Wrights illusive monster (1 Viewer)

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blattymotrs

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Jan 22, 2010
:eek:There doesn't seem to be much on this engine anywhere, so i thought it'd be a good 1st post to put up this page in Graham Whites new book on the corncob radial. I was quite surprized to see this high quality rear oblique of the illusive R-4090.
I'd still like to find out much more about this engine, I mean more than is contained in this page, or info on the Ha-50.
 

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Wright had a LOT of trouble getting the rear cylinders of the 18 cylinder R-3350 to stay cool. With 11 cylinders in each row, and even less space for air to get to the rear bank of cylinders, I would start the betting that cylinder head temperature on the rear row of the 22 cylinder R-4090 would have been a nightmare.

That is all I think I know.

Piper106
 
Your welcome "Colin 1", the book is full of juicy pics of the corncob as well it's getting pricey to buy though.

I thoroughly agree "Piper106". The only info I've found elsewhere on this engine suggested also that issues with the weakening of the crankcase due to so many jugs hanging off of it, as well as the clutter and weight of the master link set up for this monster, where most likely other hinderances.
I would add that the differences in compression ratios (more so the more link rods/cylinders are in each row) between the master cylinder and the others would have caused problems.

There'd still be an argument for it as an alternative to spreading cylinders over more rows and having to build a big 4 throw crank, all the while complicating it further by twisting it to keep the timing right with the helical fanning of the cylinders !!
 
...I was quite surprized to see this high quality rear oblique of the illusive R-4090.
I'd still like to find out much more about this engine, I mean more than is contained in this page, or info on the Ha-50.
Thanks for presenting this Wright 22-cylinder engine. I did not know any other 22-cylinder engine projects except Mitsubishi Ha-50 before.
Regarding the last you can find all known till now info here wich engin was mend to propell the Kawasaki Ki-91
And here is more of data on Japanese piston engines
Translated version of http://www.warbirds.jp/kakuki/sanko/en_japan.htm

Wright had a LOT of trouble getting the rear cylinders of the 18 cylinder R-3350 to stay cool. With 11 cylinders in each row, and even less space for air to get to the rear bank of cylinders, I would start the betting that cylinder head temperature on the rear row of the 22 cylinder R-4090 would have been a nightmare.
Piper106

Don't forget that diameter of engine is bigger then of R-3350, so spaces between cylinders could stay unchanged.

By the way, does anybody know any projects of 3-raw radials? I never found such designs but it seems that arrangement of 3 7-cylinder raws that gives 21 cylinders is even better then 18-cylinder 2-raw design. And its well known that 4-raw Pratt Whitney R-4360 radials were successful and wide application.
 
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Don't forget that diameter of engine is bigger then of R-3350, so spaces between cylinders could stay unchanged.

By the way, does anybody know any projects of 3-raw radials? I never found such designs but it seems that arrangement of 3 7-cylinder raws that gives 21 cylinders is even better then 18-cylinder 2-raw design. And its well known that 4-raw Pratt Whitney R-4360 radials were successful and wide application.

The longer heavier, crankcase and crank shaft of the 3 row tended to count against it as did the mechanics of the middle rows valve gear drive. Cooling the third row was a major problem and not really solved until P&W and the R-4360 and nobody is going to claim that engine was trouble free or didn't require careful cowl and baffling.

A few companies did try 3 row radials put put the rows in a line with over head cams to solve the valve actuation problem even though it didn't do much for cooling.:)
 
The British where working on engine called the deerhund that was a three row.
 

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Some techical data from the engines:

For Wright R-4090 you can find some data here:
http://www.enginehistory.org/ModDesig/I5 9.tif

Armstrong-Siddeley Deerhound (source wikipedia)

Projected engines in 1935-1941, only prototypes build. Sole modified Armstrong Whitworth Withley is used as testbed for engine.

21-cyl. 3-row air-cooled radial, over head cams.

