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Retired Army
06-30-2015, 01:19 PM
To the mechanical engineers in the group. Is the movement of the pistons in relation to the frame responsible for the smoothness of the flat engine? The BMW is very similar but I have never been on one to compare.

BIGLRY
06-30-2015, 03:32 PM
"A flat-6 or horizontally opposed-6 is a flat engine with six cylinders arranged horizontally in two banks of three cylinders on each side of a central crankcase. This should not be confused with the Opposed-piston engine. The pistons are mounted to the crankshaft such that opposing pistons move back and forth in opposite directions at the same time, somewhat like a boxing competitor punching their gloves together before a fight, which has led to it being referred to as a boxer engine.
The configuration results in inherently good balance of the reciprocating parts, a low center of gravity, and a very short engine length.
The movement of the pistons in a horizontal engine is all in the same plane, so it creates less vibration than in a V-configuration engine; particularly one, like a V6, with an odd number of cylinders on each side of the engine. Unlike the V6 but like the inline-6, the flat-6 is a fully balanced configuration which is in perfect primary and secondary balance. The three cylinders on each side of the crankcase tend to have an end-to-end rocking motion, like a pair of inline-triple engines, but in the usual boxer engine configuration, the imbalances on each side cancel each other, resulting in a perfectly smooth engine.

The flat-6 is also smoother than the flat-4 or inline-4 because the power strokes of the cylinders overlap in a four-stroke cycle engine. In these four-cylinder configurations, pistons are 180 degrees apart in crankshaft rotation and start their power strokes every 180 degrees, so each piston must come to a complete stop before the next one commences its power stroke. In the flat-6, each power stroke begins 120 degrees after the previous one starts, resulting in 60 degrees of overlap between power strokes and a much smoother delivery of power to the flywheel."
https://en.wikipedia.org/wiki/Flat-six_engine


I am not an engineer, but I did sleep at home last night.:301:

Retired Army
06-30-2015, 03:56 PM
"A flat-6 or horizontally opposed-6 is a flat engine with six cylinders arranged horizontally in two banks of three cylinders on each side of a central crankcase. This should not be confused with the Opposed-piston engine. The pistons are mounted to the crankshaft such that opposing pistons move back and forth in opposite directions at the same time, somewhat like a boxing competitor punching their gloves together before a fight, which has led to it being referred to as a boxer engine.
The configuration results in inherently good balance of the reciprocating parts, a low center of gravity, and a very short engine length.
The movement of the pistons in a horizontal engine is all in the same plane, so it creates less vibration than in a V-configuration engine; particularly one, like a V6, with an odd number of cylinders on each side of the engine. Unlike the V6 but like the inline-6, the flat-6 is a fully balanced configuration which is in perfect primary and secondary balance. The three cylinders on each side of the crankcase tend to have an end-to-end rocking motion, like a pair of inline-triple engines, but in the usual boxer engine configuration, the imbalances on each side cancel each other, resulting in a perfectly smooth engine.

The flat-6 is also smoother than the flat-4 or inline-4 because the power strokes of the cylinders overlap in a four-stroke cycle engine. In these four-cylinder configurations, pistons are 180 degrees apart in crankshaft rotation and start their power strokes every 180 degrees, so each piston must come to a complete stop before the next one commences its power stroke. In the flat-6, each power stroke begins 120 degrees after the previous one starts, resulting in 60 degrees of overlap between power strokes and a much smoother delivery of power to the flywheel."
https://en.wikipedia.org/wiki/Flat-six_engine


I am not an engineer, but I did sleep at home last night.:301:
Thank you, do you think Harley will ever catch on?





You can sleep tonight, your Army is.

bobbyf6b
06-30-2015, 04:06 PM
The boxer analogy doesn't make sense to me. If it was like a boxer punching his gloves together then the pistons would be facing each other.

BIGLRY
06-30-2015, 04:14 PM
Thank you, do you think Harley will ever catch on? No and because they are so entrenched with promoting the H-D almost spiritual mystic image and global marketing that any radical changes will kill their market share and effect their bottom line. IMO





You can sleep tonight, your Army is.
:lolup: good to know.

BIGLRY
06-30-2015, 04:27 PM
The boxer analogy doesn't make sense to me. If it was like a boxer punching his gloves together then the pistons would be facing each other.
See if this helps.
first a four cylinder
http://s.hswstatic.com/gif/engine-flat-4.gif
Now a six, you can see the 120 deg power stroke with the 60 deg overlap in the six, while the 180 deg four meet together at the same time.
http://auto4u.persiangig.com/Gif/Engine/Cylinder%20arragement/Boxer%20engine/Auto4u-4Cycle%20Engin_Boxer-3.gif

Look at the bases or rod ends of the pistons touching like a boxers punching their gloves together before a fight, not the tops of the pistons, it is much more obvious in the four cylinder engine.
The term Boxer came from the original Porch four cylinder engine, but is used universally now for any 180 deg opposing piston engine.

