Klimov VK-107 - help needed
- Thread starter Piper106
- Start date
Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules
jerryw
Airman 1st Class
Another great photo, Alain. What is that structure at the front of the engine in the centre, labelled "o" or "d"??
Above is a photo from the Kotelnikov book. The caption says it is VK-105 but there appears to be SEVEN exhaust ports along the side which seems to suggest it is a VK-107. Is the caption an error??
Yes, JerryW, there are seven exhaust ports and just lower you see obviously more than THREE inlet tubes. The first one (black), as far as I can see, has no carburettor... This engine is a VK-107 and caption is faulty.
And the "o" or "d" structure is unknown for me, sorry...
But... Happy new year !
Alain
And the "o" or "d" structure is unknown for me, sorry...
But... Happy new year !
Alain
lostfighters
Recruit
- 2
- Jul 13, 2013
Hello All who posted here, very interesting information
I have attached two images of a VK 107 which you will see confirms most of the posts, but not all as it only has six exhaust pipes.
Dave
I have attached two images of a VK 107 which you will see confirms most of the posts, but not all as it only has six exhaust pipes.
Dave
Thanks for these very interesting pictures...
I am sorry but I see (on right cylinder bank, back to front) :
- One free outer exhaust port = one MISSING outer exhaust pipe
- Five outer exhaust pipes
- One inner exhaust manifold with one exhaust pipe bent over (partially sourrounding propeller shaft casing)
Total, SEVEN outer pipes !
Regards,
Alain
I am sorry but I see (on right cylinder bank, back to front) :
- One free outer exhaust port = one MISSING outer exhaust pipe
- Five outer exhaust pipes
- One inner exhaust manifold with one exhaust pipe bent over (partially sourrounding propeller shaft casing)
Total, SEVEN outer pipes !
Regards,
Alain
lostfighters
Recruit
- 2
- Jul 13, 2013
Hi Alain,
Thank you for correcting my ignorance, i was totally missing the inner exhaust manifold.
Total seven outer pipes.
Regards
Dave
Thank you for correcting my ignorance, i was totally missing the inner exhaust manifold.
Total seven outer pipes.
Regards
Dave
vikingBerserker
Lieutenant General
Great pics Dave, and welcome aboard.
WJPearce
Airman 1st Class
I know this is an old post, but I have been doing some research that involves the VK-108 engine, and I think I have figured out the valve/camshaft arrangement.
The VK-107, VK-108, and VK-109 engines did not have two valves on the outer side of the cylinder bank and two on the Vee side. Rather, that arrangement was rotated 45 degrees so that one exhaust valve was positioned on the outer side of the engine and the other exhaust valve was on the Vee side. The two intake valves were positioned between the exhaust valves and on the cylinder's centerline.
A single overhead camshaft was used with three lobes for each cylinder. The center lobe acted on a follower that actuated both exhaust valves. One of the other lobes actuated the fresh air valve, and the last lobe actuated the air/fuel mixture valve. This arrangement allowed for the completely different valve timing and duration of the two intake valves.
I arrived at this arrangement because:
1) The engine's valve covers are two small to accommodate more than one camshaft.
2) The exhaust ports on both the outer and Vee sides of the engine appear evenly spaced.
3) It would simplify the camshaft action while allowing three different timings of four valves.
4) It would simplify the cylinder head casting.
5) It builds on experience; the intake valve action on the VK-105 is the same as the exhaust valve action on the VK-107, VK-108, and VK-109.
I liked Bretoal's drawing so much that I decided to try and make one of my own to explain what I'm talking about.
The VK-107, VK-108, and VK-109 engines did not have two valves on the outer side of the cylinder bank and two on the Vee side. Rather, that arrangement was rotated 45 degrees so that one exhaust valve was positioned on the outer side of the engine and the other exhaust valve was on the Vee side. The two intake valves were positioned between the exhaust valves and on the cylinder's centerline.
A single overhead camshaft was used with three lobes for each cylinder. The center lobe acted on a follower that actuated both exhaust valves. One of the other lobes actuated the fresh air valve, and the last lobe actuated the air/fuel mixture valve. This arrangement allowed for the completely different valve timing and duration of the two intake valves.
I arrived at this arrangement because:
1) The engine's valve covers are two small to accommodate more than one camshaft.
2) The exhaust ports on both the outer and Vee sides of the engine appear evenly spaced.
3) It would simplify the camshaft action while allowing three different timings of four valves.
