flatpackair
Member
Hi Everyone, I wanted to share my scratch build in case anyone else has been temped to do this kind of thing. I've read a lot of posts on other forums from people wanting to scratch build cars but not knowing where to start or if it is even possible at all, I was curious myself. My goal of this project was to see if I could make a fast, reliable and cheap RC that could perform better than the other options on the market in the sub $200 category. It had to be brushless with a lipo setup and have a full suspension. It also had to be built using a material that I could cut on a scroll saw as well as drill and tap easily. Finally it had to be cheap, i previously had a Traxxas Stampede that I picked up at a garage sale for $10, unfortunately with a 4000kv, 1200watt brushless motor I kept breaking parts and spending a fortune to keep upgrading it. If I wanted to stay in the hobby I had to be able to make replacement parts myself.
I researched cars from a bunch of manufacturers and looked at their parts support and pricing and decided to rummage through the Traxxas parts bin. Traxxas has been so popular for so long that a lot of their replacement parts are very cheap and readily available. A bunch of their 2wd trucks and cars also share the same drivetrain which helps even more. I then for more cost savings decided not to use the whole transmission but rather just the differential. This helps in two ways, it deleted a case, shaft and spur gear that I would have to buy and it changed the KV requirements. That last part was crucial as it meant I could use out-runner brushless motors which due to the popularity of multi rotors are generally cheaper than the equivalent in-runner. The lower KV, high torque out-runner was perfect for the direct drive setup .
The results have been great (after some messing around). The motor and transmission (diff, idler and steel pinion) have performed flawlessly, as have the drive axles. My first car used an all 1/4" ABS plastic construction and while it handled pretty well it was constantly breaking control arms and other small parts. For the second car I used a combination of ABS, Nylon and Nylatron GSM and if you watch the video you can see that it really paid off. I still have more parts that I want to switch over to Nylon but its getting very close. It takes a lot of punishment before anything breaks. I also learned my lesson with using super glue to thread lock most of the fasteners, it is a must and has contributed to the reliability greatly. The performance is exactly what I wanted, it can overwhelm mediocre tires at nearly any speed on any surface, can throw great rooster tails and most importantly is better than anything I could buy for the sub $200 price point which included a nice lipo charger and Turing digital radio. Please let me know what you think of the project, you can also follow the build of prototype 3 on twitter @flatpackcars if your interested.
I researched cars from a bunch of manufacturers and looked at their parts support and pricing and decided to rummage through the Traxxas parts bin. Traxxas has been so popular for so long that a lot of their replacement parts are very cheap and readily available. A bunch of their 2wd trucks and cars also share the same drivetrain which helps even more. I then for more cost savings decided not to use the whole transmission but rather just the differential. This helps in two ways, it deleted a case, shaft and spur gear that I would have to buy and it changed the KV requirements. That last part was crucial as it meant I could use out-runner brushless motors which due to the popularity of multi rotors are generally cheaper than the equivalent in-runner. The lower KV, high torque out-runner was perfect for the direct drive setup .
The results have been great (after some messing around). The motor and transmission (diff, idler and steel pinion) have performed flawlessly, as have the drive axles. My first car used an all 1/4" ABS plastic construction and while it handled pretty well it was constantly breaking control arms and other small parts. For the second car I used a combination of ABS, Nylon and Nylatron GSM and if you watch the video you can see that it really paid off. I still have more parts that I want to switch over to Nylon but its getting very close. It takes a lot of punishment before anything breaks. I also learned my lesson with using super glue to thread lock most of the fasteners, it is a must and has contributed to the reliability greatly. The performance is exactly what I wanted, it can overwhelm mediocre tires at nearly any speed on any surface, can throw great rooster tails and most importantly is better than anything I could buy for the sub $200 price point which included a nice lipo charger and Turing digital radio. Please let me know what you think of the project, you can also follow the build of prototype 3 on twitter @flatpackcars if your interested.
