Model Boat Mayhem

Mess Deck: General Section => Beginners start here...! => Topic started by: murphy1570 on February 12, 2012, 01:32:08 am

Title: propeller rotation
Post by: murphy1570 on February 12, 2012, 01:32:08 am: Hello folks
Sorry if this question sounds a wee bit stupid ,when viewing a propeller from the rear/stern, which way should it revolve when the throttle stick is moved forward, and when the stick is moved to the bottom, is it the case that shoving the stick forward the prop moves anti-clockwise, and clockwise when moved to the bottom. I do not have access to a test tank (bath), and am wary of putting my model in a local pond when I am unsure of which way it will go having spent some time getting it to this stage.

Thanks all the best, John.
Title: Re: propeller rotation
Post by: gwa84 on February 12, 2012, 01:59:19 am: normal rotation is anti clockwise for forword motion :-))
Title: Re: propeller rotation
Post by: nick_75au on February 12, 2012, 02:09:50 am: You could just feel the air blowing off the prop. ok2 the rotation could depend on whether its a right hand or left hand prop.

For correct operation air will be blowing aft when pushing the stick to give Fwd motion ;)

Nick
Title: Re: propeller rotation
Post by: MikeA on February 12, 2012, 09:27:01 am: If you watch this you tube vid it shows the operation of the propeller, from it you will be able to determine your self your own propellers which direction they need to turn to go forward:

http://www.youtube.com/watch?v=GpklBS3s7iU&feature=related

the white lines spiralling away from the propeller is the cavitation and its showing the woodscrew affect the propeller leaves in the water
Title: Re: propeller rotation
Post by: RaaArtyGunner on February 12, 2012, 12:29:55 pm: Nick,

Simple brilliant answer. :-)) :-))
Have had some problems, trying to work out which is the leading edge of a prop, and which one was left handed or right handed. O0 O0
Title: Re: propeller rotation
Post by: nhp651 on February 12, 2012, 01:05:34 pm: as for rotation, either way can be "standard".
I would normally run my single props clockwise......but it's just to your own choice, and this topic will and has rumbled on for an eternity.
neil.
Title: Re: propeller rotation
Post by: sailorboy61 on February 12, 2012, 02:28:39 pm: in my 30 experience of the real world, majority of ships I have sailed on prop rotates clockwise viewd from astern as ship moves ahead.
Title: Re: propeller rotation
Post by: mike_victoriabc on February 12, 2012, 03:38:10 pm: http://myweb.tiscali.co.uk/alanann/propturn.htm

Alans Boatyard website - helps and tips - found this helpful
Title: Re: propeller rotation
Post by: dougal99 on February 12, 2012, 03:53:56 pm: Put your boat in the water gently move the throttle forward. If the boat goes forward all well and good. If not change the servo reverse switch on your transmitter for the throttle channel. Boat should now sail forward. Job done. :-))
Title: Re: propeller rotation
Post by: Netleyned on February 12, 2012, 04:03:12 pm: Don't forget to switch back for other models O0 O0 O0

Unless you are using a Tx with model memory when
you just programme the parameters for the model in use.

Ned
Title: Re: propeller rotation
Post by: john s 2 on February 12, 2012, 04:28:04 pm: Instead of using servo reverse. why not change motor wires round? John.
Title: Re: propeller rotation
Post by: Martin (Admin) on January 30, 2013, 02:29:33 pm: Is this correct? !

Right Hand = Anti-clockwise rotation looking from the rear of the boat
Left Hand = Clockwise rotation looking from the rear of the boat

If so, WHY?!

http://www.propellerhub.com/rotation.html
Title: Re: propeller rotation
Post by: dougal99 on January 30, 2013, 04:31:25 pm: We've been here before. \Depends whether you've got one rudder or two and whther you want speed or control.
If I were you Martin, I'd use the forum's search facility :P
Title: Re: propeller rotation
Post by: Jerry C on January 30, 2013, 05:17:58 pm: Traditionally, among seamen, a propellor turning ahead when viewed from astern turning clockwise is called right handed. I have noticed since taking up modelling that this convention is reversed by European prop makers. Convention also has it that slow speed twin screw vessels have outboard turning props when turning ahead. Twin screw high speed warships on the other hand traditionally have inboard turning props. The reasons for this are that inboard turning props are said to be more efficient for generating speed. Outboard turning props are better when manoevering and turning short round as when the inboard screw is reversed the transverse thrust of each prop is added together and complements the couple between the ahead and the astern screws resulting in a faster turn. The transverse thrust is reduced when Kort nozzles are used. A Damen 2909 Shoalbuster tug I skippered had inboard turning screws but she was still very handy and even steered surprisingly well when going astern at speed. Clear as mud, yeah?
Jerry.
Title: Re: propeller rotation
Post by: Martin (Admin) on January 30, 2013, 06:04:17 pm: Quote
convention is reversed by European prop makers