4) It would simplify the cylinder head casting.
5) It builds on experience; the intake valve action on the VK-105 is the same as the exhaust valve action on the VK-107, VK-108, and VK-109.
I liked Bretoal's drawing so much that I decided to try and make one of my own to explain what I'm talking about.
GregP
Major
So it looks like the yellow circle in the pic was a crankcase vent.
GreP, not a crankcase vent, but a bearing cooling system.
Please read patent !
Regards
Alain
WJPearce
Airman 1st Class
I found two pictures that I think confirm my VK-107 (etc) valve and valve train suspicions. The single camshaft is obvious as well as the three lobes per cylinder. I think you can also see the middle valves have a follower and are positioned on the sides of the cylinder. These middle valves line up with the exhaust ports. The pictures are of a VK-107 but i think the VK-108 and VK-109 would be the same.
First image is from ??-107 ?.?. ???????:
Close up, and I think you can see the valve arrangement here:
Second image is from ????? ????? www.airforce.ru: ??????:
Close up, and I think you can see the much more rounded lobe for the air only valve on the second cylinder from the left. The first lobe of the second cylinder is the air/fuel valve and the third lobe would be the air only valve. The more rounded lobe would hold the valve open longer:
First image is from ??-107 ?.?. ???????:
Close up, and I think you can see the valve arrangement here:
Second image is from ????? ????? www.airforce.ru: ??????:
Close up, and I think you can see the much more rounded lobe for the air only valve on the second cylinder from the left. The first lobe of the second cylinder is the air/fuel valve and the third lobe would be the air only valve. The more rounded lobe would hold the valve open longer:
I've looked and looked for pictures of the vk-107 like those ones and been unsuccessful, so it's nice to see how the valvetrain works. I'm now starting to wonder something: How radical must the valve timing have been? jerryw stated that the air valve opened 65 deg. before the fuel-air valve and closed 82 deg. later than the fuel-air valve, but those numbers alone would mean that the air valve would be open for a ridiculous amount of time if the fuel-air valve had timing specs anywhere close to something like the M-105. So does this mean that the fuel-air valve is only open for a short time? WJPearce, I want to know what you think seeing as you are a fountain of knowledge on engines.
Last edited:
WJPearce
Airman 1st Class
Thank you for the kind words camman, but I can only admit to being an amateur enthusiast. Still, I will outline my best guess below.
Most engines have a certain amount of overlap, where both intake and exhaust valves are open. While this is nice to help push out all the exhaust gases, it also lets fuel flow out the exhaust without ever being burned. With port or cylinder fuel injected engines, the overlap can be increased because only air is coming through the intake valves, not fuel.
The info jerryw posted came from Manuel Lage's book "Hispano Suiza in Aeronautics." The book was originally written in Spanish, then translated to English. Something could have been lost in the translation. The book states the air only intake valve opened 65 degrees before and closed 82 degrees after the air/fuel intake valve.
Below is the valve timing for the M-105/VK-105 engine from your post about valve timing.
Klimov M-105 (@0.078")
Int. open 10 deg. before TDC
Int. close 60 deg. after BDC
Int. duration: 250 deg.
Exh. open 60 deg. before BDC
Exh. close 20 deg. after TDC
Exh. duration: 260 deg.
Overlap: 30 deg.
Lift: 13mm (.511 in)
LSA: 112.5 deg.
ICL: 115 deg.
This engine has a 30 degree overlap. Many fuel injected engines on your list have an overlap of 110 degrees or so.
The VK-107+ engines are acting a bit like a fuel injected engine. Adding 65 degrees to the 30 degree overlap would give 95 degrees of overlap. I think that is reasonable considering that it is just air entering the cylinder.
The intake duration is listed as 250 degrees for the M-105. Taking that and adding 65 plus 82 would give a duration of 397 degrees for the air only valve on the VK-107+ engines. That seems a little ridiculous to me, and I do not know why one would want the air valve to close 82 degrees after the other intake valve.
I think the air/fuel valve could have opened for less than 250 degrees, since it could be a very fuel-rich mixture. Since these engines had 1100+ mm Hg (21+ psi / 73+ inHg) of boost, it would not take long to charge the cylinder. But I still don't understand why it would close 82 degrees after the other intake valve.
Here is where things fall apart. Could it be a typo? Maybe 28 degrees rather than 82? Could it be that the air valve opens 65 degrees before the other intake valve and 82 degrees before the EXHAUST valves CLOSE? It would have an 82 degree overlap while the air/fuel valve would have only 17 degrees. That seems reasonable to me.
