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[C-3PO]

https://youtu.be/cDkaDY_OeVU

[frogman3]

Chris, Why are you fitting a 9000 rpm motor? To me, that sounds ridiculously fast. I hope that you get straightened out so that you can run reliably.
[/
quote]


HI AKira  well tiger is very heavy model so to move her these motors are just right better to have to much power then as ive foun out with them smaller motors not enough power
chrisb

[frogman3]

Bit of a left field suggestion, the mounting screws that attach the motor to the mount are not slightly too long are they? Slacken them off a turn or two and see if you can turn the motor over by hand.

YES i  could  turn it by hand but i took the motor right out of the ship to try running it in but it just got so tight only way i could turn the motor shaft was with plyiers so new motor comin
 chrisb

[frogman3]

https://youtu.be/cDkaDY_OeVU

HI JOHNATHAN thank for vid on D/R cheers sir
chrisb

[tweety777]

HI AKira  well tiger is very heavy model so to move her these motors are just right better to have to much power then as ive foun out with them smaller motors not enough power[/size]chrisb

Hi Chris,


I think Akira is more referring to the RPM's being high, the power of the engine is not related to the RPM's. These propellers should not need much more then say 4000 to 5000 RPM to move the ship at a nice topspeed, assuming 45mm propellers if I remember correctly. That means that you could perfectly add a 1:2 gear ratio to get even more power from the eniges while they most likely will run more efficiënt.


Greetings Josse

[frogman3]

Hi Chris,


I think Akira is more referring to the RPM's being high, the power of the engine is not related to the RPM's. These propellers should not need much more then say 4000 to 5000 RPM to move the ship at a nice topspeed, assuming 45mm propellers if I remember correctly. That means that you could perfectly add a 1:2 gear ratio to get even more power from the eniges while they most likely will run more efficiënt.


Greetings Josse

HI Josse yes i understand what you are sayin  an yes i would like to have fitted in a cambelt drive where the prop is geared down to 3to 1 ratio but MFA who made them dont make them any more as ive never had this prob while usein them in my big nimizt carrier an other big warships ive built but this is the very first time ive used motors in the direct drive so thats why im goin to try out them dual rattes to slow down the motor an if you think about it it better to have more power than not enough if yu get my meaning but thanks for your reply Josse
chrisb

[frogman3]

HI GUYS well been havin another look at that seized up motor as i took it out of the ship an tuningthe shaft took a pair of plyeires but when takein out the mounting holdin bolts i found that it then turned freely an ive been running it again at half throttle an it runs ok forward an back so all i can think one of the mountin bolts must be a bit to long so when i tightened it up with their allen key it must have been hitting the armature in the motor so part my fault an the manufacter an it must have locked when runnin an the shock of the locked motor broke the universal jiont so thats a mystrey clearded up an i will dump that bolt as it came in a pack of 20 bolts just my luck to pick out the bad bolt to fit in the mountin to hold the motor 
OH BOY
chrisb

[Capt Podge]

Well Chris, its good to know the problem has been identified, and good call by Unbuiltnautilus.


Cheers,
Ray.

[frogman3]

Bit of a left field suggestion, the mounting screws that attach the motor to the mount are not slightly too long are they? Slacken them off a turn or two and see if you can turn the motor over by hand.

yes sir you were right very well done it was just one which was hittin the armature in the motor would have treid your suggetion earlyer but been busy thank for your info sir as capt podge has said
  at myself lol
chrisb

[T888]

Chris,

First pleased the new motor is OK.



So this has sorted the NEW motor when you were running it in ?


Are you thinking this was the reason for the UJ braking ?

[frogman3]

Chris,

First pleased the new motor is OK.



So this has sorted the NEW motor when you were running it in ?


Are you thinking this was the reason for the UJ braking ?

HI Dave yes i am but my brand new motor has come today so im goin to fit that in an keep the old motor as a spare an i will rig it all up tomorrow an then try it out
chris

[unbuiltnautilus]

yes sir you were right very well done it was just one which was hittin the armature in the motor would have treid your suggetion earlyer but been busy thank for your info sir as capt podge has said
  at myself lol
chrisb

Glad to be of help. Over the years I have seen most things that can go wrong, go wrong! It is all about remembering how I fixed the issue these days!!

[frogman3]

Glad to be of help. Over the years I have seen most things that can go wrong, go wrong! It is all about remembering how I fixed the issue these days!!

HI  unbuiltnautilus  YES MANY THANKS for your help an the  new motor turned up yesterday so today i'll be fittin it in an bein carefull of how tight i do them motor mountin bolts up as dont want this happening again an i will chuck that old bolt away an fit a new one then connect her all up an try her out at half throttle an fingers crossed but i'll keep the old motor as a spare as its goin ok now but back to this happening  the force must have been massive as it not only broke the universal jiont but also broke the prop shaft mountin in the hull an that was fibreglassed in place so hopefully she should be ready for her last sail this yr on octber the 8th at Norwich pond as its a great lake with stright up concreate walls as i not to sure about usein sherigham pond as tiger is qiute big an that pond has over hanging concrete walls so if tiger sails close to the sides it may damage the fore mast so cheers all you guys for your info on this problem
chrisb

[unbuiltnautilus]

When reconnecting all your running gear, make sure you lock nut the UJ at the inner propshaft end. Your photo from quite a few posts ago clearly showed the lock nut hard against the propshaft bearing, not the coupling. If this happened while you were afloat it would seize up the shaft, then rip the coupling to bits. Makes much more sense than a seized up motor causing the failure. So, before sailing, tighten one against the other, don't leave if floating loose. Good luck with the sail.

