PDA

View Full Version : v4.02 P-38J ROC/TTA testing



AKA_TAGERT
02-06-2006, 08:43 PM
METHOD:
There are only two possible methods used, the air start or ground start.

1) The air start method is where the plane is flying at sea level at a speed near the best climb rate. The time starts once the pilot performs a fairly abrupt pull-up and attempts to stabilize on the speed at the best climb speed schedule at the lowest practical altitude (aka sea level). Once stabilized on the climb schedule the pilot will adjust speed as the airplane climbs so that the schedule of best climb speed is maintained as the altitude increases. The check climb ends when the rate of climb drops below 100 feet per minute or when a pre-established maximum altitude has been reached.

2) The ground start method begins at a stop on the runway by establishing Military Power with the brakes on. The time starts when the brakes are released. The pilot completes a normal takeoff with rapid gear and flap retraction. The airplane is allowed to accelerate at low altitude to a speed somewhat below the speed for best climb. The pilot then performs a fairly abrupt pull-up and attempts to stabilize on the best climb speed schedule at the lowest practical altitude. Once stabilized on the climb schedule the pilot will adjust speed as the airplane climbs so that the schedule of best-climb speed is maintained as the altitude increases. The check climb ends when the rate of climb drops below 100 feet per minute or when a pre-established maximum altitude has been reached.

The two methods are similar, but the air start method provides the best chance of the P38J matching the real life values in that it removes the time from when the plane is at rest to when it is flying level at the initial best climb speed. In my track file I actually do the ground start method, but, that portion of the data is ignored in this analysis. Therefore the data used in this analysis is that of an air start.

The in-game P38J is a newer model than the one used in the AAF test. The P38J in the AAF test has the smaller 300gal. fuel tanks, therefore I adjusted the fuel load to account for this. Bodie states the test was done at WEP, and the MP indicates 60"MP. Oleg has indicated that all planes are verified at 100% (MIL), but at that setting the P38J does not even get close. So, I decided to try it at 110% (WEP). The problem with that is the in-game P38 engines are damaged at ~22kft due to over heat. Therefore I start off at 110% (WEP) and slowly reduce to 100% (MIL).

IN GAME P38J CONFIGURATION:
MAP: Crimea
WEATHER: Clear
TIME: 12:00PM
FUEL: 70% (i.e. 300gal/426gal. ~ 70%)
WEAPON LOADOUT: DEFAULT
RAD: AUTO
POWER: 110% THROTTLE (0ft to ~11kft)
POWER: 105% THROTTLE (~11kft to ~15kft)
POWER: 100% THROTTLE (~15kft to ~33kft)

RESULTS

Here is the summary table
http://www.geocities.com/grantsenn/NACA_RESULTS/ROC/402/P38J/v402_P38J_70FUEL_110_105_100_PWR_01/v402_P38J_70FUEL_110_105_100_PWR_TBL.JPG


Here is the corresponding ROC
http://www.geocities.com/grantsenn/NACA_RESULTS/ROC/402/P38J/v402_P38J_70FUEL_110_105_100_PWR_01/v402_P38J_70FUEL_110_105_100_PWR_ROC.JPG

Here is the corresponding TTA
http://www.geocities.com/grantsenn/NACA_RESULTS/ROC/402/P38J/v402_P38J_70FUEL_110_105_100_PWR_01/v402_P38J_70FUEL_110_105_100_PWR_TTA.JPG

SUMMARY
Key things to remember
1) The real life test was done using the NACA ground start method, where as I used an air start. Using the air start saves you about 30 to 40 seconds, that is to the P38J should get to the real world altitudes about 30 to 40 seconds sooner.
2) I adjusted the fuel load down to 300gal.
3) I could not do the test at WEP for the whole test due to engine damage.

With all those things in mind the in-game P38J still did not get close to hitting the mark. As you can see the TTA graphs the in-game P38J took ~7min to get to 20kft where the real life P38J was able to do it in ~5min 37sec. This is to be expected when you look at the ROC graphs, note the real life P38J had a ROC of 4,000fpm at SL and the in-game P38J has a ROC of only 3,750. Also note that is the closest the in-game P38J ever gets to the real ROC values. Look at the ROC at 20kft, the in-game P38J has an ROC of ~2,000fpm and the real life P38J has a ROC of ~3,250fpm, that is a 1,250fpm error.

