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Holtzauge
01-30-2005, 12:02 PM
Dear Mr Maddox,

Several times the PF climb performance modelling has been the subject of discussion on this forum. The topic has been addressed in a number of posts by a number of people with a lot of discussions and opinions being voiced.

I think quite a few of us in the community consider the following to be off:

1) The absolute climb rates are generally to high (e.g Me 109 K4 rocket climb)
2) The relative climb performance between different a/c is off compared to IRL performance (as exemplified but not limited to the P-47 and Me 106 G6 relative climb rate)
3) Deviating from the IRL best climb speeds is not punished by significant decrease in climb performance

I put in a post a while back on this and there has been some debate on how realistic the prop hanging climb performance that we have in PF really is. Since my last post and all others that have been submitted on this subject by others has not led to any response or change in the FM I have tried to find some RL evidence to support these assertions.

I got lucky and found this chart from a test report compiled by the Air Fighting Development Unit, RAF Duxford October 1941. I did a test that is outlined in the picture and I think the picture speaks for itself.

I think this is one of the really big issues that needs to be addressed. Not just for the 109F, this problem seems to be a general shortcoming that affects all a/c in the sim.

So dear Mr Maddox, please do something about the climb modelling! If it's to big for PF then please say so and reassure us that this will be addressed in BoB.

I would be really dissapointed if this post ended up in a black hole like the others on the subject.

I think this issue is worthy of your attention so please give us a reply!

Best Regards,

Holtzauge

http://img.photobucket.com/albums/v210/Holtzauge/109F_allied_flight_test_1.jpg

VW-IceFire
01-30-2005, 12:10 PM
Its probably a combination of things but I'm not convinced that you or Oleg are totally correct...but PF is pretty realistic in feel and seemingly in general comparative numbers most of the time.

I haven't been sucked into a FM debate for a while. Its usually the same arguments rehashed.

Thing I see is this. There's more than one source of data, more than one interpretation of data and there's all sorts of ways to deal with how it works out. Overall, you can only argue till you are blue in the face. Then we have the argument surrounding the partial real physics that can be similated on a current day system and so on and so forth. In the end...as long as its as accurate as possible in a releativistic sort of area then I think things are ok.

But I'm sure there will be some good arguments back and forth soon. Enjoy http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

p1ngu666
01-30-2005, 03:40 PM
its basicaly that at non best climb speeds, planes climb too well. i dont understand the graphs youve put on tho, i do understand the raf document tho http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Blottogg
01-31-2005, 04:36 AM
Holtzauge, I'm confused about a couple of things concerning your post. The RAF graph you posted shows the Bf-109F maximum level speed as only 280 mph. Looking at the boost figure, at only 1.36 atm, the RL test wasn't making as much power as the simulated 109. That would go some way to explaining why the RAF couldn't get their 109F any faster than 280 mph in level flight. The max rate of climb they achieved was still a very respectable 3250 ft/min though, so I'm not sure if their engine was sick, or there was additional drag (a fuel tank perhaps?) on their test bird.

The second thing that confuses me is how flat your climb curve is. Il-2 Compare v2.5 shows ~18 m/s (3467 ft/min) climb at SL for the Bf-109F-2, so 3250 @ 5k' seems reasonable. Il-2 Compare's graph of speed vs. climb rate isn't nearly as flat as yours however, though it is broader than the RAF test curve. As a check, the RAF graph shows 2000 ft/min at ~225 mph, while Il-2 Compare shows ~2600 ft/min at the same speed (or ~13.5 m/s at 362 kph for the anachronistically challenged.) 600/2000 x 100% = 30%, which isn't a perfect match obviously, but not quite enough to get your knickers in a twist, especially since we don't know the RL configuration or condition of the test aicraft. We do know it wasn't pulling 1.42 atm of boost though, partially explaining the difference.