[frogman3]

When reconnecting all your running gear, make sure you lock nut the UJ at the inner propshaft end. Your photo from quite a few posts ago clearly showed the lock nut hard against the propshaft bearing, not the coupling. If this happened while you were afloat it would seize up the shaft, then rip the coupling to bits. Makes much more sense than a seized up motor causing the failure. So, before sailing, tighten one against the other, don't leave if floating loose. Good luck with the sail.

HI YES i will do as it may have been my fault but as id already did 3 other shafts i may have forgoten to tighten this lock nuts up but for sure it wont happen again as im goin to double check all shafts lock nuts CHEERS SIR for that reminder
atb
chrisb

[Geoff]

You may need several lock nuts because:


- one to lock the coupling in place
- two more to stop the prop shaft pulling out the coupling when going astern


Cheers


Geoff

[frogman3]

You may need several lock nuts because:


- one to lock the coupling in place
- two more to stop the prop shaft pulling out the coupling when going astern


Cheers


OK THANKS Geoff will have to go to model shop to get some more nuts
chrisb


Geoff

[frogman3]

HI CANT put any more lock nuts on that propshaft as there is no more thread on the shaft an short of movin the motors all back an the new motor is all fited in an ive tightened the lock nut up on prop shaft to  against the U/J an running the motors at just over half throttle i found out that for some reason the brass mountin is gettin very hot an i think thats the reason the plastic U/J failed so im goin to fit a small fan near it to blow cold air onto the brass mountin to cool it an i cant understand the reason for this gettin hot as none of the other 3 do an the shaft turns easy so another prob but if the fan cools it then it should be ok
OH BOY
Chrisb

[unbuiltnautilus]

You don't need fans on your coupling, that's just crazy talk! You do say you have tightened the locknut on the propshaft, you should be tightening it on the coupling! Working back from the motor it should be as follows, motor, plain brass insert, UJ, threaded insert, lock nut tightened against threaded insert, about 1/32" free floating fore and aft, a washer, the propshaft assembly, then a washer, a lock nut tightened against your propeller and the back side of the boat. Everything should run nice and free and you should have the slightest fore and aft wiggle on the coupling assembly. Now come on, crack on chap, no excuses!

[T888]

Chris,

Looking at past photos of your prop shaft install, it looks like you have Two washer between the UJ lock nut and the brass bearing mount. If I’m correct, have a look at reducing the washers to one. My reason behind this is, is the motor thrusting and coursing the washers to drag on the bearing and generating heat ? Just a thought.

Also Alan’s( unbuiltnautilus) advice is spot on.

[frogman3]

You don't need fans on your coupling, that's just crazy talk! You do say you have tightened the locknut on the propshaft, you should be tightening it on the coupling! Working back from the motor it should be as follows, motor, plain brass insert, UJ, threaded insert, lock nut tightened against threaded insert, about 1/32" free floating fore and aft, a washer, the propshaft assembly, then a washer, a lock nut tightened against your propeller and the back side of the boat. Everything should run nice and free and you should have the slightest fore and aft wiggle on the coupling assembly. Now come on, crack on chap, no excuses!

sorry unbuiltnautilus) i got that wrong the way i worded it i have tightened the locknut against  the U/J BRASS coupling an not on the prop shaft as yes it would just lock on an yes im crackin on an no exscuses
chrisb

[frogman3]

Chris,

Looking at past photos of your prop shaft install, it looks like you have Two washer between the UJ lock nut and the brass bearing mount. If I’m correct, have a look at reducing the washers to one. My reason behind this is, is the motor thrusting and coursing the washers to drag on the bearing and generating heat ? Just a thought.

Also Alan’s( unbuiltnautilus) advice is spot on.

OK Dave  an    (unbuiltnautilus) i'll take off one washer an give it about a 1mm play an just hope that stops the heat build up honest in all my 30 odd yrs of building big warships ive never had this probs an ive never done direct motor drive either but im still learning on this but cheers for your help guys chrisb

[frogman3]

OK Dave  an    (unbuiltnautilus) i'll take off one washer an give it about a 1mm play an just hope that stops the heat build up honest in all my 30 odd yrs of building big warships ive never had this probs an ive never done direct motor drive either but im still learning on this but cheers for your help guys chrisb

HI Dave  an unbuiltnautilus)  WELL I REMOVED the motor an u/j AN took off the lock nut an removed one of the washer to stop heat build up an now there is a easy tuning prop shaft an abouta 1mm of play on said shaft

AN THEN put it all back togeather an tightened up the lock nut against he U/J AN RAN THE MOTORS for about 5 min an it still gets hot an the other shaft has also fitted with 3 washers so the match but the one with red U/J DONT GET HOT crazy isnt it an some linkpics
https://ibb.co/C0KQRx6
AN HERE IVE REMOVED THE LOCK NUT AN ONE WASHER SO THERE IS ABOUT 1MM OF PLAY ON THE EASY TURNING SHAFT
https://ibb.co/GcGtmDX
AN IN THIS PIC CAN BE SEEN THE 1MM PLAY GAP
https://ibb.co/jZGKV31
AN THIS SHAFT has 3 washes on but it dont get hot
https://ibb.co/myb2crK
so will try it out but may have to buy all metal u/j

chrisb

[T888]

Hi Chris,


Just don’t under stand it. Some questions


So is it just one of the shafts that is getting hot ?


If so is it the one that broke the UJ ?


I assume it’s just the steady bearing that’s getting hot ?

Am I correct in assume that all shaft spin freely?

[Rob47]

Seems pointless to buy metal Uk, as the problem probably will still be there. Need to find out what is causing it first in my humble opinion
Bob