This next table I don€t have automated in my analysis tool yet, but I wanted to show the difference and percent error in the ROC per altitude. I had to visually get the in-game values off of my curves so keep that in mind. I will add this in later so it is automated. Here is the difference and percent error table

http://www.geocities.com/grantsenn/NACA_RESULTS/ROC/402/P38J/v402_P38J_70FUEL_110_105_100_PWR_01/v402_P38J_70FUEL_110_105_100_PERCENT_ERROR.JPG

I have also done some testing with the engine heat off, running at 110% for the whole climb does not fix the problem either. Long story short, the P38J€s climb rate is way off imho.

Here is a link to the 100% full report and track file
full report for 100% case (http://www.geocities.com/grantsenn/NACA_RESULTS/ROC/402/P38J/v402_P38J_70FUEL_100_PWR_01/V402_P38J_70FUEL_100PWR_summary.pdf)
track file for 100% case (http://www.geocities.com/grantsenn/NACA_RESULTS/ROC/402/P38J/v402_P38J_70FUEL_100_PWR_01/v.02_P38J_70FUEL_100PWR.ntrk)

Here is a link to the this (110% to 105% to 100%) full report and track file
full report for 110% to 105% to 100% case (http://www.geocities.com/grantsenn/NACA_RESULTS/ROC/402/P38J/v402_P38J_70FUEL_110_105_100_PWR_01/v402_P38J_70FUEL_110_105_100_PWR_summary.pdf)
track file for 110% to 105% to 100% case (http://www.geocities.com/grantsenn/NACA_RESULTS/ROC/402/P38J/v402_P38J_70FUEL_110_105_100_PWR_01/v402_P38J_70FUEL_110_105_100_PWR.ntrk)

ImpStarDuece
02-06-2006, 09:27 PM
A quick check of the ingame manifold pressure gauge in the P-38J gives 60 inches of mercury at 100% throttle and 60 inches of mercury at 110% throttle.

So, your tests might understandably be down on the AAF test report.

I suggest that you retest at 60 inches Hg and 110% throttle, and see if the results are any better.

AKA_TAGERT
02-06-2006, 09:54 PM
Originally posted by ImpStarDuece:
A quick check of the ingame manifold pressure gauge in the P-38J gives 60 inches of mercury at 100% throttle and 60 inches of mercury at 110% throttle.

So, your tests might understandably be down on the AAF test report.

I suggest that you retest at 60 inches Hg and 110% throttle, and see if the results are any better. Been there done that, it helps a little, but not much.. That and Oleg says to use 100% not 110%.

Tachyon1000
02-06-2006, 11:14 PM
I am wondering if you have checked your in-game TAS against the TAS on the climb data that were obtained from those historical tests in the pdf you have provided.

Waldo.Pepper
02-07-2006, 12:38 AM
I appreciate the effort and sincerity, but always wonder why you bother to do this seemingly right before a patch release. Don't you think that the release of 4.03 will likely invalidate all this effort?

Wouldn't it be better to wait till after 4.03, or to have conducted this test months ago so that it could be incorporated into 4.03?

AKA_TAGERT
02-07-2006, 12:55 AM
Originally posted by Tachyon1000:
I am wondering if you have checked your in-game TAS against the TAS on the climb data that were obtained from those historical tests in the pdf you have provided.
Did you forget already? Here is a refresher

http://www.geocities.com/grantsenn/FLIGHT_SIMULATION/REAL_WORLD_DATA/P38/P38J/BETA_P38J_60MP_CLIMB_SCHEDULE_TAS_TO_IAS.JPG

If that does not ring a bell, try this

Link to the first time I told you (http://www.acompletewasteofspace.com/modules.php?name=Forums&file=viewtopic&t=8060&postdays=0&postorder=asc&start=45)

AKA_TAGERT
02-07-2006, 12:58 AM
Originally posted by Waldo.Pepper:
I appreciate the effort and sincerity, but always wonder why you bother to do this seemingly right before a patch release. Don't you think that the release of 4.03 will likely invalidate all this effort?

Wouldn't it be better to wait till after 4.03, or to have conducted this test months ago so that it could be incorporated into 4.03? Because to draw a line.. you need at least two points. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

AKA_TAGERT
02-07-2006, 01:11 AM
update

GOYA_551st over at CWOS may have found a mistake.. Seems the PP was set to 95%. It is late, so I dont have time to check it, but, looks like I may have bumped the PP leaver during the test and didnt realise it. Good thing I plot all the DeviceLink variables of the test, and good thing some people actully read the darn thing! Thanks GOYA_551st! Ill look into it and see if that is allways the reading for a P38 or if I bumped it during the test. Seem odd I would bump it and get exactly 95? Anyway, tuesday!

