Model Boat Mayhem
Technical, Techniques, Hints, and Tips => Engineering Techniques and Materials. => Topic started by: ACTion on November 17, 2011, 09:12:10 am
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A little local skirmish on another thread led me to research Huco couplings and I found some stuff on Farnell's website here. http://www.farnell.com/datasheets/529891.pdf (http://www.farnell.com/datasheets/529891.pdf). HUCO's own website has much more detail but I'm afraid that me and Newton.Metres don't agree at this hour of the day.
The implication is that those HUCO-Pol couplings much beloved by us boat mogglers are only rated up to 1000RPM! Our Aussie agent John Darke always recommends the use of the flexible jaw type with his geared motors. They are a lot more expensive but it makes you wonder how so many of us have got away with it for so long. I shall certainly think twice before using the 'plastic rattlers' again. There's always the flexible tube type made by our old friends Marks Model Bits.
I leave the floor to the cognoscenti for further debate.................
Dave M
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Most of our models have low enough torque that the coupling can handle it, also commercial suppliers de-rate as the coupling could be used in a continuous duty application. At about 10000 RPM Ive had the "legs" that hold the spider fly apart releasing the spider.
Nick
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Dave you are correct that it is not long before a Huco joint shows play in it. Sadly whatever plastic the joint is made of wears quickly. Why do i use them? Well its the range of inserts and the ease of fitting.Youre also correct that a lot of lads down my club run them at highish speeds.John.
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In Hucos defence, I've not had a coupling go faulty or wear out that wasn't my fault.
They used to do a range of white UJ with sort of alloy inserts that seemed higher grade components but I don't seem them around these days....
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I always try and fit Mobile Marine ones with shear pins, good quality couplings.... :-))
Russ
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A little local skirmish on another thread led me to research Huco couplings and I found some stuff on Farnell's website here. http://www.farnell.com/datasheets/529891.pdf (http://www.farnell.com/datasheets/529891.pdf). HUCO's own website has much more detail but I'm afraid that me and Newton.Metres don't agree at this hour of the day.
The implication is that those HUCO-Pol couplings much beloved by us boat mogglers are only rated up to 1000RPM!
I leave the floor to the cognoscenti for further debate.................
Dave M
glad you should mention that, Dave
The reason I made the constructive comment was that I once had a Caldercraft PCF boat that I had built as a review model for (I think) Radio Control Boat Modeller and they were fitted with high revving big torquey motors (similar these days to the torpedo 850) and was fitted with the couplings that Martin mentions. The white ones with alloy couplings. I had left the end shafts connecting to the couplings protruding some two-3inches from the Tubes for access to the motors under the deck, as the rear deck was fully closed for access/water tightness.................I only did one sailing run with it.and in my younger inexperienced days way back in the early 1980's...........yes, you guessed it....one coulping shattered under the high ( think about 6 -7000rpm,) and as it shattered, the shaft bent with the inertia at that speed with half a coupling still attached to it adding weight,almost at right angles, taking some of the prop tube with it and punched a hole through the grp hull.....I had to go into the lake at Fleetwood fully clothed to retrieve a very quickly sinking boat.I still hadn't got full photo coverage for the magazine article.
The electrics ( twin robbe 200 speed controllers at the time) plus futaba receiver where kaput with the salt water ingress into the hull and I learned from my experience.
Huco are not made for high speed motor transmission and the start up torque that a lot of motors give, especially if they are put under other stresses also.
Glad you brought it up Dave, so that I could give my views in a calm and none biased manner. :-))
neil.
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i have used huco couplings & found them very good however i now use the robbe / graupner one's on all my boats now they seem a better coupling :-))
i have seen on e bay metal couplings any one else seen them or used them??? regards ray
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I have read conflicting reports on drive couplings. I will be running two Graupner 720BB motors with prop shop 55MM props.I am told that the Hugo( hope that is the right name) joints are noisy. I would like the best that I can afford & I don't want noise but I do want them to be reliable. I have NO experience with these joints, Help please, Mick B.
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Hi irishcarguy,
They shouldn't be noisy if you spend the time to align them... and align them perfectly.
If you don't feel confident about achieving perfect alignment, use two couplings back to back, which creates
a cardan type coupling like a prop shaft on a rear wheel drive car.
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I would agree that HUCO joints are noisy, even when the alignment is perfect. Both Marks Model Bits and Mobile Marine Models sell a joint which consists of two brass fittings joined by heavy duty hose - rubber or plastic depending on the duty required. These have no moving parts and so are quite silent.
Barrie
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I agree with Barrie , I replace the central part of the coupling with silicon tubing as used for exhaust pipe joiners on model glo engines. Make sure you have a size smaller than the splined parts of coupling.
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Can't agree more, changing all mine over to rubber fuel pipe, silent and with a little bit of give.
Paul.
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Don't matter which coupling type you use, still not fully effective if drive and driven shafts are misaligned.
Regards Ian.