Thanks for the chart (I'm continually amazed at what folks can dig up on these old planes), but the difference is within the range I would expect given the limitations of computational vs RL performance, the unknown details of the RL test aircraft, and the minor difference in power and test conditions.

BBB_Hyperion
01-31-2005, 10:43 AM
I think Holzauges intention was showing climb effect on different airspeeds. That is indeed something to discuss.

-
For the Climbrate shown on this Chart compared to Kennblatt F1F2.

From F1F2 Kennblatt we see 6090 lbs can only be J├┬Ąger with additional range. Takeoff weight normal 2728 kg 2979 kg with additional fuel.

For the Climbrate the Kennblatt gives 16 m/s and 18.5 at Sea Level.

What gives a climbrate of 3645 ft/min with 1.42 AtA and 2600 rpm and 3150 ft/min at 2400 rpm and 1.36 AtA for the normal fighter.

-
As personal question to Holtzauge which climbrate you would like to see on K4 as you are talking about rocket climb ?

-
When we take the relative performance from this graph we can compare for the best climb speed issue.

About 125 mph(201.17 km/h) we have a climbrate of 2700 ft/min (13.76 m/s).
About 160 mph(257.49 km/h) we have the peak of climb of 3300 ft/min (16.76 m/s).
About 290 mph(466.7 km/h) we have a climbrate of 0 ft/min. (0 m/s)

So we can see that climbing at 200 km/h reduces climb performance by 18 % (82 % of the )Best Climb while climbing at 466 km/h climb is reduced by 100 %.

The stall Margin gives the lower limit but we can interpolate the chart 110 mph (177 km/h) 1800 ft/min ( 9,14 m/s) 46% lower (54 % of bestclimb) even when the plane shouldnt be able to hang in the air then .)

Did you test the F Series if the performance drop is similar or compareable to this document Holzauge ? Be sure to use correct rpm ata.

Looking forward to your analysis.

Holtzauge
01-31-2005, 11:18 AM
Blottog, the chart shows IAS not TAS. The TAS at 5000 ft according to the Duxford test was 316 mph TAS. The top speed according to the test was 372 mph. The German 109 F2 "kennblatt" lists top speed at 382 mph so I think the "Tommies" did a good job in wringing out the Friedrich at Duxford. The weight was listed at 6090 lbs so nothing strange there either.

As to different boost this will only translate the curve up or down as will altitude. I actually have a chart for 20000 ft as well and it looks just the same: a marked drop in performance when deviating from optimal climb speed. No prop hanging is supported by Messerschmitt AG!

Your reference to Il-2 Compare makes me wonder: "Who will guard the guardians?" Is IL-2 the gospel truth or mayby this also has it's limitations like the climb model. I did the test's and call it like I see it. If the test's do not compute with Il-2 Compare then mayby Il-2 Compare needs to be debugged too. What does Il-2 compare have to say about a climb speed of 125 mph? Is prop hanging climbs supported?

Do not stare yourself blind at the curve! It just adjoins the three points from the test I did at 125, 165 and 200 mph to make the point graphically.

It makes me kind of sad that now that we have solid proof that the climb model is off that the only posts so far have been focused at looking for "holes in the cheese" that are not there. Nothing is strange about the Duxford test. The only thing reeking here is the climb FM in PF!

Personally, I'm not much for knickers unless I get to take them off a shapely female, but if this is not enough to get your "knickers in a twist" tell me what will http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Blottogg:
Holtzauge, I'm confused about a couple of things concerning your post. The RAF graph you posted shows the Bf-109F maximum level speed as only 280 mph. Looking at the boost figure, at only 1.36 atm, the RL test wasn't making as much power as the simulated 109. That would go some way to explaining why the RAF couldn't get their 109F any faster than 280 mph in level flight. The max rate of climb they achieved was still a very respectable 3250 ft/min though, so I'm not sure if their engine was sick, or there was additional drag (a fuel tank perhaps?) on their test bird.

