Topic: Motor noise...help required (Read 6736 times)

jenga · « **on:** January 07, 2015, 02:27:04 pm »

greetings-Happy New Year to you all

Fitted motor/shaft to my Envoy tug, it is aligned without any obvious wobble, I have put reference lines on the hull interior to sight the coupling to and it looks spot on. However the motor sound like a hammer drill.
I have about 1mm end float on shaft as advised on here.
I have removed coupling and attached drill to shaft.....no noise, even when moving drill from side to side/up and down
I have refitted coupling with 6mm drill bit in motor end and attached this to drill...no noise, even when moving drill from side to side/up and down
I have run motor, fixed to hull but not driving shaft...no noise
put it all back together and all hell breaks loose
Using a Hyco?/? coupling but that doesn't seem to be problem as it runs ok when powered by drill
Motor bed is firmly bedded down, no cavities underneath
It sounds to me that the motor is under stress, but all runs freely
I am running at max as speed controller no fitted yet
Motor is a MFA919d with 2.5/1 reduction
really need help with this problem, thanks in advance
Jenga

boatmadman · « **Reply #1 on:** January 07, 2015, 02:48:05 pm »

Try replacing the huco coupling with a length of silicone hose. Use the brass inserts on the shaft and motor and just slip the hose over the splined shaft on the inserts.

Use hose that is a bit smaller diameter than the insert diameter so it has something to grip with.

Ian

jarvo · « **Reply #2 on:** January 07, 2015, 02:50:59 pm »

Hi Jenga

Add to boatmadman,s advice, is one of the brass inserts even slightly loose? they should be a firm press fit, could be that they are moving slightly

Mark

jenga · « **Reply #3 on:** January 07, 2015, 03:13:11 pm »

thanks for replies,
When I power shaft including coupling from electric drill there is no noise,see above 1st post, so I doubt its the coupling, but will try what you say .
Also forgot to mention that hull is bare, no decks fitted or cross bracing, might this influence it??
and shaft is supported on the motor end by cross bulkhead approx 25mm from coupling, so no whip in shaft.
removing prop as no effect, so not a prop balance issue
jenga

roycv · « **Reply #4 on:** January 07, 2015, 03:26:42 pm »

Hi I had a similar problem and it was the Huco coupling. When it was locked with a locking nut to the prop shaft it distorted the line up. I fitted a washer between the nut and coupling and after careful tightening up it was fine.
regards Roy

rnli12 · « **Reply #5 on:** January 07, 2015, 04:26:23 pm »

Hi,
I changed all mine (couplings) to rubber (hose); plastic couplings have a tendency to resonate through the speed bands.
Hope this helps.

Rich

jenga · « **Reply #6 on:** January 07, 2015, 04:28:43 pm »

well £1.88 later (for silicone tube) I have found a definate improvement, will try another type of coupling.
any recommendations for 6mm plain X4MA threaded coupler heavy duty type?
jenga

radiojoe · « **Reply #7 on:** January 07, 2015, 04:59:30 pm »

Hi Jenga,
I have a MFA919d motor in my Envoy, they aren't the quietest of motors, metal gears etc. and mine was initially noisy when first connected to the shaft and coupling, I took in out and removed the gear cover it was nearly dry I liberally greased it with light grease and it improved it a lot, it was actually quieter after the boat had its deck and super structures on, it could be as you're running it in an empty hull that it's resonating on the unsupported hull sides,

jenga · « **Reply #8 on:** January 07, 2015, 05:35:30 pm »

Hi Joe, wife thinks the same re empty hull, will lube gearbox as you suggest
Jenga

boat captain · « **Reply #9 on:** January 07, 2015, 05:47:24 pm »

Lubricate the shaft as well that might make a difference. When in the water a lot of boats sound a lot quieter. As stated it could be resonation of the hull with it having no stiffening in it.

jenga · « **Reply #10 on:** January 07, 2015, 05:50:39 pm »

all lubed up, a little bit better, shaft was always lubed. soldier on
jenga

rnli12 · « **Reply #11 on:** January 07, 2015, 05:53:45 pm »

Hi,
Car Fuel line hose is ideal, internal bore to suit a tight fit.
RRs

Buccaneer · « **Reply #12 on:** January 07, 2015, 07:29:32 pm »

Hello Jenga,
Bear in mind that when in the water your prop will rotate a lot slower than it does on full power in the fresh air. This and the resistance of the water will give you a much more stable propshaft as well.

