[REPORTED] K-4 level speed

[Crumpp]

I agree with what Rel4y said: it should be modelled as accurately as possible, regardless of what its opponent aircraft's accuracy-of-modelling is. "Two wrongs don't make a right," and all that. If the relative balance is thrown off by making one aircraft more correct, then the correct solution is to then make the other aircraft more correct, too. The relative balance will then take care of itself.

 

Which doesn't mean I believe that there's an error, in this case. Again, if there is, then it should be corrected, regardless of what that does to the 109 vs. P-51 relative balance. (And then the P-51 amended, too, if it has an error as well.) However, it remains to be determined whether there actually is an error in the 109's modelling. Looking at the links, I'm not seeing an unbroken connection between documents and conclusions.

 

Although I disagree with the statement that relative balance is all that matters, Crumpp raises a valid point: if the aircraft are both within their historical range, then relative balance becomes more important than getting each aircraft exactly to the mean of its performance range. For example, if both aircraft are on the slow side of their historical averages, but by the same approximate percentage, then there is no real problem. Preserved relative balance, check; within historical range of individual variation, check. Good to go.

 

Would it be nice to have both firmly within the exact average? Yeah, but consider what you're asking for, then, and for what gain. If they're already within historical range of individual variation, then that's a miracle by itself. By definition, being within that range makes the sim accurate, and there isn't much to be gained by splitting hairs (and demanding that Yo-Yo move more mountains) to push them more towards that "perfect mean," if there isn't already a relative balance problem.

 

(Now, the more aircraft there are, the more likely it's going to be that relative balance is thrown off for at least one pair of them, if various examples are at opposite extreme ends of their historical range. But, we don't have enough birds for that to be a problem, at this point, and it hasn't been established that some aircraft are at extreme low end, and others at extreme high end, of historically-accurate individual variation.)

 

Who said anything about balance??

 

Relative performance is not balance.

 

This misunderstanding can completely change the meaning of what I wrote. An F-16 vs A Sopwith Camel has a relative performance that is more important than whether the camel goes 75 knots or 95 knots. If the F-16 suddenly losses 20,000lbs of thrust in a turn just so the camel players can be happy and catch it in a turn....

 

The relative performance picture is skewed.

 

:thumbup:

[Echo38]

Who said anything about balance?

Relative performance is not balance.

This misunderstanding can completely change the meaning of what I wrote.

 

I don't see the difference; sorry. Replace my term "relative balance" with "relative performance" and the point I was trying to make remains the same. In the manner in which I was using the term, "relative balance" equates to "relative performance." E.g. the aircraft (using the mean of individual examples for the given model/block/configuration) that was historically faster (at a given altitude, power setting, etc.), stays faster, and so on.

 

But, it looks to me that we're pretty much saying the same thing, and are simply getting caught up on definitions. We both agree that the accuracy of the simulation is fine, as long as each of the aircraft is within the appropriate historical mean for its respective configuration, and the distances from that mean are similar enough that there isn't a reversal of common comparative traits. Yes?

 

All that said: if the 109K is using 109G drag, then I do hope that Yo-Yo can eventually replicate K drag, when the info & time-budget allows for such. But, if the current performance is within historical mean for K, then the extra drag can be accounted for by manufacturing variation. Not ideal, but acceptable, particularly when relative performance roughly matches opponent aircraft. There are other issues which have a greater impact on the accuracy of the picture, at present, than getting every specific example 1% closer to its mean.

Edited December 27, 2015 by Echo38

[Kurfürst]

Soooo, has this been corrected....?

[Yo-Yo]

Soooo, has this been corrected....?

 

Must be in the release... at least in trunk version it was adjusted looong time ago.

[Kurfürst]

Must be in the release... at least in trunk version it was adjusted looong time ago.

 

Will check! :thumbup:

[NineLine]

Will check! :thumbup:

 

if not, remember it might be in 1.5.3 coming soon... if you have it, maybe check in 2.0.1

[Hummingbird]

Checked in 2.0.1, got 574-575 km/h at SL.

[NineLine]

Checked in 2.0.1, got 574-575 km/h at SL.

 

 

kk, I'll see if its changed internally yet and try and track down when it will be merged with release.

[javelina1]

Checked in 2.0.1, got 574-575 km/h at SL.

 

oh man, gotta check this in NTTR too.

[Solty]

Remember that NTTR is higher above Sea Level.

[javelina1]

Remember that NTTR is higher above Sea Level.

 

yep, very aware. (my thoughts too). but curious to see if I can match.

[Hummingbird]

Remember that NTTR is higher above Sea Level.

 

No, you can test at SL on NTTR as well. There's a valley on the west side of the map that goes down to SL. That's where I tested it.

 

Infact there's even a spot with -80 m below sea level on the map.

[Hummingbird]

Should be getting ~610 km/h at SL, but only getting 574 km/h on average atm.

[javelina1]

Flying over Groom Lake, right over the main runway. 574-575kph.... She just flat out hauls @$$! :)

 

I'll have to check out that valley on the west side for the SL pass.

[Hummingbird]

Flying over Groom Lake, right over the main runway. 574-575kph.... She just flat out hauls @$$! :)

 

I'll have to check out that valley on the west side for the SL pass.

 

Well there's been no improvement so not really :P

 

Should be doing around 610 km/h at SL, so she's still ~35 km/h too slow.

[Solty]

610kph at SL? According to the data available it is 610kph at 1000m and 590 at SL. Also take into consideration the temperature outside.