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I've just checked my brass Huco couplings and the splines are about 7.9mm, so I take it that any tube with a 7mm ID will be ok to use? Only problem is I can only find silicone tubing with a 6mm ID....I'm just hoping it will stretch if I buy a length.. :embarrassed:
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I must agree with Circlip O0
An engine to shaft alignment ...be it on a model ship or a full size vessel is the same
Today we have theodolite encrypted digital equipment to analyze the alignment & still get it wrong <*<
>>:-( what happened to practical engineering of 50 or 150 years ago?
I could suggest the same applies to our model engineering today..... {-) Derek
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Our couplings are free from any noise, and unlike Huco couplings don't put uneven strain on your motor and driveline, and won't break...
Andy :-)
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We have loads of 6mm ID silicone tube here. Ours stretches to 8.5mm no problems.......
Mark.
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if you want something even more heavy duty use these there great.
http://www.modelboatbits.com/index.php?p=1_58
i use mmb ones there great never had a problem they dont slip there quiet highly recommend mmb couplings :-))
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Used one of the spline/PVC tube type couplings marketed by Rip-Max more than 50 years ago to fasten an ED Racer to a propshaft on the old Seaplane tender, - broke the propshaft due to whip and that was at far less revs than some of todays Electric offerings. Another type was the Spring type, section of coiled spring (like the Sillycone ones shown) between the shaft ends. Best one we found was the single ball and pin type. Never let us down, although it was correctly aligned.
Yes DWD, what has happened to Muddle building and ingineering???
Regards Ian.
Just seen the MMBtype offered, sorry, there must be a strain on the shafts if not aligned, basic mechanical properties.
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I like the PVC and similar tubing for motor/shaft couplings for all the reasons given above. However, as boat modellers I could never understand why we use a single universal (Cardan) joint in our boats. We think of universal joints allowing for some degree of misalignment in between the driven and driving shafts, however with a single universal or Cardan joint we have to have the two shafts perfectly aligned. If we don't we get jogging in rotation, noise and the accompanying vibration. Getting shafts properly aligned in our small sizes can be quite difficult at times. When they are close enough aligned to prevent the noise and vibration, we may as well install a solid joint rather than a single Cardan coupling for all the good a single Cardan joint does.
If we use a double Cardan joint separated by 90 degrees we end up with a constant velocity joint and a for smoother quieter operation. We can have slight misalignment between shafts with no detrimental effects such as noise and vibration. The "rubber tubing" joints do this very well for our sizes. There are manufacturers of double Cardan joints, Graupner comes to mind, that do a far better than a single cardan joint.
John
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Don't forget John, cardens, either single or double, when used in industry usually have a sliding coupling (Car prop shaft) in the drive line.
Regards Ian.
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Hi Circlip & all.......
This is not a simple or silly issue....... >>:-( <*< "the installation of the prop shaft & alignment of the engine in our models"
My call is we don't need theodolite encrypted digital equipment %%......but..... O0 we may use dial indicators :o .......[a version of a dial indicator is the human eye :-X]
Possibly....one of our more senior builders may take up challenge & offer comment to help us all....... :-)) .....Derek
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I could never understand why we use a single universal (Cardan) joint in our boats. John
I agree with that. I used them on my first ship, and the transmission is noisy. I used double ball joint couplings in my destroyer and that is much quieter, which indicates that it is mechanically more efficient in compensating for minor missalignments, inevitable when using 2mm shafts despite using Plastruct tube to align the motor mountings before fixing down. Even 0.1 mm out is 5% of the shaft diameter. A single ball joint can only compensate for angle, not angle and axial missalignment.
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It is a simple issue Dereck, Lazyness and conveniance makes it complicated. Check how the old Flash steamers used to couple up.
Regards Ian.
Edit. It's not a "Senior builders" problem, It's Mechanical Engineering.
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Don't forget John, cardens, either single or double, when used in industry usually have a sliding coupling (Car prop shaft) in the drive line.
Regards Ian.
Quite right Ian, forgot to mention that.
John
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A method I've used ,with success , to get alignment with a single Cardan coupling is to couple the motor as close as you can to the correct alignment. Connect the motor to a battery with an ammeter appropriately connected between the two. Start the motor and and adjust it's alignment until you have the minimum number of amps going to the motor. You'll here the noise level, amp draw decrease as you get closer to the proper alignment.
John
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Possibly....one of our more senior builders may take up challenge & offer comment to help us all....... :-)) .....Derek
Derek
Must have missed something, thought I'd already done that.
John
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Guys.... >>:-( I think my point has been missed.......
I am sure many senior members [not necessarily in years but in building experience]....could offer say ten liners on how to :o
Consider the design......install the prop shaft.....install the engine mounting...."alignment".....bedding in the engine mounting....etc...
This may be too easy for experienced senior builders ....but the thought was for our newer or younger members.....Derek
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I like the PVC and similar tubing for motor/shaft couplings for all the reasons given above. However, as boat modellers I could never understand why we use a single universal (Cardan) joint in our boats. We think of universal joints allowing for some degree of misalignment in between the driven and driving shafts, however with a single universal or Cardan joint we have to have the two shafts perfectly aligned. If we don't we get jogging in rotation, noise and the accompanying vibration. Getting shafts properly aligned in our small sizes can be quite difficult at times. When they are close enough aligned to prevent the noise and vibration, we may as well install a solid joint rather than a single Cardan coupling for all the good a single Cardan joint does.