That's what I thought Jerry! :-))

( talking about single props Doug! )
Title: Re: propeller rotation
Post by: Bob K on January 30, 2013, 07:11:20 pm: No wonder this topic keeps coming up. The more people write the more confused it becomes.
ie: Inward turning prop. Is that turing inwards at the top, or the bottom?
Quite often it is not defined whether we are looking from aft, or forward.
From photos I am working to my current build appears to be opposite to 'convention'.

Perhaps we should all use Tug Kenny's Avatar to define rotation direction. {-)
Title: Re: propeller rotation
Post by: Jerry C on January 30, 2013, 07:16:50 pm: I said it was clear as mud diddle I. Inboard/outboard looking at the top of the prop.
Jerry.
Title: Re: propeller rotation
Post by: dave301bounty on January 30, 2013, 07:29:07 pm: Jerry ,your quite correct ,it is also a very big explanation if it was to be discused between naval achitectured type men ,its a subject on its own and very interesting but quite technical ,i had to do the study years ago for the b o trade exam ..
Title: Re: propeller rotation
Post by: Tug-Kenny RIP on January 30, 2013, 07:40:40 pm: Quote from: Bob K on January 30, 2013, 07:11:20 pm

Perhaps we should all use Tug Kenny's Avatar to define rotation direction. {-)

OK by me. :}
Title: Re: propeller rotation
Post by: RAAArtyGunner on January 30, 2013, 08:38:34 pm: From Harbor models site,,

Rivabo Brass Propellers
Props marked (*) are available in 4mm shaft size
A Word About Prop Rotation
In Europe, the rotation or hand of a prop is determined by looking at the front of the boat and watching the prop turn. Here, in North America, prop rotation is decided by viewing the boat from the aft end. Therefore, hobbyists are continually confused by which prop to purchase, left hand or right hand.

A simple way to identify prop rotation is to do the following:
1. place a prop on a table and position one blade at "12 o'clock"
2. the edge of the blade that is closest to the table top is the leading edge
3. if the leading edge is on the right side of the prop, then the prop is right handed
4. this prop should turn clockwise to push the boat forward.
5. if the left edge of the prop is closest to the table top, it is a left handed prop and it should turn counterclockwise in order to push the boat forward.
6. determine the rotation of a prop in this manner instead of depending on markings on the prop itself or packaging it came in. This is important as the markings made by a European manufacturer will be the opposite to what you want.

Boats with twin props will be set up with the port or left hand side of the boat prop turning counterclockwise. When installing the corresponding motor, you may have to reverse the power wires to the motor to achieve a counterclockwise rotation. DC powered motors are designed to run clockwise. Run the motor for at least 30 minutes to break it in for counterclockwise running.

On our site, all of our props are identified using the North American definition. However, the packaging may show a rotation as identified in Europe. Keep this in mind to eliminate being confused.

Here is what we consider to be left and right propellers:

(http://www.harbormodels.com/site08/images/prop_shop_4_blade.jpg)
LEFT HAND(http://www.harbormodels.com/site08/images/rab_147.jpg)
Title: Re: propeller rotation
Post by: NFMike on January 31, 2013, 01:15:14 am: Quote from: RAAArtyGunner on January 30, 2013, 08:38:34 pm
Keep this in mind to eliminate being confused.

(http://www.sol.me.uk/icons/rofl.gif)
No chance.

Aint it great. There are two possible conventions for this and whadyaknow, one half of the western world picks one and the other half the other.
And the UK falls in the middle as ever - like our semi-metrication.
Is this just model props or a full size thing? Given how international shipping is you'd think they have been a bit more organised by now.