 

What we do not know though if that data is actually accurate. The same data source points out that K4 should have 22m/s ROC while DCS K4 has 26m/s. These estimates that Germans did, may also be innacurate when it comes to speed in level flight.

 

 

 

While these sources claim that the K4 should be capable of 580kph at SL with WEP, and it lists the engine power at 1800PS which means 1.8ata, while at the same time the engine used is DB605DC. Still it would be the closest to what we have in DCS if it is actually that the K4 flies 575kph at SL. Last time I've checked P-51D was also a bit too slow, when compared to what data say's, so that just might be the DCS engine producing worse performance in level speed department just to keep other stats close to what they should be.

 

 

 

 

 

Edited February 13, 2016 by Solty

[rel4y]

Did you actually read this thread solty? Pretty much everything you just threw in has already been discussed in detail..

 

Climb rate figures were calculations without engine thrust included, ingame measured climbing time to altitude closely resemble historical data, level speed figures were actual measurements, the DB605 engine model on the 109K4 agrees very well with historical data, the drag area used atm is that of a G10/late G14 not a K4, 605DB and 605DC are the same engine with a few screws turned, the Rechlin docs you presented are prototype data and likely do not present production line aircraft in terms of aerodynamic features and finally if P51 speed is historically incorrect find out the reasons and proove otherwise with solid documentation as done in this thread.

 

I dont want to be rude, but I can not see a point to dispute this topic again if everything you just argued for has already been discussed. Now I dont agree with a MSL speed of above 595 km/h, because that is what historical (measured) data verifies.

Edited February 13, 2016 by rel4y

[Solty]

I don't see any reason for your hostility. Calm down.

 

You are talking to a person that reported issues with climb rates ( changed from 31m/s to 26m/s) and changes to Fw190 (29m/s to 26m/s). Together with others like Pillum and Grape Jam and Kenobi etc. And yes I've read the thread!

 

I saw YoYo say that it should be around 575kph at page 3

http://forums.eagle.ru/showpost.php?p=2613565&postcount=18

"So, the optimistic result for the plane flying 507 kph at 1270 ps will be only 575 kph presuming the same CD for the plane (that is correct for SL because M number is not high enough to get noticable increasing of CD) and for the same prop efficiency (that is not correct because of increased rpm and speed that leads to higher Mach numbers at the blade tip, so - to lower efficiency).

In-game 109 flies 568 kph at SL and it is corresponds with the optimistic limit with 1-1.5% acuracy.

 

The case is closed. "

It seems the case was closed indeed, if the 109K4 now flies exactly like YoYo said it would.

[rel4y]

No hostility intended. I know you were involved in these cases. But this time again you quotet Yo-Yo before data of different aerodynamics were presented and later confirmed by Yo-Yo himself. So what is the point in that? If you would bring up new and unknown data I would be thrilled. I wouldnt mind making the 109 slower if historical data strongly indicates, since historical accuracy for me is the goal. But I cant see what your reasoning is to dispute already discussed and concluded points.

 

Im sorry if I misunderstood you.

Edited February 13, 2016 by rel4y

[Hummingbird]

 

I saw YoYo say that it should be around 575kph at page 3

http://forums.eagle.ru/showpost.php?p=2613565&postcount=18

It seems the case was closed indeed, if the 109K4 now flies exactly like YoYo said it would.

 

And overwhelming evidence has been provided which showed that was not the case, hence the issue is now being corrected. Please read the thread before commenting.

 

Top SL speed was ~610 km/h.

[Hummingbird]

Bf-109 G-14 with DB605AM test flown performance at 1.7 ata:

http://kurfurst.org/Performance_tests/109G14_May44trials/109G14_GLCE-may44_trials.html

 

= 568 km/h at SL

 

For the K-4 you need to add at least ~12 km/h due to retractable tail wheel and another ~15 km/h due to wheel well covers (this is probably way too low).

 

Add another ~10 km/h due to a generally cleaner cowling, exhaust thrust and slightly increased power rating, and you got ~610 km/h.

 

Maximum speeds without exhaust thrust added:

http://kurfurst.org/Performance_tests/109K_PBLeistungen/files/5026-27_DBSonder_MW_geschw.jpg

http://kurfurst.org/Performance_tests/109K_PBLeistungen/files/5026-18_DCSonder_MW_geschw.jpg

Edited February 13, 2016 by Hummingbird

[gavagai]

No, you can test at SL on NTTR as well. There's a valley on the west side of the map that goes down to SL. That's where I tested it.

 

Infact there's even a spot with -80 m below sea level on the map.

 

AKA Death Valley, the lowest point in North America.:thumbup:

 

P.S. The % difference between 610km/h and 575km/h is 2%, and the 109K-4 still leaves the P-51D in the dust in both acceleration and level airspeed. This seems more like an argument over source data, and not an argument about whether the 109 matches the intended source data.

Edited February 13, 2016 by gavagai

[Hummingbird]

AKA Death Valley, the lowest point in North America.:thumbup:

 

Yup :)

[Kurfürst]

It seems the case was closed indeed, if the 109K4 now flies exactly like YoYo said it would.

 

Don't be silly, read the rest of the thread. We have the 1,8 ATA 605DB version of the K-4 which should do ~595 km/h on the deck.

[Hummingbird]

Don't be silly, read the rest of the thread. We have the 1,8 ATA 605DB version of the K-4 which should do ~595 km/h on the deck.

 

As I understand it that was without exhaust thrust added, at least based on the real life tests with the G-14.

 

The real life tests pretty much always cranked out higher speeds.