brandycmc

This is my first post. I have been lurking for a while, and this community helped me decide to get back into 'proper' RC cars, with the purchase of the newly released DB-01 RRR. For bashing only On grass mainly.

It has arrived (thank you Stella), and I am most of the way through the build. It feels like a very well designed model, with excellent quality parts.

I will initially be using existing basic electronics from my DT-02 (TBLE-02S ESC, Tamiya Torque Tuned motor, an analogue Carson servo and NiMH batteries). I think I'll need a week or so of using it to confirm what I want to put inside it, but my initial thinking is to Go Large with:

• Trackstar 4-pole 5600kV motor (assuming I can find 5mm 48P pinions locally)
• Hobbywing 120A ESC (I would have gone Trackstar 120A, but unless you $go.00 for the GenII, the specs say 2S max)
• A mid-range Turnigy digital servo
• And LiPo 3S

I would be grateful for comments on the above from existing DB-01 owners - particularly on the wisdom of putting this much torque through the (admittedly upgraded RRR) chassis.

But also my main reason for posting was to ask DB01 owners about what LiPo batteries they use. I'm new to LiPo, but there don't seem to be that many affordable options for high-capacity 3S hard case packs that will fit. Maximum dimensions look like 139x45mm (LxW) - but how high/thick can you go?
The posts for the battery strap are just over 20mm high. But if I could fit a 24mm (or even thicker) battery in without fouling the strap or body, then I could get up towards high 3000mAh territory (e.g. Turnigy nano-tech A-SPEC G2 3700mah 3S 65~130C Lipo Pack).
If 27mm would fit I could even get into the 4000mAh territory.

Thanks for your help

collector1231

My Feedback: (1)

Welcome to the forums brandycmc! That looks like a killer RC car and I think all your powerplant choices will work well. Let me help you with the servo and LiPO. It looks like 2S packs were made for that chassis, not 3S. However, Venom makes a very small 3S pack that is 5000 MAh and 50C; more than enough power.

LiPO; http://www.atomikrc.com/collections/...universal-plug

Servo; http://www.atomikrc.com/collections/...orque-hv-servo

Maj_Overdrive

My Feedback: (11)

I just did some gearing calculations based on the ratios listed in the tamiya manual, it's where the pinions are listed on page 8. With the 5600kv motor on 3s and a 16t pinion the theoretical top speed is 52mph. Now the motor might be able to handle that gearing but if it can't (and gets too hot) you cannot use a smaller pinion as 16t is the smallest listed in the manual. I'd recommend going with a lower kv motor, something more in the area of 3500kv, no more than 4000kv if you're going to run it on 3s. This will allow you to taylor the gearing to the motor and terrain you're running on to prevent overheating.

Edit: with a 4000kv motor on 3s and a 26t pinion (largest listed in manual) theoretical top speed is over 60mph while 16t is 37mph. That's a nice range to be able to dial the gear ratio in and yet you can still have a speed run car with a change of the pinion.

brandycmc

Thank you both.
Together with some advice I received over on the Tamiya forum, your advice has helped me decide that 3S lipos and a 4-pole motor is probably not the way to go. In fact it may just be too much for the transmission and chassis.
So I've cancelled the order, and gone for a more traditional 2S lipo and 2-pole brushless setup - 7.5T 4200KV. I'll start with a 19T pinion on grass and work from there.
Thanks again for your help.

collector1231

My Feedback: (1)

Sounds like a good plan to me! Make sure to keep us updated on it.