Dumbern Dirt: Curious Query

[FloatDaBoat]

Why is it that RC (FE & Nitro) Boats run races in a clockwise direction, when all the full sized ones I’ve ever observed race counterclockwise on a closed course? Question’s probably Dumbern Dirt - - But I’m curious.
Anyone have a clue as to why? Might prove to be an interesting History Lesson . . . .

[ozzie-crawl]

full size boats props spin clockwise, so because of prop torque they turn left as the prop forces more pressure on the left hand (inside sponson on hydros etc)
our rc boats use counter clockwise spinning props so we turn right as the prop torque puts more pressure on the right hand sponson
as far as i know the reason our props are counter clock wise is because ic (nitro etc) were origonaly used and when looking at them from the front spin clockwise
this is correct as far as i understand, if parts are wrong feel free to correct

[FloatDaBoat]

Ozzie-Crawl's got one answer. Thank You !!!

Newton’s Third Law of Motion: For every action, there is an equal and opposite re-action.

The counterclockwise force of the drive system creates a clockwise force on the boat hull, causing the right sponson (in the case of a hydro) to be pushed downward (dig-in), thus assisting it to turn more efficiently to the right than the left.

Duh, that’s just Plain Ole Physics - - Where’s the Colorful History . . . .

[Fluid]

Actually that theory only works on boats with sponsons, and then it is only a partial explanation. The biggest reason for course direction is prop walk. A surfacing propeller acts like a big paddle wheel, pushing the transom to the left. This obviously moves the bow to the right = prop walk. It affects every surface-drive boat, model and full-scale. There are a few FE boaters who emulate the full-scale practice of running counterclockwise courses....but they use opposite (right hand) rotation on their props.

Model boats originally used airplane engines, which all rotated left-handed. The first model boat props were for those engines, after that it made little sense to have two full lines of boat props - one left and one right. That's why our boats race clockwise. And that's the colourful history.



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[FloatDaBoat]

Thanks for the Prop Walk explanation & Colourful [Colorful for us Yanks] History Lesson, Fluid.

[tharmer]

The electric boats can run their motors either direction. THat's why the scale classes of hydro use RH props and run CCW...that's the direction the big boys run. After all, scale is scale.
-t

[FloatDaBoat]

Didn't know that the Scale Hydros ran CCW; but that's good news - - Keeping it True to Real World.

Hey ... just noticed ... I'm a 'Member' now (promoted from 'Junior' status).

Whoopie Shineola !!!

[Fluid]

THat's why the scale classes of hydro use RH props and run CCW...that's the direction the big boys run. After all, scale is scale.

Not accurate. Only one class runs counterclockwise....a provisional NAMBA 1/10th scale class run by a small minority of members. AFAIK all other scale classes in NAMBA and IMPBA run clockwise. There just aren't enough right-hand props available for more than one class, and even those folks have to compromise somewhat.



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[tharmer]

I wasn't talking of NAMBA, of course. I'm in the Pacific NW where we have over a hundred FE boats turning CCW, both 1/10th and 1/7th and 1/6.67th and 1/6th. There are enough choices in RH props for us, though not so many as LH.
-t