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[Norseman]

That was as smooth as Arkwrights Till 

Dave

[oldiron]

As an addition to my other photos of double Cardan couplings, I also have tried , and like these Marx Kardan2 couplings. The way they are designed they are almost Constant Velocity joints. They are quiet, easy to install and have a telescoping center section.
Here are links to these couplings. I have no doubt those on the eastern side of the Atlantic will have an easier time finding them than here:

http://modelbouwbloemendaal.nl/index.php?action=page&group_id=10000373&lang=EN

http://www.modelbouwbloemendaal.nl/index.php?item=marx-80110-kardan-4-coupling-assembly&action=article&aid=28832&lang=EN

John

[More Coffee]

I used to do a little bit of hot rodding ..and "phasing the drive shaft" was crucial..especially when your dropping 350 Chevy mouse motors in a Dodge that has a Ford 9" rear end.

alot of this dead straight is nice in a solid coupling .but thers a little more forgivness..If everything is just kept level and parallel.

Food for thought..

http://jniolon.clubfte.com/drivelinephasing/drivelinephasing.html

[irishcarguy]

Having started in model boating early this year I joined the forum in August, I ordered parts for my Smit Nederland from Cornwall Model boats. Malcolm sent me the double Huco setup without me asking,(I just told him I needed motors & couplings) so I would assume that he knew that was the correct setup to use, that is double Cardan joints .I am not sure if everyone knows as pointed out by John(oldiron) they MUST be installed in proper alignment ( I wonder John if you could put up a picture of the correct way to install them, thanks) As an aside the guy that really helped with all the rest including wiring diagrams was Dave from ACTion. When I first saw the couplings I was not impressed coming as I do from the auto trade, the couplings did not look up to the task required of them.Lack of a place to lubricate them was the first red light. However as time went on & I saw this was what most of us were using & basically forgot about it until I heard the noise they made, which prompted the question I raised on the forum. Now we have a problem to solve & I have no doubt that we will collectively do so. I will be missing until Jan/12 so don't worry about my lack of posts. Mick B.

[w3bby]

A world of couplings....
http://www.huco.com/products.asp?cat=46

[Arrow5]

How much less, plus postage to Oz ????

  Raarty, have look at post #3.   Thick wall silicon exhaust tube from the glo engine dept of your local model shop ( probably in the aircraft section) pushed onto Shuco or simliar splined ends. 

[irishcarguy]

Hi Arrow5, I tend to agree with you that the safest way right now is the plastic tube connector. I also would be tempted to wrap 2/3 coils of stainless steel locking wire ( preferably aircraft quality) around the tube where it attaches at the point where the splines are. Mick B.

[HS93 (RIP)]

I used to do a little bit of hot rodding ..and "phasing the drive shaft" was crucial..especially when your dropping 350 Chevy mouse motors in a Dodge that has a Ford 9" rear end.

alot of this dead straight is nice in a solid coupling .but thers a little more forgivness..If everything is just kept level and parallel.

Food for thought..

http://jniolon.clubfte.com/drivelinephasing/drivelinephasing.html

Yea that is correct IFthe two parts move and one up and down but in a boat they are supposed to be fixed (No suspension) so the first picture would be correct

[Martin (Admin)]

Didn't know any of that, very interesting read!   

I used to do a little bit of hot rodding ..and "phasing the drive shaft" was crucial..especially when your dropping 350 Chevy mouse motors in a Dodge that has a Ford 9" rear end.

alot of this dead straight is nice in a solid coupling .but thers a little more forgivness..If everything is just kept level and parallel.

Food for thought..

http://jniolon.clubfte.com/drivelinephasing/drivelinephasing.html

[RaaArtyGunner]

  Raarty, have look at post #3.   Thick wall silicon exhaust tube from the glo engine dept of your local model shop ( probably in the aircraft section) pushed onto Shuco or simliar splined ends. 

That's thinking outside of the box.
Simple and cheeeeep.  

[andyn]

How much less, plus postage to Oz ????

£5 for a lightweight (up to 700 size motors) and £6 for the heavy duty coupling.

Postage to Oz would be £2.50.

One of the red plastic things as a double coupling would be £10.34 plus post from a supplier in this country..... Plus the cost of one of our couplings when invariably it breaks

Andy

[oldiron]

A world of couplings....
http://www.huco.com/products.asp?cat=46

Yup, but these are industrial couplings.