Waldo.Pepper
02-07-2006, 01:48 AM
Because to draw a line.. you need at least two points


Yes of course this is obvious but this does not really address my point. Suppose you find something glaringly wrong in these tests. Don't you see that it is too late to incorporate any improvement based upon your discovery into 4.03 at this late date?

Therefore, wouldn't it have been better had you done this months ago rather than on the cusp of a release?

BSS_CUDA
02-07-2006, 06:15 AM
heck we've got 2 weeks brfore the patch comes out, plenty of time to make changes http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

BaldieJr
02-07-2006, 06:27 AM
if tagert would focus that energy on renewably energy we'd have all been frolicking naked in a peacefull paradise 2 years ago.

wtf kid its just a game?

BSS_CUDA
02-07-2006, 06:40 AM
Originally posted by BaldieJr:
wtf kid its just a game?

uhm actualy its not a game, its billed as a combat flight simulator, they are not the same thing http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

AKA_TAGERT
02-07-2006, 08:08 AM
Originally posted by Waldo.Pepper:
Yes of course this is obvious but this does not really address my point. Suppose you find something glaringly wrong in these tests. Don't you see that it is too late to incorporate any improvement based upon your discovery into 4.03 at this late date? Not true imho, it's never too late!


Originally posted by Waldo.Pepper:
Therefore, wouldn't it have been better had you done this months ago rather than on the cusp of a release? Hind sight.. allways 20 20

AKA_TAGERT
02-07-2006, 08:09 AM
Originally posted by BaldieJr:
if tagert would focus that energy on renewably energy we'd have all been frolicking naked in a peacefull paradise 2 years ago.

wtf kid its just a game? Your not frolicking naked allready? Heck, I have been doing that for years now! Get with the program son!

anarchy52
02-07-2006, 08:30 AM
Originally posted by BSS_CUDA:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BaldieJr:
wtf kid its just a game?

uhm actualy its not a game, its billed as a combat flight simulator, they are not the same thing http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

actually, you is wrong

AKA_TAGERT
02-07-2006, 08:40 AM
Everybody take note of the stark contrast between the 109 ROC thread and the P38 ROC thread.

Over there, everyone is very concerned about the 109, thus all on their best behavior.

But here the nay-sayers chime in with stuff that has nothing to do with the topic at hand. What do you care about what I had for breakfast? Or what I am wearing or not wearing at the moment?

If you have a question or comment on the topic at hand, please ask or comment away. If your just trolling in the hopes of starting a flame fest to take the focus off the fact that the in-game P38€s ROC is totally porked, sorry, not falling for it! To which I would say to guys like CUDA, lets just ignore them from here on out, no need to respond to that stuff. Because, any responce, good or bad and they win.

So I would kindly ask the nay-sayers to run along and play somewhere else.

Thanks!

Diablo310th
02-07-2006, 11:21 AM
Originally posted by AKA_TAGERT:
Everybody take note of the stark contrast between the 109 ROC thread and the P38 ROC thread.

Over there, everyone is very concerned about the 109, thus all on their best behavior.

But here the nay-sayers chime in with stuff that has nothing to do with the topic at hand. What do you care about what I had for breakfast? Or what I am wearing or not wearing at the moment?

If you have a question or comment on the topic at hand, please ask or comment away. If your just trolling in the hopes of starting a flame fest to take the focus off the fact that the in-game P38€s ROC is totally porked, sorry, not falling for it! To which I would say to guys like CUDA, lets just ignore them from here on out, no need to respond to that stuff. Because, any responce, good or bad and they win.

So I would kindly ask the nay-sayers to run along and play somewhere else.

Thanks!

http://forums.ubi.com/images/smilies/351.gif and every other thread like this.

Grey_Mouser67
02-07-2006, 11:37 AM
Absolutely...time to stop enabling the trolls...now if we could only get an admin or two to chip in!

AFJ_Locust
02-07-2006, 12:12 PM
Originally posted by AKA_TAGERT:
Everybody take note of the stark contrast between the 109 ROC thread and the P38 ROC thread.

Over there, everyone is very concerned about the 109, thus all on their best behavior.

But here the nay-sayers chime in with stuff that has nothing to do with the topic at hand. What do you care about what I had for breakfast? Or what I am wearing or not wearing at the moment?

If you have a question or comment on the topic at hand, please ask or comment away. If your just trolling in the hopes of starting a flame fest to take the focus off the fact that the in-game P38€s ROC is totally porked, sorry, not falling for it! Thanks!