And if one ordered a prop from China or that way, through ebay or Hobbyking for example, I wonder what you'd get? US or EU?
Title: Re: propeller rotation
Post by: Bryan Young on January 31, 2013, 09:43:17 pm: In general, the vast majority of single screw ships have a propeller that rotates clockwise when viewed from the back end of the vessel when going ahead.
This convention is mainly historic as Great Britain developed screw propulsion in the first place.
After that, ship Masters,Pilots and so on were brought up on right handed props. After that, the Nautical schools who taught the basics of ship handling always concentrated on the handling characteristics of such propellers.
So. "We" all grew up knowing that a "Right Handed" prop would, when going ahead, pull the stern out to starboard and the bows to port. An experienced helmsman would normally hand over his stint on the wheel by telling his relief that she's "carrying one (or 2) spokes". Meaning that the small angle he was giving the rudder was enough to maintain a set compass course. We all grew up with that, and it works. BY.
Title: Re: propeller rotation
Post by: NFMike on January 31, 2013, 09:58:33 pm: Quote from: Bryan Young on January 31, 2013, 09:43:17 pm
This convention is mainly historic as Great Britain developed screw propulsion in the first place.

Yes, and I'd think that 'RH' was normal because that is the way a standard machine screw thread works, and we call that a RH thread. It's probably also why the view from the stern is used as that is where you view a machine screw from when installing it.
Why Europe, or rather the rest of Europe since in the UK we tend to still use the above, decided to use another/the other way of looking at it I'd be interested to know. The US drive on the left (as do ships) so that can't be it.
Is this a recent or long standing difference?
And does it apply to 'European' machine screws (nuts, bolts, etc) as well? That would mean being careful if ordering threaded parts from European suppliers :embarrassed:
Title: Re: propeller rotation
Post by: vnkiwi on January 31, 2013, 10:07:52 pm: Interesting Bryan, thanks for that, as makes some remarks made to me years ago (1968) by the skipper of our local mv Towai, which started life towards the end of WW2 in a british yard. Apparently, she was designed as a twin screw vessel, and all material was ordered, but by the time the engines arrived, she'd been redesigned as a single screw and her sister received the right hand set, while the Towai, received the left hand set.
During her long life crossing cook strait in NZ, many a 'new' pilot was caught, expecting the normal pull, to suddenly find quite the opposite, much to his embarrassment.
Thanks for explaining
cheers
vnkiwi
Title: Re: propeller rotation
Post by: Martin (Admin) on January 31, 2013, 10:14:53 pm: Quote from: Bryan Young on January 31, 2013, 09:43:17 pm

In general, the vast majority of single screw ships have a propeller that rotates clockwise when viewed from the back end of the vessel when going ahead.
This convention is mainly historic as Great Britain developed screw propulsion in the first place.

I thought Great Britain's propeller spun Anticlock?!?
Title: Re: propeller rotation
Post by: Martin (Admin) on January 31, 2013, 10:22:42 pm: I don't care what anyone says, the "standard" in model boats is:

"5. if the left edge of the prop is closest to the table top, it is a left handed prop and it should turn counterclockwise in order to push the boat forward."

<*<
Title: Re: propeller rotation
Post by: Stavros on January 31, 2013, 10:44:23 pm: Does it really matter when it is a single prop wich way the prop turn...OK on a twin screw it is handy to have a left and right hand prop BUT not allways Necc

Dave
Title: Re: propeller rotation
Post by: TheLongBuild on January 31, 2013, 10:52:03 pm: If it the model goes forward when the prop goes one way or the other then it works.. :} if it goes in reverse when you press the controller forward then you have your tx set up wrongly.. :}
Title: Re: propeller rotation
Post by: Pirate on February 01, 2013, 08:21:27 am: My experience from model tugs;
Twin Kort;
Right hand prop, 'right handed turn' makes the tug manoeuvrable
Right hand prop, 'left handed turn' gives greater thrust with slight drop in manoeuverabvility.
Single Kort; no difference right or left handed.
Without Kort;
single prop, either right or left will prop walk in that direction at slow speed
Twin prop, right hand prop, 'right handed turn' much the same as with Kort but noticeably accentuated with the observation of wasted energy/pull if under high throttle, as this produces a rooster tail which matures to excessive cavitation.

just my observation
Regards
Pirate
Title: Re: propeller rotation
Post by: Bryan Young on February 01, 2013, 10:33:27 am: Just a minor correction to a comment by Oci.....ships of all nations "drive" on the right, not left. This is why ships heading for a head-on crash alter course to starboard so as to pass down the port side of the other.
Imagine the chaos if ships had to obey individual nationality rules! BY.
Title: Re: propeller rotation
Post by: NFMike on February 01, 2013, 03:10:18 pm: Quote from: Bryan Young on February 01, 2013, 10:33:27 am
Just a minor correction to a comment by Oci.....ships of all nations "drive" on the right, not left. This is why ships heading for a head-on crash alter course to starboard so as to pass down the port side of the other.
Imagine the chaos if ships had to obey individual nationality rules! BY.

