Never knew where the name came from until I read this article.
https://vintagedieseldesign.wordpress.com/2020/10/03/who-is-roots-and-why-does-he-have-a-blower-named-after-him/
Bunch of other neat articles on that site too.
Greetings from Alberta
-an Articulate Malcontent
Note that one of the other articles was a drawing of the "Pancake" engine. Read about these for years wrt submarines.
The original Roots blower patent (you can judge its antiquity by its number) is 2369. The "legend" is that the principle was used as a water motor first, and only as a positive-displacement blower by accident later. These are very good at moderate speed and relatively low discharge pressure.
A great innovation for two-stroke scavenge was that by George Hallett of GM Research who developed spiral multilobe rotors (2014932A, 9/17/35) Reading that patent's description will prove interesting to those with interest in how this type of blower works.
Interestingly, this was granted nearly 6 months after Lysholm filed the screw compressor application in Sweden (it was filed here one year later, but not issued until 9/26/44)
For those interested in automotive applications, consider the evolution of the general x/71 style of blower into the Eaton supercharger of the late '80s (5078583A and a SAE paper, 870355, Utloff & Yakimov, in February 1987).
I'm surprised Erik mentioned the pancake but not this:
https://vintagedieseldesign.wordpress.com/2021/01/02/the-winton-201-at-the-century-of-progress/
I've seen several accounts of Century of Progress engines, so that wasn't as novel to me as seeing a drawing (albeit just one view) of the pancake engines. I have read about the pancake engines in various books on US submarines, but never saw a drawing or picture of the beasts.
Erik_Mag I've seen several accounts of Century of Progress engines, so that wasn't as novel to me as seeing a drawing (albeit just one view) of the pancake engines. I have read about the pancake engines in various books on US submarines, but never saw a drawing or picture of the beasts.
Try these...
general motors 338 diesel engine - Bing images
I think this is the source.
General Motors / Electro-Motive 16-184 Diesel Engine | Old Machine Press
The 184 is an earlier and more successful version.
Peter
M636CThe 184 is an earlier and more successful version.
It is interesting, upon reflection, that my entire knowledge of both these engines comes from Internet sources, and when as a test I tried to see what was in 'books' about them I had much the same experience Erik did.
On the other hand, I did learn about things like quads and quints from car magazines in the '70s... but come to think of it, not particularly technically. It was often clear that the authors 'knew' but didn't think the details were important to put in an expensive print book...something depressingly true of the steam resources one could find in the '70s outside the general steam-automobile or locomotive preservation/restoration communities.
Thanks for these links Peter. When I started at EMD as a co-op student in 1968 we had a "marine division" within the factory that was still making parts for what must have been these engines. I never saw an assembled engine and never knew what the pancake engine was until I read that article you linked, although I heard old-timers talk about them.
Dave
bogie_engineer Thanks for these links Peter. When I started at EMD as a co-op student in 1968 we had a "marine division" within the factory that was still making parts for what must have been these engines. I never saw an assembled engine and never knew what the pancake engine was until I read that article you linked, although I heard old-timers talk about them. Dave
No problem. I can't remember when I found that site, but I had read about "Pancake" engines in Eugene Kettering's 1951 ASME paper on the 567 (That's on the Utah Rails site, but I was given a hard copy in 1972) so I had been wondering for some time myself.
On seeing it I was immediately reminded of the Allison X-3420 aero engine, which was basically two V-1710s (as in the P-40 and early P-51) on a single crankshaft. I imagine the Pancake designers had access to Allison designs.
While, in the case of the 338, the generator was probably heavier than the engine, I'm surprised that they didn't think of inverting the assembly putting the generator on top. While that would affect stability, you are talking about a ship with the hull full of lead acid batteries at the lowest possible point, so I'm sure they could have coped.
In fact they just cut the ships in two, welded in a new section and fitted Fairbanks Morse 38D8-1/8 engines which were much longer but highly regarded. So I guess the 338 didn't show enough promise to persevere with.
Overmod On the other hand, I did learn about things like quads and quints from car magazines in the '70s... but come to think of it, not particularly technically. It was often clear that the authors 'knew' but didn't think the details were important to put in an expensive print book...something depressingly true of the steam resources one could find in the '70s outside the general steam-automobile or locomotive preservation/restoration communities.
I assume that you are referring to multiple Detroit 6/71s used in marine and other applications.
The first I heard of these was the Victorian Railways EMC motor cars, which were rebuilt with a twin 6/71 geared to the original generator in place of the original Winton engine. I don't know if the engines were new or if they were war surplus reconditioned.
