Lavochkins beta 26.

[Tilt]

Thanks for the three tanks and the endurance modelling.


The tanks fill and empty strangely. All tanks drained thru the centre tank so it would always be full until the wing tanks had drained.

so based upon 466 litres and centre at 170 l ( wing tanks  148 each)

25% fuel would be Cen 69% and wings empty.
50% fuel would be Cen 100% and wings at 21% ea.
75% fuel would be Cen 100% and wings at 61% ea.

La's should have auto fuel forced on.

There are no wing tanks on the damage report. (yet)

Boost curves with alt.

There is a strange drop off in indicated boost during the mid teens altitude. (it may or may not be actual) If this is an attempt to show the fluctuations in power with stages of supercharger speed I applaude it.

I appreciate its difficult because there was no auto boost control.

The pilot operated the throttle in tune with the rpm and super charger speed to maintain limits.

Just to be clear.

It seems that the ASh 84 FN (V) was able to maintain 1000 milli bar boost at 2400rpm up until 4650 metres when the  super charger should be switched to is max speed (it was a two speed unit). Boost could then continue to be achieved at 1000 milli bars until approx 6100 metres (3) after which it faded presumably matching the air density degradation with altitude.

WEP 2500 rpm was advised to be used no longer than 10 mins and was able to give 1200 milli bars upto  approx 2000 metres (1)after which it faded to 1000 milli bars at approx 3300 metres  (2). Giving the same manifold pressure as could be obtained at the lower 2400rpm.

The critical  altitudes seem to be reffered to as Altitude boundries in the reports I have. I would further admit that they vary around the figures I have given based upon differing trials.

For example climbing trials seem to put the boundries lower than speed trials.......??!!

(1)-1st altitude boundary WEP
(2)-1st altitude boundary non WEP
(3)-2nd altitude boundary

I have used the speed trials figures above. The climbing trials figures I have show............

(1)- 1650metres
(2)- 2650metres
(3)- 5100metres

I would assume that air speed is the critical factor which would contribute to a higher pre booster pressure at the intake.

Whilst on the subject of AH2's lavochkins.

If/when they are re rendered will the metal frames on both forward and rear armour glass be lost............ they never had such constructions

Neither the la5 or the la7 ever had an artificial horizon instrument.

(but then they did not have auto speed/angle/level either)

[Pyro]

I had the center tank at 110 liters and ther remaining in the wing.  170/148/148 are the correct sizes?

As to the being able to manually drain the fuselage tank first, it really has no bearing and there's no reason to do that.  I can't see going through the trouble of changing the game's fuel system to stop people from doing soimething that they're not going to do anyway.

I added the wing tanks to the damage list, it'll be in the next release.

Max manifold pressure will drop when you are past critical alt.  Critical alt will also change based on your speed due to the effect of ram air on your intake pressure.

I don't understand what you're saying about the bullet proof glass.  You'll have to show me a picture.

[Tilt]

Originally posted by Pyro
I had the center tank at 110 liters and ther remaining in the wing.  170/148/148 are the correct sizes?

Yes for the 3 tank sets......... i can forward docs from home tonight.

As to the being able to manually drain the fuselage tank first, it really has no bearing and there's no reason to do that.  I can't see going through the trouble of changing the game's fuel system to stop people from doing soimething that they're not going to do anyway.

Understood....it autos as it would have now any way........any chance of always filling the centre tank or is the 25/50/75 (for all tanks) also hard coded?

I added the wing tanks to the damage list, it'll be in the next release.

Thanks

Max manifold pressure will drop when you are past critical alt.  Critical alt will also change based on your speed due to the effect of ram air on your intake pressure.

Would not have our virtual pilot have switched to 2nd supercharger speed if his speed/alt meant he was loosing max MP? Given this the MP would only die off from 1000 millibar after the 2nd critical alt (that incurred at full boost)

I don't understand what you're saying about the bullet proof glass.  You'll have to show me a picture.

See next post.

[Tilt]

The cross bars on this image are part of the rear armoured glass (just a thicker section) they are not metal straps.

The metal brackets are limited to angle clips behind the seat and a top "yoke"

A view of the top of the armoured glass can be seen here




My previous interpretation of this is below but even this has the lower brackets too high above the seat back.

Screen yellowing is common to all VVS cockpits.

[Tilt]

Presently (whilst correctly shown as differently sized) both AH lavochkins have forward armoured screens rendered showing the armour sitting in a considerable frame which supports it from inside as well as sealing it from the out side.......similar in principle to that of a spitfire...........

Infact the amount of  incockpit metal retaining the armoured screen was quite minimal.



The biggest impediment to forward viewing (by the armoured screen came when trying to look over the nose due to the sheer thickness of glass...........



the air vent is a post war Czech addition

Note. There is no internal metal work around the upper area of the armoured screen at all (but it is thick!)

We should also note how thin the general cockpit screen framework is in the forward quarter views.

[Tilt]

a quick sketch visualising the front view......... for an La7. The screen would be shorter on the La5FN.



The horizontal side bars are raised....... (infact they should also be thinner)

The armoured screen is much taller closer to the top hoop frame...

The sight fills the armoured screen and is generally higher in the cockpit and "bigger"........taller.

The frame around the armoured section is  only seen on the lower sides............. the upper edge being the "frosted effect of glass viewed thus a rough ground surface.

[Tilt]

Here is an exert from "Lavockin" by Milos Vestik  ISBN 80-902238-7-7

Its originally in Czech with translated text........ much of the data is taken from the  Historical Institute of the Czech Army (Prague) who have maintained their records of the Czech Lavochkins and still have one (White 77) at Kbely Museum Prague.

[Tilt]

Appologies for size but this describes the forward cockpit better than I .....its from the same book by  Vestsik.

I just noticed item 51!

[Tilt]

Originally posted by Pyro
I had the center tank at 110 liters and ther remaining in the wing.  170/148/148 are the correct sizes?

 

The LaGG3 had a centre tank of 110 litres plus inner (120 Litres ea) and outer (65 Litres ea) wing tanks.

This being the original "5 tank set".

Early La5's had the same set.

Latterly the set was varied. with either the outer wing tanks or the fuselage tank being removed.

Hence there seem to have been examples of La5's, La5F's and early La5FN's with............

5 tanks 480 L
4 tanks 370 L
3 tanks 350 L

In fact the tanks could be fairly easily added or removed in the "field"


With the advent of the metal sparred wing  (which permitted more space between the spars for larger inner and fuselage tanks) the tank set was changed to the later 3 tank set.

Late production La5F's and mid to late 43 La5FN's had metal sparred wings as did of course the La7.

It would be nice to think that the 170 and 2 x 148 L tanks were immediately and universally installed but this was not how Russian production was organised. If the old tanks were still available then they were used. Hence from mid to late 43 there may be a variety of  capacities based upon which factory the La5FN came out of and which tanks were still unused from stock.


eg.when Gorki was told to stop production of La5FN's in favour of La7's in May/June 44 it had such a stock of La5FN wings that production continued until October!

I think we can assume that all La7's had this 3 tank set.