The second thing that confuses me is how flat your climb curve is. Il-2 Compare v2.5 shows ~18 m/s (3467 ft/min) climb at SL for the Bf-109F-2, so 3250 @ 5k' seems reasonable. Il-2 Compare's graph of speed vs. climb rate isn't nearly as flat as yours however, though it is broader than the RAF test curve. As a check, the RAF graph shows 2000 ft/min at ~225 mph, while Il-2 Compare shows ~2600 ft/min at the same speed (or ~13.5 m/s at 362 kph for the anachronistically challenged.) 600/2000 x 100% = 30%, which isn't a perfect match obviously, but not quite enough to get your knickers in a twist, especially since we don't know the RL configuration or condition of the test aicraft. We do know it wasn't pulling 1.42 atm of boost though, partially explaining the difference.

Thanks for the chart (I'm continually amazed at what folks can dig up on these old planes), but the difference is within the range I would expect given the limitations of computational vs RL performance, the unknown details of the RL test aircraft, and the minor difference in power and test conditions. <HR></BLOCKQUOTE>

Holtzauge
01-31-2005, 11:50 AM
Hyperion, you are correct that my intention has been to raise the issue of climb rate as a function of climb speed and that that has been something I have long suspected is off in the FM affecting all a/c.

IRL, I think that different power setting will only translate the curve up or down as long as we are talking about moderate deviations from a given power setting. So I think the chart can be used to prove the point even if there are deviations in absolute numbers.

I do not wish to get into a detailed discussion on the K4 climb performance (Steig & kampl., start & notl. with and without MW50 etc etc, with DB605D this or that variant. It's a wonder the LW could keep track of it themselves!) But I will say that I do not believe in a 30.5 m/s "rocket" climb rate that was posted a while back (from a test in 3.03 i believe).

I have seen RL figures around 22 m/s and I would not be surprised if a few m/s more could be squeezed out of some versions but 30.5 m/s...

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BBB_Hyperion:
I think Holzauges intention was showing climb effect on different airspeeds. That is indeed something to discuss.

-
For the Climbrate shown on this Chart compared to Kennblatt F1F2.

From F1F2 Kennblatt we see 6090 lbs can only be J├┬Ąger with additional range. Takeoff weight normal 2728 kg 2979 kg with additional fuel.

For the Climbrate the Kennblatt gives 16 m/s and 18.5 at Sea Level.

What gives a climbrate of 3645 ft/min with 1.42 AtA and 2600 rpm and 3150 ft/min at 2400 rpm and 1.36 AtA for the normal fighter.

-
As personal question to Holtzauge which climbrate you would like to see on K4 as you are talking about rocket climb ?

-
When we take the relative performance from this graph we can compare for the best climb speed issue.

About 125 mph(201.17 km/h) we have a climbrate of 2700 ft/min (13.76 m/s).
About 160 mph(257.49 km/h) we have the peak of climb of 3300 ft/min (16.76 m/s).
About 290 mph(466.7 km/h) we have a climbrate of 0 ft/min. (0 m/s)

So we can see that climbing at 200 km/h reduces climb performance by 18 % (82 % of the )Best Climb while climbing at 466 km/h climb is reduced by 100 %.

The stall Margin gives the lower limit but we can interpolate the chart 110 mph (177 km/h) 1800 ft/min ( 9,14 m/s) 46% lower (54 % of bestclimb) even when the plane shouldnt be able to hang in the air then .)

Did you test the F Series if the performance drop is similar or compareable to this document Holzauge ? Be sure to use correct rpm ata.

Looking forward to your analysis. <HR></BLOCKQUOTE>

BBB_Hyperion
01-31-2005, 12:40 PM
Well i can only advise to read the document with 22 m/s with great care special regarding to prop types and boost testbed and mw system , engine .)

