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[Geoff]

HI Josse yes i feel you are right on the batt voltage  an i dont want to change things anymore as its all been changed abot 5 times so im goin with what ive got if i can get 15 mins sailin with her then i'll be pleased an yes this is the first time ive had motors on direct drive as all my other big ships had a 3 to 1 ratio cambelt drive an i never had any probs but i hope to cure this just got to keep tryin as ive invested to much dosh in tiger[/size]cheerschrisb


Okay, there is the miss-match. You are on direct drive so similar motors to those you have used in the past will draw massively more current. If you are using relatively high speed motors then the props are overloading them hence the unusually high current consumption. When you gear them down they are not overloaded as they have much more torque so they draw very much less current. This difference is causing all of your problems.

You need relatively slow revving engines for direct drive in this application.

The observation re current consumption on 6 volts vs 12 volts is in error as on 6 volts the potential difference is so much less the current consumption will drop significantly.

I have measured this with ammeters in the water. ID runs on 6 volts and draws 3.5 amps. On 12 volts it draws over 7 amps and has far too much power. In practical terms about 4 times. Whilst any electrical item will draw what it needs the available voltage makes a huge difference. Its quite a common practice to use 12 volt motors on 6 volts to reduce current consumption assuming the delivered performance is ok.

Many years ago I made a test rig using standard 540 type motors on direct drive for a 6 ft battleship and the current consumption was in the 20 amp range each. When I used belts to a 3 to 1 ratio they only drew 3.5 amps and gave more than enough performance.

In ID I run on 6volts and have a total capacity of 24.5 amp hours and can sail her for about 3 hours plus. The motors are two car blower motors which are designed to run on 14 volts.

The short answer to cure your issues is to do what you have before with a 3 to 1 ratio and this will transform the performance.

Cheers

Geoff

[Geoff]

As an add on it will also completely stop any direct thrust to the engines.


G

[frogman3]

As an add on it will also completely stop any direct thrust to the engines.


G

HI Geoff as an add on will stop thrust to engines ? dont understand what you are sayin sir
chris

[tweety777]

HI Geoff as an add on will stop thrust to engines ? dont understand what you are sayin sir
chris

Since the propshaft is connected to the gearbox rather then the engine there is no thrust transferred into the engine anymore. An additional benefit when using gears only is that a slight movement of the propshaft will not result in loss of power on the propshaft. When using a belt drive this is more of a problem but still less then it is now.

@Geoff,


Thanks for the clarification, I didn't expect that but if the engines are too powerful it sounds logical indeed.

Greetings Josse

[frogman3]

Since the propshaft is connected to the gearbox rather then the engine there is no thrust transferred into the engine anymore. An additional benefit when using gears only is that a slight movement of the propshaft will not result in loss of power on the propshaft. When using a belt drive this is more of a problem but still less then it is now.

@Geoff,


Thanks for the clarification, I didn't expect that but if the engines are too powerful it sounds logical indeed.

Greetings Josse

HI Josse from what i can understand here in the posts if the motors are too powerfull then i am goin to cut down the power fed to them motors by the daul rates on the T/X  to about 70 % power an see how that goes
chrisb

[tweety777]

HI Josse from what i can understand here in the posts if the motors are too powerfull then i am goin to cut down the power fed to them motors by the daul rates on the T/X  to about 70 % power an see how that goes
chrisb

I'm not really firmiliar with dual rates, if that actually cuts the voltage it could work, if not only lowering the voltage will really have effect. But I'm really only guessing here.


Greetings Josse

[frogman3]

I'm not really firmiliar with dual rates, if that actually cuts the voltage it could work, if not only lowering the voltage will really have effect. But I'm really only guessing here.


