Model Boat Mayhem

Technical, Techniques, Hints, and Tips => Other Technical Questions... => Topic started by: bosun on February 04, 2007, 05:25:45 pm

Title: noisy gearbox
Post by: bosun on February 04, 2007, 05:25:45 pm
Hy Guys
 I have just fitted a Como 6volt motor with a 6 to1 gearbox into a converted steam tug model of 43 inches, the problem I have is the gearbox makes a grinding noise when running, it does,nt get warm so it is not binding, is this the norm ,and have you any ideas how it can be quietened down.
 Thanks in advance
Bosun
Title: Re: noisy gearbox
Post by: ministeve on February 04, 2007, 06:37:35 pm
hi bosun Ive not had too much to do with gearboxes but if it is a sealed type can you not fill with a quality grease? just a thought
Title: Re: noisy gearbox
Post by: poll on February 04, 2007, 07:48:02 pm
      Hi Bosun, have you run the motor on the bench? If you have and
      the noise is still there you need to strip the gear box clean it and
      re grease it. IF the noise is only when it's in the boat check your
      prop shaft is not tight if it is this will overload the gear box.

      Regards

      John.        POLL
Title: Re: noisy gearbox
Post by: Shipmate60 on February 04, 2007, 07:53:25 pm
Most gearboxes make quite a lot of noise.
If the tug runs as you want try and go for direct drive at the same revs.
Graupner do quite a selection and give the rev range too.

Bob
Title: Re: noisy gearbox
Post by: FullLeatherJacket on February 04, 2007, 11:40:51 pm
I use these motors and boxes all the time BUT a good silicon grease is advisable, as is the other stuff. These boxes are noisy anyway; if you want quiet then belt-drives are better. Best solution is either earplugs or an MP3 player. I tell myself the noise is scale diesels.........
Be thankful you didn't get the Graupner gearboxes (skeletons in a biscuit tin)  ;)
Suit yourself
FLJ
Title: Re: noisy gearbox
Post by: Bunkerbarge on February 05, 2007, 01:14:39 am
I have a Hectaperm with a built in gearbox and that is noisey.

The only thing I would say is strip it clean it and put it back together with fresh grease but make sure that the shafts are in alignment.  The biggest single cause of gearbox noise is misalignment of the teeth.  If you do all that then it isn't going to get any better. 

Don't forget though that there are a number of real boats out there with gearboxes that also make the same noise!!
Title: Re: noisy gearbox
Post by: bosun on February 05, 2007, 01:42:19 pm
Hy Guys.
Thanks for all the collective advice, the gearbox and motor combination is new, I did,nt think I would have to grease it, as I surmised it would all be factory set, I took it out of the boat and tried it, still noisy but not so much, re,aligned it back to the shaft and that was a little better, have now convinced myself to thinking it is a diesel engine simulator, did,nt want to take it apart, I have bad memories of trying that with an old clock once (could,nt get it back together so that was a No No,) I drilled a small hole in the top of the gearbox casing and injected some grease, doesnt sound much better with a dry run, will give it a test in the bath later. On most of the fishing boats I have owned  From 16 ft to 30 ft the gearboxes were noisy, but mostly when going astern,  this little gerabox seems to outnoise them all, I think I will stick to straight through on my next boat ( St Jan ) due this week from MMM,.
Once again thanks for all the input
Bosun
Title: Re: noisy gearbox
Post by: BarryM on February 05, 2007, 02:43:12 pm
Gearboxes whirr, hum or buzz but if, as you say, it's new and it's grinding, then take it back and get it changed.
Title: Re: noisy gearbox
Post by: HS93 (RIP) on February 05, 2007, 04:17:55 pm
can you swop the gears for toothed  .belts?? Ive found them ok ,they don't sound like a cement mixer..Peter
Title: Re: noisy gearbox
Post by: Shipmate60 on February 05, 2007, 07:17:37 pm
Go for direct drive motor in the same rev range as the geared motor.
Nice and quiet.

Bob
Title: Re: noisy gearbox
Post by: bosun on February 05, 2007, 08:59:15 pm
Hy Guys,
Thanks again for all the replies, I apreciate your time. I have ordered the Lady Jan from MMM, should be here this week it  is almost exactly same size, scale ect as the one I have been building, I will go for the same motor as they recomend and get one each for the both boats, I think your right Bob,,, no more gearboxes for me ,keep to straight drives from now on.
Once again many thanks
Bosun
Title: Re: noisy gearbox
Post by: funtimefrankie on February 06, 2007, 08:49:27 am
I've just fitted a similar into my MMM "Canning" and also found it noisey. It's not been in any water yet.
I wondering whether to go down the direct drive route instead.
I've a four blade  3inch prop, what motor would you tuggies recomend? I don't think I'll be doing any towing with the boat.
I've an old Johnson marked 888, I might try.
i'm planning to run on 12 volts.
Frank