I made a complete biased test a while ago in il2 .)
(There is something wrong in this test)
http://www.butcherbirds.de/hypesstorage/K4test.pdf

But you are right K4 is another topic and we should concentrate on the lift issue.

So where are your results auf relative climb performance for F Series ?

You need peak climbspeed and various datas between then calculate relative performance loss in % to be able to compare it. Then you can present data and testing method and show differences just posting a chart isnt enough .)

ZG77_Nagual
01-31-2005, 01:34 PM
You just know Sun Tzu had no freakin aquaintance whatsoever with the word 'salubrious'..

Holtzauge
01-31-2005, 02:06 PM
Hyperion: I only have time for a short reply http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Frankly I do not know what you mean by "You need peak climbspeed and various datas between then calculate relative performance loss in % to be able to compare it". If you have some idea of a test that will prove/disprove something about the PF climb FM in relation to the chart please do the test and post it.

At the risk of repeating myself I think the chart proves the point. If the FM was correct it should be possible to translate the PF test value points up or down by varying the power setting (within reasonable limits of course!)and the resulting points should match the IRL curve rather well if the FM was correct.

Duxford chart shows that it is not possible to do prop hanging climbs IRL without a significant climb rate penalty. In PF you get away with it!

IMHO the reason that most WW2 fighter flight manuals took pains to list the IAS for best climb at different altitudes was for a reason: IRL it payed to be exact, in PF you can have a very relaxed attitude towards your IAS when climbing which reeks arcade to me!

BR/Holtzauge

PS: K4@22m/s: DB605L, S&N L+MW50, W=3330Kg, from Me report A/W/243/43 http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BBB_Hyperion:
Well i can only advise to read the document with 22 m/s with great care special regarding to prop types and boost testbed and mw system , engine .)

I made a complete biased test a while ago in il2 .)
(There is something wrong in this test)
http://www.butcherbirds.de/hypesstorage/K4test.pdf

But you are right K4 is another topic and we should concentrate on the lift issue.

So where are your results auf relative climb performance for F Series ?

You need peak climbspeed and various datas between then calculate relative performance loss in % to be able to compare it. Then you can present data and testing method and show differences just posting a chart isnt enough .) <HR></BLOCKQUOTE>

BBB_Hyperion
01-31-2005, 02:16 PM
Used a english translation from 1910 .)

You can find the quote in the
Section 11.

All armies prefer high ground to low.

The Quote i used is from the Book but is a footnote from Mei Yao-ch`en if that makes you happy .)

But you are free to deliver the F4 ingame testdata as well to stay on topic http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif .

BBB_Hyperion
01-31-2005, 02:55 PM
I agree with your theory Holtzauge as you may have noticed. But we need hard ingame data and a test method that allows to get results to compare with this data. And better more than 1 source of rl data as well for different planes to get into details of this http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

The Chart is only a indication . Now you need to proof that it is not so ingame and not just by +-<10 % margin it must be significant.

At the moment i dont have the time to do this tests can only suggest that someone does these tests in 3.04.

I can give some old data pre 3.04 not from my tests but it shows following.

Climb speed reduction best to stallspeed K4 22 %
Climb speed reduction best to stallspeed G2 16 %
Climb speed reduction best to stallspeed F4 22 %

But as you can see from my calculation on your chart.
Climb speed reduction best to stallspeed F2 18 %

Thats 4 % difference to real life data and this run was not done at full power so its something you need to dig deeper in the issue.
Hopefully you can follow this argumentation.

Willey
01-31-2005, 08:53 PM
Interesting Comparison. It shows that the climb rate at the best climb speed is dead on, but above and below that, it's exaggerated. I'm sure that this applies to all planes in FB/PF. It's hardly nescessary to find the right speed for a good climb...

