Model Boat Mayhem
Mess Deck: General Section => Model Boating => Topic started by: davejay on September 28, 2017, 09:19:01 pm
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Ok, another daft question!!
I'm building a Deans marine 1/24 BPBCo 71ft 6 in MGB77............just fitting the propshafts (one in at the mo, one to go!)..........question is that Deans recommends using two 'HUCO' type UJ couplings for each shaft joined by a splined joiner, does this make ensuring perfect alignment less necessary, I've experimented having the motor a various angles and seeing whether it affects the smoothness of the drivetrain, it appears not to.
Any input/good advice gratefully appreciated.
Cheers, Dave
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I have found it easier and quieter if instead of the coupling silicone tube is pushed over the splines.
Much more forgiving about alignment too.
Bob
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I have found it easier and quieter if instead of the coupling silicone tube is pushed over the splines.
Much more forgiving about alignment too.
Bob
Agree with this method. It's all I use now.
B
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for some reason model boaters only use one Cardan joint in their prop shafts. This doesn't make up a universal joint. Two Cardan joints phased correctly make up a proper universal joint. Would you put a drive shaft into you car with only one Cardan joint? A Huco coupling is only one cardan joint by the way.
If you use only one, the joint has to be precisley matched because there is no room for out of alignment with one cardan joint. This is why many model boaters get vibration and noise using this method.
A rubber tube is a quick simple way out.....to a point. If you are running a small size prop, you may get away with it. If you are running a large one, say what would be used on a 40" plus tug, it won't hold up.
A year or so ago, myself and Irishcarguy did a peice on "universal joints" the the whys and wherefores of them. You may find it benficial looking it up.
http://www.modelboatmayhem.co.uk/forum/index.php/topic,33847.0.html
John
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John,
Digressing off thread, how is Irish guy ???
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John,
Digressing off thread, how is Irish guy ???
I talked to him a few weeks ago on the phone. He was doing better than he was earlier in the summer. I'm not so sure his health is top notch though
John
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Hi,
I would use heavy duty rubber flexible couplings with the torque and speed you are likely to produce.
Rich
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Hi guys it is nice to know that you still remember me. Health wise I am doing O/K if I just keep from falling over. I have never had good balance but it sure has got worse over the last 18 months. I read the forum posts every day without fail unless I am not well. I have a very good doctor & has given me great care he even comes to the house to check up on me & phones me most weeks as well. I met him when I built a very special motor for his M.G.B. he just can't get over how much power it now has. He bought a used Rover v8 motor with the idea of fitting it in the M.G.(after I rebuilt it with him )but now he has second thoughts he is so happy with how it goes now. I called him one night feeling very ill & he said from the symptoms I had a very bad case of pneumonia that I would be dead in 36 hours without the pills & got me antibiotics within an hour & brought them to my house @ 12 pm. Now my fear is losing him. He has given me both his home & cell phone #s as well. I am still trying to finish my boats & have built a small workshop in the back yard to put my lathe (Chinese) & my mill (Chinese too) in it, they are at present in my workshop 12KM west from here. It will make things easier for me. I already have most tools I need at home (too much) I see the question of U/Joints still comes up. I have found in my ramblings at the model shops there is a new front wheel drive axle made by Traxxas that is a work of art & could be converted for boat use easily, it is a proper C/V joint & is about $30.00 dollars Canadian. I will convert one & try to get a picture up on the Forum ( Neil said if I send him pictures he will do it for me,) very kind of him & it is nice to see him back( Thank you Martin)I will rap up for now & thanks again for the concern, John is a great guy. Cheers from Mick B in CANADA.
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Sorry John but I have found the thick walled silicon tube stronger than the thin plastic couplings.
If you keep the tube short it is incredibly strong and tightens as the loading increases.
I have never had a failure using this method but have destroyed several plastic couplings.
Bob
PS Welcome back Mick, hope you are well, yes you are well remembered.
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:-)) :-)) :-)) :-))
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So nice to hear from you Mick. Your contributions when you can, are most welcome.
When does the Snow season start where you are ? I lived in Ontario many, many years ago and thought the snow a novelty until I went out in it by foot. Never again !
