Curious Crankshaft Configurations, Whys & Wherefores.

[J.A.W.]

If you scroll down to the last post in this linked thread page, there is a Soviet diagram revealing the 222's biz..

http://ww2aircraft.net/forum/threads/ju ... ion.22843/

No bloody wonder those Junkers Jumo engineers who subsequently 'volunteered' to work for Stalin,
took the opportunity to create the massive turbo-shaft engines which power the mighty Tu-95 'Bear', instead..

[johnny comelately]

If you scroll down to the last post in this linked thread page, there is a Soviet diagram revealing the 222's biz..

http://ww2aircraft.net/forum/threads/ju ... ion.22843/

No bloody wonder those Junkers Jumo engineers who subsequently 'volunteered' to work for Stalin,
took the opportunity to create the massive turbo-shaft engines which power the mighty Tu-95 'Bear', instead..

OK thats a good start.
Re firing order - it looks like an individual sequence though, whereas i would have thought 4 at a time?
and I am still having trouble imagining the crankshaft layout??

[J.A.W.]

Johnny, another member here, 'wuzak', has put a good bit of effort into figuring the workings of the 222,
so he might well chime in here - at some point, perhaps..

[J.A.W.]

...I am still having trouble imagining the crankshaft layout??

Think Napier Lion - mirror-imaged, along/across* - the crank centreline..


*For side/front -views.

[johnny comelately]

...I am still having trouble imagining the crankshaft layout??

Think Napier Lion - mirror-imaged, along/across* - the crank centreline..


*For side/front -views.

Crikey, here goes to establish if I am on the right path:
the Napier Lion being a W12 has three rods per journal times four carrying journals.
the Junkers Jumo 222 has an additional 12 cylinders mirror reversed around the XZ plane (Z being the crankshaft centreline and X being the horizontal axis with Y being the C/line of the middle bank vertically)
with the Russian blueprint there are only 4 throws in a flat plane, so there has to be 6 rods per throw from two lots of 3 rods as per the photo here. would you just check the timing please

[J.A.W.]

Yeah Johnny, the 222 must've had another set of master-slave rods, instead of the Lion's big-end cap..

FYI, R-R tried a slightly less ambitious variation - with their 'Vulture', it being a kind
of mirror image V12 - thus a 24 cyl X pattern, & it also failed (sadly - after being rushed into service),
- due to a fatal combination of traditionally R-R skimpy conrod design,
& unforseen dynamic-reciprocation cyclic-motion - caused fretting/harmonic-fatigue failure..

[johnny comelately]

Yeah Johnny, the 222 must've had another set of master-slave rods, instead of the Lion's big-end cap..

FYI, R-R tried a slightly less ambitious variation - with their 'Vulture', it being a kind
of mirror image V12 - thus a 24 cyl X pattern, & it also failed (sadly - after being rushed into service),
- due to a fatal combination of traditionally R-R skimpy conrod design,
& unforseen dynamic-reciprocation cyclic-motion - caused fretting/harmonic-fatigue failure..

Lucky they dont rev very high because of (amongst other things) the multitude of rod angles as it relates to your above.

[J.A.W.]

Ok engine-tech brainiacs.. guess what crankshaft configuration was used by the Junkers Jumo 222,
a 24 cyl WW 2 German aero-engine which did get off the drawings & in to metal,(to the ~200 engine mark!),
- but never made service..

Anyhow this lump was deemed a 'radialine' being a multiple of inline 4's disposed radially in six banks..
- if you can visualise the Napier Lion, which featured 3 X 4, & double it - so its six-pointed star-like, or asterisk-wise..

Right then, are ya still with me?

Then its anti-climax time.. the Jumo 222 used a basic 180 degree/flat-plane 4-throw crank..

Now as to its bloody firing pattern.. nah.. it gets my neurones grinding, later maybe..

Rightio then, if the anonymous member who just slapped a sneaky downvote on this post of mine,
citing "untrue" as a reason - could be a decent chap & provide a rationale, that'd be cool bananas..

[J.A.W.]

Here's a couple of technically interesting crankshaft configurations utilized by Nordberg..
in similar, but different, (& large) 2T radial engines..

https://oldmachinepress.com/2014/01/12/ ... al-engine/

[godlameroso]

Fascinating, thank you

[godlameroso]

If you scroll down to the last post in this linked thread page, there is a Soviet diagram revealing the 222's biz..

http://ww2aircraft.net/forum/threads/ju ... ion.22843/

No bloody wonder those Junkers Jumo engineers who subsequently 'volunteered' to work for Stalin,
took the opportunity to create the massive turbo-shaft engines which power the mighty Tu-95 'Bear', instead..

Don't just tease us mate.


One poster had this to say
"it is a 180 degree flat crank, and two cylinders fire simultaneously every 60 degrees of crankshaft rotaton, but if anyone can clarify this apparent error, that information would be apprectiated."


I thought it was 3 cylinders at a time but who knows.

[Tommy Cookers]

afaik the diagram shows .....

paired firing
eg an end cylinder in one bank fires with a middle cylinder in the opposite bank
total 6 firings per rev

[J.A.W.]

This site: http://www.epi-eng.com/piston_engine_te ... es.htm#cpo provides some fairly recent info..
Re: Crankshaft issues per metallurgy-materials (inc' functional limitations), & design reasoning/methods..