SP NG Diesel #1 (GE 50T) - Triennial or Bust

[senorgilamonster]

what gearing to I need to hit 88 MPH?

[Harold_V]

You could go back to 1955 and visit your parents with 900KW!

Oh, yeah! 900 kW is a staggering amount of energy. In fact, there's a post on the board that details exactly that. I found it interesting. Could be others will, too. Here's a link. viewtopic.php?f=24&t=105394&start=36

It's the first post on that page.

H

[NP317]

900 kW.
Think laser weapons...
~RN

[Pontiacguy1]

YES... It was definitely a Typo!

Don't think you'd be able to power a 900KW motor with any battery for very long. If you drop a 1200 HP motor into each truck, you'll definitely have more than enough power, though. I don't think you'll be able to keep it from tipping over on the curves with just 7 1/2" between the rails. You'll have to switch to a prime mover/generator setup to be able to supply enough current, so You'll need a BIG frame and chassis. At 2400 HP, you might as well build the thing to 4' 8 1/2" gauge so you'll have somewhere to possibly run it. You could make this a model of an SD24, since they were about 2,400 HP. Heck, at this point it would be a lot easier and cheaper for you to just buy a used full-size locomotive and work on restoring it!

Oh, and Dr. Brown's time machine needed 1.21 jigawatts to operate!
Not real sure how much a jigawatt is...

[senorgilamonster]

we have a saying in our house; If you have to explain it, it wasn't funny.

88 MPH is the speed of time travel. You had to get Doc Brown's Delorean up to 88 MPH.

[senorgilamonster]

back to the railroad.

I've had to slow down a bit to go faster. I've stopped on the engine to build a work area in a storage unit that I rent so I won't generate/track as many metal shavings into the house. The good news is during that time, all of the parts I ordered for the drive train have arrive. Now I am really anxious to start turning the axles, etc.

The yellow jumpers between the 18Ahr batteries are temporary. The batteries will be reconfigured and a brass buss bar will be in their place, but until I modify the 6 gauge jumper it would be unsafe to set them up in the configuration that I envision.

Wow. #25 roller chain looks small. The other thing that looks too small to me are the 8 bearings that I ordered for the ends of the axles.
INA SCE108 Needle Roller Bearing, 5/8" ID, 13/16" OD, 1/2" Width. https://www.amazon.com/INA-Bearing-1760 ... B006KT1B2G. On the other hand, the first loco had bronze sleeves so....

Q: My riding car uses a bronze "cup" where the bolster connect the truck to car. For the loco, is there any reason that I just couldn't use off the shelf thrust bearings?

[rkcarguy]

I personally don't like needle bearings, they have a very high "bearing" speed and are very finicky to conditions. Must be kept very clean and/or re-greased often. If you have a way to have them run in an oil bath, they will last a lot longer. Also, if you have any twisting loads in the trucks, they have no way to self align to that and it will accelerate wear.
Remember, because our wheels are so small, the bearings are turning the same speed as a car going down the highway to reach 7-8 mph on a 1/8th scale train. Although I don't care for the appearance, my choice was 4-bolt flanged self-aligning bearings. I'm using the 1" on my 2" scale S12, but I'd go with these if I was going to build 1.5" scale.

https://www.amazon.com/UCF204-12-Pillow ... ck+bearing

[Pontiacguy1]

Here's the deal. Having worked for a major bearing company for nearly 20 years of my career, I can tell you that your needle bearings will not like running on a machined non-hardened shaft. As you have already alluded to, your needle bearings will also absorb no amount of thrust from side-loading. Needle bearings running directly on the axle need to have smooth and hard surfaces. They are made to run on a 60 rockwell C hardness shaft. Anything above 45 Rockwell C should be OK or most loads and speeds. For the novice, needle bearings should be avoided unless you will also be using a hardened and ground inner race like the Allen Models Main driver boxes do on the Mogul,Ten wheeler, etc...
The BEST thing for a novice to use for bearings are radial sealed ball bearings. You can get them in ODs and IDs that are suitable to what you need. A ball bearing will also absorb thrust. A typical ball bearing can absorb 30% of it's radial load rating in thrust. That is more than enough for what you are doing with it. With a ball bearing, the OD does not need to be fully supported like your needle bearings will. In using a ball bearing, the revolving member needs to be secured to the bearing. In other words the shaft needs to be a press fit or loctited into the bearing inner race. The OD can run freely in the axle box and be loose enough so that it can pivot and re-align enough so that your axles can float. Ball bearings have some amount of realignment (radial play) built into them.