Stay cosy
regards
ken
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I too use silicon tube couplings. And agree that they are strong, reliable and quiet. I went over to them after Hugo style couplings failed. I use them on 380, 540,550 size motors, direct and geared drives. One model has a 60 mm prop and has been fine for 3 years.
The importance of accurate lining up of motor and shaft is hard to overstate, I always get the best alignment I can.
Chas.
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So nice to hear from you Mick. Your contributions when you can, are most welcome.
When does the Snow season start where you are ? I lived in Ontario many, many years ago and thought the snow a novelty until I went out in it by foot. Never again !
Stay cosy
regards
ken
Thanks Kenny. I've got a kit Irishcarguy couldn't finish.. The Imara, I promised him I'd finish it and post the thread on here. so you'll see me back.
The four letter word "SNOW", yuk. Could be back any time from the end of October. That said, its going to -3C tomorrow night. We'll see what happens.
John
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I too use silicon tube couplings. And agree that they are strong, reliable and quiet. I went over to them after Hugo style couplings failed. I use them on 380, 540,550 size motors, direct and geared drives. One model has a 60 mm prop and has been fine for 3 years.
The importance of accurate lining up of motor and shaft is hard to overstate, I always get the best alignment I can.
Chas.
Glad you've had good sucess. A proper U joint is there to take misalignment, intended or other wise. Here again, I go back to car , or any other vehicle, drive shaft (either front wheel or rear wheel.. Porperly done, they are designed to take misalignment.
John
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Having just gone through this, the Huco joints are fine if you are only having low revs, I was running one through a 2.5:1 reduction gearbox and it was fine, as soon as I needed to remove the gearbox and it was turning at 11,000 revs the coupling was screaming - even in perfect alignment. so I swapped over to silicon rubber tubing and its been fine. dont heavily grease the prop shaft, the motor slows down and gets hot. suffice to say I now have a bigger motor on my model and its finally performing as I want it to.
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A single Cardan joint, Huco or other wise can be a great frictional drain on a drive system as well as producing noise and vibration. Granted a rubber (call it what you will) tube will do for smaller props (the tug in my head picture runs a 94 mm prop), I doubt if a rubber tube would last long. This is where you need the strength of a double Cardan joint.
Since the question, initially was about Huco joints, the solution to them is , as I've mentioned before, a double, phased Cardan joint. If they are not double and not phased, they are a total aggrevation. Done properly, which model boaters seldom do, they are an absolute pain. Why not do them right?
John
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John,
Once again I will take exception to your theory on Huco couplings versus thick-walled silicone tubing.
From an engineering point of view the Huco coupling is not made for large props or high speed.
The defining strength is in the rivet through the thin plastic body.
When placed under high loads or speed either the rivet or the plastic where it is thinned to allow the joint to move.
With the silicone tube you can ensure that the coupling ends are aligned and within a few mm of each other. this ensures that "kinking" is impossible and as the forces increase the tube tightens on the coupling end.
I my years of experience using both these methods I have had several Huco failures on high speed and large props bun so far have never had a tubing failure using the splined end and a suitable size inside diameter and at least 3mm walled tube.
Bob
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John,
Once again I will take exception to your theory on Huco couplings versus thick-walled silicone tubing.
From an engineering point of view the Huco coupling is not made for large props or high speed.
The defining strength is in the rivet through the thin plastic body.
When placed under high loads or speed either the rivet or the plastic where it is thinned to allow the joint to move.
With the silicone tube you can ensure that the coupling ends are aligned and within a few mm of each other. this ensures that "kinking" is impossible and as the forces increase the tube tightens on the coupling end.
I my years of experience using both these methods I have had several Huco failures on high speed and large props bun so far have never had a tubing failure using the splined end and a suitable size inside diameter and at least 3mm walled tube.
Bob
My point is from the start, , whether they be Huco or some other Cardan style coupling, from an engineering a=standpoint model boaters don't use Cardan joints correctly. They expect one joint, no matter what the manufacturer to make a proper universal joint. Like you. I've had years of experience on U joints, both from an indutrial stand point and a model aspect, and you can't use a single Cardan jopint and expect it to operate as a universal. Propely used Cardan joints don't need the shafts closely aligned, thats why they are used.
