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[First Build] Electronics Review for 1/10th Rally Car

Old 09-12-2022, 06:19 AM
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Default [First Build] Electronics Review for 1/10th Rally Car

Hello RCU,

I'm in the midst of my first RC build and was hoping to get more experienced eyes on my initial electronics selection before I pull the trigger. There are so many options and I've never done this before, so have been researching as best I can-- but may easily be overlooking or misunderstanding something.

The base chassis/ platform I have is the HPI RS4 Sprint 3 (edit: creator edition), which is normally on-road, but is being modified into a mixed-surface rally car akin to the more popular Tamiya TT-02 and XV-01/2 builds I see a lot of. The use case is general hobbyist bashing on dirt and gravel. There are actually a couple of 1/10th dirt tracks in my area but a) they have more jumps than this build is designed for and b) this build would never qualify for the types of competitive racing they do. I may take it to those sites occasionally for some Sunday Funday practice at slow speeds...but that's really as adventurous as I see myself getting with this.

I have a number of suspension, drivetrain, and weather modifications going in for the on-road to off-road conversion, and generally feel good about those. But the core components below is where I could really use your input:

Motor: Castle 1410 3800kv sensored brushless
  • It seems the general on-road motor for this chassis would be something more like the Castle 1406 4600kv. Since I am running mixed-surface 4WD however, I opted for the higher torque// lower RMP motor, which evidently runs cooler and seems better suited for my use case. I am not interested in top speed/ speed-running.
  • The stock gearing on the chassis is 32T pinion and 66T spur. I have some flexibility to change this as needed between HPI and aftermarket parts availability.
  • Power plant will be 2-3s lipo (haven't gotten to battery selection in my research yet, so I don't have an exact pack identified at this time).

ESC: Castle Copperhead 10 sensored ESC
  • The Copperhead appears to be the 'goldilocks' ESC option in the Castle line-up, sandwiched between the Sidewinder 4 un-sensored and the Mamba X sensored. According to their website, it looks like I could run the Sidewinder with this build on 2s lipo (losing the sensor benefit), but probably not so much 3s on 4WD off-road. If I'm misunderstanding the charts and specs, definitely chime in.
  • As mentioned above, power plant will be 2-3s lipo (haven't gotten to battery selection in my research yet, so I don't have an exact pack identified at this time).

Steering: Recommendations wanted!
  • Unlike some of the other electronics, there seem to be so, so many options for steering servos. Given this is for general hobbyist bashing, I don't know that the use case warrants a top-of-the-line brushless servo. I would love recommendations on something mid-market that favors durability and reliability over speed and accuracy. Is there a price range or brand list I should use to focus my search in on?

Radio & Receiver: DUMBO X4 2.4GHz...for now...
  • I know, it's a cheap $40 pair. The thing is, I don't really know what I want/ need/ like yet. This is my first RC. Unless there's something glaringly obvious that's wrong about starting here, I would like to get something cheap that does the job for now. Once I have time with this kit under my belt I will have a better sense of what bells and whistles I care strongly about (if any)-- and can use that criteria to guide the shopping search for something more robust. If there's a better entry-level, bare bones pair definitely don't hesitate to throw it out there.

I think that's it for now! Looking forward to learning from you all, and sharing my progress along the way.

Thank you,

Last edited by 7h3C47; 09-12-2022 at 06:29 AM. Reason: It's the creator edition of the chassis, so does not come with electronics, hence the post
Old 09-13-2022, 09:08 AM
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7h3C47 (09-23-2022)
Old 09-22-2022, 07:35 PM
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I like your motor and esc choices, Hobbywing has a few comparable choices as well.

couple decent waterproof metal gear servos:
Savox SW-0230MG
Hitec HS-646WP

For radio gear have a look at Flysky GT3B

Did you know there is a rally version of the RS4?
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Old 09-23-2022, 04:13 AM
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Thank you so much for the recommendations for servo and radio! Great to have a few options to compare.

I did come across a couple different rally-style cars from HPI when doing some research, yes. I hope to improve upon the platform with the modifications I have going into the Sport 3 chassis!

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