Motors and Reductions - question

[wayne frey]

I was thinking about what size motors and reductions to use in my 1/96 Typhoon.
I would think either a 500 or 600 would be close. I do not want to underpower it,but do not want to put too much in it either.Gear reductions come into play here also. 3-1 is pretty common,but maybe I should drop down a little deeper.
The goal,of course,is good performance and run time.
This is also a good general question for those that custom build,rather than go with the kits that we already know what works. Is there a formula,or is it "this is about right" kind of thing?

[bob the builder]

Wayne,


John T. VanderHeiden used 500

[color=#000000]Wayne,


John T. VanderHeiden used 500 series motors in his project, with 3]

[tom spettel]

Wayne go to Hobby lobby's

Wayne go to Hobby lobby's web site they have everthing
you want in motors and gear boxes. just went there yesterday and they have "new" corless motors with
gear box attached for about $70.00!!!! also they have a high torgue corless motor that the center of the case rotates instead of the comutater!! neat stuff man check it out

tom

[wayne frey]

Since we seem to have

Since we seem to have the ball rolling....
I see "speed 500" motors and torque motors.
I picked up a 700 BB torque engine for the Akula.
I know the BB stands for ball bearing.What about torque vs speed motors? Looking at the specs at some websites there is a difference in draw,amps, that kind of stuff.
What about reductions?
Is it the prop rpm we are looking at matching to peak engine output? If so, is there an ideal speed? Or does "gearing down" output have other factors to come into play?
I have found many different versions of the 5-700 motors at the Tower Hobbies website.
Also,since we are here.Do people see advantages in belt drive over gear drive reductions?
I do not know for sure,but I would think belt drives would be a little more quite.

[adriaticsea]

Hi Wayne,

well, I can at

[color=#000000]Hi Wayne,

well, I can at least answer the question about gear boxes]

[Guest]

In a boat of that

In a boat of that size and displacement, I would fit two heater blower fan motors, direct drive (simple, silent).

Have a look in your local scrapyard for a couple of decent european cars of the same make and model(i.e. Volkswagen etc.) and liberate the heater fans.

Running at 12 volts, these will give a shedload of torque at low RPM and will give excellent slow running (these motors usually have around 11 pole armatures or greater), as well as drawing low current.

They'll be much cheaper than Speed 500's too!

For some guidelines on motor sizing/gearing-

http://www.modelcontrol.com/electricmotor1.htm

Andy



Edited By Sub culture on 1095969544

[wayne frey]

That was a good last

That was a good last response.Great links. Thank you.
Today I have heard from two that are running Typhoons. It seems a 500,which I am ok with trying, with a 3-1 will work on the Typhoon well enough.
The 1/72 Akula I think will be a different story. It throws a pretty big prop. I considered a 900 size motor.Seemed like too much though.Thinking about run time also. The 700 BB torque seemed the logical choice. I do know I will have to gear that bugger down a good bit. Seaking peak efficency, I am guessing a tug boat pull of around 6 to 1. Even 9-1 has been suggested. She is a big hull. Up to real scale speed will be fine.
This link is getting a lot of views. More feedback may help others in their choices.
Thanks so far..

[graydon]

In a boat of that

In a boat of that size and displacement, I would fit two heater blower fan motors, direct drive (simple, silent).

Have a look in your local scrapyard for a couple of decent european cars of the same make and model(i.e. Volkswagen etc.) and liberate the heater fans.

Running at 12 volts, these will give a shedload of torque at low RPM and will give excellent slow running (these motors usually have around 11 pole armatures or greater), as well as drawing low current.
For some guidelines on motor sizing/gearing-

http://www.modelcontrol.com/electricmotor1.htm

This is very true. I work in HVAC with GM. The blower motors that we use on some of our new cars are very powerful. Some of the more powerful ones will draw 25amps at 14VDC (think of the newer Cadillacs and big Buicks/Oldsmobiles). They will move alot of air. The motors we have on the radiator fans are quite powerfull too but be carefull here because on most modern rad fan motors, the motors are short and fat. I think to fit in a sub, the older style rad fan motor (long and narrow) would be more appropriate. Most current blower motors are long and narrow. Most are either 10 or 12 poles too which helps them to provide smooth torque. They should be pretty cheap in a salvage yard.

Another thing to consider is that the HVAC modules use some rather powerful electric actuators on some of the newer cars which would make nice servos or general actuators in a sub.

There are smart ones with internal processors, dumb ones with external processors and really dumb ones with no feedback even. (In some of the newer cars, we do not use feedback from the electric actuators - we use feedback from outlet temperature instead which is really slick.)

HTH

[anonymous]

I have two Graupner 900

I have two Graupner 900 bb torque motors for sale. You can have both for $120.00 plus shipping. Both new in their original boxes. These are excellent efficent motors, with ample power. Perfect for a 1/96 Typhoon direct drive. Excellent slow rpm performance too. Unavailable in the United States. These motors are used often and highly prized in Europe.

See motor stats here.

http://homepage.ntlworld.com/edward.....ner.htm

Steve Reichmuth





Edited By Dolphin on 1096074382

[koeze]

These are excellent efficent motors,

[color=#000000]

These are excellent efficent motors, with ample power. Perfect for a 1/96 Typhoon direct drive. Excellent slow rpm performance too. Unavailable in the United States. These motors are used often and highly prized in Europe.

Absolutely true.