If we use a double Cardan joint separated by 90 degrees we end up with a constant velocity joint and a for smoother quieter operation. We can have slight misalignment between shafts with no detrimental effects such as noise and vibration. The "rubber tubing" joints do this very well for our sizes. There are manufacturers of double Cardan joints, Graupner comes to mind, that do a far better than a single cardan joint.
John
John, I understand what you're saying about the 'double joints' which are soooo much better than a single U/J (of any size), due to the difficulty of setting, and maintaining, a single joint.
However, strictly speaking the joints are 'universal' and a Cardan is a shaft assembly with a U/J at each end - so you can't really have a 'single cardan joint'
Mark.
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There are several quite easy ways to align the motor to the shaft.
One of the simplest is to simply cut a length of brass tuning the same length as coupling and fit over the splines.
If you use this method you will need to cut a spiral in both ends.
This is so the tube can be a good tight fit and will not affect the alignment (eg droop) too much.
Do not let the motor hang on the tube but adjust your mounting till you get a good sliding fit.
Another way is to fit heat shrink around the universal joint and use as avove.
With a little patience it is not so terrible to get good alignment.
And lastly of course there is by good old eye and slow running.
One additional problem is that some of the coupling ends are not bored true so even lining up exactly CAN still lead to vibration.
The rubber tube type couplings can take misalignment and although will use additional friction, surprisingly little, and of course with no moving parts no noise.
These can still be aligned as above.
Bob
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Martin
At Derek's worthwhile suggestion, I offer my name into the hat to do a write up on motor mounts and U joints in model boats if there's interest. It'll be along the same line as the air brushing tutorial I did.
I'm due to give a talk on this subject at one of our upcoming boat club meetings, so I may as well do both.
if interested let me know.
John
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Guys.... >>:-( I think my point has been missed.......
I am sure many senior members [not necessarily in years but in building experience]....could offer say ten liners on how to :o
Consider the design......install the prop shaft.....install the engine mounting...."alignment".....bedding in the engine mounting....etc...
This may be too easy for experienced senior builders ....but the thought was for our newer or younger members.....Derek
as well as the less senior ones , that is, less experienced O0 O0
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Old iron,
I am interested :-)) :-)) you are never tooooooooooo old to learn
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Thanks oldiron......... O0 ....everyone 'sort of' thinks they know 'the best way' about couplings >>:-(.....but thats why the subject keeps cropping up :embarrassed:
Now....an example.....if a new member asks.........how do I go about spraying my model?...........easy answer ...."just read the tutorial on the subject by oldiron"......... :-))
Derek
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One of the simplest of ways to align a shaft and motor is to get a various brass rods made up by someone with a lathe bored out to teh relevant shaft dia.
I have had some made up with 2mm/3mm/4mm/5mm dia the right length of a Huco coupling and never get a missalighned coupling.The more solid the coupling for alignment the better it is
Dave
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Thank you all, it is obvious that this is a topic that needs some more research & discussion from what I am reading here, so John I think it would be very good if you did just as you suggested. In the auto industry I have found on several occasions propshafts have been assembled wrong because the u/joints at either end were not aligned with each other & caused massive vibration. Usually we find it right after a customer installed their own u/joints(mechanics get it wrong too) What does surprise me is that no company has made a constant velocity joint which today are nearly universal in front wheel drive cars. Now there is a challenge for one of our interprising companies.The response to my question leaves me in no doubt that this is an ongoing problem & an area in modeling that could be greatly improved with some research. Not everybody in our hobby has the skill to make sure that drivetrains are in perfect alignment. My final thought is that the use of plastic tube in the joint is the safest bet for now. So once again thank you fellow forum members as always you all have been a great help to me & others reading this thread. Mick B.
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I'll start to put something together on the subject. Give me about a week to get prose and pictures together.
John
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Hi guys
As a newbie this alignment issue has been a big problem to think about pre restoration (fifties Hales Spraymaster). Just slowly turning the prop I could see a little movement at the unsecured motor. A friend has just made me a mount that has a little adjustment possible and is better layed out for my ex IC boat- so I really think I can do it now......... but I remain puzzled how one could tell the motor thru red moveable joint and on to the prop is perfectly aligned before I tighten everything up .............. after all the beeping red thing is loose and moves in a couple of planes at once and seemingly at will. {:-{
Yes please lads- a nice sticky lesson with the various options explained would be lovely for anyone new like me. :-))
Regards Dave
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I use the Dumas 'dogbone' connectors because they are easy to extend or shorten and they 'float', allowing the propshaft to slide under load without putting pressure on the motor.
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Thanks John, I will be glued to my computer & hanging on every word. I think it has been needed for a long time & it will benefit a lot of members. That is very kind of you to take the time. Mick B.
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One of the simplest of ways to align a shaft and motor is to get a various brass rods made up by someone with a lathe bored out to teh relevant shaft dia.
I have had some made up with 2mm/3mm/4mm/5mm dia the right length of a Huco coupling and never get a missalighned coupling.The more solid the coupling for alignment the better it is
Dave
It follows logically, that if the shaft et all, are aligned as per the above and other similar methods, then why is it necessary to fit any type of "flexible/universal" type coupling, why not a direct rigid connection shaft to motor.