I for one would love to see the p38 adjusted to its historical climb rate TODAY IF POSSIBAL http://forums.ubi.com/images/smilies/11.gif

I mean heck everyone that truly loves this sim should want all ac to be accuratly modled......

Wouldnt that be wise & fair ?

I think several ac need a tuneing up/and down

Waldo.Pepper
02-07-2006, 02:38 PM
For the record I'm not a nay-sayer. Like I said originarlly I appreciate the work and the sincerity of your efforts.

I just think your timing on this (and the 109) is perhaps more in a effort to be proven right about the issue, rather than more contructively motivated at improving the situation.

In all sincereity you are doing more on the issue that I thats for sure!

However, perhaps you are right and that it is never too late. I hope that if fault is found it can be corrected, and if you contribute to that congradulations and my humble thanks.

AKA_TAGERT
02-07-2006, 02:54 PM
update

I was reading what Oleg said

"the climb should be measured on nominal power. Not with wep. This is right term for all planes."

But, that was in context to the Bf109K4, so maybe when he said all planes he ment all 109K4s?

So, I re-ran the test at 110%, I left the links in for the 100% case just encase he did mean all as in all.

Tachyon1000
02-07-2006, 05:11 PM
Originally posted by AKA_TAGERT:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Tachyon1000:
I am wondering if you have checked your in-game TAS against the TAS on the climb data that were obtained from those historical tests in the pdf you have provided.
Did you forget already? Here is a refresher

http://www.geocities.com/grantsenn/FLIGHT_SIMULATION/REAL_WORLD_DATA/P38/P38J/BETA_P38J_60MP_CLIMB_SCHEDULE_TAS_TO_IAS.JPG

If that does not ring a bell, try this

Link to the first time I told you (http://www.acompletewasteofspace.com/modules.php?name=Forums&file=viewtopic&t=8060&postdays=0&postorder=asc&start=45) </div></BLOCKQUOTE>

It's a simple question. Have you compared the results for what you obtained for TAS against TAS from the source you are testing against? The reason I ask is actually to help not hinder your cause. It would seem to me that if you can achieve similar speeds in a climb then perhaps the problem is not one of power, but perhaps lift or weight.

Since you've prodded me, I'd also suggest that Military Power for the J is 54" MP as per the pilots manual. Whether or not it was rated to be used at 60" or 70" is immaterial unless you are specifically requesting performance at those levels to be in the game. I would suggest that you have merely tested the plane at the equivalent of 54" MP as 100% is military power.

Now if you would like to argue that 100% throttle should correspond to climb performance at 60" MP, that is a separate but related issue and it seems there is alot of evidence to support either of these claims. However, this test is at military power. For this model in the game, I'd argue that is 54" MP.

AKA_TAGERT
02-07-2006, 06:05 PM
Originally posted by Tachyon1000:
It's a simple question. Have you compared the results for what you obtained for TAS against TAS from the source you are testing against?
Yes, very simple, question. So simple I answered it with a 1000 words aka. A picture. What part of the picture do you not understand? It clearly shows the TAS to IAS conversions, and if you would be so bold as to click on the full report you will see the in game IAS during the test, at which point you will see the two are very close. Now before you split hairs and say they are not close, be my guest and do a better job of it!


Originally posted by Tachyon1000:
The reason I ask is actually to help not hinder your cause. It would seem to me that if you can achieve similar speeds in a climb then perhaps the problem is not one of power, but perhaps lift or weight.
There are many things that could cause it, I dont claim to know what the cause is, all I know is the ROC and TTA is wrong. But, you be my guest to *guess* at which one of a dozen things it is until the cows come home. Because I don€t care what you or anybody elses *guesses* at it. Ill leave the cause of it up to the experts like Oleg, not the nay-sayers here or anywhere else.


Originally posted by Tachyon1000:
Since you've prodded me,
Sorry, must have been someone else, I don€t swing that way.


Originally posted by Tachyon1000:
I'd also suggest that Military Power for the J is 54" MP as per the pilots manual. Whether or not it was rated to be used at 60" or 70" is immaterial unless you are specifically requesting performance at those levels to be in the game. I would suggest that you have merely tested the plane at the equivalent of 54" MP as 100% is military power.
Are you still operating under the false impression that I care what you think let alone what you suggest? How many times in how many different forums do I have to tell you before you get it? Especially in light of the fact that you have yet to realize that the test I am comparing to is NOT done at 54"


Originally posted by Tachyon1000:
Now if you would like to argue that 100% throttle should correspond to climb performance at 60" MP, that is a separate but related issue and it seems there is allot of evidence to support either of these claims. However, this test is at military power. For this model in the game, I'd argue that is 54" MP.
Clearly you are confused, I'd recommend you actually reading the full report instead of guessing what is inside. If you do, pay close att to the part where it says 60"MP and WEP.

