Gears - Another question

[uss silversides]

As usual I have another question. Could someone PLEASE try to help me find some gears? What I want is metal ?pinion? gear on the shaft of the motor running 3:1 reduction to a plastic gear on the drive shaft. My problem is that I don't know where I can inexspensivly buy good gears, and I don't really understand all of the terminology associated with gears, but I CAN put together a good drive system if I have the gears. Sooooo..... if someone out there could find me some gears that will mesh together smoothly to form a 3:1 reduction with a metal gear on the motor and plastic gear on the drive shaft, I would be most grateful .

-Note- The gears must be small enough to fit in the stern of a Gato (so there will be two units).

I might be asking a way too much, but I thought I'd ask any way..........

Best Regards,
Jonathan



Edited By USS Silversides on 1070419617

[wheels]

Jonathan....Why not use belt drives

Jonathan....Why not use belt drives as they are more efficient. You can get them from SubTech or Ship N Things. Either of these two vendors will help you decide what's best for your application.

Jim Wheeler

[Guest]

Only toothed belt drives tend

Only toothed belt drives tend to be more efficient than gears, and they are generally much more expensive than gearboxes, especially if bought ready made.

Theoretical gear transfer efficiency is in the region of 90% with toothed belt around 93-94% at best.

The main advantage of using belt drives, is that they run virtually in silence. To get silent running gears requires a helical cut tooth pattern, and those gears can prove as expensive to purchase as a belt drive.

Some UK links for gears. They are all happy to deal with modelmakers]http://www.hpc-gears.co.uk[/url]

http://www.muffett.co.uk

http://www.davall.co.uk

BTW, metal pinions are not required except for very high RPM or torque applications in my experience.

Cheers

Andy

[uss silversides]

Thanks for the input! Yes,

Thanks for the input! Yes, I have considered a belt drive, but balked at the high prices . All I really want is something cheap and reliable (I don't care if it makes some noise; the real ones made noise, didn't they?). Andy- these links you gave me look great, but my problem is that I don't know which gears to get. All I'm looking for is a couple of plastic gears that will mesh together smoothly to form a nice 3:1 reduction. On the small side of course, because I'm going to need to fit two of these units in my boat. As I said before I do not understand all the terminology associated with gears. So if anyone else does, and has a little spare time, I would be very grateful if you could find me what I need.

Jonathan



Edited By USS Silversides on 1070494096

[Guest]

Hobby Lobby sells a nice

[color=#0000FF]Hobby Lobby sells a nice 3]

[uss silversides]

If that would be too

[quote]If that would be too costly for you, maybe you would want to use one motor driving a 3]

That's EXACTLY what I wanted to do, but it seemed to simple to work. I am going to be building a wtc from Greg Sharpe's plans, and I would like to have one shaft running out of the cylinder and then the option of attaching another shaft. Okay, some of you are thinking that this is ridiculous, but it would be perfect for several different models, some having one screw, some having two. Anyway, my real problem is that I still do not know which gears to get. Anybody want to help?

Jonathan

Oh, one more thing.... with that setup I would probably want to use a bigger motor, right?



Edited By USS Silversides on 1070500098

[tmsmalley]

How well would a gear

How well would a gear setup to drive the screws work in the wet portion of the sub?

Would there be "friction(?)" caused by the water "stuck" in the teeth of the gears?

I know guys use them in low speed applications like bow planes, but utilizing them wet at higher speeds?

[tmsmalley]

How well would a gear

How well would a gear setup to drive the screws work in the wet portion of the sub?

Would there be "friction (not sure if that's the right word?)" caused by the water "stuck" in the teeth of the gears?

I know guys use them in low speed applications like bow planes, but would there be problems utilizing them wet at higher speeds? Need bigger motor, more amps, etc?

[Guest]

Using gears in the wet

[color=#000080]Using gears in the wet portion of a sub works just fine. Probably imparts a little more friction, but I reckon this is minor.

I'm sure Dave merriman uses this principle on some of his WTC's and I know that Craycraft WTC's used to implement this feature on twin screwed boats.