My Walrus 1]

[wayne frey]

That 900 is an interesting

[color=#000000]That 900 is an interesting hoss.
Ok,here is a good general application question,for me and for others.
Say I run the duel 900's in direct drive.Would I loose run time due to higher amp draw,or would it be about the same as running say a 500 with a 3-1 reduction? Is there a math table or something that would show us? If I were better off to use the 900's,it sounds like many people are missing the boat on this approach.Direct drive would be easier to rig and surely quieter. It is the mission of the boomer to be silent]

[bob the builder]

I'm thinking more and more

I'm thinking more and more about simply pulling my existing motor and WTC for it and dropping it in my Typhoon. That was my initial idea when I designed my WTC with Greg... fully 'plug and play'.

What I'm thinking about now is a dual output gearbox with a [b]2] ratio. My motor spins at a max 2000rpm, pulling only 4amps under full (near stall) load. Normal cruising is more around 1.5 to 2amps and fulll stall is 14amps.

By doing this, I can eliminate the need to construct yet another WTC, and I get the great performance of my tried and true rad fan motor!

I was looking at jumping on those 900's, but they're about the same size as my rad fan motor, pull more juice, and spin at three times the speed as my existing motor. They also cost many times more than my surplus motor (which I paid $4 CDN for, brand new).

Now I just need to find a good source for gears...

[boss subfixer]

Hey Bob the builder, I

Hey Bob the builder, I had to replace a gear in a 1970's vintage roto tiller some years ago and found it at a place called "Boston Gear" (www.bostongear.com).They have an area called gear theory linked on the left side that may help you figure out what you need and you should also be able to get the gears through them or a distributor. I don't know much about current pricing sorry.
Hope this helps.
BSF

[Guest]

That 900 is an interesting

[color=#000000]That 900 is an interesting hoss.
Ok,here is a good general application question,for me and for others.
Say I run the duel 900's in direct drive.Would I loose run time due to higher amp draw,or would it be about the same as running say a 500 with a 3-1 reduction? Is there a math table or something that would show us? If I were better off to use the 900's,it sounds like many people are missing the boat on this approach.Direct drive would be easier to rig and surely quieter. It is the mission of the boomer to be silent]

I think people tend to stick with what is known to work, rather than sit down and quietly think through an alternative approach.

Direct drive is always preferable to a gearbox. Less friction, simpler, no noise (although belt drives are pretty much silent), cheap, easy to install.

However it isn't always possible to achieve this, because most model motors are built with low windings for high revs and small diameter armatures/cans which makes for a lightweight motor.

When geared down (if required) these small lightweight motors can provide a lightweight, torquey and fairly efficient power system perhaps to swing a large prop or propel a R/C truck. However is this what we need for a mdoel sub or boat?

Well unless we're building very small or an underwater fast electric- nope!

I have been making models for a number of years and have tried most types of electric motors. Folk producing kitted submarines and WTC's need to use off the shelf motors with a consistent supply- they can't go looking for small batches of surplus or scrap motors in breakers yards or at model shows.

However, if you are growing your own WTC or building a boat from scratch, then you have the freedom to source a better motor for the job.

If building a small boat, I look for surplus Buhler or Maxon motors, if building a larger boat I go down the local breakers and dig out an old heater fan motor. Windscreen wiper, radiator fan and electric window/seat motors are also viable alternatives. These motors rarely cost more than a couple of pounds and are far better quality than anything you'll find in the model shop.

Another source of motors are electric powered caddy's. I was given four of these, all of them had broken frames but the motors and gearboxes were working. These turned out to be fantastic motors- 12 pole, ballraced, replaceable brushes and will last forever in a modelling application.

Another good source of small electric motors are old video recorders. The motors used for fast forward and rewind are often DC and low voltage. I found a couple of nice Maxon motors in an old Grundig VCR once.

Most of these motors produce between 3000-6000RPM, the ideal range for scale marine. They draw very little current, are extremely well made and give more than adequate torque.

Andy

[anonymous]

These 900 bb torque motors

These 900 bb torque motors would be ideal for a Typhoon or even a 1/32 scale Fleet boat. They would be more efficient than a smaller motor with a belt/gear reduction, since energy loads are not wasted in a gear reduction even if the set up is done by the most fastidious model engineer. Clean, simple propulsion arrangement. I no longer need these motors, so I would like them to see a good home. These would also be perfect direct drive for a 1/30 scale German 212, a similar size Dolphin, a large scratch built Seawolf model too (direct drive even with it's PJ!) in say 1/64 to 1/48. A single Graupner 900 bb torque in a 1/72 to 1/48 scale Russian Alfa too. Wow!

My projects now are all smaller and I am using Swiss-made Maxon motors. For a large building project such as a Typhoon in 1/96, the Graupner 900 bb torque is ideal. The only motor that would approach this would be a Maxon, but none are available in the size similar to the Graupner 900 bb torque. If you did find some large Maxon's, they would easily cost ten times as much or more than a similar sized Graupner motor. Maxon motors are moving around on the surface of Mars in the Mars Rover (s) space craft.

Running direct drive, in Europe the rule of thumb is roughly the motor case diameter near parity with the propeller diameter as a measure of torque and ease on the motor.

Offer still stands, but now I have posted the same offer also now in the SubSwap forum. My wife and I are heading off to Alaska tomorrow, back in a week. But will be checking my email in the meantime.

Steve Reichmuth
skipjack@earthlink.net



Edited By Dolphin on 1096079859