Meatball Racing

Radio Control Blog

Archives for March 2018

200mm TC6

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I did this mod to my TC6.1 because it’s a dedicated VTA racer. To be honest, 99% of the people out there racing VTA are using 190mm touring car chassis’. However they’re all also running 200mm bodies on them, which can sometimes look a little weird with the wheels tucked way up underneath.

Many of the 200mm VTA bodies that we use today were created by HPI in the early 2000s before the USVTA series existed. They were originally intended to be used with their RS4 chassis which included settings for both 190mm touring car bodies (The chassis actually measured 180mm), and 200mm for their wider bodies. The rear vintage wheels and tires have an offset so the 200mm bodies don’t look too bad on a 190mm chassis. But a select few bodies like the ’70 Charger and ’68 Camaro have an extra-wide 210mm rear. This is when the wheels tucked under look a little silly. Let’s fix that…

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R/C and VRC transmitter speed

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After having some troubles playing VRC, I started to look at my hardware to see if there was some gains to be had there because while I’m not a great racer in real life, I’m also not terrible 😎 I wound up doing a lot of research regarding the relative speed and latency of various tx/rx brands and models. The most concrete measurement I could come up with is the PWM frequency sent from the receiver to the ESC & servo(s). PWM signals are often much faster than PPM signals that are used by buddy-box or direct servo control systems. This is important in regards to playing VRC.

I gathered results measured by myself and others using the SkyRC Program Box. It is not a foolproof measurement of end-to-end latency – the delay from when you give a controller input and the ESC reacts to it. But it’s a clear metric, and part of the overall latency we can measure easily.

Much of this may not even matter to you. The average human reaction time is on the order of hundreds of milliseconds. For transmitter latency we’re talking about tens of milliseconds or less. Also, the transit time on the fastest servos are around 50 milliseconds, so that is another part of the equation that is difficult to reduce. But just because the measured latency is less than what we as humans can react to, it doesn’t mean these delays can’t be perceived, even if it’s just in the way something feels.

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