John
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Hi John, in your example of a car etc, the ujs are there to cope with designed in or expected misalignment. They are a necessary part of the design. In a correctly installed model boat installation, there should be no or next to no misalignment. The coupling is just a coupling, and the smoother and quieter it runs the better. Silicon tube does just that, and if I ever need to use a larger prop than the 60 mm I've used so far I will have no hesitation in continuing with what I consider a strong and proven method.
Chas.
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Hi John, in your example of a car etc, the ujs are there to cope with designed in or expected misalignment. They are a necessary part of the design. In a correctly installed model boat installation, there should be no or next to no misalignment. The coupling is just a coupling, and the smoother and quieter it runs the better. Silicon tube does just that, and if I ever need to use a larger prop than the 60 mm I've used so far I will have no hesitation in continuing with what I consider a strong and proven method.
Chas.
no one said you had to change, Don't take it personal.
But engineering is engineering no matter what the size relative to Cardan style joints.
John
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No problem John, I have the utmost respect for your view. I just prefer another method. It's all part of the fun of modeling.
My whole point was that the need for a good uj shouldn't normally arise .
Chas
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John,
From an engineering point of view there are several types of marine cardan shaft that do use bonded rubber interior parts so in full size engineering we could BOTH be correct.
Bob
retired Sea Going Marine Engineer.
Not boasting just letting you know I am Marine Engineer.
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John,
From an engineering point of view there are several types of marine cardan shaft that do use bonded rubber interior parts so in full size engineering we could BOTH be correct.
Bob
retired Sea Going Marine Engineer.
Not boasting just letting you know I am Marine Engineer.
Now that we have the chest waving out of the way, can we get back to the first question that started this list for the poor chap that has probably run off by now.
I think the poor lad has got the picture by now
John
Not boasting but stationary engineer and marine engineer and nuclear engineer
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Personally I don't favour direct drive. I have always preferred pulley drive. It makes alignment a doddle and has the great advantage of enabling you to gear down the motor to the prop which enables both to run much nearer to their optimum efficiency. What's not to like?
Colin
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I agree, this is getting silly. The unfortunate chap only asked a reasonable question.
In my experience, no matter how accurately you try to align model boat motors and their shafts, there will always be a very small misalignment in 1 to 3 planes. Stiff foam rubber around the clamped motor helps, but you should always plan to fit a coupling. A single joint is better than nothing, but double is theoretically ideal.
What type you use it up to you, all have advantages and disadvantages.
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Double joints do make for a long coupling which can impose mounting problems.
As I implied earlier, this topic seems to concentrate on varieties of direct couplings when in fact a degree of gearing using a pulley drive will give a much more efficient result.
Colin
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stationary engineer - you made paper planes ? {-) :P
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Crikey........I never thought I would cause such an uproar in opinions, I guess that what forum posts do sometimes. My intention wasn't to cause a global contest in what is better and what is not, we should leave that to Trump and the little rocket man!
My issue with the coupling thing is.....if I use one Huco UJ it brings the motor closer to the shaft end and because the motors are mounted on a plastic type dedicated motor mount there is not enough free space under the mount to bolt/screw the mount to a ply sub base, using two Huco UJ's pushes the motor and mount further towards the fore and gives me sufficient space under the mount to build a sub mount under the motor mounts which would in turn glassed in to the hull and the motors would be in the right place for the centre of balance (crucial apparently on planing hulls).
My initial question was......with two couplings is perfect alignment crucial..........I like to do things perfectly and both couplings will be perfectly aligned (as near as poss).
Cheers Dave
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Hi Dave if you are happy using two huco couplings go for it. During our conversation I did say that I two couplings on my fishing boat due to mis alignment it works fine no vibration or noise. Hope all goes well looking forward to some pictures.
Stan. :-)) :-)) :-))
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The simple answer is , a SINGLE huco type UJ will NOT allow an offset drive line . . . the centre line of the motor & the centre line of the propshaft MUST intersect at the centre of the coupling , you can angle it sideways , up or down but not off the centre lines . . . a double UJ with an insert to connect the UJ's to each other will allow an offset centre line , not too far off tho' otherwise you'll lose power , I notice a lot of solid couplings now with high speed Brushless motors , could this be the way to go , make an custom extended coupling to suit your set up ? just a thought . . . .