Something like this is what I would recommend you use: www.thebigbearingstore.com/6000-series/

[Harlock]

The #25 chain looks small, but the interesting thing is all of the scooter motors ship with it, so it must be rated to take the load or people would complain a lot about broken chains. And sure enough I've had no problems with it, even pulling large loads. I had originally wanted to replace the sprocket with a #35 sprocket, but it was such a pain to adapt to the existing shaft I gave up and went with the #25 for the first set of sprockets. With the high speed and low torque on that end, turns out it's not a problem at all. Never had any issues. Also, you'll likely need to stick to smaller chain to start with so that the physical size of the sprockets remains small on your trucks. On my two axle speeder I have the entire chassis to spread out on so I went with #40 chain for most of it (already had some sprockets for #40, or I would have used #35) but you have to fit it above each truck.

This photo shows the other side of the motor mount that went on the chassis, with the #25 chain set, and you can see that I had to make a large reduction to the jackshaft and then I made a further reduction from the jackshaft to the axles. That big sprocket in anything more than #25 chain would have been massive.

To assist in calculating the correct ratio, I made this excel sheet. Plug in all the numbers in the yellow cels, and it will give you the rest. In this way I was able to play around with sprocket combinations until I got the top speed I wanted. When I tested it with a GPS tracker, it came out almost exact. Grab it here: https://www.dropbox.com/s/mbvcmx7vxdwp4 ... .xlsx?dl=1 If you plan to not have an intermediate shaft and only one set of sprockets reducing, you can make the sprocket teeth on one set identical in the XLS file.

[senorgilamonster]

Thanks for your replies. I tried to read up on the subject and make an educated selection, but should have just asked in the first place.

I won't use the needle bearings. I opened the package for one and was surprised at how much resistance it gave. Way more friction than a roller bearing.

Harlock - I had read some of your posts on chain size which is why I ordered the #25 chain and sprocket...and came to the same conclusion that fitting a #35 sprocket to the motor would be a PITA.

how about springs for the equalized trucks?

[rkcarguy]

You may try looking into #219 chain and sprockets from the go kart market. I am running this on my race kart, and get a whole season out of a chain behind a 7200 RPM 15HP 4-cycle motor, 435# kart/driver, racing on asphalt. The final race of the season has standing starts where I basically go full throttle full brake and lift the brake when the flag flies, and never have broke one yet. A lot of guys that run the 2-cycle classes will only run the chain a few races then toss it, its a great chance for freebies if can visit the track out there in Auburn. There is no master link for this stuff, but the tool is only about $10 that presses the pins out and back in.
I was able...barely, to go with Honda Rebel CM250 rear sprockets in 520 chain, as I'm doing 2" scale and 7" wheels, with the chain wrapped around the sprocket, I've got 3/8" clearance above the rails. This stuff should outlast me.

Also, if you haven't ordered the pillow block bearings yet, I found something that might work well. There is a 2 bolt flanged bearing in 3/4" that uses a stamped sheet metal housing, and they are still self aligning. The sheet metal housing makes it far more low profile, and I thought these could be installed from the back of the truck side plates, which would provide minimal intrusion visually on the outside of the truck. It could then be covered with a faux bearing box to match your prototype.

The picture attached is of the industry standard codes for all the different pillow block type bearings made, you're all welcome to save it to your computer it's a handy sheet to have. My searching those letter codes, you'll find a lot more options that won't come up in a descriptive google search.

[Pontiacguy1]

That is not the industry standard code for pillow blocks. Most manufacturers have different codes for these types of units. That may be what this particular company is using, but we made pillow blocks in our plant right up until last year, and none of the nomenclature is the same as what that shows. You have to look it up to cross-reference from one company to the other.

The flange units you are talking about can come in a couple of different configurations. The most common has two plates which sandwich together and then bolt onto the mounting surface. Using the stamped mounts, the plate they bolt to has to be rigid, something like 1/4" or so thickness to give it stability, and the most common ones are also not flat on the back. there has to be a hole large enough for the rear part of the housing to protrude through. Most of your 2 bolt iron flange units are going to be flat on the back and can be bolted straight on to something. The stamped units derive a lot of their rigidity from the surface they are mounted on, and they have to be bolted directly to that surface.

What I would recommend doing is making your axle boxes out of whatever material you want, bore your hole for your bearing about 0.020" oversize, and then put the ball bearing directly on the end of the shaft by pressing or using sleeve retainer. That will work well. Have a step in your axle box bore so that the bearing will bottom out against it and absorb the thrust. That is a simple method and it will work and last a long time. I have used this method quite a number of times and they are all still running. Biggest failure modes: (1) the bearing can move on the shaft and will either wear the shaft down or the shaft comes out of the bearing bore (2) get them soaked/submerged in water and get water in the bearing (3) bearing seals fail and all the grease runs out of them. This last one, may happen because of abuse, hitting or bending it on installation, or just from time. When the seals fail, it's over with.