Tug-Kenny RIP · « **Reply #13 on:** January 07, 2015, 08:17:59 pm »

Quote

I am running at max as speed controller no fitted yet

Bit of shock when connected up ......mmmmm instant top speed.

Try it with a speed controller with a gentle start and then rev her up slowly. You will be able to analyze it better then.

ken

Davenotdone · « **Reply #14 on:** January 07, 2015, 09:14:14 pm »

I had the same problem with a model boat with the Huco coupling, really noisy and lots of vibration. Changed to one of Marks Model Bits rubber type of couplings ( i think he makes any size you want ) and instant smoothness and allso silent. I allso noticed everything is smoother and less noisy in the water than running it dry on the work bench, regards, Dave.

jenga · « **Reply #15 on:** January 07, 2015, 10:58:59 pm »

fitted ESC and problem is much reduced up to 3/4 throttle, it is definately the gear box. I can live with it now. thanks for your advice.
jenga

slug · « **Reply #16 on:** January 08, 2015, 07:27:28 am »

bought a couple of huco type couplings last year...they made a hell of a row...the brass inserts had been drilled off centre ....regards tony

Tug-Kenny RIP · « **Reply #17 on:** January 08, 2015, 10:40:41 am »

So pleased for you. Glad it's traced.

Try filling the box with new thick grease and surround it with speaker felt. As mentioned, it also won't sound so bad when at sea surrounded by water.

Cheers

ken

jenga · « **Reply #18 on:** January 08, 2015, 12:12:15 pm »

cheers for that tug kenny, I have well lubed the gears, but to be honest the machining of the gears seems a bit wanting so what I got is the best I'm gonna have. If I sent it back, I bet they would say its up to standard, coupled with the hassle, is it worth it, look on the bright side....saves fitting a horn to warn others Im there...lol. pity it wasn't more deisel engine sounding...onward and upward
jenga

radiojoe · « **Reply #19 on:** January 08, 2015, 01:10:02 pm »

I wouldn't worry too much Jenga, these are industrial grade motors, when the gears bed in a bit they get smoother and quieter, yes you can hear my tug coming as it approaches, but I actually like the sound she makes, especially when going astern to stop her, it sounds quite realistic, and I've yet to hear a silent full size tug.

Stavros · « **Reply #20 on:** January 08, 2015, 02:34:05 pm »

Quote from: Tug---Kenny on January 08, 2015, 10:40:41 am

So pleased for you. Glad it's traced.

Try filling the box with new thick grease and surround it with speaker felt. As mentioned, it also won't sound so bad when at sea surrounded by water.

Cheers

ken

Ken Personally I wouldnt advocate filling ANY gearbox with grease.....a light smearing YES BUT filling it up will cause a couple of problems

1 you can double and poss trebble the amp draw of the motor as it has to work HARDER to overcome the grease

2 Grease everywhere as it gets warm and ozzes out of the gearbox

3 HEAT build up in the gearbox.....could cause HIGHER amps to be drawn

Dave

inertia · « **Reply #21 on:** January 08, 2015, 03:14:23 pm »

I had the same problem with the two geared motors on the ACTion show demo board, so I drilled a small hole in the top of each of the plastic gearbox covers and give them a squirt of aerosol oil now and again. They still sound like two skellybobs making whoopee in a biscuit tin but they're a lot quieter than before.
I think Dave J is right ref using grease - I avoid the stuff except for propshaft end bearings. BTW I had the same setup in my Envoy and it sailed beautifully.
DM

radiojoe · « **Reply #22 on:** January 08, 2015, 03:18:07 pm »

Quite right, grease should always be used liberally and should be light grease or better still ceramic grease, these are only models after all.

Netleyned · « **Reply #23 on:** January 08, 2015, 03:20:59 pm »

Quote from: radiojoe on January 08, 2015, 03:18:07 pm

Quite right, grease should always be used liberally and should be light grease or better still ceramic grease, these are only models after all.

'Liberally' Don't you mean 'Sparingly' Joe ?

Ned

jenga · « **Reply #24 on:** January 08, 2015, 04:10:21 pm »

I only used enough to coat the gears, turned it by hand to distribute it, its a teflon based waterproof light grease. It did take away the metalic messing noise so it will help, I know not to stuff prop shafts etc with grease because of extra loading on the drive so I did take care. many thanks peeps
jenga

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Author Topic: Motor noise...help required (Read 6736 times)

Stavros

inertia