F1technical.net

Check out this image of a BMW coordinated engine management system from ~70 years ago.

Yeah sure, why not shuffle the more intellectual minded away from the instant image/no comment thread..

Anyhow..
..from the fish or fowl dept.. a recently posted even numbered cylinder format 2-stroke engine had me wondering..
..4-stroke radials run odd numbered cylinder per bank layouts, so is the Junkers Jumo 222 a "radial" or not?

http://www.enginehistory.org/German/Jumo222.shtml

6X4=24, but is it more like a semi mirror-image of a broad-arrow Napier Lion inline, than a true radial?

J.A.W. wrote:Yeah sure, why not shuffle the more intellectual minded away from the instant image/no comment thread..

Anyhow..
..from the fish or fowl dept.. a recently posted even numbered cylinder format 2-stroke engine had me wondering..
..4-stroke radials run odd numbered cylinder per bank layouts, so is the Junkers Jumo 222 a "radial" or not?

http://www.enginehistory.org/German/Jumo222.shtml

6X4=24, but is it more like a semi mirror-image of a broad-arrow Napier Lion inline, than a true radial?

It is a real radial.

I imagine that the crankshaft would be arranged like an in-line 4, and the set of 4 would fire in the same order as an in-line 4. Each cylinder would fire in sequence, so that every other revolution the row would not fire, but one of the others would.

You 'imagine' a crankshaft layout? Really?
So, no actual data on it then?
Was it a real anything.. ..the report writers are a bit coy, seemingly wanting a quid each way..
As well, the posted report is rather lacking in specific details,
& the Ju 222 had turned out a dud - like most other 24cyl aero-lumps..

I haven't seen a description of the crankshaft or its firing order.

There is this:
http://www.enginehistory.org/German/Jumo222.shtml

wuzak wrote:I haven't seen a description of the crankshaft or its firing order.

There is this:
http://www.enginehistory.org/German/Jumo222.shtml

Yeah, I've seen that before ( hint: a couple of posts above - in this very thread) - but is oddly vague/evasive/secretive..
..on the crankshaft detail..

J.A.W. wrote:

wuzak wrote:I haven't seen a description of the crankshaft or its firing order.

There is this:
http://www.enginehistory.org/German/Jumo222.shtml

Yeah, I've seen that before ( hint: a couple of posts above - in this very thread) - but is oddly vague/evasive/secretive..
..on the crankshaft detail..

It's an intelligence report during the war. I don't think they had access.

Yeah well, in the initial report they only do a somewhat cursory examination but reckon they want to run it later..
& in the 2nd they have it on hand to suss out, but again avoid mention of crankshaft function except that they didn't
even rotate the recip' assembly.. ..odd..

This post-war overview of German piston aero-engines..
.. written for Flight by Roy Fedden includes a brief Ju 222 appraisal..

"...showed promise - although there were various connecting rod troubles..."

http://www.flightglobal.com/pdfarchive/ ... 02394.html

That National Archives of the UK have some files from 1946 relating to the Jumo 222.

Interestingly they call it a "radialine".

http://discovery.nationalarchives.gov.u ... r/C4024847
http://discovery.nationalarchives.gov.u ... r/C2429972
http://discovery.nationalarchives.gov.u ... r/C4019598

&/Or verbatim - "Radioline" ( likely a typo).

Wuzak - I agree the crank was most likely a 180 degree 4cyl arrangement (for balance reasons). Certainly there were only 4 crankpins with a master/slave con rod on each. This arrangement would dictate 12 paired cylinder firings per cycle. The arrangement raises a lot of issues. For example, did they have provision for different ignition timing on each (4 cyl) bank since slave/master rodded cylinders have different piston phasing and velocity profiles?

I don't know what was done for ignition timing. The issue must have been the same on radials, or the Vulture. Even the 1931 version of the Rolls-Royce R had a slave and master rod arrangement.

I think it likely that they didn't provide for different ignition timing between banks.

A. Rowledge designed both the Napier Lion & R-R type-R, with master/slave big end/recip' arrangements
& Lions were used to power German aircraft.. ..again the Ju 222 does look like a mirror image Lion..

The Germans ran different ign' timings between plug sets ( & even comp' ratios per bank) on their V12s..