Working on powered trucks

Re: Working on powered trucks

Postby CSD » Tue Feb 18, 2014 9:11 pm

DKRickman wrote:... I am NOT trying to step on any toes here...


Not to worry. Everyone is welcome.
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Re: Working on powered trucks

Postby ConducTTor » Tue Feb 18, 2014 10:54 pm

DKRickman wrote:By the way, I want to point out that I am NOT trying to step on any toes here, and I don't want to compete with someone who is making a viable product. My only goal is to help make some new models available, doing my little part.

Also, I have no intention of making these trucks available RTR. I don't have the time, and it would just make things more expensive since I'd have to pay the same price as anyone else and then charge more for shipping and my time. However, I don't mind a bit if someone else decides to make and sell them. In fact, I'd love to see that happen.


No worries at all. Any ideas/help are welcome!
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Re: Working on powered trucks

Postby DKRickman » Tue Feb 18, 2014 11:00 pm

Just a reminder, these trucks are still in the R&D phase. I've had a couple people order some, but Shapeways doesn't tell me who placed an order. I'm thrilled that people want to try them, but I want to make sure everyone knows that they are untested, unproven, and potentially complete failures. So if you're willing to accept that risk and help me make these things work, then order away! If you're looking for a proven design, please give me a little time to make sure they work, and I promise I'll do whatever I can to make your wait worthwhile.
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Re: Working on powered trucks

Postby richardedmonds » Wed Feb 19, 2014 2:54 pm

I just bought some Ken, I take your points about it all in R&D mode, but I do like your ideas about this thing and of course nothing ventured nothing gained. LOL maybe I trust you because you ride the old N&W tracks and maybe I saw you from England on the Roanoke Rail Cam
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Re: Working on powered trucks

Postby DKRickman » Wed Feb 19, 2014 9:26 pm

richardedmonds wrote:I just bought some Ken, I take your points about it all in R&D mode..

I look forward to hearing your thoughts, Richard. I definitely need people to try these things out and let me know how they work. If there's anything I need to change, that's how I'll know.

richardedmonds wrote:maybe I saw you from England on the Roanoke Rail Cam

It's a good possibility. I was just in Roanoke last weekend, and it's one of the places I regularly run to.
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Re: Working on powered trucks

Postby DKRickman » Thu Feb 20, 2014 3:11 am

I am thrilled at the positive response I've had so far, and also grateful for the advice, comments, and suggestions I have received.

While I am waiting for the feedback on the truck design from those who have ordered it already, I thought I'd play with another related design. Nobody needs trucks for an SD45, do they? :think:
Image
https://www.shapeways.com/model/1723825/tt-truck-3-axle-13-7-quot-wheelbase.html

No sideframes yet, though I have been asked to do some, and I am hoping to have a drawing ready eventually. If/when I do, I'll probably update the truck design to accommodate them in whatever way seems best.
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Re: Working on powered trucks

Postby Carsten » Thu Feb 20, 2014 5:22 am

You should offer it in FUD. All other materials are not exact enough. I did already some trucks and started with WSF.
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Re: Working on powered trucks

Postby scaro » Thu Feb 20, 2014 6:42 am

Isn't FUD more susceptible to heat and prone to warp though? I thought WSF had the virtue of being ugly but stronger.
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Re: Working on powered trucks

Postby DKRickman » Thu Feb 20, 2014 9:28 am

I don't really see a reason to have these in FUD, to be honest. WSF is cheaper by half, stronger, and more than accurate enough for the purpose. From the Shapeways web site:

WSF: accuracy is given as ± 0.15 mm, then ± 0.15 % of longest axis
FUD: accuracy is given as ± 0.025 - 0.05 mm for every 25.40 mm

That means that the total error over the length of the truck could be nearly 0.2mm, or just under one scale inch. I seriously doubt anyone would notice even if two trucks with opposite extreme errors were sitting side by side. Also, that is the extreme case, and I have not seen the error be that extreme often. In other words, I believe that WSF is more than good enough for the purpose.

Whenever I get around to doing detail parts like sideframes, those would almost certainly be done in FUD. The better detail and smoother surface are important in that case, and strength is not an issue. I try to use the right material for the job.
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Re: Working on powered trucks

Postby krokodil » Thu Feb 20, 2014 11:37 am

Hi Rick

I do not want to duscourage you, but this design from mechanical point of view is very weak. Those belt drives does not promise any long life performance ( i have also some experience with similar designs in H0). The simple O rings provide just a load for the small motor ( much more then a flywheel would do). Additionally you have 2 of them on the motor axle. If you want to stay with belt drive you should look for a miniatur cog belt, what does not requires tension, and rather add a flywheel, because especially in two axle vehicles the flywheel is the only guarranty for smooth movement and power pickup. In top of that to exchange the belts you have to disassemble the whole truck!
You guys spent so much energy for the nice molds, the mechanism should be at least on the same level.
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