StraightWings
06-30-2015, 04:40 PM
Both the bike and the summation regarding the engine. Excellent explanation. .notworthy. Nice work, Biglry.

Retired Army
06-30-2015, 04:50 PM
Mystic makes me really ill I can't even stand next to it.

BIGLRY
06-30-2015, 05:18 PM
Mystic makes me really ill I can't even stand next to it.

ˈMYSTIC:
noun: mystic; plural noun: mystics
a person who seeks by contemplation and self-surrender to obtain unity with or absorption into the Deity or the absolute, or who believes in the spiritual apprehension of truths that are beyond the intellect.
https://www.google.com/search?sourceid=navclient&aq=hts&oq=&ie=UTF-8&rlz=1T4GZGN_enUS515US515&q=Mystic


:icon_rolleyes: or were you perhaps thinking of MASTIC the glue?:icon_biggrin::shrug:

vstar09
06-30-2015, 05:42 PM
Very good explanation.....

Steve 0080
06-30-2015, 06:20 PM
Larrry, you are in rare form tonight !!! :039:

bobbyf6b
06-30-2015, 06:28 PM
Sounds far fetched to me. If you imagine a boxer punching his gloves together then the pistons would face each other and share a combustion chamber. I call BS on the boxer moniker.

:duck:

I'm being facetious. :icon_razz:

BIGLRY
06-30-2015, 08:02 PM
Sounds far fetched to me. If you imagine a boxer punching his gloves together then the pistons would face each other and share a combustion chamber. I call BS on the boxer moniker.

:duck:

I'm being facetious. :icon_razz:and that my friend is called a "split-single" or "Twingle" engine it is a variant on the two-stroke engine with two cylinders sharing a single combustion chamber.
The following post is from https://en.wikipedia.org/wiki/Split-single

https://upload.wikimedia.org/wikipedia/commons/thumb/7/75/Two_stroke_Valveless_engine%2C_working_cycle_%28Au tocar_Handbook%2C_Ninth_edition%29.jpg/300px-Two_stroke_Valveless_engine%2C_working_cycle_%28Au tocar_Handbook%2C_Ninth_edition%29.jpg
"Valvless engine of 1919, showing the operating cycle

The rationale of the split-single two-stroke is that, compared to a standard two-stroke single, it can give better exhaust scavenging while minimizing the loss of unburnt fresh fuel/air charge through the exhaust port. As a consequence, a split-single engine can deliver better economy, and may run better at small throttle openings.

A disadvantage of the split-single is that, for only a marginal improvement over a standard two-stroke single, the "Twingle" has a heavier and costlier engine. Since a manufacturer could produce a standard twin-cylinder two-stroke at an equivalent cost to a Twingle, it was perhaps inevitable that the latter should become extinct.

There have been "single" (i.e. twin-bore) and "twin" (i.e. four-bore) models. Unusually for a motorcycle engine, some Twingles have the carburetor mounted on the front of the engine, beneath the exhaust.
The first split-single engine was patented in 1912 by Italian engineer Adalberto Garelli. His company, Garelli Motorcycles, produced a 346 cc version for use in motorcycles for road use and for racing. Production continued until 1926, by which time Garelli was increasingly concentrating on the military market. Garelli motorcycles remained in business until the late 1990s, but they did not further develop or produce these engines.

Trojan (invented 1913)The Trojan two-stroke, as used from 1913 in the Trojan car in the UK. The "fore-and-aft" layout of the cylinders means that the V-shaped connecting rod has to flex slightly with each revolution.:yikes: Unlike the German/Austrian motorcycle engines, this engine was water-cooled.

Puch 1923-1970 Sears marketed considerable numbers of the Puch SGS split-single fitted with both these innovations as the "Allstate 250" or "Twingle" in the US(I had one, it was an oil burning, sparkplug fouling SOB).

DKW 1931-1939, In 1931 split-single engines produced by Ing Zoller were used in motorcycle racing and helped DKW dominate smaller motorcycle racing classes between the wars.

Duray Indiananpolis 500 In 1932 the Mallory Special car driven at Indianapolis by Duray used a Duray 16-cylinder two-stroke using a split-single configuration

Monaco-Trossi 1935 the Monaco-Trossi Formula One car was built with a 16-cylinder radial engine using a split-single configuration

TWN 1946-1957 German TWN motorcycle company (originally part of Triumph Motorcycles in the UK) experimented with split-singles in 1939 and started producing two models when production resumed in 1946.
https://en.wikipedia.org/wiki/Split-single
https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Puch_Doppelkolben.jpg/220px-Puch_Doppelkolben.jpg
Post WWII arrangement, carburetor to the front under the exhaust (neither visible). Transfer port visible at back. One connecting rod 'piggy-backed' on another.

shooter
06-30-2015, 09:32 PM
Sounds far fetched to me. If you imagine a boxer punching his gloves together then the pistons would face each other and share a combustion chamber. I call BS on the boxer moniker.

