View single post by dan3192
 Posted: Tue Mar 26th, 2013 05:03 pm
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dan3192

 

Joined: Thu Oct 14th, 2010
Location: Connecticut USA
Posts: 226
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Hi Jim,

I've been at this now for 4 years and built one of my first battery r/c HO models about 1-1/2 years ago. All other factors aside, smoothness and low end speed are readily achievable, but you will have to give it some thought when selecting the drive components. A chain is only as good as the weakest link.

The motor I used was a surplus Escap 6Vdc 23mm dia. 9-pole high efficiency Swiss motor with ball bearings. It was purchased from allelectronics.com ($8.50). RPM is around 8,500 with a no load draw of 40mA, and it uses approx. 200mA when my locomotive (an Athearn AMD-103) is running on the track at medium speed. An A-line 3mm bore brass flywheel is mounted on the motor shaft to provide smoothness. The motor drives a universal shaft and gear tower mounted on the front power truck (by Hobbytown). The front truck drives the rear truck. This gives me more space for the batteries above the frame.

The electronics consist of a 12mm x 13mm Del Tang 3-6V combination Rx/ESC ($47.00). It is a 2.4 GHz (frequency) chip with DSM2 (modulation), and has an 800mA reversing ESC output for the drive motor. It is a perfect match for my Spektrum DX5e transmitter ($59.95). This chip has outputs for servos and LED lighting and a second 1-way ESC motor output that I plan to use for sound. The throttle stick (Ch1) is arranged for full speed with stick full forward, and zero speed with the stick full back. Smoothness and low speed operation could not be better. I found a way to use the throttle trim control to start the motor only 1 notch up from full off position. 

Batteries on this model consist of 8-1.2V NiMH AAA's ($16.00) arranged to give 4.8V and 1,600mAh. I'm using these types because I'm still in the testing stage and will soon switch to Li-ion batteries (w/DC-DC converter to stay below 6V), which have about twice the capacity. Ultimately, a custom frame will be used to accomodate AA Li-ion batteries, which will double the capacity once again.

I'm close to getting basic engine sounds, but don't yet have a method for triggering whistle, horn or bell. There are several methods, and the chip should be capable of providing the input required.

I think metal shells are a problem with r/c. Unless you can get the antenna on the outside, good reception is not likely. Take a look at the comments relative to this via this link: 

http://www.spektrumrc.com/Technology/Multilink.aspx 

Here's a video that convinced me to go with Spread Spectrum Technology.

http://www.youtube.com/watch?v=QaoXipp_288&feature=player_embedded

I hope some of my comments will be helpful. There are many ways to approach r/c. I chose an open source approach rather than some manufacturer's proprietary method and accompanying products. I'm glad to see you exploring r/c for cab control. The more you look, the more you'll like.

Dan

 

    

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