propellers

[Jake KnightParticipant @jakeknight71345]

just wondering why cant you use 2 of the same propellers on a twin screw boat

will it make the boat go around in circles?

[Paul TParticipant @pault84577]

Hi Jake

There is a long and a short answer to this question.

The long answer involves complex maths, hydrodynamics, thrust vectors, prop wash vortex and the coriolis effect.

The short answer is …….Yes. your boat will go around in large arcs 

Paul

[Jake KnightParticipant @jakeknight71345]

thanks paul i guess i should stay away from the long answer

[ManxmanParticipant @manxman]

No Jake – ask for the long answer !

I want yo see how long it takes Paul to write …

[Paul TParticipant @pault84577]

Bug***r off Ken

I’ve got enough on my plate redesigning the TID to include free flooding, sometimes I just write to much and get myself into all sorts of bother. 

Building the TID is going to take weeks and I am still refitting the Trent in readiness for the Birchwood show. So writing 20 pages of technical blurb that no one will read is just out of the question.

But thanks for thinking of me.

Paul

[Bob Abell 2Participant @bobabell2]

Hello Paul and Ken

As a matter of  fact………………….My old Broom launch has got the same hand of props on and it has no noticeble tendency to go off course!…………..and Ducky the new owner, assumed they were handed and had them contra-rotating!……….No wonder his wife was disappointed with it`s handling!

I`d like to know how you`re gonna fill 20 pages on the subject?

Bob

[Jake KnightParticipant @jakeknight71345]

hi bob does your old broom launch go fast ?

[Bob Abell 2Participant @bobabell2]

Hello Jake

It has two 540 motors….no water cooling and runs at just a little over scale speed.

There is a photo of it in my "Other boats" gallery

Regards …Bob

[Paul TParticipant @pault84577]

Hi Bob

You have got me again… of course I realise that 20 pages is a gross understatement on the amount of math involved but I didn’t think that anyone would pick me up on it, we both know that Hasslberger’s equations will fill at least 9 pages and as for Einstein’s contribution!!!!

Still it is nice to know that a fellow mathematician is also a first class model builder.

Paul

[Jake KnightParticipant @jakeknight71345]

ok thanks bob

i already have 2 same handed props so il give them a go

if not il just have to buy some

thanks again guys

[ashley needhamParticipant @ashleyneedham69188]

Jake.. A little tip… use large rudders and there will be no problem (just a bit of inefficiency in the drive !)   Ashley

[merlinParticipant @merlin]

Jake

 Although both props with same hand will work by using some opposite rudder,you will definitely find that your boat will turn tighter and faster in one direction, you will also not be able to turn at high or low speed using just the propellors, and for the life of me I can’t think why you would want to limit yourself in this way for the sake of one propellor      Whatever you decide enjoy your boating!

[Jake KnightParticipant @jakeknight71345]

why cant you use 2 of the same………

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