PS, from here forward I am going to ignore all your replies, feel free to PM me if you want to learn some more, but I will not muddy up this thread telling you things I have already told you several times before in several different forums.

BaldieJr
02-07-2006, 06:39 PM
I don't trust your testing methodology and I think you are a likely candidate for chronic halitosis.

Tachyon1000
02-07-2006, 10:32 PM
My mistake on the TAS numbers. I see that now. Thank you.

Oops, my bad, I see that you did test at 110% which should be 60" MP. Man, you plane is messed up.

Tachyon1000
02-07-2006, 11:30 PM
One thing i did notice is that you turned nearly through 45 degrees in heading over the course of the test, with the worst turning occuring after take-off and near the end of the climb check. I am not sure that is kosher.

Gibbage1
02-08-2006, 02:10 AM
Originally posted by Tachyon1000:
One thing i did notice is that you turned nearly through 45 degrees in heading over the course of the test, with the worst turning occuring after take-off and near the end of the climb check. I am not sure that is kosher.

Did I miss the thread where you posted your own track files? No. You claim the P-38 in game meets or exceeds historical charts, yet you have yet too prove it. All you do is dispute other people's testing. Why dont you post a track that proves the P-38 can climb like you say it can?

AFJ_Locust
02-08-2006, 04:30 AM
bump for the P38

Tachyon1000
02-08-2006, 12:11 PM
At this point I am also curious if running at 110% actually does anything at all. If one flies level at 110%, does the plane go faster than at 100%? Perhaps 110% really does nothing. Something to consider.

Tachyon1000
02-08-2006, 12:14 PM
Originally posted by Gibbage1:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Tachyon1000:
One thing i did notice is that you turned nearly through 45 degrees in heading over the course of the test, with the worst turning occuring after take-off and near the end of the climb check. I am not sure that is kosher.

Did I miss the thread where you posted your own track files? No. You claim the P-38 in game meets or exceeds historical charts, yet you have yet too prove it. All you do is dispute other people's testing. Why dont you post a track that proves the P-38 can climb like you say it can? </div></BLOCKQUOTE>

At this point, I make no such claims. My testing was flawed as the right test conditions were not used, i.e 100% throttle, 100% fuel. If I redo the test, I'll state the results and my conclusions at that time. From what I can see now, the check climb data from TAGERT makes all the P-38s look grim.

Gibbage1
02-08-2006, 12:33 PM
Originally posted by Tachyon1000:
At this point, I make no such claims. My testing was flawed as the right test conditions were not used, i.e 100% throttle, 100% fuel. If I redo the test, I'll state the results and my conclusions at that time. From what I can see now, the check climb data from TAGERT makes all the P-38s look grim.

Its a rare thing around here when someone admits an error. Bravo.

Tagert is not the only one who has done climb testing on the P-38 and found this error. Many people have done the same test to "prove" Tag and the others wrong and simply cant reach the climb charts. Not even the higher horsepower L "Late" can reach the climb speeds for the standard J model's! Nobody has yet to produce a track that proves us wrong when we say the P-38's climb is porked.

Tator_Totts
02-08-2006, 12:38 PM
O boy anothe allied plane not to specs just a coincedence. http://forums.ubi.com/images/smilies/53.gif

Grey_Mouser67
02-08-2006, 04:55 PM
First thing first...get Oleg's attention and energy focused on fixing the Lightning...then make sure all 3 models are fixed....and please, oh please don't forget about the elevator/compressibility.

AKA_TAGERT
02-08-2006, 10:41 PM
Originally posted by Tachyon1000:
At this point, I make no such claims. My testing was flawed as the right test conditions were not used, i.e 100% throttle, 100% fuel. If I redo the test, I'll state the results and my conclusions at that time. From what I can see now, the check climb data from TAGERT makes all the P-38s look grim. Takes a big man to admit an error, I can respect the heck out of that.. So, consider this point forward a fresh start, clean slate, by gones be by gones! S! With regards to the hard treatment from me to you! http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif As for trust, that is earned! Only time will tell! http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif