La5FN speculation

[Wulf]

Hmmmm ... okay some interesting, and in some instances quite imaginative, speculative comments on the subject of La-5 FN fuel tanks.

 

Gordon and Khazanov state the following in their book Soviet Combat Aircraft of the Second World War, Volume One

 

"The fuel system was altered to use three fuel tanks instead of five, reducing fuel capacity from 118.5 to 102 gallons and eliminating the wingtip tanks which hampered manoeuvrability."

 

These comments are made after an extensive discussion of the alterations that were made to the aircraft to reduce its overall weight.

Edited October 7, 2017 by Wulf

[Finkeren]

I have read that book, but I didn't remember that the reduction in fuel load was that small.

 

I mean 14% is still something, but I thought it was more like 25%.

[JtD]

The central tank and the inner wing tanks were enlarged considerably. That was also possible because of the reconstruction of the wing, metal wing spars needing a lot less space than wooden ones. Originally, the outer tanks held about 200 of the 540l on board a La(GG).

Edited October 7, 2017 by JtD

[Irgendjemand]

Well that would be an obvious and shocking piece of cynical manipulation.  People have been complaining for years that the La-5 rolls too fast and those people have been dismissed and ignored.  How could the devs turn around now and correct things without losing credibility?  I don't think they can.  Once you set this sort of thing in motion you're stuck with the consequences.  Either you release an uber monster and look foolish or you make last minute corrections to the La-5 and look foolish. 

Haha, well put.

[JtD]

Well, I think anyone who re-evaluates his work and makes changes for the better, is not foolish at all.

 

As opposed to some individuals on these forums.

[Willy__]

 

 

Well, I think anyone who re-evaluates his work and makes changes for the better, is not foolish at all.

 

 

You missed the point he made. 

[-=PHX=-SuperEtendard]

Control linkage however can make an extreme difference. Not only was the aileron range changed from 49° to 36°, meaning a significantly improved roll rate at high speed at the expense of low speed roll rate. Linkage can also completely change roll behaviour by stiffness and friction properties. Frise aileron characteristics as used on the La are extremely dependent on the cross connection between left and right.

 

Is there a way to predict/model how much the increase would be? Being this a 1943 series it would still have the wooden wingspars iirc?

Edited October 7, 2017 by -=PHX=-SuperEtendard

[JtD]

If only the gearing was changed to reduce the total angle from 49° to 36° then rough estimates could be made. It could be treated as a linear relationship, where low speed roll rate would decrease by 25% (less aileron angle) and high speed roll rate increase by the same amount (better leverage = more aileron angle). Peak roll rate would be achieved at indicated air speeds of ~550km/h instead of the ~400km/h we have on the La-5. Ballpark. Trend. Simple answer.

 

But already there the difficulties of Frise ailerons come in, because the relationship of control forces over aileron angle is not linear, and neither is the relationship of rolling moment over aileron angle. As a general trend, control forces increase progressively at some point, meaning high speed roll on the La-5FN could even be better. At the same time, rolling moment at some point increases less than linear, because the ailerons stall. Meaning low speed roll might not suffer as much.

 

All in all, if based on the La-5 we have and simply extrapolated, 5FN high speed rolling performance would be the best of any WW2 fighter I've ever seen a figure for, and low speed roll still very good. I consider this highly unlikely. But with Frise ailerons being as delicate as they are, I would need to see actual, detailed La-5 or La-5FN test data to prove the point. I've tried without, but there are just too many unknowns when working from the general principles and calculations.

[Flitgun]

I think that this is 100% speculation and wish to nerf red planes. initoal roll rate topic mentions p40 roll rate and then the conclusion comes: i16 and la5 roll too well :D

 

You mean those arguing the present La5 roll rate is too uber are 100% speculating? I think that is what you mean.

 

Some of it sounds plausible, in my opinion, to be fair. But, I'd like to see the evidence that the present roll rate is based on the FN. Without that, all this about uberness is just waffle as far as I'm concerned.

 

And even if I do see it, I'm just going to shrug lol. It's all a bit finicky.

 

I really do look forward to an La5FN - rock on with that devs!

[6./ZG26_Klaus_Mann]

The High Speed Roll of the early Lavochkins is too high. Clearly. But at low Speeds they should be quite good, although not supremely agile. 

[Haza]

Well that would be an obvious and shocking piece of cynical manipulation.  People have been complaining for years that the La-5 rolls too fast and those people have been dismissed and ignored.  How could the devs turn around now and correct things without losing credibility?  I don't think they can.  Once you set this sort of thing in motion you're stuck with the consequences.  Either you release an uber monster and look foolish or you make last minute corrections to the La-5 and look foolish. 

 

Wulf,

 

I tend to disagree here.  The FW190 was re-modeled and I do not think anybody lost credibility nor were they stuck with the consequences as this has all now been forgotten, as we now move onto the next thing to moan and complain about. 

I for one care little about developers looking foolish, however, I care that they try and do things correctly and as accurately as possible. Surely making a PC game based on sometimes incomplete data etc for airframes that are older than my Father can be hit and miss.

Or perhaps I'm the foolish one for having faith in the game and for buying everything

 

Regards

[Wulf]

You mean those arguing the present La5 roll rate is too uber are 100% speculating? I think that is what you mean.

 

Some of it sounds plausible, in my opinion, to be fair. But, I'd like to see the evidence that the present roll rate is based on the FN. Without that, all this about uberness is just waffle as far as I'm concerned.

 

And even if I do see it, I'm just going to shrug lol. It's all a bit finicky.

 

I really do look forward to an La5FN - rock on with that devs!

 

 

I had an email exchange with Han.  He said they based the La-5 roll rate on the German flight test data for the La-5 FN.

[Boaty-McBoatface]

Where is the proof that the current series 8 la5 aileron performance is in fact that of an la5FN?

 

Wulf, all this gossip- could we please be shown proof? It's about time.

 

We need to know if our current la5 is actually a series 39 ailerons performance, and if so it needs to be fixed.

Edited October 8, 2017 by Boaty_McBoatFace

[Wulf]

Wulf,

 

I tend to disagree here.  The FW190 was re-modeled and I do not think anybody lost credibility nor were they stuck with the consequences as this has all now been forgotten, as we now move onto the next thing to moan and complain about. 

I for one care little about developers looking foolish, however, I care that they try and do things correctly and as accurately as possible. Surely making a PC game based on sometimes incomplete data etc for airframes that are older than my Father can be hit and miss.

Or perhaps I'm the foolish one for having faith in the game and for buying everything

 

Regards

 

 

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.

[Haza]

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.

 

Wulf,

 

Yes, I think that we get that you feel let down and I for one expected you to be a sceptic from all your previous posts.  However, I think that we can talk about the hostile replies from both sides, however, the fact remains that something was done, although perhaps not as quickly as people might have wanted or liked! 

 

I notice that you mention that you had a reply from Hans regarding the roll rates of the different La-5 models (or at least one being modeled on another version) and therefore would expect this to be actioned accordingly to ensure historically accuracy as perhaps you have provided information to Hans regarding fuel tanks etc, that might cause this issue to be addressed.  However, asking for something to be done, yet in the same breath mentioning developers being seen to be foolish if they did or foolish if they didn't, I'm not really sure what you exactly want? 

 

I guess 'Caveat emptor' might be used here, although thankfully something appears to be always sorted in the end and I'm sure you can't say that is not the case, although perhaps not in the time-frame(s) you or others would like.  I'm sure that no sim in the world can be as accurate as the real thing and I for one do not believe that this flight sim is the real thing!  However, If anything I have seen from this team, is that they will make changes to ensure that this game is as accurate as possible, so perhaps we should just wait and see what happens and provide what ever evidence that we have to assist them with this task.

 

Regards  

[Wulf]

Where is the proof that the current series 8 la5 aileron performance is in fact that of an la5FN?

 

Wulf, all this gossip- could we please be shown proof? It's about time.

 

We need to know if our current la5 is actually a series 39 ailerons performance, and if so it needs to be fixed.

 

 

My understanding is that the German roll rate data for the La-5 FN is the only stuff available i.e. there are no known sources of data for the rolling performance of a bog standard La-5. 

[Haza]

Gents,

 

Does anybody own this book or able to comment on whether it is worth buying, before I purchase?

 

 

https://www.bookdepository.com/Lavochkin-Fighters-Second-World-War-Jason-Nicholas-Moore/9781781555149

 

 

 

In addition, anybody own the following book as it is no longer available but I would be happy to discuss a price.

 

https://www.bookdepository.com/Lavochkins-Pistonengined-Fighters-Yefim-Gordon/9781857801514?ref=grid-view&qid=1507432708781&sr=1-2

 

 

Regards and Thank you.

Edited October 8, 2017 by Haza

[II/JG17_HerrMurf]

The last time I saw this discussed (over a year ago - could be foggy) I thought the answer was the La-5 data was EXTRAPOLTED from German sources on the -5FN. Not simply transposed. That leaves a lot of wiggle room in the interpretation for the sim regardless of your perspective on the current model in game.

[Boaty-McBoatface]

My understanding is that the German roll rate data for the La-5 FN is the only stuff available i.e. there are no known sources of data for the rolling performance of a bog standard La-5.

So the la5FN can roll at 450kmh in under 4 seconds and has tremendous aileron efficiency, as mentioned in the German test report.

 

This is understandable as the large ailerons make for over 8 percent of wing surface area and it has a shorter wingspan than FW190 (which has better initial roll acceleration response with the larger wingspan and wing area) However it definitely doesn't seem to roll as well as FW190 at high speeds above 500,600.

 

Perhaps we can expect the la5FN to roll better than current la5 series 8 at higher speeds and slightly slower at lower speeds, since the aileron deflection was reduced on the FN (series 39).

Edited October 8, 2017 by Boaty_McBoatFace

[JtD]

The effective aileron area on the La is just 6% of the wing area, you'd need to include the aerodynamic balance to get to 8%. But typically you don't, because the balance is hidden inside the wing and does little for rolling. It does quite a bit for reducing control forces.

For comparison, the effective aileron area on the Fw190 was 7.5% of the wing area, 10.5% including aerodynamic balance. Enough to compensate the slightly larger wingspan, but not enough to compensate the larger maximum aileron angles used on the La-5.

[Finkeren]

It's not just about wingspan but about the shape of the wing as well. The design used on all Soviet fighters of the era with relatively stubby wings that are very broad at the wing root and pointy at the tip does lend itself to a higher roll rate (though the main reason for that design probably was to reduce induced drag at low speeds)

 

The squared-off wings of the Fw 190 on the other hand is not really ideal, and I think it is testament to just how well-engineered the 190 was that it rolled as well as it did.

[Boaty-McBoatface]

Jtd, do you agree that the LA5 series 39 will probably roll slightly slower at low speeds and better at high speeds than our current series 8?

 

It seems all the hype is surrounding the la5 FN roll rate. Personally I don't see it as being all too different to our current LA5, given it's the same aileron surface area, same wingspan, more or less same rolling moment of inertia, same stick length.

Edited October 8, 2017 by Boaty_McBoatFace

[Boaty-McBoatface]

 

The squared-off wings of the Fw 190 on the other hand is not really ideal, and I think it is testament to just how well-engineered the 190 was that it rolled as well as it did.

Why do you think that? Emil model 109 undoubtedly had better roll rate, with ailerons nearly right up to the tip of wingspan for better rolling moment.

[JtD]

It's not just about wingspan but about the shape of the wing as well. The design used on all Soviet fighters of the era with relatively stubby wings that are very broad at the wing root and pointy at the tip does lend itself to a higher roll rate (though the main reason for that design probably was to reduce induced drag at low speeds) The squared-off wings of the Fw 190 on the other hand is not really ideal, and I think it is testament to just how well-engineered the 190 was that it rolled as well as it did.

Various wing shapes were tried in wind tunnels and it was found that aspect ratio (stubby or long wings) and taper ratio (square or pointy wings) did not really matter.

 

What mattered most when it came to basic geometry was aileron size relative to the wing (spanwise and chordwise distribution) and total wing span.

 

If you have a source that confirms your statements about the wing shapes, please share it, I'd really like to know origin and context.

 

As for the particularities of the Fw190 ailerons - they were extremely efficient. Confirmed both by NACA and by German testing. Definitely well engineered, top of the class, 10%-20% better than the average competition. Unfortunately, there's no comparison with the La.

 

Jtd, do you agree that the LA5 series 39 will probably roll slightly slower at low speeds and better at high speeds than our current series 8?

Yes, see post #88. The La-5 right now is better than the Fw190 at low speeds, the La-5FN would probably be just worse, but due to the changed gearing, the high speed roll rate would be extremely high if extrapolated straight from the current La.

Edited October 8, 2017 by JtD

[56RAF_Roblex]

I wonder if people are making an error of logic?   They say that the devs have admitted to using the La5FN roll rate when building the original La5 and have taken that to mean they gave the old La5 the *same* roll rate as a FN.   Perhaps they just said 'If the FN rolls this fast and was said to be 10% faster than the old model at X altitude then we will make the old model 0.91% slower than an FN at X altitude'     

 

As for not being able to correct the old La5 without looking inept.   Have they not changed several FMs eg P40, without anyone thinking they are covering up something dodgy?

[=ARTOA=Bombenleger]

So people think because the roll rate of the La5 is based on the FN, they will make the roll rate of the FN better than it was according to their sources?
Thats ridiculous, the worst case scenario is that we have an La5 that rolls better than it should and thats because of missing sources not because of devs that dont give a shit. 
I agree devs have sometimes overreacted to cristicism, but in the end they improve things and they add things and exceed expectations in reagrds to quality and quantity.
All that being said I dont understand the reason for people freaking out over tha La5FN, we have no reason to believe that the plane will be uber, because it seems that there are reiable sources and the ability and willingness of the devs to delliver the absolutely best product possible can hardly be doubted anymore.

[Boaty-McBoatface]

So people think because the roll rate of the La5 is based on the FN, they will make the roll rate of the FN better than it was according to their sources?

Thats ridiculous, the worst case scenario is that we have an La5 that rolls better than it should and thats because of missing sources not because of devs that dont give a shit.

I agree devs have sometimes overreacted to cristicism, but in the end they improve things and they add things and exceed expectations in reagrds to quality and quantity.

All that being said I dont understand the reason for people freaking out over tha La5FN, we have no reason to believe that the plane will be uber, because it seems that there are reiable sources and the ability and willingness of the devs to delliver the absolutely best product possible can hardly be doubted anymore.

Yes but believe it or not- without mentioning names of individuals or groups, to this day, despite the communication and update diary entries from the developers, there is rampant Luftwankery that will only accept inferior performance to their beloved 109 Hartmann machines.

 

That's just the way it is and unfortunately these individuals will insist until the end of time that they kill the enemy with impunity.

Edited October 8, 2017 by Boaty_McBoatFace

[Wulf]

Yes but believe it or not- without mentioning names of individuals or groups, to this day, despite the communication and update diary entries from the developers, there is rampant Luftwankery that will only accept inferior performance to their beloved 109 Hartmann machines.

 

That's just the way it is and unfortunately these individuals will insist until the end of time that they kill the enemy with impunity.

 

 

Well, if you want to terminate a conversation around here that's as good a way as any I guess. 

[6./ZG26_Klaus_Mann]

[CanadaOne]

Kitties are nice.

[Wulf]

 

 

So what's happening to you out of frame Klaus?   You appear to be in pain.

[6./ZG26_Klaus_Mann]

So what's happening to you out of frame Klaus?   You appear to be in pain.

It serves as distractionary Pain from the La-5 guys turning into the 190 and P-51 sort of Luncatics. 

[Flitgun]

Well, if you want to terminate a conversation around here that's as good a way as any I guess. 

 

Another way of terminating a conversation would be saying something along the lines of: 'The La5 has uber roll rate; I know this because someone told me in an email, which I'm not showing you'.

[6./ZG26_Klaus_Mann]

Another way of terminating a conversation would be saying something along the lines of: 'The La5 has uber roll rate; I know this because someone told me in an email, which I'm not showing you'.

 

But Rabbits are a way cuter way. And mine are the best. 

 

Or how about Sir Patrick Stewart.

 

Edited October 8, 2017 by 6./ZG26_Klaus-Mann

[[CPT]milopugdog]

Hi, I like flying the La-5, and I have a few questions about the FN.

 

Do any of you know if the FN engine has any automation over the normal one?

How would the other Allied fighters in BoK such as the Yak-7, Yak-1, P-39, and Spitfire perform (roughly) in comparison to it?

Is the construction all metal, or just more metal than the current one we have in game?

[Inkophile]

It will be operated i the exact same way as the current M-82/M-82F engines are. The only notable difference is its increase in power through direct fuel-injection.