John

[oldiron]

Hi Arrow5, I tend to agree with you that the safest way right now is the plastic tube connector. I also would be tempted to wrap 2/3 coils of stainless steel locking wire ( preferably aircraft quality) around the tube where it attaches at the point where the splines are. Mick B.

  I agree with Arrow5 too for the majority of our boat applications(as I mentioned in post #12), however, like yourself I'd like to see a twist of wire at each end for security. They are quick and easy couplings to make, or to purchase,  not too expensive from one of the posting suppliers.
  I believe you have to watch for one thing, the amount of fore and aft lash in the prop shaft. This must be kept to a minimum on any axially solid joint otherwise the motor will be taking the propeller thrust to the boat hull. Don't forget, on full size vessels there is a larger thrust bearing fastened to the boat hull that transmits the propeller thrust to the hull. The thrust doesn't go through the engine.
 You may say it doesn't matter. Depending on how much running you do it will, over time, wear the motor out. These motors aren't designed to take much axial thrust.

John

[Norseman]

Just reading the medical thread it seems eyesight is a problem to consider, yet it seems much is
aligned by eyesight alone. Perhaps a jig is in order? or for Huco a drilled but otherwise solid blank
that has a 50% reveal cut out at the motor end. This would provide at the point of contact a better
sighting of what is in line or in what plane/angle any deviation occurs.

I have some painting to do pre putting my motor and mount in but I can already see the face of the
mount is not lying perfectly in the same plane as the propshaft (yes I can sort it). I just think that it
would be much easier and more reliable to see this error in a reveal at the point of contact.

What do you lads think - I'm new so I won't be offended if it's not a practical idea - I don't
have a lathe and mill to make one and try it out as a practical excersise or I would do so.

Dave

Dave

[HS93 (RIP)]

Just reading the medical thread it seems eyesight is a problem to consider, yet it seems much is
aligned by eyesight alone. Perhaps a jig is in order? or for Huco a drilled but otherwise solid blank
that has a 50% reveal cut out at the motor end. This would provide at the point of contact a better
sighting of what is in line or in what plane/angle any deviation occurs.

I have some painting to do pre putting my motor and mount in but I can already see the face of the
mount is not lying perfectly in the same plane as the propshaft (yes I can sort it). I just think that it
would be much easier and more reliable to see this error in a reveal at the point of contact.

What do you lads think - I'm new so I won't be offended if it's not a practical idea - I don't
have a lathe and mill to make one and try it out as a practical excersise or I would do so.

Dave

Dave

Is this done by eye or have you used some sort of tool to check it and what plane is it out in ?

Peter

[Circlip]

Weapon of choice for alignment was a solid piece of bar drilled one end for the shaft and the other for the motor concentrically so that you had a rigid connection between the two. If the shaft was secured in the hull first, then by using a series of packings under the motor mount and fastening down, alignment was ensured.

  Doesn't seem to be missile technology do the same but put a big splodge of epoxy under the motor mount and "Cast" the packing in situ.

  One thing that does seem to have disappeared from the catalogues is the good old "RMA" (RipMax Marine Accessories) ball joint couplings. These were the truly universal joints as they had the sliding feature built in and comprised only two parts.

  Regards  Ian.

[Norseman]

Hi Ian / Peter

for several reasons (partly ex IC) the standard mount wasn't meeting my needs so I have a custom one which is perfect
but for one slight adjustment that might be needed after it is first fixed. The tiny adjustment in the plane the mount lies in
was discussed when the mount was first made. I could do as you suggest Ian and put some epoxy under there but -
the foot area of the mount isn't very big (for a reason) and more importantly the kind gent who made the mount said it
might only need a tiny little bend to get perfect. As I said above after reading the medical thread, our/my worsening
eyesight needs any help it can get; hence the thought above, but I am here to learn. 

Re 'solid piece of bar drilled one end for the shaft and the other for the motor concentrically' yes I can see that is good if
you have the tools to drill a thin bar to suit - or if it could be purchased with M4 holes already.

Dave

[RaaArtyGunner]

Weapon of choice for alignment was a solid piece of bar drilled one end for the shaft and the other for the motor concentrically so that you had a rigid connection between the two. If the shaft was secured in the hull first, then by using a series of packings under the motor mount and fastening down, alignment was ensured.