Blottogg
02-01-2005, 12:00 PM
Holtzauge, I'll have to go into the sim and spot-check Il-2 Compare's data, but in the past when I've done so it's been more accurate than I have. Since the FM is encrypted, and the data for Il-2 Compare comes from the (presumably cracked) FM, I haven't asked too many questions concerning how the data was generated. I'd be more inclined to distrust it if it disagreed with my experiences in the sim, or with RL flight data posted here from time to time. So far the only data in disagreement is your personal flight test, hence my incredulity.

The top speed at 5000' looked a little low to me (even accounting for IAS/TAS conversion... apparently the test was done in the summer since it would take 70-80 deg F to convert 280 IAS to 316 TAS), but the 1.36 atm boost partly explains it. Another possibility is that the Brits ran the climb tests with the radiator set to open instead of automatic, in order to preserve the motor. That wouldn't affect climb performance much, but would knock down the top speed. FWIW, Il-2 Compare has the F-2's max speed at this altitude as ~ 320 mph @ 100%, or 332 mph @ 110%. Assuming 100% is about 1.36 atm and 110% is about 1.42 atm, the program is within noise level on the speed figures at least.

Let me go muck around with the sim. If your numbers are correct, I'll be able to climb the F-2 faster at 200 kph than at 250. I can't see any problem with how you tested, but it doesn't agree with what I've experienced climbing aircraft in the sim myself.

Blottogg
02-01-2005, 03:47 PM
While it wasn't as exacting as Holtzauge's test, there does seem to be an undermodelling of induced drag on the back side of the L/D curve.

Flying on the Crimea map, 100% fuel and ammo, engine overheat and limited fuel turned off, I got these climb rates:

170 kph = 14.9 m/s (2875 ft/min) (1:07 time for 1000 m)
200,250,300 kph = 17.2 m/s (3320 ft/min) (0:58 time for 1000 m)
350 kph = 12.5 m/s (2410 ft/min) (1:20 time for 1000 m)

Using Holtzauge's technique of measuring time from 200 to 1200 meters (trimming for the target airspeed at 100 meters in level flight, applying full power and allowing the first 100 m of climb for the power and airspeed to stabilize.)

FWIW in the game 1.36 atm corresponds to ~ 93% power, not 100% as I had assumed earlier. I may go back and try this again at 93% to see how close I can come to the RAF climb curve. The numbers I got agree pretty closely with Il-2 Compare (within the limits of my ability to hold an airspeed), except for the 350 kph value. It just dawned on me that I didn't have the rads closed for the test though, so I'll have to go back and try that one again. Compare shows 10 m/s at 125 kph though, so I think Il-2 Compare is a valid representation of aircraft performance in the sim.

Mine was only a "back of the envelope" test (no data aquisition software, just the game gauges and a stopwatch), and limited by my ham-handedness (especially at the lower speeds.) As I said in a previous thread, I think the sim engine is limited in accurately depicting induced drag at low speeds, and not just for the F-2. Keep digging if you like, but I think this is another limitation of the engine we're going to have to live with.

hop2002
02-01-2005, 04:08 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>The top speed at 5000' looked a little low to me (even accounting for IAS/TAS conversion... apparently the test was done in the summer since it would take 70-80 deg F to convert 280 IAS to 316 TAS), <HR></BLOCKQUOTE>

Don't forget whilst we use IAS - TAS conversion as a quick shortcut, there's no such thing. The correct conversion is IAS - CAS - TAS, with CAS being "actual" air speed corrected for errors in the pitot tube.

So 280 IAS can easily convert to 316 TAS with only minor errors in the ASI readout. As an example, the early Tempest V test showed IAS of 398 mph at sea level, which corrected to 376 TAS, with an error correction of 21.8 mph (-23.9 mph position error, +2.1 compression error)

Blottogg
02-01-2005, 06:16 PM
Good point. I tend to treat IAS as CAS, when calibration errors can often be non-trivial, especially with older designs.

