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>> Home > Tags > coupling

Motor, mount & prop-shaft. by robbob Fleet Admiral!   Posted: 8 days ago
The prop-shaft, coupling and motor mount that I ordered from ModelBoatBits has arrived so it seems a good a good time to make up a supporting wedge for the mount to fix to. I do have a rigid brass motor alignment aid that I used when building the Crash Tender but do you think I can find it in the workshop?....nope! 😡 I expect it will turn up when I need it least! 🤞 Not wanting to waste time I used a length of heat shrink tubing over the motor coupling to make it as rigid as possible, a trick I had seen done elsewhere, and this enabled me to position the motor on its mount in the desired position and measure the angle that the mounting wedge needs to be made to. I used an offcut of beech that I had in the workshop which I cut to size and then shaped it on the rotary sander that I bought in Lidl, fantastic piece of kit !!. The wedge was then drilled to take the nylon motor mount and also the fixing screws that pass through the beech block, through the balsa base of the box and into the ply reinforcing plate that I put in during early construction of the hull. After cleaning up the hole through the keel the prop-shaft was keyed with some abrasive, smeared with some epoxy and then pushed through to mate with the motor coupling. I used the excess epoxy resin around the shaft inside the hull and used some packing tape to stop it running out when I inverted the hull to seal the lower end. A quick spin on the motor confirmed that the alignment was spot-on and the hull set aside while the epoxy set. The next step will be to plank the deck.

Fast Patrol Boat by jelley_baby Captain   Posted: 15 days ago
Hi BOATSHED, The wooden block is screwed and araldited ti the keel and supports an Aluminium bracket designed for holding a Brushless motor in an Aeroplane, use what’s available I always say. The coupling is Silicon tube fitted to brass universal coupling fittings and because the way brushless run is very quiet compared to a normal Unversal Joint assembly. Will post it running shortly. Thanks for you interest. Graham

Fast Patrol Boat by BOATSHED Fleet Admiral!   Posted: 15 days ago
How does the coupling work, as it looks to be a flexi coupling. There also looks like you have a wooden support under the motor? With the torque on brushless motors will it not wave about? I look forward to seeing her on the water, hope you do a bit of video of her.

New bits by steve-d Commander   Posted: 1 month ago
Right, just been given some nice bits. Brushless outrunner FUSION 3535/05 1500kv ESC Top Edge 60A water cooled SC060B Plus a coupling. So now to go shopping. Which make of Lipo3 and from where? What type and size of brass prop? Where to buy silicon wires and the fancy gold terminals? Steve

Net bins by GrahamP74 Fleet Admiral!   Posted: 1 month ago
Thanks I am having a new coupling made.. the cable junction was to check everything runs.. it actually works quite well!!

Searcher (Nimbus2) by rpbidgood Petty Officer   Posted: 2 months ago
"Searcher" was a Graham Goodchild design offered as a free plan in "Model Boats" in December 1981. Here is my version , many years in the building and finally nearing completion. Access to the hull on the original design was via a hatch above the cockpit - I had no faith in my ability to make it water tight so went for removable grp. hatches. The model is activated by a reed switch just in front of the rear hatch, which saves me the hassle of doing/undoing all the nuts (this had not been fitted when I took the first picture). The rear hatch gives me easier access to the drive coupling. The name "Nimbus2" is in honour of one of Dan Dare's spaceships in the Eagle comic. The third picture shows the ship in its final state with added 'enhancements' and working lights.

Smoke generator by RNinMunich Fleet Admiral!   Posted: 2 months ago
Hi Rowen, Looks very similar to what I fitted to my Sea Scout. I bought it from Krick here in Germany. They ship round the world and very fast👍😉 Copes with my Propdrive 1000kV on a 3S very well 😊 You can buy the basic coupler and inserts for various motor/prop shaft diameters separately to mix and match as required. Copes with the power, is silent and slop free 😊 Cheers, Doug 😎 PS I turned up a rigid alu coupling in a few minutes on the lathe to do the setting up and alignment, much much quicker than faffing about with the 3D printer. Yes I do have one, but seldom used. The lathe and miller are quicker for one-offs.

Smoke generator by RHBaker Fleet Admiral!   Posted: 2 months ago
Good looking destroyer, the prettiest of all in my mind. What type of shaft couplings are those? Look rather unusual

Boat shaft connectors (which stuffs to use and which is good) by TheBlacksmith Chief Petty Officer   Posted: 2 months ago
The couplings you appear to have are noisy as they are built to rather generous tolerances but if you can find a piece of rubber of a sufficient diameter you can cut a narrow band and put it on the coupling at the point where the pins are. I used this method on my converted Southampton and it is still going well with a much, much reduced noise level