 

Not even the La-7 which was planned to have much more engine automation - inspired by the Fw 190's Kommandogerät, the more simple automation in the 109s, and from lend-lease planes - was scrapped in favour of production numbers, so that factories wouldn't have to be re-tooled even more and more complex moments added to the production cycle.

Edited October 8, 2017 by Inkoslav

[6./ZG26_Klaus_Mann]

Hi, I like flying the La-5, and I have a few questions about the FN.

 

Do any of you know if the FN engine has any automation over the normal one?

How would the other Allied fighters in BoK such as the Yak-7, Yak-1, P-39, and Spitfire perform (roughly) in comparison to it?

Is the construction all metal, or just more metal than the current one we have in game?

It's Fuel Injected, so it may not require a Mixture. Cowlings should still be all Manual. 

 

Our FN is a very early series, the first Production with the FN Engine, and mostly unchanged over the F. The Metal Wings appeared shortly before the Introduction of the La-7 in 44. 

So ours will still be all Wood. 

 

It's Speed on the Ground will be very Good, Performance above 2000m just about average, fast, but feels home below that. 

Against the Yak-1b, well it is generally better than it everywhere in pretty much ever way except Turn Radius expectedly, but that is for all Soviet Fighter Types. 

 

I guess, similary to the Yak-1s Top Speed Adjustment (It became 10kph slower) when the Yak-1b came, the current La-5 will get a different Roll Behaviour, better at Low Speeds, worse at high. 

Don't underestimate the Yak-7 though. It will be a very good Aircraft. 

 

What I don't understand is why they didn't make a Combination La-5F&FN as a late series F and an early FN. 

Edited October 8, 2017 by 6./ZG26_Klaus-Mann

[Boaty-McBoatface]

I guess, similary to the Yak-1s Top Speed Adjustment (It became 10kph slower) when the Yak-1b came, the current La-5 will get a different Roll Behaviour, better at Low Speeds, worse at high.

 

Klaus,

 

I didn't think Yak speed was changed- I thought Yak 69 was always 514kmh? You're saying it used to be 524kmh, basically as fast as a 109?

 

You think after all the work over the past several months for the FM overhaul that they need to change their roll behaviour of series 8 LA5 again?

 

Personally I'm not sure if that's going to happen. They put in a lot of research and work for those changes already.

 

Regards

Edited October 8, 2017 by Boaty_McBoatFace

[6./ZG26_Klaus_Mann]

Klaus,

 

I didn't think Yak speed was changed- I thought Yak 69 was always 514kmh? You're saying it used to be 524kmh, basically as fast as a 109?

 

You think after all the work over the past several months for the FM overhaul that they need to change their roll behaviour of series 8 LA5 again?

 

Personally I'm not sure if that's going to happen. They put in a lot of research and work for those changes already.

 

Regards

Yep, check the old Changelogs. Effective Combat Speed dropped by a lot, pretty much 500 on the Deck Continuously. Used to be much higher.

 

Well, we shall see, and I shall stand uncorrected. 

Edited October 8, 2017 by 6./ZG26_Klaus-Mann

[Brano]

Hi, I like flying the La-5, and I have a few questions about the FN.

 

Do any of you know if the FN engine has any automation over the normal one?

How would the other Allied fighters in BoK such as the Yak-7, Yak-1, P-39, and Spitfire perform (roughly) in comparison to it?

Is the construction all metal, or just more metal than the current one we have in game?

Difference ASh 82 FN engine vs M-82/82F:

- vysotnyi korrektor (mixture) has been removed and replaced by automatic regulator PC-2 (RS-2)

- 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.

 

Danil wrote that our La-5FN will be of 2. series = wing is still with wooden longerons.

 

As JtD mentioned,change from 5 fuel tanks to 3 fuel tanks was 536l to 464l. One of my sources gives info that wingtips tanks were removed onType 37 from 9th series. Technical description didnt mention it specificaly.

Fuselage and centroplane tanks comparison: 

Type 37 till 8th series:

Fuselage tank....110l

Centroplan tanks L/R....115l/115l

Wingtip tanks L/R....98l/98l

 

Type 37 from 9th series,Type 39 and Type 41:

Fuselage tank....168l

Centroplan tanks L/R....148l/148l

 

What technical description mentions specificly,is that ailerons movement range has been changed from Type 37 9.series. From +24°/-25° to +18°/-18° (with tolerance range of 1°)