  Doesn't seem to be missile technology do the same but put a big splodge of epoxy under the motor mount and "Cast" the packing in situ.

  One thing that does seem to have disappeared from the catalogues is the good old "RMA" (RipMax Marine Accessories) ball joint couplings. These were the truly universal joints as they had the sliding feature built in and comprised only two parts.

  Regards  Ian.

Ian,
For some of us drilling holes concentrically at each end of a solid bar, a very good practical solution, is out of the question/unachievable.

[tobyker]

If you examine the brass tube from your local metal centre you will find one that is a tight sliding fit over the HUCO inserts. Cut a piece of this the right length and you can use it to line everything up while you fix the motor mounts and prop shaft.
My objection to the "double UJ" fitting is that it is so long.
 I liked your belt arrangement, Colin, but it is sad that you have to bolt a pulley to a gear wheel. I'd have thought there would have been a market for pulleys made with centres to fit the common sizes of motor and propellor shafts.

[Colin Bishop]

I liked your belt arrangement, Colin, but it is sad that you have to bolt a pulley to a gear wheel. I'd have thought there would have been a market for pulleys made with centres to fit the common sizes of motor and propeller shafts.

I was just being pragmatic. The cheap pulleys that you can buy these days tend to be a pushfit on a 2mm shaft. I don't like pushfits on principle. You used to be able to get Ripmax pulleys with a 2.3mm grubscrew collet which fits the shafts of many smallish motors. I'm running a bit short of these at the moment and this isn't a very important model so I simply bolted the pulley to the grubscrew fitted gearwheel I happened to have.

At that point I was using a small motor that actually developed too much power for the model, even at 4.8 volts. I had a 6 volt Monoperm sitting in the bits box and this was much more suitable  but it had a 2mm shaft. So what I did was to wind fine fuse wire around the shaft and solder it on. Then I simply ran the motor with a flat file against the shaft until the diameter of the shaft gave me an interference fit with the collet on the gearwheel. Then I just enlarged the hole in the pulley and bolted it to the gearwheel using 10BA bolts and nuts. It actually runs pretty true. At the shaft end I used a succession of taps to put an M4 thread into the nylon pulley so I could screw it onto the shaft and fit an M4 locknut. Crude engineering I agree but in fact it runs very sweetly and much better than using a double Cardan coupling which was very noisy even when lined up accurately. Granted the motor is a bit high in the hull but it is a lightweight one and won't appreciably affect stability. Apart from the gearing down which allows the motor to function more efficiently, it also means that I can easily withdraw the shaft inside the model below the motor without having to dismantle the rudder and its supports.

But as I said earlier, this sort of arrangement is only really suitable for small to medium sized scale models but it does work very well indeed in that situation.

You can buy aluminium pulleys with specified collet sizes and grubscrews but they can be relatively expensive. Once you start going down that route, and especially if your model is bigger, then you are better off with toothed belts and matching pulleys as sold by SHG models. I am a great fan of belt drive as it avoids the problems with universal joint couplings and the horrendous noises you usually get with any sort of toothed gear arrangement.

Colin

[Peter Fitness]

As I have a lathe, I make my own pulleys from suitable size aluminium rod. An example can be seen in my Billing Nordkap. This set up is very quiet, and not as critical as regards alignment as other types of couplings.

Peter.

[oldiron]

Having started in model boating early this year I joined the forum in August, I ordered parts for my Smit Nederland from Cornwall Model boats. Malcolm sent me the double Huco setup without me asking,(I just told him I needed motors & couplings) so I would assume that he knew that was the correct setup to use, that is double Cardan joints .I am not sure if everyone knows as pointed out by John(oldiron) they MUST be installed in proper alignment ( I wonder John if you could put up a picture of the correct way to install them, thanks)  Mick B.

Mick:

 I'm hoping the picture attached will answer your question. If not let me know.

John

[irishcarguy]

Yes it does John, you are once again on the ball as usual, Mick B.

[Martin (Admin)]

  Do belt drives tend to wear the bearings more Peter?

[Circlip]

Ultimately it must as the load is overhung.

  Regards   Ian

Modded. Depends on tension put on belts. Most light loads will be OK.