Boat shaft connectors (which stuffs to use and which is good) by DodgyGeezer Lieutenant   Posted: 2 months ago
1 - I concur with figtree7nts. You don't want a long length of unsupported floppy tube transmitting power. You will see that my illustrations show the unsupported tube to be very short. 2 - You also want thick tube to transmit power. if you have thin 2-3mm tube that will easily kink. I make my own connectors at the ends of each shaft to bring the internal tube diameter up to about 6-8mm. 3 - If you want to try a quick fix for what you have, I would suggest putting a small piece of wood or plastic inside the unsupported section of your tube, which will stop it collapsing when it is twisted. This may work if the torque is not high. And it's a quick, cheap thing to try. 4 - if you want to try making your own, you could get something like this - check the correct shaft size - or this: and then buy a length of something like this - checking the diameters that you need, of course... Here is a similar Eezebilt to your craft. It's the OSA Missile boat. You can see that the unsupported length of silicone is short, and this boat at 32 inches takes quite a lot of power...

Boat shaft connectors (which stuffs to use and which is good) by DodgyGeezer Lieutenant   Posted: 2 months ago
I'm not sure what you mean by 'earthquakes' - do you mean there was lots of vibration? The prop-shaft and the motor shaft should be aligned as precisely as you can manage. Though a universal joint will accept some misalignment, you should aim to get things so precise that there is no need for a joint! That tube looks rather thin. I use tube which is 10-12mm in OD, with about 3-4 mm thick walls. You are correct that I 'make the shafts larger' by putting little knurled knobs made from aluminium bar on them. If you do not have a lathe, you can buy similar couplings like this:

Boat shaft connectors (which stuffs to use and which is good) by figtree7nts Fleet Admiral!   Posted: 2 months ago
Hi Sakibian, Why can't you use couplings from Cornwall Model Boats! Maybe you can take a picture of your project to show us. What you are working on! I think the shaft should be close to the motor. Or the rubber hose will tear! Try looking for plastic tubing. Of the diameter you need! Or harder rubber tubing.... Regards, Ed

Boat shaft connectors (which stuffs to use and which is good) by DodgyGeezer Lieutenant   Posted: 2 months ago
I am not sure that you mean 'latex'. The most usual soft tubes are silicone rubber. Not neoprene, as it is usually too stiff. There are all sorts of universal joints available. Here are some metal ones from Ebay: These are surely too strong for small boats, however. The Eezebilt range are typically 30-50cm long and I use silicone rubber joints on brushless motors there quite satisfactorily. You just need to be sure that the tube wall thickness is sufficient - typically 3-4mm. Here is a picture of the Eezebilt PT Boat (50 cm long) motor connector, with a picture of it running. You will see that it can go at a reasonable speed. See

HMS BRAVE BORDERER by RHBaker Fleet Admiral!   Posted: 2 months ago
Finally the new brass propellers arrived, delayed about a month in one of Canada's regular postal disruptions. After minor modifications to the boss profile (the brass are more streamlined and thus longer than nylon) to give clearance with the rudder leading edges, they were easily installed. Could now refit the electrical equipment previously removed to get access to the shaft couplings. Inevitably took the opportunity to make “improvements”, so then could not get anything to work! After much frustration determined the problem was not from my improvements, but from the cheap and nasty slide switches provided with ESCs. These must have got damp during the test runs and corroded internally. Suggest when using these switches they be consigned to the garbage and replaced with proper toggle ones. Had decided to use the centre brushed motor/propeller for manoeuvring and low speed operation and then the outer brushless for high speed. Brushless ESCs do not modulate smoothly and motor operation is erratic. This was particularly evident when going from forward to reverse and vice versa. Using a lever control Tx, it was also easy to inadvertently operate the brushless control along with the brushed making the model response unpredictable. After some thinking, decided to insert a small relay into each of the white signal wires for the brushless motor ESCs. These relays would be controlled by a RC switch operated by another channel on the Rx. Hoping this way the brushless motors could be switched on and off whenever desired. The two relays would retain the ESCs as separate circuits and avoid any interference between them. The idea worked, can now operate the brushed motor confidently knowing the brushless will not be inadvertently triggered. This means low speed manoeuvers can be gently undertaken using the modulation and control ability of the brushless motors and, by selecting the auxiliary control, can add the high speed capability of the brushless. Am also hoping that when the Li-Pos trigger the low voltage cut-outs in the ESCs, this will retain a “get-home” facility on the brushed motor as that ESC operates independently. Much to look forward to when next on the water.

kipper by keithtindley Lieutenant   Posted: 3 months ago
aero-naut mowe 2 kit. my first rc model boat with a few extras.The kit was ok to build but the prop coupling was a length of silcone tube ? it spun off at the first test run.This was the start of me fitting universal couplings to my boats.The company were being mean using a cheap piece of tube.It runs very quiet and smooth but needed a lot of front end ballast .i made this to try and drag my grandson away from his ipad,phone and the game of fortnite .I tried to get him to help build and run it but to no avail.I now am enjoying a second childhood building boat kits !