You do not need two seperate units to power a twin screwed boat, unless you wish to run the screws independantly for enhanced turning capability. A single motor with twin driven gears will suffice.

In relation to your question regarding what gears to select, this is quite straightforward in a basic sense, but can get a little long winded when you get into the nitty gritty of it all.

It is all fairly straightforward, but wordy, and frankly I haven't enough time to write a small book on this posting.

All the gear manufacturers I have listed supply booklets or CD-ROM's giving formula's and info on selecting the right gears for your project.

Second guessing a system for you is difficult if not nigh on impossible, as you have given no information on the size of the Gato you wish to power, the motor you wish to use, the prop you would like to swing and the speed you would like the boat to run at.

How did you arrive at the need for a 3]



Edited By Sub culture on 1070560276

[uss silversides]

Tim- I thought of that,

Tim- I thought of that, but I too was concerned about the resistance of the water. Even though Andy cleared that up, I still will probably put a "cage" around the gears to keep the accasional seaweed, etc. that drifts in the hull from playing havoc with the gears.

Second guessing a system for you is difficult if not nigh on impossible, as you have given no information on the size of the Gato you wish to power, the motor you wish to use, the prop you would like to swing and the speed you would like the boat to run at.

Duuuuhhh!!! I should have thought of that! The boat is a 1]http://www.subcommittee.com/forum/icon_biggrin.gif[/img] .

Speaking of sealing rings (here we go again..... off the topic), I would like to make my own. How should I do this?

To get back on the topic]Subconcepts[/url]

Jonathan



Edited By USS Silversides on 1070594736

[Guest]

The motor you linked to

The motor you linked to is a Speed 400 motor. A bit too small for the model you are building IMHO.

Two working in parallel might be sufficient. You'd probably want a bigger gear reduction too, as Speed 400 rev a little higher than larger motors.

If you have room for it I'd take a look around your local breakers yard, and take a peek at the motors you find in fan heaters and radiator cooling fans in junked cars. Other sources include windscreen wiper motors and electric window winder motors.

These motors are cheap, torquey and much better quality than the average model motor.

They're also inherently efficient and their multi pole design lends well to low speed running.

They do tend to be heavier and more bulky than the average model motor, however in a boat of 52" you should be able to accomodate one.

Seals are available from Norbert Bruggen and Subtech. I recommend the simmering style of sealing.

A cheaper alternative is the use of a silicone O-ring.

May I suggest you invest in a copy of 'Model Submarine Technology' by Norbert Bruggen.

Available from Traplet at]http://www.traplet.com[/url]

It will enlighten you no end.

Cheers

Andy

[uss silversides]

I actually already have Norbert's

I actually already have Norbert's book. A little technical, but it's definitely a good book. As far as the motors go, do the junked motors run well off of 6 volts? Do they draw much current? Will they fit in a 3" tube?

Jonathan

[bob the builder]

I can vouch for the

I can vouch for the car rad motors (mine, at least). It's about 2.5" diameter, 3.5" long, and has a 5/16 shaft. It pulls 1A free running, 4A under full (I mean FULL) load, and 14A at a complete stall. I think mine spins at about 1300 rpm (which is fine for my 3.75" diameter prop).

Cost me $4CDN, brand new from a surplus store.



No idea what this motor came out of, but it sure does the job! The shot below is taken in by bathtub testing facility at 1/2 throttle!
.

The shot below is of the motor mounted in my first generation WTC section. The tube is 3.25" diameter (3" ID) material.


Full details of my project can (as always) be found at
RC-Sub.com

[uss silversides]

Thanks! Isn't 4amps a lot

Thanks! Isn't 4amps a lot though?

[bob the builder]

Everything is relative, I guess.

Everything is relative, I guess. I'm running a 7Ah battery, so I've got plenty of run time. When I said that 4A was full load, I meant that the motor was bogged down to many times what the normal load would be.

A better guess would be about 2 to 2.5Amps at full throttle.

(Just to be sure we're comparing apples to apples here, I'm running on a 12V system, not 6V)



Edited By Bob the Builder on 1070652612