At one stage I became involved in the onging maintenance of the Royal Australian Navy's heavy landing craft. At this stage I discovered some drawing office practices that I hadn't previously considered. When this ship was drawn up. the draftsman copied details from an existing similar design by tracing from the old drawing. What drew my attention was the note "twin GM Diesels" on the drawing. The ship in question had a V-12 71 on each shaft, but evetually I realised that the wording referred to a predeccessor with twin 6/71s on each shaft. Sadly, much more had been copied, including the ship framing aft of the cargo deck. The predeccessor had minimal superstructure but the new ship had a tall wheelhouse structure. The framing was too light for this design and the after hull and deck plating was extensively buckled, at least on HMAS Brunei, the ship I inspected. Brunei was docked and received new hull plating, and I managed to get a sister ship that had spent most of its life on a hardstand restored to service since it was still more or less straight.
However an example of multiple engines was the "Silver City Comet", an Australian equivalent of the GM&O rebels, built in 1937 but kept in service for more than 50 years...
https://en.wikipedia.org/wiki/Silver_City_Comet
The original Harland & Wolff engines were so bad that the railway itself cast new four valve heads to try to get enough power from the engines. These were replaced post WWII by pairs of 6/110s, so four per power unit, driving new Allison transmissions. There were two more HEP engines, 4/71s fitted transversely at each end of the car. I suspect the single crewman suffered from hearing loss....
But six roots blowers on each power unit....
Here's a rebuilt EMD blower being tested. Only time I've ever heard the blower by itself:
https://www.youtube.com/watch?v=BSObd_L5-FQ
M636C On seeing it I was immediately reminded of the Allison X-3420 aero engine, which was basically two V-1710s (as in the P-40 and early P-51) on a single crankshaft. I imagine the Pancake designers had access to Allison designs.
One difference betweenthe X-3420 and the pancake engines is that the two 60 degree Vee's were spaced 150 degrees center to center, or 90 degrees between the inner banks and 150 degrees between the outer banks (60+90+60+150=360). The (limited) production engines were two V-1710's joined together with separate crankshafts. Engines were designated V-3420. I think the engines were developed about the same time, and wouldn't be surprised if there was active communication between the EMD folks and Allison folks.
Erik_Mag M636C On seeing it I was immediately reminded of the Allison X-3420 aero engine, which was basically two V-1710s (as in the P-40 and early P-51) on a single crankshaft. I imagine the Pancake designers had access to Allison designs. One difference betweenthe X-3420 and the pancake engines is that the two 60 degree Vee's were spaced 150 degrees center to center, or 90 degrees between the inner banks and 150 degrees between the outer banks (60+90+60+150=360). The (limited) production engines were two V-1710's joined together with separate crankshafts. Engines were designated V-3420. I think the engines were developed about the same time, and wouldn't be surprised if there was active communication between the EMD folks and Allison folks.
Obviously I am confused.
However, the same site has lots of information.
https://oldmachinepress.com/2017/04/20/allison-v-3420-24-cylinder-aircraft-engine/
It appears that there were versions with both one and two crankshafts...
Gentleman,
First thanks to the OP for sharing the link. That is my blog. Be sure to spend some time and look through it (check out the "Post Archives" entries for listings of everything). Myself and several others have a number of articles in the works for it (just posted one today). A "Locomotive tech" series is something we will be doing in the future as well.
Few other things to note:
Overmod - Thanks for those Patent notes. Interesting to see that GM can be credited for the spiral lobe design!
338 Engine - I hope to do a wirteup on them at some point this year. I have a full set of blueprints for the engine (over 2,000 sheets, anyone want to build a new one?). Very few 338's were built, the Albacore still has hers, and the rest were repowered. What I have yet to really dig into is how the Cleveland 338 differed from the EMD 184A, other then one driving the generator, and the other a CP prop. Quite a number of 184A's were built. I have the manuals, parts book, guide book and supplementary manual for them, but nothing for the 338 outside of the drawings, and some Cleveland articles. The 184A was a WWII engine, and the 338 was a mid-1950's engine - I think alot of it was "Here, you guys take this thing, we have locomotives to build", since by then EMD was going full steam with railroads, and Cleveland was still handling all of the Marine and Stationary engines.
- That Allison is a neat engine, something I have never seen before, and certainly reminds me of the Detroit Twin and Quad packs more then the Pancake engine. Detroit Diesel also made lay down 71's (and I think 53's) used in buses, that were also known as pancakes to some.
- The 338/184A "grew" in that the same basic pricipal was used to create the 16-358H engine, a much larger engine offered in diesel or spark ignition, used for power generation or pipeline pumping. Unfortunatly we do not have the records for the 338 or 358H's to know exactly how many were even built.
