Scale Time?

Discussion in 'FAQs' started by 77railer, Apr 12, 2005.

1. 77railerMember

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Before I start I realize that time is time and no matter how small or large you are time remains a constant, however, having stated that, I am thinking about one of the modules for the club depicting Yellowstone. More specifically, old faithful and the lodge that is located mear yards from it. Being that I model in ho scale which is 1/87th scale would it be correct to assume that if old faithful took 15minutes from start to finish to erupt and I wanted to re-create that eruption in 1/87th scale that it would last 1/87th of the time? If that is presumed to be correct then 1hr in "real" time would equal 45 sec in 1/80 time. Which I realize is a little off scale but nice easy numbers to manipulate. I got this by figuring
1/10hr=6min
1/20hr=3min
1/40hr=1.5min or 90sec
1/80hr=.75min or 45sec

Now while we can figure the exact 87th of an hour I think this figure will serve it purpose. So if the eruptions lasts 15min in "real time" which is 1/4 of an hour then the scale eruption should last 11.25sec.

If you agree with the above cool...if not tell me where I went wrong....the real question is how do I model an eruption that has a duration of 11.25 seconds? Steam would work but would be a safety hazard, perhaps a smoke chamber that fills its bladder and then is expelled using a small air pump to imitate the eruption.....would have to be a really large bladder to last 11.25 seconds of forced air, not to mention the cost of the smoke liquid needed to fill the chamber with smoke. Any ideas,Help guys.....

77Railer
2. MasonJarIt's not rocket surgery

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Time does not scale... sorry or at least it is not usually done the way you describe.

There are "fast-clocks" that run "scale time", but that is really to compensate for the fact that most of us do not have scale miles of track between destinations. Fast clocks make it easier to imagine that a train leaves one place at 2pm and arrives somewhere down the line (miles and miles in the prototype, but only a few feet - therefore fractions of a scale mile - on the layout) at 2:24, for example.

The fast clock in the above example would run at 6:1 (6 "fast" minutes to one real minute). That way, the train only has to be actually moving on the layout for 4 minutes to make the required 24 minutes pass.

There are fast clocks that run at 4:1 or 6:1, or even 12:1 (mostly for ease of calculation). 4:1 means 1 scale hour take 15 real minutes,6:1 = 1 scale hour requires 10 real minutes, etc.

As far as the eruption - I don't know how you could do that... I remember vinegar and baking soda volcanoes from elementary school science fairs, but that would make a heck of a mess. Maybe you could make a sign with one of those little clocks indicating that the next event is in X hours...?

Hope this information is helpful. Reminds me of the debate you see every once in a while about the 10 hour "metric" day...!

Andrew
3. ezdaysOut AZ way

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Yeah, you're close enought timewise that nobody is going to notice, that is if you really want to scale time as well.

To start with, how high is the stream of Ol' Faithful? I doubt that you'd be wanting to use steam since it would probably ruin the rest of the layout in no time, plus it is a bit dangerous. Smoke might work, but how about using something like carbon dioxide, from a fire extinguisher? Just a thought, but it would evaporate and wouldn't leave any residue I would think. I could be wrong, but that's the first thought that came to mind.
4. ezdaysOut AZ way

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Oh yeah, if you were scaling time too, and Ol' Faithful went every hour, you'd have one 11.5 second eruption every 45 seconds.

As far as how, well, whatever you used would go through some tubing that had a valve on it. You would open and close the valve using a timer.
5. 77railerMember

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CO/2 now why didnt I think of that. All those games of paintball at the house. We even made a field and had people come from all over. Had a heck of a big tank of co/2. Lasted a long time. It cost like \$75 to refill. I imagine a smaller tank would last a good while. Could test it at the clubhouse and then make it run or rather erupt every 3 minutes or so. Regardless of where you were on the modular layout (speaking from a spectators point) you couldnt help but notice a stream of co/2 erupting into the atmosphere.
6. 77railerMember

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Wonderful Wonderful Internet. After doing some research on old faithful I have found that the eruptions last 1.5-5mins in length and reach an average height of 130 feet. So I need to re-calculate this thing.
1hr=45secs in scaled time
5min=3.75 sec

So the eruption needs to last about 3sec which is alot more doable for lack of a better word. Now just gotta scale the height when I have time....

77Railer
7. Doc HollidayMember

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77,
130 ' would scale about 1.5' in HO.

As to the CO2, I think it is doable. I've got a beer tapper at home with both 5# and 10# tanks, (both about the size of a small fire estinguisher, but different diameters). Each costs about \$13 to fill (minimum service charge). The 10#er lasts about 8 kegs. I don't have any idea how many 3 second eruptions that would equal.
Doc
8. VunderBobMember

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You can get CO2 bottles for paintball use for \$20 or so. They'd hold have plenty of capacity for a 5 sec shot every minute or so. Might also be able to convert a fire extinguisher, too.

