La5FN speculation

[Finkeren]

Interesting Brano. Since we're getting a very early series La-5FN, you're saying that it's pretty much an La-5F with a different engine?

 

Should make it a bit more of a fair fight for the German (and make it really easy to create an La-5F engine mod )

[Inkophile]

- Supercharger gear switch lever coupled with Forsazh on/off switch = when supercharger in 1st gear,forsazh is ON. When supercharger in 2nd gear,forsazh is OFF.

 

Dang, the automatic mixture regulator I had missed out on. That'll be a nice addition.

 

However the quoted section: Is that really how it is? I always understood it as that Forsazh is coupled with the supercharger in such a way that the mode cannot be enabled unless the supercharger is in 1st gear, unlike earlier engines where it can be enabled on 2nd gear as well.

[Voidhunger]

So in La5 you have to manualy press forsage when the supercharger is at stage 1.

 

In La5F there is no forsage and in La5FN forsage is automatic at supercharger stage 1. Is that correct?

[6./ZG26_Klaus_Mann]

Interesting Brano. Since we're getting a very early series La-5FN, you're saying that it's pretty much an La-5F with a different engine?

 

Should make it a bit more of a fair fight for the German (and make it really easy to create an La-5F engine mod )

We should suggest it before it hits Beta. 

[Inkophile]

In La5F there is no forsage

 

The M-82F engine (i.e. La-5F) has Forsazh as well. It just has no time-limit on how long it can be run in that mode, while the M-82 engine has a very limited duration of it before it is "clock-locked" by the engine.

[Brano]

M-82 forsazh limit was 2400rpm and 1140mmHg for 5min. 

Source: Инструкция летчику по эксплуатации самолета Ла-5 с мотором М-82,ВКАП СССР, ОБОРОНГИЗ 1942 

 

This was changed for FN engine to 2500rpm and 1200mm for 5min (or in total 6h until overhaul of the engine).Its nominal was set to 2400rpm and 1000mmHg.

Forsazh for FN engine was engaged on same lever as supercharger switch lever. Moving lever to stage 1 switched off pressure regulator RPD-1F allowing boosting engine from 1000mmHg nominal to 1200mmHg forsazh regime. To prevent this high boosting on 2nd stage of supercharger (which would lead to damage/destruction) RPD-1F was switched on with limit 1000mmHg. 1st stage forsazh on,2nd stage forsazh off.

Source: самолет Ла-5ФН  с мотором М-82ФН,описание конструкции,государственное издательство оборонной промышленности,1944

 

M-82 (111) and M-82A (112) had forsazh limited to 5-10min

M-82F had unlimited forsazh but pilot had to keep max 1000mmHg MP at 2nd supercharger gear,otherwise engine could be damaged

M-82FN had carburetors AK-82BP replaced with NB-3U injection pump and unified lever for supercharger switch with pressure regulator RPD-1F,thus preventing overboosting at 2nd stage of supercharger automatically.

[Finkeren]

Very informative Brano. I wonder why we don't have the engine damage modeled when using Forsazh in 2nd gear?

 

Obviously, it would technically be possible to run the supercharger in 1st gear above the designated switch altitude to keep access to the extra boost. However, the power gain would eventually be cancelled out with increasing altitude, because the supercharger in 1st gear wouldn't be able to keep up. At which point does the overall benefit from the forsazh disappear?

[Inkophile]

Very informative Brano. I wonder why we don't have the engine damage modeled when using Forsazh in 2nd gear?

 

Obviously, it would technically be possible to run the supercharger in 1st gear above the designated switch altitude to keep access to the extra boost. However, the power gain would eventually be cancelled out with increasing altitude, because the supercharger in 1st gear wouldn't be able to keep up. At which point does the overall benefit from the forsazh disappear?

 

There's a lot of stuff not modeled in the game, like damage to extended radiator flaps at high speeds, operation of undercarriage or wing flaps at above maximum operation speed but below maximum deployed speed, and sudden throttle input doesn't seem to do much either, at least not in a way that easily can be tested or even noticed in-game by engine sound/uneven rpm. (note I have managed to break the engine on my Yak-1B when rapidly moving the throttle back and forth, but the way this damage occurs seems very unpredictable and impossible to detect before immediate engine failure).

Edited October 9, 2017 by Inkoslav

[Voidhunger]

The M-82F engine (i.e. La-5F) has Forsazh as well. It just has no time-limit on how long it can be run in that mode, while the M-82 engine has a very limited duration of it before it is "clock-locked" by the engine.

And in game forsage is always on in the La5F or you have to switch it manualy ? because i didnt noticed difference when i pressed the forsage key.

 

Edit: dont tell me that i have to press the forsage, because i always thought the F engine is without manual forsage. I always fly without it.

Edited October 9, 2017 by Voidhunger

[II/JG17_HerrMurf]

Well then I guess it's an individual thing because I still feel let down over the 190 (and just so we're clear; I purchased the game because it included a 190).   I'm far more sceptical about the product as a result of that rather ugly little episode.  And in the main that had nothing to do with the teething problems concerning the actual quality of the model.  It was the often hostile respond to what were genuinely felt concerns that  set alarm bells ringing for me.

 

Most people who cared about the issue were, in my opinion, simply magnanimous enough to let the issue go after the decision was finally taken to fix the thing.

To be fair, that was under different leadership. Jason's guidance regarding customer service is very different and it shows in both the forum interactions and the overall product. Same creative team but vastly different response by management.

Edited October 9, 2017 by II/JG17_HerrMurf

[Inkophile]

And in game forsage is always on in the La5F or you have to switch it manualy ? because i didnt noticed difference when i pressed the forsage key.

 

Edit: dont tell me that i have to press the forsage, because i always thought the F engine is without manual forsage. I always fly without it.

 

You need to manually activate it with the boost toggle switch, and it only works below 2000 meters (works best at 1000m or lower). I really recommend being at full military power (including full rich fuel) before doing so.

Edited October 9, 2017 by Inkoslav

[[CPT]milopugdog]

Very informative stuff. Thanks all!

[JtD]

The announcement of the La-5FN got me to look through a couple of books again and I (re-)found something interesting that so far I wasn't aware of. Or I had forgotten already.

 

As you know, the colour scheme of the VVS was changed from a green camouflage to a grey camouflage in the last two years of the war. The reason for this allegedly being a faulty yellow colour pigment used in the green (yellow-blue mix), which wasn't sufficiently resistant to heat and cold and mechanical stresses. It caused cracks in the paint, that in turn negated any protective effect of the paint, exposure to rain and sun in turn weakened the underlying wooden construction, which resulted in cracks in the wooden structure, which in extreme cases caused structural failures, apparently even fatal ones, including a La-5.

 

Here I was thinking that they decided to go to grey because they liked the colour better for whichever reason, but apparently people died because of faulty paint. I'll be using grey skins from now on, just in case it is modelled.

[Finkeren]

I never heard that story JtD, interessting if true. I always just heard, that they wanted to phase out the green paint because of shortages of chromium oxide, and because the high-contrast black-on-green was too visible at close range.

 

I read somewhere, that one factory that made Yaks started using the grey-on-grey camo all the way back in 1942 where they created the two nuances by blending the standard black with the sky blue for the underside.

 

In the end the grey-on-grey pattern was just quite effective, cheap, durable and largely negated the need for special winter camouflage - you see far fewer examples of Soviet fighters with winter distemper from the last two winters of the war - so after some back-and-forth bickering in committee, it was standardized for new aircraft in July 1943.

[JtD]

Yes, I recall shortages were involved. The original green used was weather proof, but the chemical composition was changed at some point mid war, which lead to trouble. I don't even remember the book I found it in, so please don't ask me to look up the details.

 

I agree that the grey camo looks as effective if not more effective, which is why I thought that this was the sole reason for the change.

[ShamrockOneFive]

I knew pieces of that story but I've never heard it together all at once. Really quite interesting.

 

I had always thought that the change to gray had more to do with effectiveness in being difficult to spot while in the sky (rather than the green being ideal for being spotted on the ground). Almost everything military is just painted gray these days.

[Finkeren]

At longer distances grey is an effective camouflage because it doesn't stand out against any background.

 

At some point it was discovered, that to be effective, aircraft camouflage should be low-contrast, and not too dark, because planes in the air really don't have to hide amongst shadows. High contrast camouflage with dark elements are quite good for ground vehicles though, because they blend in with the shadows that are almost always present around them.

 

In the Danish Army that I am familiar with(as well as many other NATO forces IIRC) standard camouflage for ground vehicles is a black-on-green that is strikingly similar to the one used by Soviet aircraft 1941-43.

[Brano]

I never heard that story JtD...

https://forum.il2sturmovik.com/topic/24806-your-skin-suggestions-yak-1b/?view=findpost&p=382740

 

and even older one

https://forum.il2sturmovik.com/topic/20679-bos-fighters-roll-comparison/?view=findpost&p=326340

 

[Max_Damage]

I expect it to be something like 580 kmh at deck, 24 m/s boosted climb. No idea about turn rate but probably around 20 sec.

[Finkeren]

I expect it to be something like 580 kmh at deck, 24 m/s boosted climb. No idea about turn rate but probably around 20 sec.

Sustained turn even better than that, if this data sheet can be trusted:

 

http://www.wio.ru/tacftr/lag.htm

[=WH=PangolinWranglin]

I'm interested to see what the fuel consumption is like. I ran some tests with an M82F engine on Moscow Autumn at ~200 meters, with boost constantly on, and the thing sucked down ~10 (+ or - 1) Liters of fuel per minute. I wonder what the FN will do. 

[Finkeren]

Probably not a whole lot more. But if Brano is right and the very early La-5FNs still had wing tip tanks, it is not looking as bad for endurance, as I would have thought.

[Brano]

Probably not a whole lot more. But if Brano is right and the very early La-5FNs still had wing tip tanks, it is not looking as bad for endurance, as I would have thought.

Nope,La-5FN didnt have wingtip tanks. You had to read my post wrong

Fuel consumption and range of FNs strongly relied on:

- how good was your NB-3U pump. Early production suffered with quality. (But it was even worse with carburetor M-82/82F where difference could be up to 20% with the same adjustment)

- how good was your automatic mixture regulator PC-2. They used to overrich the mixture at 2nd stage of supercharger after 15-30h of work

- what rpm and MP you used. It could be anywhere between 580 - 900km    Usually for La-5FN the average range is given around 770km

EDIT:

- also depends on how much time you spend running the engine in the air and how much on the ground. During military trials of La-5FN at 32.GIAP at Bryansk front 25.5.-25.8.1943,engines had run total 782h 25min. Out of that time 636h 42min in the air and 145h 43min on the ground.

Edited October 9, 2017 by Brano

[=WH=PangolinWranglin]

 

 

Early production suffered with quality.

It'll be interesting to see what we get in game, since we don't have irregularities in our engines. I wonder if we'll get earlier or later FNs. My current guess is probably earlier models.  

[Finkeren]

 I wonder if we'll get earlier or later FNs. My current guess is probably earlier models.  

 

We get a 2nd series  FN, so it's very, very early.

[Bullets]

We get a 2nd series  FN, so it's very, very early.

 

I wonder what the decision behind that was.. fear of giving the reds something to good that the luftys would all break their keyboards?     

[LLv24_Zami]

I wonder what the decision behind that was.. fear of giving the reds something to good that the luftys would all break their keyboards?

Of course, that's what drives their decisions.

 

Nothing to do with historical accuracy for example.

[Bullets]

Of course, that's what drives their decisions.

 

Nothing to do with historical accuracy for example.

 

Twas a joke.. 

Edited October 11, 2017 by Bullets

[LLv24_Zami]

Twas a joke..

Mine too, I don't really think like that..

 

Typing with a phone so short on smileys

[Bullets]

Mine too, I don't really think like that..

 

Typing with a phone so short on smileys

 

Smileys are essential to online communication    the sarcasm in a sentence often gets lost in the cloud and doesn't get picked up on 

[Brano]

2nd series fits the time period devs want to cover in campaign.

   Ramp up of the serial production of FNs was slow,hampered by many problems with lack of and quality issues with NB3-U pumps and also sever problems with the engine itself.

During factory trial on 16.5.1943 there was a problem with burning engine due to weak tubing in fuel system. Made of stiff steel tubes it could not withstand vibrations. It just broke during the test flight and spilled fuel over exhausts. Pilot managed to land the plane,but had to abandon it quickly as the engine caught the fire and plane burned down.

   There were also problems with low assembly quality at production line of Zavod No.19. 23.7.1943 during another factory trial the engine started to smoke and disintegrated. After inspecting the wrackage it was found that cylinder nr.12 was not fastened well into its fittings. This led to catastrophic engine damage.

 

More serious problem has been found with crankshafts of one of the production batches. As a result 168 engines had to be recalled from Zavod no.21 back to Zavod no.19 and production of FNs in fact ceased in july 1943.

Forsazh was used only for 3-4min because of faulty sparkplugs ВГ-12 type. They couldnt withstand prolonged period. New ВГ-25 were urgently required by field units. Comparing to La-7 techspecs,it could run 10min on forsazh as in that time new AC-130 type plugs were available to remedy the problem.

[Bullets]

Thanks Brano great info!! 

Heres hoping in the future we could get an La7 collector plane! Externally not that different to the FN ? About as much work as creating the f2 from the f4 or g4 from g2 ? 

[Brano]

Well,it was not all fairytale with La-7 either. Moving air intakes from the top of the engine canopy into wingroots caused lot of engine seizures due to sucking up the dust during taxi and take off from field strips. Pilots preferred in that time more reliable La-5s.

[Alexmarine]

Thanks Brano great info!!

 

Heres hoping in the future we could get an La7 collector plane! Externally not that different to the FN ? About as much work as creating the f2 from the f4 or g4 from g2 ?

Keep the La-7 for the release (maybe one day) of IL-2 Battle of Berlin

[LukeFF]

 

 

Externally not that different to the FN ?

 

No

 

 

 

About as much work as creating the f2 from the f4 or g4 from g2 ? 

 

No 

[Finkeren]

Thanks Brano great info!!

 

Heres hoping in the future we could get an La7 collector plane! Externally not that different to the FN ? About as much work as creating the f2 from the f4 or g4 from g2 ?

Aside from the fact that development of the La-7 was more akin to the move from the E7 to the F2, it is also very much a late war plane, only seeing frontline action for the last 6 months of the war. There is nothing in our planeset or set of maps that is fit for the La-7.

[ShamrockOneFive]

There's a ton of changes for the La-7 that make it another jump forward for the series. Its not just an improved La-5FN but a rework of a lot of different pieces to make it even higher performing on basically the same engine. It'd be some work for the devs to be sure. IL-2: Battle of Berlin with La-7, Yak-3, Yak-9U vs Bf109K-4 and FW190D-9? Yes please :D

 

Sorry... back to the La-5FN.

Edited October 11, 2017 by ShamrockOneFive

[Bullets]

No

 

 

 

 

No 

 

Okay boss 

There's a ton of changes for the La-7 that make it another jump forward for the series. Its not just an improved La-5FN but a rework of a lot of different pieces to make it even higher performing on basically the same engine. It'd be some work for the devs to be sure. IL-2: Battle of Berlin with La-7, Yak-3, Yak-9U vs Bf109K-4 and FW190D-9? Yes please :D

 

Sorry... back to the La-5FN.

 

Phworrr that  sounds good > 

[blitze]

Oo, Oo - Battle of Berlin, do the Germans get horses to taxi to the runway with???

 

Interesting info you guys have posted on the La5 +

Good read.  Thanks.

[Livai]

Look another La-5 was under testing The La-5 M-71 (Shvetsov M-71 Engine @ 2,200hp (1,641 kW) ) was flight tested by G Mischenko from late April to early June 1943.  The aircraft was extensively tested in the autumn of 1943. In a game there are no problems with unavailability of M-71 engines in sufficient numbers and to upset the already organised process to put the plane into production. History repeats with the La-5FN again to receive the M-71 Engine same as the old La-5 received the M-82F Engine.   

 

---> The La-5 overtakes hostile fighters, albeit slowly, gets on their tails during banked turns, and in a vertical air combat always turns to get above the enemy'.  

Edited October 12, 2017 by Livai