My understanding is a "flexible" coupling compensates for any miss alignment.
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"My understanding is a "flexible" coupling compensates for any miss alignment. "
Yes but also, allows for other separation of the shaft and motor... mind you a solid coupling would do that.
Another thought is that the shaft and motor are mounted independently ( an uncommon datum? ) so the
coupling should compensate for this. Things like servos, drills, food mixers, internal combustion engines all share
a common chassis that is internal to the construction of the machine, I don't think a boat's hull truly provides that.
There are a few motor mounts that do sort of do that, the Robbe & Graupner straight-to-shaft mounts and integral
gear reduction drives.
.... my science teacher, Mr Davies, was right, "Are you listening boy?"
(http://www.astecmodels.co.uk/catalog/images/g2328.jpg) (http://www.cornwallmodelboats.co.uk/acatalog/1972_lrg.jpg)
(http://matthewsmodelmarine.files.wordpress.com/2009/06/mas30303.jpg)
(http://www.modelboatmayhem.co.uk/My_models/Springer/images/Springer_017.JPG)
( also see: http://matthewsmodelmarine.wordpress.com/writings/all-geared-up/ )
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Although you would think that a solid brass coupling with grub screws is infallible, it's not.
I have a couple of these that have double grub screws, 2 at each end. I have found that if the motor shaft is not exactly the same diameter of the bored hole, when tightening the grub screws up onto the shaft, one will always tighten before the other, throwing the shaft off centre. it the same thing happens at the other end, but opposite, the 2 shafts end up well out of alignment and vibration is quite bad....
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There is hope!
Hi all, I am just setting up a Huco coupling in a bare not completed hull. Mine was noisy with vibration. I tried everything, 2 sets of joints you name it, I have lots of spare inserts etc.
After a long morning I found the culprit. The threaded coupling locked onto the prop shaft was slightly misaligned when the locking nut was tightened.
I put a washer between the lock nut and the coupling and carefully tightened up (counter turning nut and coupling), keeping it nice and 'square'.
I put the power on again and it just went silent! Vibration and noise all gone.
Mind you I have to disconnect for painting and hope I can again get a nice free running connection.
Hope this helps, Roy
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Roy,
Did you use a "locking" washer or plain washer?
Bob
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Hi Bob, just a plain washer a bit less than 1mm thickness. So that it did not deform.
I have in a previous boat used a plain end with grub screw but it was a tight fit onto the shaft. This worked OK.
regards Roy
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Just a thought Roy, might be worth a spot of locktite on the threads as the washer will reduce the effectiveness of the locking.
Bob
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Hi Bob, thanks, I will do that on final assembly.
regards Roy
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"My understanding is a "flexible" coupling compensates for any miss alignment. "
Yes but also, allows for other separation of the shaft and motor... mind you a solid coupling would do that.
Another thought is that the shaft and motor are mounted independently ( an uncommon datum? ) so the
coupling should compensate for this. Things like servos, drills, food mixers, internal combustion engines all share
a common chassis that is internal to the construction of the machine, I don't think a boat's hull truly provides that.
There are a few motor mounts that do sort of do that, the Robbe & Graupner straight-to-shaft mounts and integral
gear reduction drives.
.... my science teacher, Mr Davies, was right, "Are you listening boy?"
( also see: http://matthewsmodelmarine.wordpress.com/writings/all-geared-up/ )
Martin,
Thank you :-)) :-))
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Hi all, I raised the issue on another thread last week as I noticed during some tests that the Huco couplings were very noisy, no they were not misaligned !. I am waiting for some bright engineer to design a C/V joint like we use on cars, or even some company with skilled designers should be able to do it . Any ideas anybody?.
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metal uj's do exist allready. http://www.ebay.co.uk/itm/universal-joint-coupling-3-18mm-4mm-rc-model-boat-scale-/150676441577?pt=UK_ToysGames_RadioControlled_JN&hash=item23150409e9
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Hi All
From a newbies point of view it would be helpful if someone could post up pics of the various couplings available.
Thanks guys - now back to lurking :}
Dave
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MODEL BOAT UNIVERSAL JOINTS
I can hear the voices emanating form the work sheds and shops again …….. ”universals! Which, what , how, why?”
This is a subject that many tend to gloss over and a few ponder. It’s a topic I don’t think I’ve seen/heard anyone delve into, why do we use them, what is the theory behind them, what s the best to use for my application. With this tutorial I’m going to attempt to clear up some of the above questions about these mysterious little necessaries in the hulls of our vessels.
DEFINITION
What is a universal joint by definition?
A universal joint, universal coupling, U joint, Cardan joint, Hardy-Spicer joint, or Hooke's joint is a joint or coupling in a rigid rod that allows the rod to 'bend' in any direction, and is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges located close together, oriented at 90° to each other, connected by a cross shaft.
HISTORY
The Universal joint is recorded to have been invented by an Italian mathematician by the name of Gerolamo Cardano in 1545.