Retesting the 350 kph climb with the rads shut yeilded the same time, so the difference caused by the additional drag is less than the slop in my piloting. I couldn't hold 125 kph without falling off a wing, but the 150 kph number in Il-2 Compare checks out (~ 13.9 m/s, or 2675 ft/min.) Extrapolating the RAF chart puts that (at 93 mph) about 1000 ft/min too high.

The numbers for 1.36 atm are well below those of the RAF test, but I'm assuming that's caused by a difference between manifold pressures as depicted in the sim and those on the real aircraft. Given that the sim gauges probably weren't programmed with flight test in mind, I'll assume that the sim MP gauge is off by 0.06 atm at max power. Assuming max power for both the sim and RL (with one or the other MP gauge calibrated a little off), the numbers for max climb speed and above match up pretty well.

The parasitic drag modeling seems good, but the induced drag model is generous on the back side. Again, I think this is a sim engine limitation, not a persecution of the 109. If I get really bored, I'll drag out AHT and mess with a couple of the US fighters. Aside from the CAS/IAS/TAS snafu, anything else I could have missed?

WWMaxGunz
02-01-2005, 09:44 PM
It's ALL the planes Blotto. Has been more and less that way since FB 1.0, patch to patch.
FB 1.0 for instance was really bad and got toned down pretty well I think in AEP at least
compared but never to what IL2 was before FB. PF has been a resurgence of that. Try the
P-38J right down to buffet speed and see if you can maintain 2000 ft/min up to 7 km still.

Hey, people cried nonstop for less bleed in turns for the 190's in FB. So, we got less
bleed in turns as of FB and how do you do that? Maybe some new ways of figuring AOA?

Minor penalty for doing anything slow or just being slow. Minor penalty for turning hard,
but people still manage to overdo that and yes, still complain on the basis of their own
interpretations of "I read that...".

Well, scant sales means no more sims. And if the majority of egos can't fly FR and come
up with test-pilot performance (or better) then the sim don't sell. Makes me wish the sim
had some lower reality switches that actually aren't or switches labelled "extra drag",
"lessened acceleration", "used engines", just for people who want "other realism".

Hmmmm, OR for "Other Realism" settings? Other meaning other than popular opinion driven
results. Then the egos can have their FR and I can have planes that have to be flown
carefully to get the max out of, and 1C can survive to make more FR/RR/OR sims.

Holtzauge
02-02-2005, 11:48 AM
Blottog, thanks for taking the time to do some tests to look into this! http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

It seems that we basically got the same test results in the 200-300 km/h range which shows the "flat top" PF climb performance model contradicted by the distinct max in the IRL test.

I have now also done two more tests, one at 170 km/h and one at 400 km/h to complement the three earlier test points. Each climb rate charted is an average of three flights, Smolensk map, 100% fuel, 200 to 1200 m steady state climb. I have added your test points in the chart (the green dots).

It seems that the deviation is most marked on the low speed side of the envelope. If one extrapolates the IRL curve to 170 km/h (106 mph) the IRL curve shows around 1900-2000 ft/m. The reason that we do not have any real life values at 106 mph is probably due to the fact that no one doing the evaluation thought it worth the effort. (The evaluators were limited to IRL aerodynamics, poor souls!)

If we compare the IRL extrapolated values to the 2875 ft/m from your result and my reading of 3183 ft/m we get a deviation of 30-40%. Quite a big number IMHO.

An interesting thing is if you switch to external you will see that the slots are out quite some distance at 170 km/h. How/if this affects the flight model is of course difficult to know. Mayby it is just graphics? However, IRL, Slots deployed during climb should really mess up the aerodynamics and lead to a lot of drag.