Bill
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Hello All
I have had this problem of alignment of the motor and after three days I finally got it right.
It all works OK direct drive, but what pain in the butt !!
So, I had my go to mate make a disc with a 4mm centre hole for the shaft and the holes for 28 and 35mm motors.
You can change this to your requirements.
My next boat I installed the drive shaft and before skinning the hull.
I setup the engine mount with the alignment disc bolted to the motor mount.
A close alignment of the motor mount and with a reinstall to epoxy glue the motor mount bracket all done!!
Installed to motor and direct drive coupling(my go to club mate, again ) .
The drive shaft went straight in and after two years of running, no bearing problems.
This is all running in a brushless motor setup in a little Sea Hornet at a loaded rpm of about 20,000 rpm max.
Forward planning of setting up you boat is the big key in saving you a lot of headaches, time and money.
I built this boat and I am installing motor, drive lines and radio's later!!!!
Canabus
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Hi Dave, my apologies for helping to distract the thread from your question. In my opinion, go for the double Hugo coupling. They might not be my favourite, but they are commonly used and recommended by Deans, who definitely know their business. You mention getting as near perfect alignment as possible, that all any of us can do.
As for getting a lot of opinions, try asking about using grease or oil for the prop shaft.......wow, that can raise some hackles.
Best of luck with the build.
Chas
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If you need the space for additional motor clearance the easiest way is to use the double coupling.
Bob
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Guys, I really appreciate all of your feedback, even if it did digress slightly, that's what happens in conversations (I've been to enough team briefings to know that!).
Anyway, I will go with the dual Huco couplings as it allows the clearance I require under the mount. These will be aligned as near as perfect as possible even if dual couplings do allow for some mis-alignment!
The motors going in are Deans Kestral V, not an over torqued motor I presume and are brushed motors rather than brushless..........I presume brushless motors have more torque and therefore a silicone type coupling would be more appropriate.
I tend to over-engineer things, hate the idea of failings etc.......comes from my RC aircraft days.........over-engineering is king with these guys!
Next question is....................oil or grease for the propshaft?..................JOKING!! :}
As I said, thanks for the feedback and taking the time to answer my question. Top guys on a top forum.
All the best Dave
Stan, I will endeavour to get pics on here sometime..........although they wont match the superbness of your builds, I can only dream of matching such glorious modelling. Thanks also for taking time to chat on the old dog and bone. Cheers mate and enjoy Blackpool!
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If you need the space for additional motor clearance the easiest way is to use the double coupling.
Bob
My thoughts too Bob.
Cheers Dave
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Hi Dave, my apologies for helping to distract the thread from your question. In my opinion, go for the double Hugo coupling. They might not be my favourite, but they are commonly used and recommended by Deans, who definitely know their business. You mention getting as near perfect alignment as possible, that all any of us can do.
As for getting a lot of opinions, try asking about using grease or oil for the prop shaft.......wow, that can raise some hackles.
Best of luck with the build.
Chas
Hi Chas, no need for apologies, I value your input. :-))
Wont ask the question about oil or grease!.......Although I might........may be not! :}
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Hi Dave,
As for grease or oil a lot depends on what type and how much.
In my opinion;
If you are using grease, a thin coat will do the trick, you have to watch to see how the operating temperature goes. Used to run a tug with grease, which worked fine in the summer, but when the temperature both air and water you could barely turn the prop over by hand. Flushed all the grease out and then applied a thin coat, the model would then even work in ice water.
If you are using oil you want it thick enough that it does not seep past the bearings, and as with oil you have to watch the temperature.
As for the debate on couplings vs tubing, except for small models I prefer couplings.
Regards,
Gerald.
