Engine Rotation

[Harry]

Silly question but confirming - engine rotation direction please?

[Tomnistuff]

Counterclockwise as viewed from the driver's seat.

[Harry]

Thanks!

[MikeSimon]

Most engines turn "right" - clockwise - when you turn them on the front nut on the crankshaft. Actually, I do not know a single one that does not - but, unfortunately, I have not worked on ALL engines ever built.

[Tomnistuff]

On multi engine aircraft (I think) half of the engines turn the opposite direction and one of the twin inboard engines on some (at least) boats turn the opposite direction.  Ford used to (maybe still do) sell V8 boat engines that turned clockwise when viewed from the rear. (Some significant differences)

Tom Kizer

[Benz Dr.]

On multi engine aircraft (I think) half of the engines turn the opposite direction and one of the twin inboard engines on some (at least) boats turn the opposite direction.  Ford used to (maybe still do) sell V8 boat engines that turned clockwise when viewed from the rear. (Some significant differences)

Tom Kizer

Yes they do. Makes things fly or sail better.

[cfm65@me.com]

Gents,
Very few aircraft have engines turning the other way. Most airplanes fly with a slight nose-up attitude. Even more so when on one engine, therefor the down going blade delivers more bite (thrust) than the up-going blade. Piper had a few models with, what were then called, counter rotating props. The Twin Comanche, Navajo and Chieftains. The idea was, in the event of an engine failure, to have the live engine thrust( down going blade)as close to the centre line of the aircraft as possible. IIRC Cessna also made a C300 series with CCR props, C313, 340
Mostly, this was an effort to improve underpowered aircraft single engine performance.
Regards
Chris

[Pawel66]

It could have happened on some of the old double-stroke Saabs that the engine went backwards. You figured it out when you engage the first gear...

[Shvegel]

The ship I work on has one clockwise and one counter clockwise engine.  The NASCAR legend Smokey Yunick bent the rules and made a counter clockwise engine that would load the outside wheels in the corners.

[MikeSimon]

I can see that in special applications, the torque reaction could be utilized for a specific purpose, thus making the direction of rotation important. I don't know, why a clockwise rotation (viewed from the front of the engine) in most internal combustion engines is selected. The answer to this question is as interesting and as elusive as to why the side-stands (kick-stands) on motorcycles are on the left side...

[jeffc280sl]

Think about Henry Ford and the hand crank start of pre 1919 engines.  Nearly all engines rotate clockwise because that arrangement best suited a right-handed man.

[Pawel66]

... The answer to this question is as interesting and as elusive as to why the side-stands (kick-stands) on motorcycles are on the left side...

I do not have much experience with motorcycles, but had one when I was young. You get off it to the left - you have more control when holding far side of the steering with the right hand. Kick starter is also usually on the left so that you can use your right leg (there were some motor bikes with kick starter on the left and all of them were considered odd). When you walk aside your bicycle you are also on the left. So I think the side stand question may have an answer...

[jeffc280sl]

again look at the past.  mounting a horse comes to mind

[MikeSimon]

I do not have much experience with motorcycles, but had one when I was young. You get off it to the left - you have more control when holding far side of the steering with the right hand. Kick starter is also usually on the left so that you can use your right leg (there were some motor bikes with kick starter on the left and all of them were considered odd). When you walk aside your bicycle you are also on the left. So I think the side stand question may have an answer...

Confused about the kick starter, Pawel..Left or Right. You usually would swing a leg over the bike and stand over it when you kick-start it. Thus, the kick starter kicked with the right leg, would have to be on the right. All these arguments go by the wayside if you consider that not everybody is right-handed/-footed.
The "horse" argument has been brought up before. May be the only logical explanation.

[Pawel66]

 

Perhaps the difference was that in the communist countries you were never sure if you would actually start it! So you kicked it before you sat on it - to save time and not to show excessive confidence.

But seriously - most of the bikes, as I can recall, had a kick start on their left. Those bigger ones that could have gondola attached as well.

But you are right - could have been on both sides.

[MikeSimon]

Maybe you are thinking of the BMW-design bikes, Pawel. These 2-cylinder "boxer" engines have a longitudinal crankshaft, much like a car. Therefore, the plane of the kick-start movement is perpendicular to the bike and it has to be "kicked" before you get on. All my other bikes that have a kick-starter, have it on the right side - Kawasaki, Honda, Harley Davidson

[Pawel66]

Yes, indeed - a certain type of bikes. I am not an expert, I just recalled this when I was thinking about the topic. I am sure you have much more experience in this area.

So how have we come here? We have shafts rotating clockwise as you face the engine because we mount horses from the left side?