Sadly, we can come up with a bunch of different plausible scenarios and be no closer to reality.
What I think I see in the pictures is an air valve that opens significantly sooner that the air/fuel valve. The air/fuel lobe appears to have a relatively sharp point, while the air only lobe is very blunt. So, the air/fuel valve has a much shorter duration of being open than the air only valve. But the closing of the intake valves seems pretty close. The exhaust lobe also appears to be less sharp than the air/fuel valve.
I think the air only valve could have opened 65 degrees before the air/fuel intake valve. I think the air/fuel intake valve might have had an open duration of less than 250 degrees (but maybe not). I think the air valve closed after the air/fuel valve, but only by a little (maybe 28 degrees).
I have labeled the close up pictures of the VK-107 valve train. Look at the lobe difference between the air and air/fuel lobes. Look at how they appear to close about the same time. Compare the size of the exhaust lobe to the air and air/fuel lobes.
Of course, all this is speculative based on some grainy images and something written about a Soviet engine in Spanish then translated to English. We might need to go to Russia to figure this out.
GregP
Major
Hey Tomo,
Reference post # 5. I can see the rating is 1650, but I am doubtful the units are horsepower since the Soviet Union was metric. Can you tell me what the units are?
ps? cv? or some internal Soviet unit?
Thanks!
Reference post # 5. I can see the rating is 1650, but I am doubtful the units are horsepower since the Soviet Union was metric. Can you tell me what the units are?
ps? cv? or some internal Soviet unit?
Thanks!
In Russia adopted metric units — and also "metric" horse power (лошадиная сила; in Germany PS as Pferdestärke, French term CV is cheval-vapeur). This metric units is in all defined as 75 kilogram-meter per second (rounded equivalent to HP — 550 lb-ft per second —, not rounded is about 76.04 kg.m/sec), or circa 0.735 498 75 kW.
1650 лс ... 1213.573 kW ... circa 1627.43 H.P.
1650 лс ... 1213.573 kW ... circa 1627.43 H.P.
Last edited:
Russian engine Klimov M-105PF, VK-107A ...
1100 milimetres Hg ... is circa 43.3 in Hg ... or (british equivalent) boost pressure +6.574 P.S.I.
Last edited:
WJPearce
Airman 1st Class
My mistake. I was under the impression that Soviet/Russia used gauge pressure rather than absolute. As in:
1100 mmHg boost (gauge) + 760 mmHG atmospheric = 1860 mmHg (absolute) / 21.27 psi (gauge) / 73.23 inHg (absolute)
Rather than:
1100 mmHg (absolute) - 760 mmHG atmospheric = 340 mmHg (boost) / 6.57 psi (gauge) / 43.30 inHg (absolute)
6.57 psi (gauge) / 43.30 inHg (absolute) seemed low for a "high boost" 1944 engine. Those numbers are 1938 boost levels for the Merlin. Late in the war years, Merlins had a boost of 18, 20, even 25 psi (65, 70, and 80 inHg), and that matched up to the numbers I gave. Of course that was not for continuous power, just war emergency.
On the other hand, the numbers I gave did seem high. I also did not think about fuel (nothing over 100 octane I think), which would make it difficult to produce the high boost values.
Thank you for the correction.
Hi, Bill,
Of all Soviet engines, only the AM 42 might be described as a 'high boost' engine. Main part of the reason why other were 'low boost' engines lays indeed with the fuel - Soviet standard from 1940/41 until the end of the war being 95 oct fuel. The AM 42 circumvented the dangers of detonation by using low compression ratio, some 5.5:1 (1565 mm Hg of manifold pressure for take off and emergency, or some 2 ata/61.6 in Hg). The Klimov's engines used between 6.5 and 7.1:1, the VK 107 was at 6.75:1.
Of all Soviet engines, only the AM 42 might be described as a 'high boost' engine. Main part of the reason why other were 'low boost' engines lays indeed with the fuel - Soviet standard from 1940/41 until the end of the war being 95 oct fuel. The AM 42 circumvented the dangers of detonation by using low compression ratio, some 5.5:1 (1565 mm Hg of manifold pressure for take off and emergency, or some 2 ata/61.6 in Hg). The Klimov's engines used between 6.5 and 7.1:1, the VK 107 was at 6.75:1.
