[CLOSED] Climb rate appears to be to high, even for 109k

[Solty]

I enjoy it too. Figuring out that BMW801 and the systems on that Focke Wulf was lots of fun.

 

And for other data out there.....some food for thought.

 

If you look at the Kennblatt for the Bf-109K4 it agrees with the following chart:

 

 

 

 

 

 

 

From the chart posted in this thread, it looks like 1.98ata caused an issue with climb rate. I suspect the increased power loading caused an issue with the propeller design.

 

 

The first chart is based on a plane that had different, thin bladed prop called 9-12199. "A wide-chord, three bladed VDM 9-12159A propeller of 3 m diameter was used"-DCS website. The second chart is for K4 with DB605DC engine, The DCS Bf 109 K-4 is modeled with the DB 605 DB engine.

 

The first document posted is unreadable.

 

http://www.digitalcombatsimulator.com/en/products/kurfurst/index.php

Edited January 15, 2015 by Solty

[Yo-Yo]

1.98 Grundenstelig obviously seems to be not the actual MP but the kind of engine blower automatics adjustment.

[GrapeJam]

1.98 Grundenstelig obviously seems to be not the actual MP but the kind of engine blower automatics adjustment.

 

Can please clarify this further?

[Solty]

1.98 Grundenstelig obviously seems to be not the actual MP but the kind of engine blower automatics adjustment.

It is the MP that is acomplished with C3 fuel and MW50. The engine which we have in game is incapable to run it.

 

This chart is for DB605DC engine. We have in game DB605DB

That is what the main page states.

"The DCS Bf 109 K-4 is modeled with the DB 605 DB engine."

"The DB 605 DB could use B4 fuel which, with MW 50 Methanol Water injection equipment, generated an emergency power rating of 1,600 PS at 6,000 m (1,160 PS maximum continual at 6,600 m), and take-off power of 1,850 PS at 0 m, with a maximum supercharger boost of 1.8 ATA. The DB could also be run on higher octane C3 fuel, but use of MW 50 was forbidden."

http://www.digitalcombatsimulator.com/en/products/kurfurst/?PAGEN_2=3#826074

Edited January 15, 2015 by Solty

[MiloMorai]

http://www.enginehistory.org/German/daimler-benz.shtml

 

For DB605 engines

http://www.enginehistory.org/German/DB6xx/ged0110.html

 

[Friedric]

@solty . Dont do capitals its not polite and its anoying .

[Solty]

@solty . Dont do capitals its not polite and its anoying .

Wait capitals? I have not over used capital letters!!?!!?!?!?!? That is how you write names of those items. Engine is called DB605DB. It is not my fault.

 

YoYo is clearly talking about an engine that we don't have in game. Why is that so hard to understand?

Edited January 15, 2015 by Solty
Clarification!

[MiloMorai]

@solty . Don't do capitals its not polite and its annoying .

 

It is not db605dc and db605db.

[GrapeJam]

It is not db605dc and db605db.

 

But we've already shown a chart about the K4 with DB engine, it has an 22m/s at with 9-12159A prop, while the in game K4's climbing at 31m/s at SL.

[Crumpp]

The first chart is based on a plane that had different, thin bladed prop called 9-12199. "A wide-chord, three bladed VDM 9-12159A propeller of 3 m diameter was used"-DCS website. The second chart is for K4 with DB605DC engine, The DCS Bf 109 K-4 is modeled with the DB 605 DB engine.

 

The first chart is just labeled DB605D.

DB605DC and DB605DB refers to the fuel used in the engine btw. C = C3 and B = B4.....

 

The second chart does not say which propeller is used, just that both are tested. Again, you have to know what you are looking at and in this WE do not. I am not saying either chart is correct and what should be modeled.

 

Understand our variation over a mean average is even wider for climb performance than it is for level speeds. Weight and atmospheric conditions have a huge effect on climb performance.

 

Let Yo-Yo review the sources and code. If there is an issue, I am confident he will fix it.

 

Jcomm says:

I am sure the final version will be the best Bf109 K4 available in any sim, just as the p51d is the best EVER modeled Mustang in a flight simulator that I know of....

 

As much as I strive to get accuracy ( even when I am not aware what it is, specially when it comes to ww2 fighters performance because that was never my cup of tea... ) I am unable to find any of flight dynamics that offer me what DCS models do...

So... let's wait for the updates!