WWMaxGunz: I agree with you that the problem we see is probably due to how the induced drag is modelled but I guess it could depend on other things as well like how thrust is modelled as a function of speed and prop efficiency etc. I guess it would be difficult to isolate which of these factors is the culprit so it really would be nice if Mr Maddox put in an apperance to explain how the FM works in this area and if this will be fixed in PF or (I certainly hope so) in BoB. I also think your idea with a "real reality" option would be a great feature for us who do want speed to bleed in hard turns and do not want to hang by the prop! http://forums.ubi.com/images/smilies/59.gif

Unfortunaltely, I tend to agree with you that this is probably something basic in the Il-2 series FM since it seems to affect all a/c and that it might be so that we have to do without it here but I think we at least owe it to the producer of this fantastic sim to point out a weakness, not as a criticism, but as a potential improvement.

I would feel more reassured if someone from the 1C team responded in some way and assured us that this will be fixed here or in BoB.

I find the silence disturbing.

BR//Holtzauge

http://img.photobucket.com/albums/v210/Holtzauge/109F_allied_flight_test_3.jpg

WWMaxGunz
02-03-2005, 12:06 AM
Yes, prop thrust could be doing it as the nose points up so much at low speed straight
flying. And most "tests" are done with power high too... going 170kph and climbing at
100% power for instance.
There was conjecture here and at SimHQ that prop efficiency in the sim does not fall
off as real and even some information about that but we can only get so far with any
of that. Some fighters could not be run full power standing with brakes on or off,
I understand, because they would flip over or other problem. That's a lot of power
made even at dead stop so the curve doesn't exactly ground out below stall speed.
But is it enough to hold the plane up this much?
What I was meaning is that I think due to making less bleed in curves, something was
done that has made other things also be tweaked. And then there is tweaking to try
and make the models fly to historic. And when new FM behaiviours are added, do they
start from the bottom or just keep tweaking? I dunno. Doubt any of us do.

I've seen this before where crowd insistance on meeting tables and "my plane doesn't
turn enough" has screwed a whole FM that was not table-based. Before that company
tried so hard, it at least flew somewhat naturally and glided likewise. Not perfect
or even having all the behaviours, but far better than after they did what they did.
I just hope very much that 1C gets PF closer to real in the shape of the curves and
lets the end numbers be in the ballpark.

Blottogg
02-04-2005, 09:33 AM
I'm also unsure of how the slats are modelled. If they are more than just eye candy (and I suspect they are) they would actually reduce drag at low speeds. The additional surface area and interference drag would increase the drag, but that would be more than compensated for by keeping the airflow attached along a signifcant portion of the span. A hard leading edge (assuming similar airfoil and wing loading) would begin to stall at a lower AoA (higher speed), with separated airflow and high drag associated with the stall. Slats don't do much good at high speeds, but they help L/D at low speeds, which should bump up the low speed side of the climb curve. Not above RL test data for the same aircraft of course.

I'm a little worried by the lack of news/information/updates from the 1C crew as well, and not just about this issue. Nature hates a vacuum, even an information vacuum. The result is all kinds of speculation and conspiracy theories as to what's going on with our favorite sim. Hopefully we'll hear something about the patch soon. In the meantime, I've got campaigns I'm still flying, imperfect FM or not.

Holtzauge
02-04-2005, 01:38 PM
Blottog, I am aware of the slots ability to keep the flow attached and that the drag would be worse without them. My point was that the overall a/c aerodynamics is messed up when the slots are out. The slots are there to improve things like aileron authority at high AoA and things are probably starting to get shaky around the wing root leading to extra drag of the overall configuration.

I still think it weird though to get the best climb rate when the slots are deployed....

Like you I am not happy about the silence from the development team. I truly understand if Mr Maddox himself does not always have time to join in but in this case I think delegating this work to someone from the 1C team would be the decent thing to do.

Since I'm doing this in my spare time I want to have fun! Since shouting in the desert does not fall into this category I'm gonna give this forum a rest for a while and do something that is fun: an "abschwung" into some Augsburg documentation on the 109 which has the added benefit of polishing up my rusty German!

I have truly enjoyed talking to you and a lot of others on this forum. See ya'll around!

Hals und Beinbruch!