Some more on Cleveland Diesel in this post: https://vintagedieseldesign.wordpress.com/2019/12/07/cleveland-diesel-engine-division-gms-war-hero-turned-ugly-stepsister/
Very few people know just how much history is in Cleveland, EMD seems to have gotten the limelite, especially after being merged into them in 1962.
M636CI assume that you are referring to multiple Detroit 6/71s used in marine and other applications.
I believe they got their nickname from the Dionne quintuplets.
Sam Berliner III had a whole page on these at one time. The view of the gear end alone would sober you.
Overmod Chrysler A57 "Multibank". What you put in tanks when they get 4 tons too heavy for a nine-cylinder aircraft radial engine... I believe they got their nickname from the Dionne quintuplets. Sam Berliner III had a whole page on these at one time. The view of the gear end alone would sober you.
I was always amazed by the gearbox on the Armstrong Siddeley Double Mamba
https://en.wikipedia.org/wiki/Armstrong_Siddeley_Double_Mamba
The thought of a gearbox that took two side by side shafts and powered a contrarotating propeller was enough but when I realised that you could shut one turbine down and feather the propeller while continuing to fly on the other...
And of course I saw these very early in life ....
The Double Mamba was, as I recall, actually fairly straightforward -- one engine to one propeller. Not to take anything away from splendid design.
On the other hand there was the contemporary Allison T40 -- two shafts with output that could be blended. The world's fastest flying boat (not counting the P6M or Bartini's A57) was powered by them -- over 400kt which is when you think about it astounding for that type of aircraft.
Neither the P6M nor the Tradewind succeeded, which when you give the matter some thought is not much surprise...
M636C Obviously I am confused. However, the same site has lots of information. https://oldmachinepress.com/2017/04/20/allison-v-3420-24-cylinder-aircraft-engine/ It appears that there were versions with both one and two crankshafts...
Not too confused...
My source for the information on the X/V-3420 was the first source listed on the bottom of the webpage in the link above. I bought a book on the R4360 a couple of years ago, saw the "Vees for Victory" for sale at Karen's Books and figured it might shed some light on the V-1710 vs Merlin debate for the Mustang.
Erik_Mag M636C On seeing it I was immediately reminded of the Allison X-3420 aero engine, which was basically two V-1710s (as in the P-40 and early P-51) on a single crankshaft. I imagine the Pancake designers had access to Allison designs. One difference betweenthe X-3420 and the pancake engines is that the two 60 degree Vee's were spaced 150 degrees center to center, or 90 degrees between the inner banks and 150 degrees between the outer banks (60+90+60+150=360). The (limited) production engines were two V-1710's joined together with separate crankshafts. Engines were designated V-3420. I think the engines were developed about the same time, and wouldn't be surprised if there was active communication between the EMD folks and Allison folks
One difference betweenthe X-3420 and the pancake engines is that the two 60 degree Vee's were spaced 150 degrees center to center, or 90 degrees between the inner banks and 150 degrees between the outer banks (60+90+60+150=360). The (limited) production engines were two V-1710's joined together with separate crankshafts. Engines were designated V-3420. I think the engines were developed about the same time, and wouldn't be surprised if there was active communication between the EMD folks and Allison folks
One of those 3420 Allison engines found it's way onto the tractor pulling circuit in the seventies. I forget his name, but he was dubbed the Michigan Madman for some of his vehicular creations. The tractor was named 'Double Ugly'......
Randy Vos
"Ever have one of those days where you couldn't hit the ground with your hat??" - Waylon Jennings
"May the Lord take a liking to you and blow you up, real good" - SCTV
rvos1979 One of those 3420 Allison engines found it's way onto the tractor pulling circuit in the seventies. I forget his name, but he was dubbed the Michigan Madman for some of his vehicular creations. The tractor was named 'Double Ugly'......
https://themichiganmadman.com/tractor-pulling/
It ain't going to replace what you get with this kind of adding-cylinder-arrangements design for boat engines, though...
https://m.youtube.com/watch?v=GfR2vXgwEDU
(Note the existence of a site called www.tractor-pulling.de which is interesting in a number of respects... )
For technical interest compare this cross-section:
https://oldmachinepress.files.wordpress.com/2016/08/zvezda-m503-cross-section.jpg
As an interesting detail, the original turbocharger produced more power at high rpm than that needed for nearly 16psi boost pressure, and backdrove its low-speed coupling as a form of turbocompounding...
(And yes, there was a 42-cylinder crazy-Ivan aircraft predecessor to that engine (Yak M501)... and yes, there are 56-cylinder versions out there. Wouldn't two of the latter with Bowes drives make the basis of a nifty ALPS?? )
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