 

:thumbup:

[Solty]

The first chart is just labeled DB605D.

DB605DC and DB605DB refers to the fuel used in the engine btw. C = C3 and B = B4.....

 

The second chart does not say which propeller is used, just that both are tested. Again, you have to know what you are looking at and in this WE do not. I am not saying either chart is correct and what should be modeled.

 

Understand our variation over a mean average is even wider for climb performance than it is for level speeds. Weight and atmospheric conditions have a huge effect on climb performance.

 

Let Yo-Yo review the sources and code. If there is an issue, I am confident he will fix it.

 

 

 

:thumbup:

Read that again! The first chart you provided is for a different type of propelor. The second chart(which doesn't have the prop stated, because it runs with standard prop I presume) is for The DB605DC.

This one is for DB605DC. Look at the top:

 

 

The DB605DB can also run C3 fuel at 1.8 ata but without MW50, same as DB605DC can run B4 fuel. So it is irrelevant why their names varry.

 

PS: I don't want to undermine YoYo's ability to code the FM, I am just aware that one man with confusing numbers of data can loose track of what is right and what is wrong. It is clear in those all German tests posted, what versions of the plane are tested whitch type of engine is used and what power setting is used.

 

 

PS 2: The DCS site defines very strictly what type of engine we have in game and with what fuel and propeller used.

 

That is:

DB 605 DB Engine with B4 fuel, with MW 50 Methanol Water injection equipment.

"A wide-chord, three bladed VDM 9-12159A propeller of 3 m diameter was used, as on the G-6/AS, G-14/AS and G-10."

Edited January 15, 2015 by Solty
Clarification

[Yo-Yo]

About the base adjustment for 1.98 or 1.8 ata. The engine has a hydrolic transmission to the blower that was controlled with the atmospheric pressure. The adjustment of this automatics was optimised to get the most even power performance throughout the whole altitude range. As you can see 1.8 ata adjustment is more preferrable for 1.8 ata working MP, though if you allow 1.98 ata MP (C3 with MW-50) this adjustment would be insufficient to maintain 1.98 ata from 0 to 7-8 km depending on ram pressure and readjustment is required.

 

All these knees I can move on my grahps :) turning only one screw, and possibly today I am discovering America on this forum giving the explanation of 1.8/1.98 ata base adjustment. :)

Edited January 15, 2015 by Yo-Yo

[Crumpp]

The second chart(which doesn't have the prop stated, because it runs with standard prop I presume) is for The DB605DC.

This one is for DB605DC. Look at the top:

 

Which is the chart presented in this thread on what the Bf-109K4's climb rate should be in this game. You do know that? You just proved my point.

 

:smilewink:

 

 

Crumpp says:

 

Again, you have to know what you are looking at and in this WE do not.

 

Let Yo-Yo review the sources and code. If there is an issue, I am confident he will fix it.

[Solty]

About the base adjustment for 1.98 or 1.8 ata. The engine has a hydrolic transmission to the blower that was controlled with the atmospheric pressure. The adjustment of this automatics was optimised to get the most even power performance throughout the whole altitude range. As you can see 1.8 ata adjustment is more preferrable for 1.8 ata working MP, though if you allow 1.98 ata MP (C3 with MW-50) this adjustment would be insufficient to maintain 1.98 ata from 0 to 7-8 km depending on ram pressure and readjustment is required.

 

All these knees I can move on my grahps :) turning only one screw, and possibly today I am discovering America on this forum giving the explanation of 1.8/1.98 ata base adjustment. :)

But according to all the data gathered in this topic. The engine we have in game DB605DB is not able to run at 1.98ata. The only possible setting is B4+MW50 at 1.8 ata and C3 at 1.8 ata.

 

1.98 setting is only achievable in DB605DC engine with C3+MW50 setting.

 

Please tell me why do we even bother with looking at DB605DC engine's performance when it is not the engine we have in game? I beg you for clarification. It is just too confusing.

Edited January 15, 2015 by Solty

[Crumpp]

All these knees I can move on my grahps turning only one screw, and possibly today I am discovering America on this forum giving the explanation of 1.8/1.98 ata base adjustment.

 

Spiders in a jar.

