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12 cylinder straight engine? Ideas?


Connor

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Does anyone know if it is possible to use two straight six motors and connect them in some way in order to make a straight 12? I will probably never get around to trying this I just was wondering peoples thought on the idea. Maybe there is someone out there who has tried and maybe even succeeded at doing this. Just a curiosity.

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I've seen V-8's connected in tandem with a short flexible coupling. There might need to be some calculations to match power strokes if smoothness is a factor and some consideration to getting such a beast started ..............Bob

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The big question here is what is the point of making a straight twelve? It has to have so much metal to make it rigid enough that it weighs a lot more than say a v12. Packard did it but did not do anything with this engine. Straight eight engines also have this liability but before the technology was advanced enough to make monobloc v8s they could compete on price. When this happened , straight eights disappeared from the market plce.

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Technically, it is extremely difficult to adequately support the long crankshafts of a Straight Eight above about 5,000 rpm, and a Straight Twelve would be subject to a massive amount of crankshaft flex and "whip". Fiat actually did make a V-24 aero speed record engine in the 1930s. You can see one at the Kalamazoo Air Museum in Michigan.

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It could be done. Drag racers and Bonneville racers have been coupling V8s together for 50 years. You need to make some kind of bracketry to fasten the 2 engines rigidly together. Then put a big sprocket on the ends of the crankshafts. Wrap a double row chain around the sprockets to couple the engines together. This gives enough flexibility that it does not matter if there is a slight movement between the engines.

Incidentally years ago I read one of Tom McCahill's columns in which he mentioned seeing a straight nine engine in Studebaker's experimental department in the thirties. He said it was very smooth and powerful but they never followed it up because they didn't think the public would go for it.

I can well believe that a straight nine would be a great engine, because you could use a 120 degree crankshaft like a straight six. This would make it even smoother than a straight eight or V8 with their 90 degree crankshafts.

West is that a gag picture or did they really make a straight 12?

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The Six cylinder Franklin car of early years was the Model H. Legend has it that the factory built up a race car engine that coupled TWO of the H engines end to end and the transition piece between the two crankcases provided a perfect place to install a thirteenth cylinder. (Franklin used individually cast cylinders throughout their production so adding a cylinder here or there was no big deal). This was the elusive and ultimately unsuccessful 13 cylinder Model H2O air-cooled racing town-car.

The H2O was a logical development of the historical Vanderbilt Trials Racer that had two Four-Cylinder (Type C) engines coupled together to make a straight-eight.

(I could not resist:D)

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Hi West,,,What is the source of that beautiful photo ??

Talking at the 1955 Grand classic,,,the meet hosted by Packard at the Packard track,,

Rod Blood ,myself,Dick Teague [chief stylist for Packard at that time ],and others

Were chatting,,The subject of the existance of a 12 in-line car came up,,Dick said the old timers insisted it had existed,,

Dick said he had actually found 2glass plate negs of the car,which he sent down to the photo dept' for copys,, After a wait,,, he inquired about the job,,They now couldn't find the negs,,He tried repetedly,,,no luck,,

The reason some of these factory photos are so good,,They are on 8x10 glass

taken outdoors,,,AND with photo flood lamps to hi-lite better,,The real deal,,!!

Later,,after the meet ended,we went to Dicks house for lunch,,

Why does 14040 keep coming to my feeble mind,,

Somewhere here we went to Jackson,Mi for a VMCCA meet [regional]

Of course Rod knew the old timers,,He had been VMCCA President back in the

war years,,1943-45 I think

AAAh,,,Memories,,Ben

[i had just past my 20th birthday,,]]

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West -- I was delighted to see this photo. I didn't realize one existed of the engine, though I had seen photos of the car -- it had a really long hood. I remember reading that they took two six-cylinder engines and lined them up end to end. I was looking for signs of where the blocks were joined, but you can't tell with the manifold and other equipment in the way. I also read that the engine was removed from the car, which then received a straight 8 and was sold into South America.

I also remember a past Forum poster who vehemently denied that Packard ever built a straight 12.

