Alpha-sensor in exhaust of Klimov M-105 - a standard feature

[Kari Lumppio]

Hello!

In the book about bombers used by Finnish Air Force (Jukka Raunio: Lentäjän näkökulma IV, ISBN 951-96866-2-2) it is mentioned that for leaning purposes (IIRC) Pe-2 engine had alpha sensors in exhaust channels. The sensors measure CO (carbon monoxide) amount and were apparently used for getting the fuel/air mixture right.

Was these sensors standard feature of Klimov M-105 engine? Or were those found only on bombers (=Pe-2)? I guess they were legacy from Pe-2 intended orginal career of high altitude interceptor. Does anyone know?

BTW How did the auto-lean function work on US radial engines? Did it use any sensors on exhaust channels? As I understood it on the M-105 leaning had to be performed by the pilot manually.


Cheers,
Kari



(PS I am not usually that interested in motor technology, but the lambda-sensor of my car broke down and the topic of older technology - alpha sensor - sort of popped out when I tried to find info about lambda-sensors on Internet...)

[Christer Bergström]

Jukka, I can confirm that my Rex Comet Cross moped (very small motor cycle) was equipped with such a manual device back in 1975. Although my Rex was more modern than the Soviet WW II fighters, it had no M-105 engine. 8)
(Too lazy to mention any source. . .)

This was the fateful year when I chose to spend the whole summer with a pretty girl, and turned down Adolf Galland's invitation from the previous year - "nächstes Mal fliegen wir"! I found that girl to be more pretty than Adolf Galland. And as a matter of fact, I still think she was. 8) 8)


Check out a photo from those days - the second photo from above:

http://www.bergstrombooks.elknet.pl/bc-rs/veterans.htm

However, there will be no photo of the girl in question, only Galland and me.

[John Beaman]

...love the 70's clothes in the photo. That would bring big bucks from the "retro" teenagers in the US!

[Jukka Juutinen]

Kari, I will have to check my sources but IIRC US Bendix pressure carburettor mixture control measured both manifold pressure and manifold air temperature to determine mixture ratio. Auto-lean and auto-rich positions had different sized main jets, i.e. moving from auto-lean to auto-rich meant an abrupt enrichment of the mixture. Full rich position had IIRC similar sized main jet as the auto-rich but had no altitude compensation. A sort of crude "limping back home" design.

As for the alpha sensors, doesn´t Raunio mention that at least the SB has similar system and perhaps the DB-3 as well?

[Juha]

hello Kari
I happened to read an article in an old AM (3/02) and it's database is on LaGG-3 and there is a reprint of an article originally published in the technical magazine Aircraft Engineering in Oct. 1943, based on reports from Sweden on the trials of the trio of LaGG-3s captured and tested by Finns. So, not the best possible source (maybe one can find the original evaluation report from Sota-arkisto). But even if there is much info on different systems, for. ex. one learns that M-105P had 3 valves per cylinder and 6 carburettors, pressure type and the use of cooled and filtered exhaust gases to reduce fire risk is descrbted, there is no mention of an Alpha-sensor in exhaust of Klimov.

Jukka, You asked on one board the effect of radiator flap on P-51s max speed. I have no answer on that but in early LaGG-3s the effect of its radiator flap, which effects surely are nearer of that of P-51's flap than those of Bf 109G's, was appr. 14km/t, that's from Gordon's and Khazanov's book, which You probably had but maybe You have missed that piece of info.

HTH
Juha

[Jukka Juutinen]

Juha, I have the G&H book you mention and I did indeed miss that data. BTW, didn´t Raunio write a tech article on the Lagg-3 using that Finnish report for Ilmailu in 1990? I think I do have that mag somewhere.

BTW, those 6 carbs were diaphragm type carbs, a bit similar as used in chainsaws (no negativism intented), i.e. they can operate regardless of g.