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11-cylinder radials

 
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jjuutinen



Joined: 13 Jul 2003
Posts: 180

PostPosted: Fri Dec 15, 2006 10:05    Post subject: 11-cylinder radials Reply with quote

Did anyone actually build succesful 11-cylinder radials?
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rhaus



Joined: 08 Feb 2005
Posts: 20

PostPosted: Fri Dec 15, 2006 11:06    Post subject: Reply with quote

I've never seen one referenced in any of my books...I suspect the reason for this is that the additional cylinders would dictate a larger diameter engine to make room for them all...this would increase the frontal area significantly....look at how big around some 9 cylinder per bank engines are...image the extra drag by making it another foot or two bigger...my guess is it was better all around (no pun intended) to just add a second row to increase displacement. ...that's my two cents worth anyway......sincerely, rh
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jjuutinen



Joined: 13 Jul 2003
Posts: 180

PostPosted: Fri Dec 15, 2006 13:47    Post subject: Reply with quote

My reasoning is smaller "pots" (what was that going off, Graham:), i.e. to have smaller but higher pressure and hence higher power cylinders, in the 11-cyl than e.g. in the 9-cyl engine. E.g. the Nakajima Homare was a 2000 hp engine with only 36 litre-displacement. How could they achieve that has in my opinion something to do with modest cylinder dimensions (130 mm x 150 mm).
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rinkol



Joined: 13 Jul 2003
Posts: 35

PostPosted: Sun Dec 17, 2006 11:52    Post subject: Reply with quote

There were apparently a couple of efforts at building twin row 22 cylinder radial engines.

One was the Ha-51 which was intended to put out 2450 hp at 3000 rpm using 130 mm x 150 mm cylinders.

I have a recollection that Wright worked on a 22 cylinder design based on R-3350 technology, but am not sure how far this went.

Suzuki writes in "The Romance of Engines" that such arrangements have the problem that the angle between the intake and exhaust valves is constrained if the engine diameter is to be kept small and that this is undesirable from a cooling standpoint.

Robert
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gwhite



Joined: 13 Jul 2003
Posts: 58

PostPosted: Sun Dec 17, 2006 12:32    Post subject: Reply with quote

I'd be cautious about relying on information contained in Romance of Engines. A number of years ago I served on SAE's Historical Committee and that book was roundly censured by the Committee due to the blatant errors it contained.
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jjuutinen



Joined: 13 Jul 2003
Posts: 180

PostPosted: Sun Dec 17, 2006 18:35    Post subject: Reply with quote

And that valve angle problem, if true, could be avoided by using sleeve valves. Neither would it be a problem with Bristol Pegasus/Mercury style valve arrangement.
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rhaus



Joined: 08 Feb 2005
Posts: 20

PostPosted: Tue Dec 26, 2006 10:46    Post subject: Reply with quote

I did a little more searching, apparently Nordberg made a successful 11 cylinder radial, but it was for industrial purposes...They were used for running generators (in a vertical shaft arrangement) In the early 1950's ALCOA put nearly 200 of them in one of their aluminum smelter plants in Texas making the place the largest internal combustion driven power plant at the time, some 400,000 horsepower....I do not know if any of these are still around or not.
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szielinski



Joined: 13 Jul 2003
Posts: 96
Location: Canberra, Australia

PostPosted: Tue Jan 02, 2007 04:35    Post subject: Reply with quote

Speaking of the "Romance of Engines", how tender would the bearing be in an 11-cylinder engine?

That's only ~65 degrees between each power stroke, not a lot of time to squeeze any oil into the bearing space!
_________________
“Make everything as simple as possible - but not simpler” – Einstein.
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rhaus



Joined: 08 Feb 2005
Posts: 20

PostPosted: Tue Jan 02, 2007 11:59    Post subject: Reply with quote

I've never seen one of those Nordberg radial diesels that I mentioned before, but I am sure everything about them was massive....you are correct that the bearing area would no doubt need to be huge to withstand the loading/lube conditions present....fortunately for the Nordberg, industrial engines run SLOW, giving more time to get oil into needed areas.....And unlike the aircraft engines, industrial units must run and run and run with minimal maintenance schedules. Maybe one of our members in the Texas area could inquire as to what became of these machines?? ...who knows, maybe Alcoa still runs a couple of them???

rh
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pshort



Joined: 13 Jul 2003
Posts: 51
Location: Auckland, New Zealand

PostPosted: Tue Jan 02, 2007 17:43    Post subject: Reply with quote

RH,
I am sure the big Nordberg radials were 12 cylinder.

Nordberg used at least two interesting systems for giving the rods a true motion, thus better balance. One system used a geared counterweight, the other uses 'restraining cranks' and knuckle pins. All had identical con rods, no master rod. Two-stroke with ports for scavenge and exhaust. I think there was a mechanically operated gas valve on the spark-ignition version. These engines could run on diesel, gas (spark igintion) or both.

These engines were large (14" bore, 16" stroke), water cooled, vertical crank. Scavenge options were engine driven pump or electric motor driven pump, or twin turbos and intercoolers.
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rhaus



Joined: 08 Feb 2005
Posts: 20

PostPosted: Wed Jan 03, 2007 09:45    Post subject: Reply with quote

I know they made both 11 and 12 cylinder versions (Alcoa had bought some of each, according to the book I was reading.) ...but I have no other info, so the additional info you provided is much appreciated...you wouldn't happen to have any photos of these would you?

thanks,
rh
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pshort



Joined: 13 Jul 2003
Posts: 51
Location: Auckland, New Zealand

PostPosted: Wed Jan 03, 2007 18:52    Post subject: Reply with quote

rh,

there is quite alot of stuff here about Nordberg:

http://www.oldengine.org/members/diesel/Nordberg/Nordmenu.htm

Also check US patent 2,584,098 for one of the Nordberg crank patents.

(Jukka, apologies for getting off the topic)
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dyonker



Joined: 13 Jul 2003
Posts: 1

PostPosted: Fri Jan 01, 2010 12:12    Post subject: Reply with quote

Better late than never! Check out Graham White's "Allied Aircraft Piston Engines of WW II". On page 372 is the description and a photo of the Wright R-4090 22 cylinder two row radial. You'll have to judge for yourself whether it could be described as successful.
jdy
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