 

:megalol:

 

Of course there is only harmony and community thoughts on the Russian forum.... :smartass:

[NineLine]

R

 

PS: I don't want to undermine YoYo's ability to code the FM, I am just aware that one man with confusing numbers of data can loose track of what is right and what is wrong. It is clear in those all German tests posted, what versions of the plane are tested whitch type of engine is used and what power setting is used.

 

You need to relax a little, this is Yo-Yo's day job. I dont think he is going to lose track of any numbers, at the very least he doesnt need our help to keep track, I am sure he appreciates any new data, but I think we can trust him to manage, collect, apply and test that data. If you read his post on the initial problem, it sounds like it was linked more to the data to code conversion not anything wrong with his data, but how the sim was using it...

 

Unless you have anything new to add about the issue I would ask you to stop clogging the thread up with redundancy... hard to pick out the good stuff with all the extra fluff.

[Pilum]

23 seems a little bit pessimistic. What did you presume as the L/D max, prop efficiency and jet thrust?

 

I have two different prop models in the C++ simulation: One more conventional using advance ratio J and disc loading coefficient Cp. The other uses a NACA defined propeller analysis coefficient called the propeller speed coefficient Cs.

 

However, both give simulation results that are quite similar: In the figure I posted earlier in post #27 using Cs as a base the sea level climb rate is 23.2 m/s while using Cp and I got a bit more: 23.9 m/s. I also think that 22 m/s would be on the low end given that they are based on a thin bladed propeller optimized for speed.

 

Finally, the more detailed data you asked for above I have send via PM to avoid this thread being spammed with red underlined NACA reports and ending up like the one on Spitfire longitudinal stability.:)

[Pilum]

Sorry, can't send PM: It seems your mail storage has exceeded the limit Yo-Yo ;)

[Crumpp]

You could just answer the questions Yo-Yo asked. They are reasonable and almost the exact same ones I had when I saw some of your C++ musing and noticed the results.

 

Crumpp says:

Here is the whole report from the NACA on a method of estimating propeller efficiency. You might find it useful to fine-tune your estimations to better agree with measured results.

 

Good Luck and have fun!!

 

http://forum.il2sturmovik.com/topic/6830-bf-109-g-2-climb-data/?p=126852

 

 

http://forum.il2sturmovik.com/topic/6830-bf-109-g-2-climb-data/

[julian265]

You need to relax a little, this is Yo-Yo's day job. I dont think he is going to lose track of any numbers, at the very least he doesnt need our help to keep track, I am sure he appreciates any new data, but I think we can trust him to manage, collect, apply and test that data.

 

The problem is that Yo-Yo stated that he thought 23m/s was pessimistic, which disagrees with the data in this thread. It would be nice if we knew the target performance numbers that Yo-Yo is aiming for.

[NineLine]

The problem is that Yo-Yo stated that he thought 23m/s was pessimistic, which disagrees with the data in this thread. It would be nice if we knew the target performance numbers that Yo-Yo is aiming for.

 

Well that might be a short coming of this thread, it might not contain all the available data for the 109K-4 ;)

[USARStarkey]

Well that might be a short coming of this thread, it might not contain all the available data for the 109K-4 ;)

 

If you Yo-Yo has more conclusive data, then please post it.

[NineLine]

If you Yo-Yo has more conclusive data, then please post it.

 

Why would he need to do that? Much of the research done for these aircraft was purchased, I am sure he will give information on performance like he has already, but I dont see him posting his documents, nor should he have to.

Edited January 15, 2015 by NineLine

[Hiromachi]

Why would he need to do that? Much of the research done for these aircraft was purchased, I am sure he will give information on performance like he has already, but I dont see him posting his documents, nor should he have to.

 

Well, I assume person claiming that something is not correct would have to post exactly the documents and graphs as a proof to his ... "bug report". And with all due respect Mr. SiThSpAwN but we also purchased something. Wasn't it cheap, and as a customers I assume we all expect as high as possible standards for the price we paid. For both the product and service.

Now I don't expect the scanned and dropped here documents, rather single graphs and parts or at least the titles of the sources with unit, time and place they were issued, so I could possibly find and purchase them myself.

[USARStarkey]

Why would he need to do that? Much of the research done for these aircraft was purchased, I am sure he will give information on performance like he has already, but I dont see him posting his documents, nor should he have to.

 

He can do what he wants obviously. But you cant expect anyone here to just take you guys word for it without any data to back it up. Until hard data is posted All we have is allusion to information that we cannot see. You cannot expect people to just take ED's word for it.