In 1678 and English man wrote of universal joint for Cardano’s device in his book called ‘Helioscopes’. Since then the names Cardan(o) and Hooke have been linked to the universal joint device. The Hooke or Cardan joint was initially used as a single element in a shaft with a an angular displacement and resulting non uniform rotating speed across the joint. Hooke proposed using a second Hooke joint on the same shaft, shifted by 90 degrees, to eliminate this variation in rotating speed. Although it wasn’t 100% successful, it did reduce the rotational speed problem. A later CV or constant velocity joint eliminated the speed difference entirely.
In model boating, most off us have used a single universal (Hooke, Cardan) joint to connect our motors and prop shafts. In many cases this is attended by excessive noise and vibration with queries as to why? With a single Cardan joint, the two shaft ends have to be perfectly aligned. Any discrepancy in alignment between the ends of the shaft will cause binding with an accompanying vibration and noise. A single Cardan joint can allow one shaft to have a slight (usually no more than 15 degrees) angular misalignment. However, the two ends of the shaft must be perfectly aligned as the center block on the single Cardan joint won’t allow for horizontal or vertical displacement. Only a double Cardan joint can allow for vertical or horizontal displacement to some extent.
Shaft joints could be can be offset in four different ways. (see below):
(http://s7.postimage.org/tfd7hg6tj/universal_alignmnet.jpg) (http://postimage.org/image/tfd7hg6tj/)
Any one of the above discrepancies in alignment will cause noise and vibration when our model operates. In order to get a truly aligned shaft, these discrepancies have to be taken out of the alignment of the two shafts. Putting in a coupling shaft with two Cardan joints will compensate for some of this, however, the closer two shafts can be aligned, the quieter, smoother running the motor/shaft combination will be and the less amps the motor will draw.
Automobiles, at least the older ones with rear wheel drive, use a drive shaft with two Cardan joints. Like our boats, they wouldn’t work very well with on Cardan joint. Front wheel drive cars use constant velocity universals, a different animal from the Cardan joint.
SHAFT ALIGNMENT
On larger shafts dial test indicators, verniers and feeler gauges are used to set alignments of shafts accurately. That isn’t really possible on our small cramped quarters, so other options have to be looked at.
The simplest, but not necessarily the most accurate method of shaft alignment is visual alignment of the two shafts, taking into consideration the four directions a shaft can be out of alignment. This method will certainly get you close enough into the ball park to allow the use of a double Cardan shaft to take out most of the differences between the prop shaft and motor.
A more accurate method would be to slide a piece of firm tubing, such as brass, over the motor shaft and prop shaft. This will hold the motor and prop in alignment until you have the motor mount permanently fastened in its proper location. Remove the motor from the mount and install the double Cardan shaft. (note: we will look at motor mounts in a future section of this tutorial).
Another method of checking alignment of motor and prop shaft is to install the motor and connect it to the prop shaft as is normal. Allow the motor mount to be adjustable as to position, or allow the motor to be adjustable inside the mount. Set up an electric supply to the boat motor with an ammeter in series with the motor leads. Bring the motor up to a moderate speed and watch the amp load on the meter. Adjust the motor position to get the lowest amp reading (you’ll note quite a change in motor noise as you do this; it gets quieter as you get closer to the correct alignment). When satisfied that you have the lowest amp reading and noise level, fasten the motor into position and recheck. This method can provide a very accurate alignment for our small vessels with a minimum of hassle.
MODEL UNIVERSAL JOINTS
What’s available for model boats? Most use the single Cardan Huco joint for model boat applications. However, as you’ve seen above this is not always adequate. Two Huco joints back to back or on the ends of a shaft 90 degrees offset will work. Huco also make a conversion to take two of their Cardan joints with a center piece to make a proper double Cardan shaft. These can work very well. Graupner offer a similar item but in a slightly small size that is adequate for most vessels.
Dumas make a nice simple little unit consisting of two brass ends with a preformed nylon wishbone. This gives the double Cardan effect with a 90 degree offset. They’re reasonably priced and simple to install. The design of the ends allows the wishbone to move and take up any differences in distance between the motor and prop shaft.
As has been pictured above, there is also the rubber coupling. These can work well in vessels with prop sizes less than 1 ½” diameter. They are quiet, when properly set up, and easy to install.
(http://s9.postimage.org/wbf0ff5nf/IMG_2265_2.jpg) (http://postimage.org/image/wbf0ff5nf/)
Graupner double Cardan joint
(http://s7.postimage.org/offr9i16v/IMG_2269_2.jpg) (http://postimage.org/image/offr9i16v/)
Huco single Cardan joint
(http://s7.postimage.org/q7mi9mop3/IMG_2272_2.jpg) (http://postimage.org/image/q7mi9mop3/)
(http://s7.postimage.org/pks6xuh6v/IMG_2274_2.jpg) (http://postimage.org/image/pks6xuh6v/)
Dumas double Cardan joint
(http://s7.postimage.org/w64wxlx1j/IMG_2262.jpg) (http://postimage.org/image/w64wxlx1j/)
scratch built double Cardan style with dog bone
I hope this gives some insight into model boat universal joints and the correct way to go to get them to work properly. I all answer any questions I can.