Greetings Josse

HI Josse yes dual rates work well cutin down the power to the motors BUT they are in the T/X an it says so in my T/X instruckions that i can do this an when my new motor arrives in about novemeber   an lord knows why its takin so long to come but when it does i'll fit it in an let it run for a while to bed it in an then  try out these D/R just got to hope it works on seperate channels an not all of them at once as i have these D/R on my 40 meg futtaba 6 cha R/C  an they do cut down the power  to my HMS NORFOLK  FRIGATE or fit in a ratchet on the throttle on my carsons  T/X so i know they work ive just got to find out how on my carsons 14 channel T/X
cheers for your reply sir
Chrisb

[T888]

Hi Chris,


PM and email sent to Martin

[T888]

Great your back online 

[frogman3]

Great your back online 

Yes Dave  ITS GREAT TO BE BACK i felt as though id lost my best freind    an thank you Martin    many thanks from me to you BOTH
chrisb

[frogman3]

HI GUYS now im back on site any of you got any ideas of why my motor has seized up as i did what someone said that it may need runnin in so i let it run at half throttle for 30 mins an it just got worst an i put a little 3in 1 oil on the bearins an sqirted some wd40 into the motor an now its seized up funny this as ive never had this happen before with a motor so what you guys think ?
chris

[T888]

Chris,


The motor should not have seized on no load run, did the motor get hot? I assume it a new motor or was it the old one ?

[frogman3]

Chris,


The motor should not have seized on no load run, did the motor get hot? I assume it a new motor or was it the old one ?

HI Dave it was a brand new motor that i bought what martin recommened an my god they are powerfull as ratein is 12 to 36v an no it was not under load just fitted in its mountin an screwed down to table top an let run for 30 mins at half throttle
chrisb

[T888]

Then there is an issue with that motor from new, it’s good that you test run it as it could have seized on the lake.

[frogman3]

Then there is an issue with that motor from new, it’s good that you test run it as it could have seized on the lake.

WELL Dave its the motor that broke the universal jiont an prop mountin in side the hull why it did that i dont know as the prop shaft turned easy an all the other 3  motors run great so perhaps it was faulty as i contacted the person who  was sellin them motors to tell him that it has seized up but no answer yet an i'll post a pic if i can of them motors what martin kindly shew me
chris

[frogman3]

HI again Dave here is a linkpic of them motors that Martin recommened an they are a very powerfull motors an im very pleased with them as they moved tiger with ease
https://ibb.co/58Lntjc
an im thinkin of orderin 2 more for my next ship if i do one
chrisb

[T888]

Chris,


They look powerful    the last time I had to use powerful motor like that for a warship model was on HMS Clyde, for her I used 2 MFA Torpedo 800 motors.

[frogman3]

Chris,


They look powerful    the last time I had to use powerful motor like that for a warship model was on HMS Clyde, for her I used 2 MFA Torpedo 800 motors.

any clue on why its seized up though Dave ?
an i may do that hms clyde or hms starling as that has gun turrest on an look a nice ship so at them moment just got to get tiger all set to go
ATB to you an Andrea
chrisb

[frogman3]

Chris,


The motor should not have seized on no load run, did the motor get hot? I assume it a new motor or was it the old one ?

AN NO Dave motor has a big coolin fan fitted in it so no not got hot just started to go slower as it seized up an yes all 4 motors are new an this one had about 5 mins run on load on pond
chrisb
chrisb

[T888]

Chris,


No, but you did say that Tiger blow a 30amp fuse and you fitted a 40 amp fuse, so other than if the prop was jammed, locknut came loose and locked up against the prop or coupling. Without sitting down with you face to face and to go through everything that happened, it’s a bit of guess. sorry can’t help.

[frogman3]

Chris,


No, but you did say that Tiger blow a 30amp fuse and you fitted a 40 amp fuse, so other than if the prop was jammed, locknut came loose and locked up against the prop or coupling. Without sitting down with you face to face and to go through everything that happened, it’s a bit of guess. sorry can’t help.

Never mind Dave yes it did but the prop shaft was not locked an it turned easy an no weed in pond unless i hit a big fish as there are some in the pond an that caused the prop to stop abrutly well never know an cheers for your help today sir
atb
chrisb

[Akira]

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.

[unbuiltnautilus]

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.

[T888]

Good call Alan,   Chris worth looking at.

[Geoff]

My understanding of Dual Rate simply means that you can adjust the throw of a servo - same as with a speed controller. It just means that when you move the stick instead of getting 100% of the power you only get a lesser amount of power. You get the same physical movement but it limits the throttle so the motor won't go as fast. Rather like just using a little throttle instead but fundamentally it may not change the issues of the props overloading the motors. If you geared the motors down or used toothed belts as you have in your other models all of the issues you are having will be resolved.


Cheers


Geoff