Deerhound Mk.I: 1115 hp @ 1500 rpm, Bore 5,26 in (135 mm), Stroke 4,95 in (127 mm) 2258.8 cu.in (37.016 l) ??? Note difference from imperial and metric units ???, build 4 pcs

Deerhound Mk.II: 1500 hp, With increased displacement (both Bore and Stroke) 2509 cu.in (41 l), build 6 pcs

Deerhound Mk.III: 1800 hp build 1 pcs

There is a projected engines similar as Deerhound ("paper engines"):

Boardhound: Enlargement of desing to produce 2250 hp, none build.

Wolfhound: 24-cyl. 4-row radial, 3733 cu.in (61 l) 2800 hp, none build.

If somebody have a facts for Deerhound engines, I am pleased to hear it.

- Keke -
 
WOW! 0.0
That's a R-4090 Biggfugginmoter, isn't it?
I'd imagine the reason the 4-row radials were more popular is that they give the same displacement for a much smaller frontal area. Maybe the 4090 would have worked in a low-speed high-power application, but by the time the big 4-rows came in, people were all about speed.
That, and if you think about it, a 4-row 28-cylinder would have the power divided into 28 shorter power strokes, which is good. The R-4090 would have a longer (presumably) moment arm on the crank, but it would probably make less maximum RPM's as a result.
I dunno, I guess it's more or less a toss. The R-4360 for higher-speed airliners/bombers, and the R-4090 for transports sounds good to me! But judging by the fate of Lycomings monster R-7755(!) Wright figured it was a waste of money to develop an unwanted engine to compete with the R-4360, which probably had already unofficially been chosen for the B-36 as well as several airliners.
Thanks for bringing it up though...I'd never even heard of it until today. Learn something new all the time! =D
 
Oh, yeah...the Lycoming R-7755!
-7,755ci
-~5,000BHP
-0.64 hp/in³
-0.82 hp/lb
-10' x 5', over 6,000lbs
-36 cylinders, 4 rows, 9 cylinders per row, not rotated (9 straight banks, not "corncobbed" like the R-4360)
-Liquid cooled, turbosupercharged
-SOHC with 2 separate cams, selectable by the pilot, for economy cruise, and full takeoff power (variable valve timing!)
-XR-7755-2 had twin-output gear reduction box for contra-rotating props
-The reduction box itself had two speeds, since the was to much power to utilize by adjusting the props alone.
-Damn big azz engine.
It was delivered to the USAF, who (according to Wikipedia) told them to "dump it on the ground". It disappeared, only the single test engine was saved.
Nice, ey? Although you should check out the Russian "Zvezda M503": 7 x 6-row 42-cylinder diesel marine radial! Liquid cooled, 8,763ci. Not much of an aircraft engine (4,000BHP + 12,000lbs = 0.32 hp/lb! (vs the R-7755 @ 0.82hp/lb)
 
Oh, yeah...the Lycoming R-7755!
-7,755ci
-~5,000BHP
-0.64 hp/in³
-0.82 hp/lb
-10' x 5', over 6,000lbs
-36 cylinders, 4 rows, 9 cylinders per row, not rotated (9 straight banks, not "corncobbed" like the R-4360)
-Liquid cooled, turbosupercharged
-SOHC with 2 separate cams, selectable by the pilot, for economy cruise, and full takeoff power (variable valve timing!)
-XR-7755-2 had twin-output gear reduction box for contra-rotating props
-The reduction box itself had two speeds, since the was to much power to utilize by adjusting the props alone.
-Damn big azz engine.
It was delivered to the USAF, who (according to Wikipedia) told them to "dump it on the ground". It disappeared, only the single test engine was saved.
Nice, ey? Although you should check out the Russian "Zvezda M503": 7 x 6-row 42-cylinder diesel marine radial! Liquid cooled, 8,763ci. Not much of an aircraft engine (4,000BHP + 12,000lbs = 0.32 hp/lb! (vs the R-7755 @ 0.82hp/lb)

Heres a picture of it.

http://www.ww2aircraft.net/forum/engines/engine-design-gone-wild-lycoming-r-7755-a-21563.html
 
with that size and power how big does the propeller need to be and still work. you cant overspeed the tips on it. love to know what pitch/diameter it would have used in service. the only bigger radial i can think of is the Zvezda . there is one in a tracter puller on you tube.
 

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