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well I have been looking at the coupling for the second of two identical models, well they are not quite identical, as on the second I can just squeeze q 35mm prop on, whereas the first can only take a 30mm.
unfortunately inside the boat, the prop shaft is lower in the hull, and there is less space for the motor, time for a rethink.
looking in my box of model bits, I found a half shaft from a nitro car, with fittings, and a sort of cv joint.
the good part, the huco splines are a perfect fit inside the end pieces, so playing around with these pieces, I have found you can get quite a mis alignment of motor and prop shaft and still not lose any power. one of these pictures is the motor running at full chat - 7750 rpm
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Those are Dog Bone couplings, they will take a fair amount of misalignment, but like a couplings work best when aligned as straight as possible.
Gerald.
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Hi Chas, no need for apologies, I value your input. :-))
Wont ask the question about oil or grease!.......Although I might........may be not! :}
No need to, it has already been done O0 O0 as has the coupling, do a forum search, there is loads of good valuable commentary. :-)) :-))
Knock yourself out. O0 O0 {-) {-)
It's "Model Boat Mayhem" for a reason O0 O0 %% %% %%
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Somewhere on this forum there has been a very long & some heated discussion & conclusions on the forum previously. Because of my background as an Automotive Technician ( ex U/K & X RAF trained I have removed & installed my fair share of U/Joints).
Most rear wheel drive vehicles(skip the double & dual shaft ones) have two Cardan joints & they need to be aligned correctly or the dreaded vibration arrives & it is very nasty. However it is easily corrected if aligned properly. Here I say read the manual & then READ it again. If you use solid connectors you will need an assortment of these i.e.: one end to fit the motor shaft & the other end to fit the drive shaft. when connected properly you can now join them (motor & prop shaft ) in what should be as close to accurate as you can get with this setup. Now we move on to the C/V joint that has found its way into most front wheel drive cars these days. In my humble opinion this is still the best one. The curve that the ball bearings run in is very accurate & it can drive through a 29 degree angle in any plane without any measureable loss of power, the originals were first made for the B.M.C. Minis & had some teething problems but Sir Alex ( IGGI to his friends) & his brilliant team of engineers solved their problems but got very little praise for them. There are some 20,000,000 minis on the road today (or wrecking yards) all with C/V joints taking the power to the road without much problems. My last word on these C/V joints is read the workshop manual & then READ IT AGAIN. It is well worth the trouble if doing it right the first time can be considered trouble. Mick B. Irish car guy.
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CV joints ? A bit BIG for model boat's Mick O0 tho' if any one can miniaturize them put me down for a few , come one you 3D printer's get designing , show us your skill's . . . .
Bill
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Hi all, if you use a Shuco coupling that is threaded then it is essential to make sure this is square to the shaft. If the plastic centre fails, they usually crack around the brass spline and are not always noticed but they can be replaced also a thick tube will do a great job as well.
Heat the plastic tubing up with boiling water first and it will slip nicely into place and resolve any stresses there might have been if fitted cold.
regards Roy
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Hi All
Have a look at the metal uni joints at banggood website part No.87379.
Good price!!
3 to 4mm/3.17 to 4mm/4 to4mm/5 to 4mm and 5 to 5mm.
Free postage too!!!
Canabus
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Hi All
Have a look at the metal uni joints at banggood website part No.87379.
Good price!!
3 to 4mm/3.17 to 4mm/4 to4mm/5 to 4mm and 5 to 5mm.
Free postage too!!!
Canabus
Also available from Aliexpress with free postage.
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Hi All
Have a look at the metal uni joints at banggood website part No.87379.
Good price!!
3 to 4mm/3.17 to 4mm/4 to4mm/5 to 4mm and 5 to 5mm.
Free postage too!!!
Canabus
I was going to offer this solution, the adverts keep popping up on my facebook page for r/c cars %%
https://www.banggood.com/Feiyue-FY-01FY-02FY-03-Upgrade-Rear-Wheel-Transmission-RL-RC-Car-Spare-Parts-p-1084002.html?rmmds=search
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Another way round this is parallel shafts and either straight cut or worm and spur gears. Experiment I always say In extreme circs they could be at right angles to each other . Now that's put the cat among the pigeons
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Hi John it might put your cat among the pigeons but not mine L.O.L. Mick B. in Canada.
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Glad about that {-) One of our cats will be 30 on 5th next month and she chases seagulls here .The only pigeons are wood pigeons and they have more sense to land in our garden :}