Brushless truggy conversion: HoBao Hyper ST PRO

For my second brushless conversion, I have chosen HoBao's truggy, the Hyper ST Pro. Truggies are great. They have big tires and offer high ground clearance like a monster truck, but have similar layout to and handle like a buggy; hence the name, truggy.

Hyper ST Pro has a good reputation for being able to turn on a dime. It is also very durable, which is evident from the robust component it has. Because of the beefy shock towers, chassis braces and so on, the truggy is also on the heavy side. No matter though, a decent brushless system will have no problem flinging it around.

This conversion is a work in progress and I'm currently on the planning stage. This is a long process, especially with a huge of selection brushless systems and LiPos that is currently available. Actually, putting everything together is the easy part, but it is almost done.

Here is a list of components that are being considered installed:

• RC-Monster motor mount or custom fabricated one
• Castle Creations Mamba Monster Max (MMM) with 2200KV and 13T 14T pinion or Tekin RX8 with 1700KV and 17T pinion
• Zippy Flightmax 5000mah LiPo packs in the configuration: 2x2S1P, 2S1P+3S1P, or 2x3S1P
• Two RC-Monster custom battery trays

With 6S (22.2V), either the MMM or RX8 can push the truck to about 85 km/h and the electronics should not be hot with the above gearing. With a bit more gearing, going pass 90 km/h can be done safely still. However, this is too fast for racing and gearing down to more reasonable speed may cause the motor to get too hot due to over revving. 4S or 5S is more suitable.

I hope to be able to complete the conversion by Spring.

Having dual packs at the rear and the motor up front with the rest of the electronics on the opposite side, the truggy exhibits good weight distribution. To have this setup, notice that the center differential have been switched around. A little mod to the chassis is required to position it that way, but it is worth it.

It is also more flexible to use dual packs as different battery configurations can be utilized aside from 2x3S: 3S+2S for 18.5V and 2x2S for 14.8V.

After a few outings with the truck, all I can say is that I'm very satisfied with the conversion. With the MMM on 6S, the truck is quick and it'll pop wheelies on command. With so much power, however, the system tends to unload too much to the front wheels, expanding the tires and turning them into pizza cutters. To minimize this, I had to put thicker fluid in the center differential: 120,000wt oil. I expected the handling to suffer, but it didn't. Also, after playing with the ESC settings, the wheelies are minimized and acceleration is smoother rather than being a violent jolt.

I found that the truggy jumps well too - it is easy to control in the air and soaks up landings nicely, even the bad ones. So far, only one piece broke; a shock rod after hitting a storm drain.

If you would like to read more, click here for a thread about this build on RC-Monster Forums.