Quite right Bryan, my mistake. Probably had left hand drive in my head. :embarrassed:
Same applies to aircraft as well of course.
Title: Re: propeller rotation
Post by: Martin (Admin) on February 01, 2013, 03:43:32 pm: ... OK, what about left and right handed screw threads?! %)

Edit: speel corrected! :embarrassed:
Title: Re: propeller rotation
Post by: Colin Bishop on February 01, 2013, 07:32:19 pm: Quote
... OK, what about left and right handed screw threads?!

Doesn't matter, either the prop will come off going forwards or in reverse. Both ways you'll have lost it!

Colin
Title: Re: propeller rotation
Post by: Martin (Admin) on February 01, 2013, 08:15:47 pm: O0
Title: Re: propeller rotation
Post by: RAAArtyGunner on February 01, 2013, 09:03:15 pm: Which raises the question for the novice, on the real item, is there a thread on the prop or a Spline, cog or what??????????.
Title: Re: propeller rotation
Post by: Bryan Young on February 02, 2013, 11:46:03 am: I wish that readily available props did come with a sline instead of a thread. Of course, this would mean buying splied shafts as well, so farewell to making your own shafts (and props) It would also increase the cost by a fair amount.
The "locknut" system is prone to failure ....especially when doing an emergency stop with a heavy model.
Another way would be to use a key and use the prop boss as the locknut.
I've found the easiest method for us amateurs is to drill and tap into the boss and fit a grubscrew. BY.
Title: Re: propeller rotation
Post by: phil b on February 10, 2013, 04:00:49 pm: another novice question.
How mutch rudder movement (angle of travel) do you need?
Title: Re: propeller rotation
Post by: Netleyned on February 10, 2013, 04:08:30 pm: 35 degrees either side of straight ahead is the norm for most builds.

Ned
Title: Re: propeller rotation
Post by: phil b on February 10, 2013, 06:18:41 pm: thanks I am building a small boat and there is not much room for travel and also using a mini servo. I can just about get 35 degs
Title: Re: propeller rotation
Post by: justboatonic on February 11, 2013, 09:08:37 pm: You need to determine which way your motor turns and get the right handed prop for it.

Despite what many may think, many brushed motors operate more efficiently running one way than the other. That's why (or rather partly) why one motor terminal is marked with the red dot.

If you are into fast electrics this is especially so. Not so important for general sailing though.
Title: Re: propeller rotation
Post by: Stavros on February 11, 2013, 09:19:31 pm: Phil b I know the problem you are having ........what you need is a tiller arm that instead of a left right orientaion as you look from the rear of the boat,is one that goes straight ahead this will cure yuor rudder problem.....sorry dont have a pic as I got to get one myself

One like this

http://www.ebay.co.uk/itm/Tiller-arms-rudder-steering-for-model-boats-/310503331543?pt=UK_ToysGames_RadioControlled_JN&hash=item484b70d6d7 (http://www.ebay.co.uk/itm/Tiller-arms-rudder-steering-for-model-boats-/310503331543?pt=UK_ToysGames_RadioControlled_JN&hash=item484b70d6d7)

Dave
Title: Re: propeller rotation
Post by: old shrimper on February 16, 2013, 01:57:41 am: the leading edge of a prop ( in forward motion ) is the edge closest to the bow / or dead wood /or stern bearing , which ever your fa-miler with :-)) farthest from the rudder ok2

just look at the prop and revolve it and visualize it in a solid,
its only a screw that screws its way through water
Title: Re: propeller rotation
Post by: dpbarry on December 30, 2013, 05:50:38 pm: Quote from: Martin (Admin) on January 31, 2013, 10:14:53 pm

I thought Great Britain's propeller spun Anticlock?!?

If the Captain had spun it clockwise in 1846 after a navigational error, it wouldn't have landed on a beach in Dundrum Bay and stranded for nearly a year :embarrassed:

Declan
Title: Re: propeller rotation
Post by: Netleyned on December 30, 2013, 06:13:58 pm: And the Lord said unto Moses 'Go to Port'
Moses not being a seafaring man went
to Starboard and ended up in the Bulrushes
:-))

Ned