John
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Martin:
I'm trying to add more images to this tutorial via "ADD IMAGE TO POST" and it doesn't seem to want to let me do it. Any suggestions
Thanks
John
No worries, problem found.
John
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Hi John
this is interesting and I was lookingfor something like a lesson too - so thanks.
Just reading elsewhere about Huo being speed rated too - that's what got me
interested. Hope you post more up.
Dave
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Hi John
this is interesting and I was lookingfor something like a lesson too - so thanks.
Just reading elsewhere about Huo being speed rated too - that's what got me
interested. Hope you post more up.
Dave
Thanks Dave. Glad you found it interesting
I'm going to add more. May have to wait till after Christmas though.
John
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John,
Thank you. O0 O0 O0
Was also able to save it as a Word document complete with the pics :-)) :-)) :-)) :-))
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Hi all, I raised the issue on another thread last week as I noticed during some tests that the Huco couplings were very noisy, no they were not misaligned !. I am waiting for some bright engineer to design a C/V joint like we use on cars, or even some company with skilled designers should be able to do it . Any ideas anybody?.
Mick:
You may be interested in what I just put on this thread:
http://www.modelboatmayhem.co.uk/forum/index.php?topic=34327.msg341675;topicseen#msg341675
John
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With regard to HUCO couplings and RPM's, don't forget this web site (http://www.farnell.com/datasheets/529891.pdf) gives specs relative to industrial joint applications. Our red model boat joints aren't shown on the charts on this sheet.
Industrial RPM's tend to be lower for a given application than our model marine applications.
John
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With regard to destruction of HUCO, and other u joints at speed, don't forget vibration is the biggest destroyer of U joints. The biggest cause of vibration is misalignment of the driven and drive shafts.
john
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Thank you John, this is very informative, please continue. I assume you already know that we in the auto trade run into the problem of the sliding joints on the propshafts (driveshafts in North America)being installed out of alignment after being separated for repair. If this happens the vibration is horrendous & can wreck the shaft in a very short amount of time. I would love to see some manufacturer come up with a C/V joint for our drivelines.(I will be away over Xmas but will catch up when I get back) Mick B.
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A company in the states called 'small parts' used to supply miniature CV joints. They weren't cheap, and they don't seem to list them now- perhaps they didn't sell well.
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Hi John I think we are popping back & forth between two threads which is O/K as it exposes the subject to a wider audience. It is certainly a subject that needs a good discussion, I just wonder how many models out there have misaligned shafts/couplings without the owners actually having any idea that they are wrong. I think your thread will help a lot to make members more aware of the potential problems that may be affecting their drivelines John. Mick B.
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Thanks Micjk and Raaarty, trying to help out where I can.
John
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Thank you John, this is very informative, please continue. I assume you already know that we in the auto trade run into the problem of the sliding joints on the propshafts (driveshafts in North America)being installed out of alignment after being separated for repair. If this happens the vibration is horrendous & can wreck the shaft in a very short amount of time. I would love to see some manufacturer come up with a C/V joint for our drivelines.(I will be away over Xmas but will catch up when I get back) Mick B.
I ran into that with my 1966 Chevelle. Put the drive shaft back and the vibration was amazing. Turned it a quarter and it settled down. Never had that problem before though.
John
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I still maintain that for our purposes it is loony to use a UJ that will tolerate no axial (I think) misalignment. I think there's a lot to be said for a pin and disc arrangement so there's a air gap between the motor shaft and the driven prop shaft. After all the Huco type of UJ is primarily used in car drives where the driven shaft can, and has to move as the axle or wheel moves. In the case of our shafts we don't have to accomodate movement of the driven shaft.
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I too have been unhappy with the performance of conventional couplings so wherever possible I prefer to use belt drive which effectively decouples the shaft from the motor. Of course this is only really practical in scale type models where only moderate power is being transmitted but in this application it is very effective and allows easy gearing down as a bonus..
Colin
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Hi John I think we are popping back & forth between two threads which is O/K as it exposes the subject to a wider audience. It is certainly a subject that needs a good discussion, I just wonder how many models out there have misaligned shafts/couplings without the owners actually having any idea that they are wrong. I think your thread will help a lot to make members more aware of the potential problems that may be affecting their drivelines John. Mick B.
Mick:
You're quite right about many model boaters falling into the trap of using a single U Joint and expecting it to compensate for misalignment. I've seen it in just about all the model boats in our club, and many others besides. I've built up a number of cars over the years and one wouldn't think of only using a single Cardan joint on a drive shaft, however, model boaters do it regularly.
I hope the write up gets some people thinking about what they are doing.
John
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I still maintain that for our purposes it is loony to use a UJ that will tolerate no axial (I think) misalignment. I think there's a lot to be said for a pin and disc arrangement so there's a air gap between the motor shaft and the driven prop shaft. After all the Huco type of UJ is primarily used in car drives where the driven shaft can, and has to move as the axle or wheel moves. In the case of our shafts we don't have to accomodate movement of the driven shaft.