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I remember vividly,,,,,that afternoon chatting to Dick,,,with Rod Blood,,who had the largest collections of Packard,,,18 under 1 roof,,and more elsewhere,,mostly 4 cyl cars,,few classics

just 1 36 big touring,,,and not to forget Mr Blackmores engine from the saw rig,,a single

I wonder if anyone got a pic,,

It was logical they would have pushed the envelope,,with all the research done for the twin-6

and the racing program of the teens,,

The 8 really did not replace the Twin-6 in any chauffeurs mind I am sure

To just put it in 3rd and let out the clutch,,,No dynaflow even,,can you imagine trying to sell a "modern" car to these old chauffeurs who had just parked a 66 Pierce,,Crane Simplex,,Packard or 70hp Napier back in the carriage house,,

We had the engineers and the know-how on tap

Does anyone remember the radio program,,with the big limo comming in to dock

Mrs ""Bufforpingtons"" big long limosine,,It just hadda be an in line 12

I wonder how long the car existed,,and if more plate negs exist

There were many jokes about long hoods,,,

Pump attendent to chauffeur,,,hey shut it off so i can catch up""

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Is a nightmare or Would Be a nightmare? Has anyone done it?

Twelve throws at 60 Deg, paired end for end; 4, 5, 7 or 13 mains: Sounds doable. There might be other schemes such on the throws such as a 3:6:3. You would probably want to make it hollow and fat to keep the twisting down. An engineering challenge and an interesting design exercise, not a nightmare.

I agree it's doable but it's seeking a clever answer to a bad premise, that's what I meant. As was pointed out Packard built one but the disadvantages of the approach outweighed the advantages. You could build up the crank in pieces like Porsche did (don't recall the model).

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There are two 320 cubic inch Buick engines already coupled together in California for sale! All the engineering was done by Malcom Bauer before he died. His son and daughter are looking for someone to take on the "Sweet Sixteen".

PM me if you are interested... I will be glad to get you in touch...

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These coupled together straight engines don't always qualify as a lot of them have the power taken from where they are coupled. This would reduce the flexing of the crankshafts to the level of the individual engine. Still the question arises of why would you want a straight twelve for anything other than bragging rights. Even with the most massive of cranks, the engine would be severely limited as to rpm.

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I have often wondered about the strain that is put on the last journal of a coupled engine. After all, it was designed only for the hp. the single engine produced.

Never heard of one breaking, even in drag cars producing 3 times the stock HP, with several clutch dropping axle snapping starts per day.

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You all have me thinking about the harmonics. The harmonics of two sixes linked would be horrible. The idea of a strait 12 though would offer a multitude of piston rod degrees to play with and crank troughs to harmonize. The only application I can think of where such a design would be useful is a submarine.

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You all have me thinking about the harmonics. The harmonics of two sixes linked would be horrible. The idea of a strait 12 though would offer a multitude of piston rod degrees to play with and crank troughs to harmonize. The only application I can think of where such a design would be useful is a submarine.

This is where a slight flexibility in the coupling comes in, to act as a vibration damper. If you use 2 sprockets you could sandwich a piece of leather between them before you wrap the chain around.

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Let's get really creative, shall we....how about Chrysler's multi-bank engines built for Sherman tanks during WWII. They used five (count them....5) six cylinder engines, each radiating out in a star pattern from a central crank case. Each engine did, however, have its own individual crank, with each flywheel ring gear driving a central ring gear on the output shaft.

Here's an interesting article on it.

http://www.autospeed.com/cms/A_112613/article.html

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Let's get really creative, shall we....how about Chrysler's multi-bank engines built for Sherman tanks during WWII. They used five (count them....5) six cylinder engines, each radiating out in a star pattern from a central crank case. Each engine did, however, have its own individual crank, with each flywheel ring gear driving a central ring gear on the output shaft.

Here's an interesting article on it.

http://www.autospeed.com/cms/A_112613/article.html

In Sturgis <st1:place w:st="on"><st1:State w:st="on">Michigan</st1:State></st1:place> there was a National Guard unit for tanks. A friend of mine would take me out there to play with the tanks back in the early 70s I remember seeing variations of that engine. I also remember hearing horror stories about rebuilding and or replacing that engine.

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The 30 cylinder Chrysler was a stopgap. Ford was supposed to furnish the engines but they were several months behind schedule. Chrysler whipped up their engine in a few weeks.

These were mainly relegated to training duties. But they proved very reliable in service and would continue running if one bank was knocked out in combat.

One problem was if the bottom engine got cylinders full of oil while sitting, it could lock up the motor and you had to take the spark plugs out before it would start.

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The 30 cylinder Chrysler was a stopgap

One problem was if the bottom engine got cylinders full of oil while sitting, it could lock up the motor and you had to take the spark plugs out before it would start.

They say that also was a problem on the "X-8" engine that was being developed as a replacement for the Ford Model T.

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