Question: 540 direct drive motor for Bronco's Type XXIII

[redboat219]

Acquired a couple of stock Tamiya RS540 silver can motors. Plan to use it in my Type xxiii. Will this motor be sufficient on direct drive or would I need a gear system?

[Subculture]

Too big, and too high revving.

For direct drive you want a motor that does no more than about 4-5000RPM unloaded. A better choice would be a 385 geared down 3:1.

[Albion]

Too big, and too high revving.

For direct drive you want a motor that does no more than about 4-5000RPM unloaded. A better choice would be a 385 geared down 3:1.

Go on the engel site, they have some nice low speed 540 cans and ship o seas for reasonable price

[redboat219]

Shoot!
Might as well finish the Kilo first.

[He Who Shall Not Be Named]

Shoot!
Might as well finish the Kilo first.

Test, test, test (tapping sounds)... test, test (feed-back squeal), is this thing on???....

Did Romel just say something about his long-suffering KILO project?

M

[redboat219]

David looks like you have a bad case of Presbycusis

http://en.m.wikipedia.org/wiki/Presbycusis

[crazygary]

Ey??? What's that ye say, sonny????
CG

[Subculture]

Don't think he believes me, noticed the same question has been freshly asked on rcgroups.

Okay to illustrate my point, don't know the exact size of the Type XXIII prop, but estimate somewhere in the region of 1 3/4" or about 45mm.

The silver cans from the Tamiya kits spin about 15-16k RPM unloaded. They're a three pole motor with a 27 turn wind. As such they're designed to be geared down to provide the high torque required to accelerate a model car adequately.

With a scale prop, lets say pitched at a 1:1 diameter to pitch ratio, we can calculate with 25% slip

15000x1.75/1408= 19 mph

Lets say the motor loads down by 25% and is working at, or close to maximum efficiency.

11250x1.75/1408= 14 mph

As you can see this is far too fast, and in fact it is academic, as the boat just won't handle that power.

Now if you were to gear the motor down 3 or 4:1 then you'll have a working set-up, but it will be rather inefficient, as those motors are quite thirsty even when run unloaded.

[redboat219]

What ever made you think i don't believe you?

Thanks for info.

Thinking of getting one of those 12 volts from the auto salvage yard. Would those work?

[Subculture]

I don't know. What you need is a motor that can do about 4-5000 RPM unloaded. Any more than that and you will have a speed boat on your hands, and it's likely to be inefficient as the motor will be overloaded on a scale prop.

But, get your Kilo finished and going first.

[redboat219]

Guess that also rules out the only other available motor I was offered, a Permax 400, it has no load rpm of 16,800. Will look for a 380.

[He Who Shall Not Be Named]

No!

Drop all this secondary, distracting **** and pull that KILO down off the shelf, dust it off.... AND FINISH IT!

Crawl, stumble, walk, run, and only after you've done all that, SPRINT!

FOCUS!!!!!

M

[redboat219]

Found a local shop selling electronics/ robotic equipment. This is what they got https://www.google.com.ph/url?sa=t&s...FmS81xlJPpnlWQ

[redboat219]

Like i said, will finish the Kilo first and figure the Type 23 drive motor dilemna later...