,3, etc)/speed/radius/Degrees per second

0 / 168 / 764 ft / 18.47
1 / 161 / 730 ft / 18.54
2 / 149 / 654 ft / 19.14
3 / 136 / 653 ft / 17.49
4 / 130 / 633 ft / 17.26
5 / 121 / 610 ft / 16.67

If I push REAL hard with full flaps, I can get the P-51B down to 115/ 595 ft / 16.11, but it's wallowing like a pig.

I have mentioned elsewhere that the best turn rate and radius are obtained at 3 notches of flaps for both P-51s.

I'm not thrilled with the way the new drag model penalizes the Mustangs, considering they were the slickest fighters of the war on terms of drag and induced drag. However, that's what we have. Clean, with no flaps, the P-51s should turn considerably tighter than the P-47s, but in AH2, post 2.07 they do not.

This certainly needs attention by HTC before Combat Tour is released. At 9,500 lb, the P-51D has a wing loading of 40.7 lb per sq/ft. At 14,300 lb, the P-47D-25 has a wing loading of 47.67 lb per sq/ft. There's no way they should be equal in turn radius, but in AH2 they are.

My regards,

Widewing

[TDeacon]

OK, but if it's drag, why does it happen suddenly at 4/5 flaps, and why only with the P51s?  If it is a global behavior (code / data appliying to all planes), you should see it with all planes.  Still seems like a bug.  

Remember Pyro's comment about a zero missing from a parasitic drag data element associated with the P38's full flap setting?  Something like that.  

I'm not in a position to argue that plane A should turn better than plane B, but discontinuities like this should not be there unless they are intentional, and based on real-world data, and sanity tested against real-world anecdotes (spelling?).  

BTW, thanks for taking an interest in this issue.

[Pyro]

First, I did note that the flaps on the P-51s changed in the readme so that's not my fault if you're upset about that.

Second, I disagree with your test results.  I just ran your test under the same conditions, (P-51B, full ammo, 50% fuel, 3k alt, mil power) and here are the results.  Accuracy is +/- 0.5 mph.

Flaps IAS 360Time DPS Radius
0   161   22.1   16.3   831
1   160   21.8   16.5   814
2   149   22.2   16.2   772
3   139   22.7   15.9   737
4   130   23.5   15.3   713
5   122   24.7   14.6   703

Third, I'm very confident with the way the flaps are now modeled on the P-51s.   I didn't change a whole lot but I did get the lift and drag interpolations smoothed out.  I have really good data on the 51s flaps so I'm pretty happy with it now.  I know there are other planes that need attention in this area but that will have to be handled on an individual basis.

[TDeacon]

Thanks for the very complete acknowledgement, Pyro.  

I assume from your numbers that your test "pulls harder on the stick" than mine.  I turned at just short of the shuddering effect.  I could have pulled more Gs, but consistency would have been worse.  Unlike you, I have to test manually.  

I will test again when I get home from work; hopefully my results will be similar to yours.  I will do a full re-install of 2.08-2, in case that makes any difference.

Again, I appreciate the post; part of the frustration is not knowing whether anyone reads these things.  

[TDeacon]

BTW, the frustration with the release notes was based on the link on the main web page, which refers to the new release.  I did not see any zipped "readme", as I used the auto-update feature.  Here's what the home page link for 2.08-2 says, and there is nothing on P51s.  I say this not to complain (you guys do a great job), but to show that I am trying to be well-behaved when I post on alleged bugs:



This patch addresses several issues and is available through the auto-updater for Version 2.07 Patch 2, Version 2.08 Patch 0, and Version 2.08 Patch 1 users. You can get more details from here.

(click on "here", and the following is displayed)

Version 2.08 Patch 2 Released June 7, 2006

Changes from previous release
--------------------------------------------------------------------------------

Clipboard positions now save for each location (tower, hangar, o'club, flight) with a separate save location for both the swingout page being open and closed.


There are now two modes for mouse controlled flight. One mode requires a hold down key to activate the mouse for flight control and the other mode uses a toggle key. These new functions can be mapped in the global keyboard and joystick maps.


The left mouse button can now be mapped.


Fixed a bug with the mouse causing it to appear to need calibration.


Removed the Select primary weapon function. All weapons are now selected with the select secondary weapon function - both in planes and in tanks.


Added a wheel brake-both analog function for mapping your brakes to a single analog input.


Changed the default up hat view to forward instead of up.


Added a checkbox in the Map Controls menu that automatically selects Mode 1 or 2 at the start of a sortie depending on whether you are in a vehicle or plane. Make sure that you have Mode 2 mapped if you plan to use this feature.


Fixed a bug that caused clusters of trees to disappear at certain distances and angles.


Disabled the alpha fade-in of trees. This will be reinstated in a future release pending more work.


The button to upload a squad motd is no longer hidden.


Changed the joystick file naming convention to support 2 duplicate controllers on the same system.


Mouse look should now functions normally again.


Changed the carrier hangar so that it does not disappear if your object detail slider was set low.


Fixed a bug that caused the mouse to sometimes disappear when you minimized Aces High.


Added analog control output numbers to the map controls dialog.


Fixed numerous issues with force feedback support.


Fixed a CTD bug in the mission editor.


Added waypoint buttons to the mission editor.


Made an optimization on the carrier groups and airfield to improve frame-rate.


The alpha slider in the GUI preferences now presents a live update to the display.


Correct the alignment of the flap gauges on the various P-47s.


Fixed a bug in the mission editor that would set your mission parameters back to default when you clicked on a flight.


Field/ship gunner selection now functions and displays correctly.


You can now double-press buttons on your joystick to map them.


Fixed a texture mirroring error on the B-17 nose.

[Pyro]

The reason it's not listed in the Patch 2 changes is because it wasn't changed in Patch 2.  It was changed in 2.08 so it was listed in the 2.08 readme.

[TDeacon]

We're out of synch, then, because THIS thread was started in response to changes I observed in 2.08-2.  My measurements, which I will redo after a complete reload of 2.08-2, were taken with 2.08-2, and seemed to show a movement of the discontinuity from 5/5 in 2.08-1 to 4/5 in 2.08-2.  After making the measurements, I then checked the release notes I quoted above, etc.  

Maybe I was spaced out last night.  I will reload AH and remeasure.  Wish me luck.

[Pyro]

I guess so, your initial post only referenced 2.07.2 and 2.08.2.  At any rate, we haven't shipped any model changes since 2.08.0.

[TDeacon]

I just retested.  It's close enough so I accept your results for the P51.  

I assume you have automated your testing to eliminate use of a joystick?  
The major risk of error in my *&$!! measurements comes from my using the joystick to maintain a constant speed and altitude.  I try to reduce this by circling multple times; however, this risks my miscounting the number of circles.  I have the bad feeling that I may have done that last night.

[Widewing]

I just ran some tests comparing the P-38J, P-47D-25 and P-51D.

All were loaded with 25% fuel. Tested turn radius and turn rate. All aircraft clean, no flaps. Power setting was WEP.

Radius / MPH / Rate in degrees per second.

P-38J: 865 / 174 mph / 16.9
P-47D-25: 860 / 161 mph / 15.7
P-51D: 771 / 165 mph / 17.0

Therefore, based upon this test, ignore the second part of my first post in this tread. My perception was incorrect.

My regards,

Widewing