U joints can and do accommadate axial misalignment up to 15 degrees. It cannot be done with one U joint as most model boaters do. One needs two Cardan joints back to back, or on the ends of the same drive shaft, and set 90 degrees apart. The Huco outfit sells the appropriate parts to make their traditional red U joint into a proper double Cardan joint that gives proper axial displacement. I'm not sure why, we as modelers, don't use the proper set up , but insist on doing half a job and then complain that it doesn't work. See this thread if you haven't already:http://www.modelboatmayhem.co.uk/forum/index.php?topic=34327.msg341675;topicseen#msg341675
John
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For those who insist on using Huco joints, here is what you need to convert a single Huco Cardan joints to a proper double Cardan coupling. I've found several of these available on Ebay at present.
John
(http://s12.postimage.org/6lk49jbix/Huco_double_Cardan_joint_converter.jpg) (http://postimage.org/image/6lk49jbix/)
This is used to convert your single Huco joint to a proper double Cardan joint that will accept axial displacement and make your motor shaft set up run quieter.
(http://s9.postimage.org/ahvnnlv8r/Huco_double_Cardan_joint.jpg) (http://postimage.org/image/ahvnnlv8r/)
This is what you have after you have installed the converter.
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Or for much less money, fit one of our silicon couplings that will never give you any such trouble as the awful red plastic ones....
Andy %)
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John,
You may need to check the link couldn't get it to work.
A minimum would seem to be, two of the universal joints back to back or better still a double.
as you say why aren't we promoting doubles for boating use.
Besides the one illustrade in your 'tutorial' what other "Doubles" are available
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try http://www.modelboatmayhem.co.uk/forum/index.php?topic=34327.msg341675;topicseen#msg341675
Dave
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How much less, plus postage to Oz ????
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Thanks Dave :-)) :-))
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That was as smooth as Arkwrights Till {-)
Dave
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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
(http://s9.postimage.org/k4imjuqgb/Marx_joint.jpg) (http://postimage.org/image/k4imjuqgb/)
(http://s10.postimage.org/88wraunet/Marx_joint_in_springer.jpg) (http://postimage.org/image/88wraunet/)
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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
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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.
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A world of couplings....
http://www.huco.com/products.asp?cat=46 (http://www.huco.com/products.asp?cat=46)
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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.
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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.
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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
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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
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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. :-)) :-))
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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 :-)
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A world of couplings....
http://www.huco.com/products.asp?cat=46 (http://www.huco.com/products.asp?cat=46)
Yup, but these are industrial couplings.
John
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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
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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
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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
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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.
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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. O0
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
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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.
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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.
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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
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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.
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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
(http://s9.postimage.org/x9a8qib97/Huco_double_Cardan_joint.jpg) (http://postimage.org/image/x9a8qib97/)
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Yes it does John, you are once again on the ball as usual, Mick B.
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Do belt drives tend to wear the bearings more Peter?
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Ultimately it must as the load is overhung.
Regards Ian
Modded. Depends on tension put on belts. Most light loads will be OK.
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And, further to my last, another disadvantage of the HUCO type UJ is that the plastic bits are a very tight fit on the brass ends, so it is impossible to disassociate shaft end float from motor end float. I suspect a double cup and pinned ball arrangement might be more satisfactory all round - cups on both the motor shaft and the prop shaft, with a free floating dogbone in the middle.
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Do belt drives tend to wear the bearings more Peter?
I suppose they would, Martin, but I've never had a bearing fail yet. I guess that's mainly due to the fact that they are only used for an hour or two a week. Also, as Ian said, the tension is light, just enough to stop slippage.
Peter.
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And, further to my last, another disadvantage of the HUCO type UJ is that the plastic bits are a very tight fit on the brass ends, so it is impossible to disassociate shaft end float from motor end float. I suspect a double cup and pinned ball arrangement might be more satisfactory all round - cups on both the motor shaft and the prop shaft, with a free floating dogbone in the middle.
Like so.......
.......or , one can run the next size larger drill through the hole in the red plastic coupling to allow the freer movement of the brass block in the yoke.
John
(http://s11.postimage.org/9zblufzfz/IMG_2272.jpg) (http://postimage.org/image/9zblufzfz/)
(http://s11.postimage.org/54hww614f/IMG_2274_2.jpg) (http://postimage.org/image/54hww614f/)
Dumas dog bone style coupling with a nylon dog bone
(http://s8.postimage.org/qhb1s0jnl/IMG_2262.jpg) (http://postimage.org/image/qhb1s0jnl/)
Scratch built
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Goodness oldiron {-) ...I knew this was a subject for discussion & that is why I suggested it be put under one tutorial thread
We now have an extra 25 comments from members with their thoughts & experiences...which naturally I respect.......... :kiss:.
However :police: ...we still need to sort the fact from fiction %% or the good from the not so good O0 in the final washup tutorial......
regards to all ....Derek
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Goodness oldiron {-) ...I knew this was a subject for discussion & that is why I suggested it be put under one tutorial thread
We now have an extra 25 comments from members with their thoughts & experiences...which naturally I respect.......... :kiss:.
However :police: ...we still need to sort the fact from fiction %% or the good from the not so good O0 in the final washup tutorial......
regards to all ....Derek
Really started something here. I think we need a moderator to combine both threads. Its getting a little unwieldy with two going on the same subject.
