Engine technology free-for-all

[J.A.W.]

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

[flyboy2160]

I couldn't find another thread to capture the engine technologies you guys want to discuss, so I've started one that lumps them all together. If you want to start separate threads for Wankels, 2 strokes, etc. go ahead. The OT posts from the engine image thread will be moved here.

[J.A.W.]

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?

[wuzak]

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.

[J.A.W.]

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..

[wuzak]

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

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

[J.A.W.]

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..

[wuzak]

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.

[J.A.W.]

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..

[J.A.W.]

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

[wuzak]

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

[J.A.W.]

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

[gruntguru]

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?

[wuzak]

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.

[J.A.W.]

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..