:duck:

I'm being facetious. :icon_razz:

Bobby how do you know Larry isn't shinin you on again? I wouldn't trust him if I was you.

BIGLRY
06-30-2015, 11:01 PM
Bobby how do you know Larry isn't shinin you on again? I wouldn't trust him if I was you.
https://artofpio.files.wordpress.com/2014/05/wpid-who-me.jpeg

Old Ryder
07-01-2015, 06:29 AM
Anybody ever build a bike with a "Wankle" engine? I have always thought the compact design and smooth power would be right at home on a bike. :shrug:

RickJ
07-01-2015, 08:37 AM
Anybody ever build a bike with a "Wankle" engine? I have always thought the compact design and smooth power would be right at home on a bike. :shrug:

YES- Theres one at my local HonYamKawa dealer. I THINK it's either a suzuki or Kawa...cant remember and it's about 30 years old.

BIGLRY
07-01-2015, 02:13 PM
Anybody ever build a bike with a "Wankle" engine? I have always thought the compact design and smooth power would be right at home on a bike. :shrug: Suzuki RE5 is a motorcycle with a Wankel rotary engine that was manufactured by Suzuki from 1974 to 1976.
https://en.wikipedia.org/wiki/Suzuki_RE5

http://www.angelfire.com/retro/roadster/re5_mmmm.jpg

hiflyer
07-01-2015, 02:40 PM
[SIZE=3][I]Suzuki RE5 is a motorcycle with a Wankel rotary engine that was manufactured by Suzuki from 1974 to 1976.


I remember that bike like it was yesterday. Unfortunately I can't remember where I put my keys today.

BIGLRY
07-01-2015, 03:44 PM
I remember that bike like it was yesterday. Unfortunately I can't remember where I put my keys today.:icon_lol: and one reason why I went keyless on my VTX1800 in 2008.:icon_lol:
http://www.californiavtxriders.com/phpBB3/viewtopic.php?f=26&t=34961

woody
07-01-2015, 04:11 PM
Norton also built a rotary.

BIGLRY
07-01-2015, 04:30 PM
Norton also built a rotary.
:yes: Correct, the Suzuki's RE5 was one example of the very few Wankel engine motorcycles that were produced. One of the other MC makers that used the rotary engine was DKW along with Norton Motorcycle Company's Norton Interpol 2, Norton Classic, Norton Commander.
https://en.wikipedia.org/wiki/Suzuki_RE5

RickJ
07-01-2015, 09:37 PM
:yes: Correct, the Suzuki's RE5 was one example of the very few Wankel engine motorcycles that were produced. One of the other MC makers that used the rotary engine was DKW along with Norton Motorcycle Company's Norton Interpol 2, Norton Classic, Norton Commander.
https://en.wikipedia.org/wiki/Suzuki_RE5

WOW an audi motorcycle...well sort of, remotely- he mentions motorcycles about 5 or 6 paragraphs down in the link...

http://blog.lanemotormuseum.org/2011/03/the-complex-history-of-the-dkw-brand/

BIGLRY
07-01-2015, 10:21 PM
WOW an audi motorcycle...well sort of, remotely- he mentions motorcycles about 5 or 6 paragraphs down in the link...

http://blog.lanemotormuseum.org/2011/03/the-complex-history-of-the-dkw-brand/
Well Audi did buy Ducati http://news.discovery.com/autos/drive/audi-audi-audi--its-all-about-audi-today.htm and there has been some concept spy stuff on the web of a Audi V4-powered 10R Supersport. :yikes:
http://i.imgur.com/YDLrwqi.jpg

Now if ya want to know about the old motorcycle build by Audi you have to know where Audi comes from.
"Today's AUDI AG looks back at a history that spans more than 100 years of automobile construction. An exciting voyage through time that started in the late 19th century. The Saxon brands of Audi and Horch from Zwickau, Wanderer from Chemnitz and DKW from Zschopau played a decisive role in motor vehicle development in Germany. These four brands amalgamated in 1932 to form Auto Union AG – with the sign of the four rings."

The bike was called the "Wanderer" to see some cool pic from the 1902 "Wanderer", to the 1923 Lomos Sesselrad "DKW" to the 1952 NSU Prima D motor scooter and all their other motorcycles, which became Audi in 1932 http://www.audi.com/corporate/en/company/history/models.html

woody
07-02-2015, 03:32 PM
interesting photo's. Thank you for sharing.