I have no idea about hoses and nozzles, though.
9. spitfireActive Member

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This is a pretty cool idea 77Railer!! I wouldn't worry too much about the time thing if I were you. Just pick an interval between eruptions, and a workable length of time for the eruption. We run our trains in real time at scale miles per hour, but then we may or may not run them on a fast clock that is 4:1, 6:1 or even 12:1 as Andrew pointed out. So there's clearly a lot of leeway there. Main thing is to find something that works for you.

Val
10. TrainClownMember

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I would use dry ice to do this effect.

TrainClown
11. 77railerMember

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I think I can rig it with a release valve and manually pull it off. Not sure if I have the no how to rig a timer and such....will have to give it some more thought....guess I need to get my butt out in the shop and start with building the module,lol. Will have to keep yall updated on how it works out.

77Railer
12. 60103Pooh Bah

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I think you may want to fudge the time factor a bit. Most time does not scale -- locomotives look ridiculous with their drivers spinning at 87 time the actual rate.
Where time needs scaling is in movies when a model train falls off a bridge. Gravity does not scale, so a fall that would take the prototype 3 or 4 seconds happens in a fraction of a secong in the model. The movie people shoot the fall with very fast film and slow it down.
Some people watchinbg your Old Faithful erupt will know how long the prototype takes and be disappointed if it just goes "Brrrp". You could cut down the interval between events.
13. jetrockMember

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Time really doesn't scale that way, but it does compress.

Think of it this way. A real object moving at five feet per second takes twenty seconds to travel 100 feet.

Example #1: An HO (1/87) scale object moving at five HO scale feet per second takes twenty seconds to travel 100 HO scale feet.

The concept of "fast time" is used by model railroaders to simulate timetable operation and make up for the fact that HO scale railroad stations on a layout are typically MUCH CLOSER than scale distance from each other than those in the real world.

Example #2: Bob's HO scale layout features two stations, Alpha and Beta. The real-world Alpha and Beta stations are located six miles from each other, but on Bob's layout they are separated by 60 feet, or about 1 HO scale mile. Bob uses a 1:6 fast clock, which "compresses" time for scheduling purposes--thus, where the real Alpha to Beta travel distance is six miles, the HO scale Alpha to Beta distance is one HO scale mile multiplied by six (the fast clock multiplier) to bring the "apparent" distance traveled to six miles, for scheduling purposes.

Would CO2 provide a "geyser" for this effect? CO2 cartridges produce a little bit of visible offgassing but not very much--and sustained bursts would empty one of those \$75 CO2 bottles fairly quickly.
14. TrainClownMember

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Dry Ice Idea Details

Ok, so you want to model Ol' Faithful. Now the problem with Co2 gas is that, it is just that, a gas, and once you release it, it goes up and out into the atmosphere and that's it. Plus the fact that all that pressure would not look like the real thing.

Now here is how I see this effect being accomplished. Get yourself an old coffee pot. Like the ones from the 50's, tall and metal. I collect old coffee pots and have a few of them. Some of them have lids that snap on, this would be a good thing, but not necessary. Now these old percolators have a basket for the grounds and it sits on a pedestal. Discard the pedestal and keep the basket. Drill 2 holes the size of a coat hanger wire in the lid, one on each side. Cut the hook off a coat hanger and straighten it out, then bend it into a "U" shape wide enough to feed the 2 ends through the holes. Do that and then bend a loop on the ends and hook them to the basket. This is all so you can lower the basket into the hot water when you want to.

now if you can't find a piece of rubber tube that fits over the end of the spout, then fins some that fits over a piece of brass tube and fix that into the end of the spout with some plumbers putty. 3/8" to 1/2" inside diameter rubber hose will work best to transfer the mist up to the layout. You will want to experiment with the nozzle before you build it into your module, to get the desired squirting action. Additional height can be achieved by drilling a hole in the unit someplace and then squirting compressed air into the pot while the reaction is happening. By doing this you would need less dry ice too.

So you wold have the coffee pot under the table top with about 3 cups of water in it and plug it in to heat up the water. Once the water was good and hot, lift the lid and put a few pellets of dry ice in the basket (if the glass perk knob is large enough, just remove it and stick the dry ice in there) When it's eruption time, lower the basket into the hot water and watch her spout! You will see the steam/mist will rise up and then descend down again giving a realistic look to it. It dose this because the mist is so cold. :thumb:

This will work. I have made a few special effects using dry ice for my puppet shows. I use to have a friend who ran a Dairy Queen and he use to give me dry ice that came in shipments of ice cream he would get on occasion. If you have a real good cooler, a bag of dry ice can last a few weeks. I had a space ship that flew in over the heads of the kids. It was about 2 feet across and hung on a long stick with lights all over it. And I tell you, when that dry ice hit that hot water, there was a wonderful reaction and the space ship would overflow with this mist. It looked great and made a big hit with the kids, who thought it was a real flying saucer. Dry ice is always fun.

TrainClown

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15. TrainClownMember

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An old-timer like one of these bad boys would be perfect! :thumb:

TrainClown

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16. MasonJarIt's not rocket surgery

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Old timer coffee pots....?! I think my parents still use the one on the left...

Andrew