John
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Do belt drives tend to wear the bearings more Peter?
Yes I know you mean the nice peter not me :o , but I use toothed belts because you don't have to have them as tight, I run stainless steel ball races anyway so no problems with side forces except if you run a motor with bushes just make shore that the bushes are oiled.
peter
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Oldiron - right on, Mate. Happy Christmas and where can I get some?
(I usually "ease" the holes in the UJs too!)
Happy Christmas.
This is a really useful thread addressing a problem common to many of us.
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Oldiron - right on, Mate. Happy Christmas and where can I get some?
(I usually "ease" the holes in the UJs too!)
Happy Christmas.
This is a really useful thread addressing a problem common to many of us.
Thanks......Merry Christmas your way too.
I bought the Dumas couplings at my local hobby store. Here's the web site for Dumas: http://www.dumasproducts.com/index.php?cPath=39_86
The unit in the other picture I scratch built since I have a lathe. Helps a bit, but not everyone is as lucky.
I'm surprised how wide spread the problem is
John
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To further complicate the issue %) , here is a photo of some scratch built couplings I made from brass rod, turned in the lathe, and a short length of speedo cable for flexibility.
They are fitted in my Armidale class patrol boat and work a treat.
Peter.
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Very clever design Peter, also John I think your design solves the problem about 95% as well. There would still be a slight friction on the pins I would think, but a very big improvement on what most of us are using today. Who would have thought when this thread started that so many problems existed, How many boats are running with misaligned shafts/motors ?. your writeup is very timely John, certainly needed from reading the posts on here. A question Peter, did you soft solder the speedo cable into the brass couplings,?.Mick B.
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Hey Peter (HS93)
That motor arrangement in your first picture above is really neat and compact - it looks great. O0
Dave
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I use this method for setting up a mount I have a spare long shaft that has a point turned on the end I fit the piece of metal I am using for a mount and push the shaft till it Marks the centre for the motor I then drill it etc then re fit and put a small flange on the end of the shaft bring it up to the mount and adjust till the two faces are the same, I also have some flanges the same dia that will fit motors so I fit one and if they line up with no gaps then the motor is spot on , I then put in the normal shaft and fit the coupling, I found this to be the most accurate , bits of tube can be used but if the angle is wrong on the mount it will still tighten up but be out of line when finished.
Peter
this took 5 attempts had to load each part separately picture at a time or I got the normall 504
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Really started something here. I think we need a moderator to combine both threads. Its getting a little unwieldy with two going on the same subject.
John
We can do that John but when we merge topics, they merge according to the time stamp on each post so it may get quite confusing!
Martin
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Hullo Martin & oldiron......... {-)
It may be a little confusing at the first read when the two threads are combined..........but still far better than as two seperate threads.....
However ..."we still need to sort the fact from fiction or the good from the not so good in the final washup tutorial" ...... & we should leave this up to oldiron as he is doing a great job......... :-))
Derek
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But he hasn't mentioned pin and disc or Leather disc couplings - - - - Yet. {-)
Regards Ian.
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Hey Peter (HS93)
Now that last post was worthy of a standalone thread in itself :-)) and having such a
nice clear explanation with the pictures, made it really easy even for me to follow. O0
From looking at the ply base you must have worked out all the dimensions in advance
so it looks perfectly built rather than just an ad hoc assembly. Any more posts like that
and I just might have to free up a few tired old brain cells to absorb your demonstrations.
Dave
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Hmm. Another hour gone! As is the way of the web, you go looking for answer to A, end up getting answers to B, C and a lot of other stuff you didn't know you wanted to know. (I love looking in tool catalogues - just to see the tools for jobs I never knew needed doing.)
Anyway, back to topic, I have acquired (by default really) Raboesch 'single' universal joints, which having read all the above I will probably convert to doubles. However the splined brass inserts to go to the shafts are not a very tight fit in the couplings. I'm thinking from some of the above that they are meant to allow for the half mm of longitudinal play in the prop shaft (between ahead and astern) and so the motor should be installed with a little bit of clearance between the shaft ends and the coupling parts. Or should one or both of the splines be glued in place?
If I do double them I'm thinking it would be a good idea to glue at least the link insert into the centres of the couplings, to ensure it's a solid shaft there. Opinions?
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great info
subscribed
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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.
Now I love 'a man who can' and Mick (Irishcarguy) is certainly one of those who can 'engineer'. Having been less that satisfied with what he had found on offer he went away and arrived at a solution (not that he has yet finished with all possible improvements yet). I am sure he will reply and explain all, but basically he has taken a constant velocity joint from model car racing and adapted it to usage in a boat. You need to machine the correct shaft diameter and thread when converting but you'd expect that. Mick very kindly made me one for a Tosher I have in mind. I couldn't stop twiddling with it - nice weighty thing compared to the Hucos I have used. I should have posted pix by now but have been extremely busy visiting hospital this week. I have taken a couple on the iPhone and if I can't get them up in the next hour I will email them to Pettyofficernick before I go to work. .... So hopefully pix will appear later this evening.
Dave
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The info ended up at http://www.modelboatmayhem.co.uk/forum/index.php?topic=41338.msg415414#msg415414
Dave