Captured German La-5 flight test

[VooDoo]

 Its 6-7-8 pages of the manual.

[HoHun]

Hi Voodoo,

>"Then using supercharger second speed - do not allow manifold pressure higher than 1000 mm hg to avoid detonation..."

>Its from La-5FN manual.

Thanks! :-)

Is there anything in the manual indicating that full 1200 mm Hg can't be used in initial climb? The Tsagi climb chart seems to indicate that instead of 1850 HP, only 1725 HP were used.

Regards,

Henning (HoHun)

[HoHun]

Hi Tilt,

>this would vary  by a few hundred feet as to whether the ac was in climb or level at speed [ram effect again]

Do you have any data on the amount of altitude variation introduced by ram effect?

>but 50kgs still seems a lot even for this phenomenom.

Remember it's not really mass what we're talking about but torque. A smaller weight difference near the wing tip can suffice to provide the observed difference in scale readings. If the aircraft had wooden wings, which were subject to some weight variation, that might be the explanation we're looking for.

>I too struggle to find the diameter of the la5 prop (same as Lagg3)......I know the La7 prop. I know its longer than the la5 prop I know the gear is 120mm longer on the La7 to compensate for the longer prop.

Roger that. I've found a mention of a 3 m propeller now.

>The only dif between the FNV and the FN (that I know of) was the 2nd stage super charger speed. (other than the later addition of a true MP/RPM governor)

Do you have the actual ratios? I found it surprising to see that the Ash-82F and the Ash-82FNV have the same supercharger gear ratios according to a German document.

Regards,

Henning (HoHun)

[HoHun]

Hi Tilt,

>Do you have any data on the amount of altitude variation introduced by ram effect?

I looked at your site, and you have :-)

The data confuses me a bit. It seems the La-7 got about 1 m/s of extra climb from its larger propeller, but that the gain from ram wasn't as large for both types as I had assumed.

Regards,

Henning (HoHun)

[HoHun]

Hi again,

Looking at the Tsagi data, it seems that the La-5 gets nowhere near the same benefit from ram effect as the La-5FN or the La-7.

I assume this shows the success of the La-5FN's redesigned air intake.

What I've been unable to determine was the difference between the La-5 and the La-5F as the engine data quoted in various sources seems to be identical for the Ash-82A of the former and the Ash-82F of the latter.

However, as the Squadron/Signal book quotes the La-5 top speed as 509 km/h, I assume that this must be without the use of WEP.

Accordingly, I'd assume that the distinguishing characteristic of the La-5F with the Ash-82F was the capability to actually use WEP, which would be no surprise since the "F" stands for the Russian term used for WEP :-)

Regards,

Henning (HoHun)

[joeblogs]

Sure the latter is not the ASH-82FN? Specs on that engine are considerably better.  I think you know that already...

-Blogs

Originally posted by HoHun
Hi again,

Looking at the Tsagi data, it seems that the La-5 gets nowhere near the same benefit from ram effect as the La-5FN or the La-7.

I assume this shows the success of the La-5FN's redesigned air intake.

What I've been unable to determine was the difference between the La-5 and the La-5F as the engine data quoted in various sources seems to be identical for the Ash-82A of the former and the Ash-82F of the latter.

However, as the Squadron/Signal book quotes the La-5 top speed as 509 km/h, I assume that this must be without the use of WEP.

Accordingly, I'd assume that the distinguishing characteristic of the La-5F with the Ash-82F was the capability to actually use WEP, which would be no surprise since the "F" stands for the Russian term used for WEP :-)

Regards,

Henning (HoHun)

[VooDoo]

 Is there anything in the manual indicating that full 1200 mm Hg can't be used in initial climb? The Tsagi climb chart seems to indicate that instead of 1850 HP, only 1725 HP were used.

Regards,

Henning (HoHun)

65. At altitude of 100-150 (one hundred) meters set nominal settings if forsazh setting was used on take-off and you dont need it any more.

And some more things...

69. Dont use supercharger second speed while using take-off settings no matter of the flying altitude.

[dankes]

@HoHun

Have you found propeller types & diameters for La-5/7?

This source
source states that ViSH-105V-4 were being installed on La-7, and gives the diameter roughly as 3.1 meters. Dunno whether this will help you or not

[HoHun]

Hi Dankes,

>This source
source states that ViSH-105V-4 were being installed on La-7, and gives the diameter roughly as 3.1 meters.

