Author Topic: Another steam thread  (Read 5829 times)

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garethashenden

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Re: Another steam thread
« Reply #30 on: November 05, 2013, 01:16:25 PM »
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garethashenden:
How many teeth are on the large side of that double-gear (the worm gear that mates to the motor worm)?
From the photo, it's hard to tell, but there might be 32. How many are on the small side?

I'm curious to figure out the gear ratio.

The first gear has 30 teeth, the other two are 14/18. I think this makes the ratio 23:1 but I could be wrong.

mmagliaro

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Re: Another steam thread
« Reply #31 on: November 05, 2013, 02:17:37 PM »
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The first gear has 30 teeth, the other two are 14/18. I think this makes the ratio 23:1 but I could be wrong.

I'm a little confused there.  The small gear on the double-gear, it has 30 teeth on the larger diameter part,
and how many on the smaller diameter half?  (14 or 18?) 

Does it go from:
motor worm -->  fine-toothed half of double gear (30 teeth) -->
       coarse-toothed half of double gear (14 teeth) --> coarse-toothed gear on the driving axle (18 teeth)
   

Assuming that the double-gear advances only 1 tooth for every rotation of the worm on the motor,
that would be 30:1.  If the small side of the double gear is 14 and the driver axle gear is 18, that gets you
another 1.28:1 so the final ratio would be 38.4:1  which is actually pretty good.

What diameter are the drivers on that engine?


garethashenden

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Re: Another steam thread
« Reply #32 on: November 05, 2013, 03:11:54 PM »
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That is correct. The 30 tooth gear is driven by the worm, the 14 tooth gear is on the same axle as the 30 tooth gear. (It's two gears, not a double gear) The 18 tooth gear is driven by the 14 tooth gear.
The drivers on the model are 9mm diameter. On the prototype they are 55".

mmagliaro

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Re: Another steam thread
« Reply #33 on: November 05, 2013, 04:15:24 PM »
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Ah, good.
So, if the motor RPM maximum is around 15,000 (just a guess, it could be anywhere from 11,000 to 18,000).
We get
15000 / 38.4 = 390.6 RPM at the drivers.
9mm = 56.5" diameter  (which is very close to your prototype 55", by the way!), --> 178" circumference.
Or...  .0028 scale miles per revolution.

.0028 x 390.6 = 1.097 scale miles per min or about 65 scale mph, at maximum speed, which seems like
a very good number to me.

Whew.   That's what all this was about.  I was trying to see how low it was geared and how
the speed range would be.  It seems good to me.  I put all the steps in there in case I made an arithmetic mistake
and somebody catches me.


garethashenden

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Re: Another steam thread
« Reply #34 on: November 05, 2013, 04:27:31 PM »
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Yes, except that this isn't actually N scale, it's 2mm finescale. 2mm=1ft or 1:152. So 9mm wheels are actually a scale 54". But I don't think it matters particularity when estimating the top speed.

Kisatchie

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Re: Another steam thread
« Reply #35 on: November 05, 2013, 08:56:53 PM »
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...I put all the steps in there in case I made an arithmetic mistake
and somebody catches me.


Hmm... it won't be Kiz...

Two scientists create a teleportation ray, and they try it out on a cricket. They put the cricket on one of the two teleportation pads in the room, and they turn the ray on.
The cricket jumps across the room onto the other pad.
"It works! It works!"

up1950s

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Re: Another steam thread
« Reply #36 on: November 06, 2013, 08:06:20 PM »
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Been contacted that Kato traction tires are back in stock . This ought to last for many seconds .

garethashenden

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Re: Another steam thread
« Reply #37 on: November 15, 2013, 11:49:30 AM »
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So I've got the brakes on one side and the body on the chassis.


Last night I took in to my club and ran it around the club's 2mm layout Copenhagen Fields. With a jury rigged coupler it had no trouble pulling six coaches.
Unfortunately the locomotive is a bit blurry, should have posed it for a picture instead of taking one as it went by.

VonRyan

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Re: Another steam thread
« Reply #38 on: November 15, 2013, 02:20:55 PM »
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 :o
I love Copenhagen Fields.
Spectacular layout.

I might have to trouble you for a chance to see it while I'm in the UK in late-May/early-June.  :D


-Cody F.
Cody W Fisher  —  Wandering soul from a bygone era.

superturbine

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Re: Another steam thread
« Reply #39 on: November 15, 2013, 09:23:33 PM »
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I like it! :D

mmagliaro

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Re: Another steam thread
« Reply #40 on: November 16, 2013, 01:21:28 AM »
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Coming along great!
  Wow, those brake and those driving wheels look fantastic in the photo.
The drivers look so clean and precise now.  Did you do some clean-up on the spokes?   They just didn't look
as good to me in the previous photos and now they look amazing.

peteski

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Re: Another steam thread
« Reply #41 on: November 16, 2013, 01:48:36 AM »
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Coming along great!
  Wow, those brake and those driving wheels look fantastic in the photo.
The drivers look so clean and precise now.  Did you do some clean-up on the spokes?   They just didn't look
as good to me in the previous photos and now they look amazing.

+1
The track looks to be really low profile. Is that code 40?
. . . 42 . . .

nstars

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Re: Another steam thread
« Reply #42 on: November 16, 2013, 03:50:21 AM »
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:o
I love Copenhagen Fields.
Spectacular layout.

Copenhagen Fields is indeed one of the best layout I have seen. recommended.

Marc

garethashenden

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Re: Another steam thread
« Reply #43 on: November 16, 2013, 05:23:17 AM »
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Coming along great!
  Wow, those brake and those driving wheels look fantastic in the photo.
The drivers look so clean and precise now.  Did you do some clean-up on the spokes?   They just didn't look
as good to me in the previous photos and now they look amazing.
I think the only difference is that they are now in focus. I was having some trouble getting the camera to focus on what I wanted it to. They are very high quality and worth the $10 or $12 a pair they cost.

+1
The track looks to be really low profile. Is that code 40?
Yes the track is all hand laid code 40.

For those of you who are unfamiliar with Copenhagen Fields there are some very good pictures here: http://www.themodelrailwayclub.org/Pages/CopenhagenFields.aspx


:o
I love Copenhagen Fields.
Spectacular layout.

I might have to trouble you for a chance to see it while I'm in the UK in late-May/early-June.  :D


-Cody F.
Please do come by the club. Thursday evenings are when it's open, I'll be happy to show you around. I don't however know if Copenhagen Fields will be up then or not, there are more layouts than space so they can't all be set up at once...

VonRyan

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Re: Another steam thread
« Reply #44 on: November 16, 2013, 05:57:23 AM »
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Thursday evenings you say? Same as the N-Trak club I belong to.
Shame all my UK stock is just N-Gauge or I'd bring something to run.
You'll have to put me to work instead.  :D


-Cody F.
Cody W Fisher  —  Wandering soul from a bygone era.