Thanks! I had found ca. 3.0 m for the La-5FN, so ca. 3.1 m for the La-7 makes very good sense :-)

Regards,

Henning (HoHun)

[4510]

Originally posted by Mister Fork


It's one of the diamonds in the rough...

I don't fly the plane..
Does it have the wing slats referred to in the report?  I assume the slates are leading edge ala the 109s....

[dtango]

F4UDOA:

Great post and find.  Which board(s) are you venturing?  I had been on the allaboutwarfare boards to find info like that but with that being shutdown didn't know what other sources existed.  I'd be interested since I'm looking for some prop data.

Thanks!

Tango, XO
412th FS Braunco Mustangs

[HoHun]

Hi everyone,

Here's my current picture of Lavochkin history, picking the main versions though there were more and transient versions, too:

La-5 (ASh-82A):

- carburetor
- 1.29 ata/2400 rpm
- high rear fuselage
- 580 km/h @ 5.8 km (Tsagi chart)
- 14/17.5 m/s @ sea level (Tsagi chart, Normal/Forzash)
- 3360 kg
- introduction 9/1942

La-5F (ASh-82F):

- carburetor
- 1.36 ata/2400 rpm
- low rear fuselage
- 580 km/h/590 km/h @ 6.1 km (Tsagi charts)
- introduction 3/1943

La-5FN (ASh-82FN):

- fuel injection
- individual exhaust jets for greater thrust
- improved cowl for reduced drag
- improved air intake for greater ram effect
- improved control surfaces for better manoeuvrability
- 3290 kg
- 635 km/h/640 km/h @ 6.2 km (Tsagi charts)
- 17/22 m/s @ sea level (Tsagi charts Normal/Forzash)
- introduction: 7/1943

La-5FN (ASh-82FNV):

- different supercharger gearing (?)
- introduction: ?

La-7 (ASh-82FNV):

- improved aerodynamics for reduced drag
- improved radiator for greater effectiveness
- 3240 kg
- 675 km/h @ 6.1 km/670 @ 5.9 km/660 km/h @ 6 km (Tsagi charts)
- 17.5/22.7 m/s @ sea level (Tsagi charts Normal/Forzash)
- introduction 6/1944

I've mostly relied on Tsagi charts and on Squadron/Signal "La 5/7 Fighters in Action", as well as on what I learned here on this board :-)

Any comments? That's only a rough sketch so far.

Regards,

Henning (HoHun)

[TBolt A-10]

F4UDOA.  Great post.  

If you find one on the La-7, please share it.  I'm betting it'll say, "OMG...THE LA-7 IS UBER!  We should surrender on all fronts immediately!  So UbEr!"

[Badboy]

Originally posted by F4UDOA
Here is a report of the La-5 captured by the Germans.

The report by the Luftwaffe Test Pilot Hans-Werner Lerche, posted at the start of this thread comes from his book.

The book contains the full report posted at the start of this thread and the authors description of flying captured aircraft while at the Luftwaffe Test Centre at Rechlin, including the B-17, B-26, B-24, the P-39, P-47, P-51, the La-5 and Yak 3, and the Tempest. It is a very interesting book and an enjoyable read. It was first published in 1977 as "Testpilot and Beutefugzeugen" and the English translation is detailed below:

Book title: Luftwaffe Test Pilot, flying captured aircraft of World War 2
Author:  Hans-Werner Lerche
Published by: Jane's Publishing Company Ltd  1980
ISBN: 0 7106 0031 3

Not sure if it is still in print, I picked up my copy second hand some years ago, but the details I've posted should at least enable anyone to search the used book shelves.

Good luck...

Badboy

[TBolt A-10]

Originally posted by Karnak
Like all aircraft in AH it lacks the individual quirks such as not being able to use WEP in a climb, the poor oxogen system or the fumes in the cockpit.

Just thinking that...
1) HTC could code the LA-5 to lose WEP once the a/c is put into a climb at a given rate.
2) The La-5 pilot could start to pass out at altitudes higher than 11,000 ft. due to the lack of proper oxygen supply.

I wonder if HT has this book.  Little intricacies, like these, might make things interesting in AH2.