specs & features
1/12 scale '64 Chevy Impala Resin body using Maisto G-Rides Body
Full working suspension controlled by 3 15KG torque servo's
U-bar type of front suspension with articulated A-arms
380 Mabuchi type motor for hopping with tough braided fishing line
Planetary gear drive motor, drive train, U-joints and working rear axle
RC controlled lights including signal, parking and brake lights.
Custom made resin wire wheels with 520 style polyurethane tires
Custom paintjob by Artist Francisco Pancho Barron
Back in 2014 I decided to start creating these 1/12 scale RC lowriders for customers which turned out to be a venture I would regret soon.
I created a new design for the chassis completely build for hopping using new drive motors with planetary gear heads and new diferential rear axle.
A lot of time went into testing and making all the parts fit right.
Making '64 Impala mold
For casting the model I used the original 1/12 scale Maisto G-Rides '64 Chevy Impala body.
I created a cost effective 15mm thick layer of Smooth-On Mold Max 30 silicone supported by a mother mold made out of acrylic resin reinforced with fiber glass cloth.
I didn't want to waste a lot of silicone on the second, inner, half of the mold either so I went with a hollow mold. To further save cost I grinding old silicone molds with a meat grinder and mixed the granules with freshly mixed silicone. In between silicone layers I added band aid to make improve the tear strenght of the mold.
Reinforcing the '64 Impala bodyI added strips of styrene to the sides of the Maisto '64 Impala model to make it stronger and less flexible.
Prepped body and mold preparationThe primered model placed on a bed of plasticine clay in such a way that releasing the model from the mold will be easy.
Model wrapped in cellophaneBefore applying a layer of clay I wrapped the model in with kitchen cellophane so there's no need to clean it afterwards.
adding a clay dividing layerThis 15mm clay dividing layer is a placeholder for the silicone mold that will be poured inside the mother mold later on.
Finished acrylic resin mother moldAcrylic resin reiniforced with glass fiber is a cost effective way of creating mother molds. The funnel on top is for filling the mold with silicone.
I poured 480ml of mixed Smooth Cast 325 resin with added color pigment inside the mold and carefully slushed it around creating a thin impression layer. Immediality after that I pushed the inner mold in place and used bags of rice to make sure the roof, trunk and hood areas received enough weight/ pressure to ensure the body will have the same wall thickness all around.
I Also created molds of the front end and rear bumper placing the parts on a bed of clay making walls using Lego type blocks.
The first resin cast copies usually come out bad because the mold needs to wear in but I was lucky to get two almost perfect copies straight from the bat.
The front end, rear bumper and side mirrors were later on proffessionaly vacuum chrome plated by Metalrys in Poland.
Filling the mold with siliconeI drilled holes on several spots on the mothe mold to maker sure the silicone reaches every spot inside with no chance of entrapped air.
Inner silicone mold halfTo save costs I made grannuls from old silicone molds using a meat grinder and mixed it with fresh silicone. To further save on costs I made a hollow inner mold.
The silicone outer and inner moldI placed the mother and outer mold in a bucket made out of wood. The inner mold is also reinforced with band aid covered by silicone.
First resin copy using the moldUsually the first copy turns out bad because the mold needs to worn in. This time the first '64 Impala cast came out pretty clean by slushing the mixed resin around in the mold and gently placing the inner mold inside the outer mold.
Second '64 Chevy Impala cast in pinkFor the second body I added red So-strong pigment resulting in a pink resin cast.
Chassis design & construction
To build a RC lowrider with hopping action the chassis needs to be designed specifically for this purpose.
Flexing and vibrations will have a negative impact on the hopping performance so I used High Impact Polystyrene and aluminum beams to build a strong and rigid chassis.
With two Turnigy 2200 mAh lipo batteries sitting in the trunk making up for most of the weight it is necessary to create a strong bridge between the middle and rear section using aluminum parts.
For the front suspension I went with a sliding setup creating a shaft using four aluminum pillars and U-bar style slider with a micro servo placed in the center. The lower A-arms and springs retract the slider back up to creating more force to make the car hop.
Plastic and alluminum chassis3mm thick High impact polystyrene and aluminium beams to create a lowrider chassis without too much flexing and vibration.
Rear axle reinforced chassis rearReinforced resin cast rear axle sitting in the aluminum bucket that forms the rear of the chassis.
Rear section of the lowrider chassisWith most of the weight sitting in the trunk this rear piece of the chassis needs to be strong enough and tightly mounted to the middle section.
RC lowrider chassis top viewThe chassis with the assambled rear section holding two modified high torque TGY1501 servos to lift and lower the rear and the 2800 RPM planetery gear motor that powers the car.
Turnigy high torque servosThe two highly modified Turnigy TGY1501 High torque servos rotating 180 degrees to lift both sides of this lowrider car.
Motors and Servos
The 2800 rpm high speed drive motor I bought on Ebay from seller RC-sub-workshop and it delivers both enough torque and speed.
I casted my own rear axle and drive shaft using part I bought at Hobbyking.
Inside the rear axle there's a differential which is important to make car steer properly with most of the weight sitting in the back.
To make sure the rear axle will not bend I reinforced it with a strip of aluminum.
To make the car I used a speedy 380 motor with brass collar attached to the shaft. It's very important that the hopper string runs freely to the front without any friction.
After an unsuccesfull attempt to make the lowrider car hop with a full A-arm suspension I went with a slider setup and lower A-arms attached to make the front suspension move up and down. In the center of the suspension sits a micro steering servo.
The front of this RC lowrider hopper car has double action: a hopper motor for hopping and a TGY1501 servo to lift and lock it.
RC lowrider chassis build upThe complete chassis mounted with a full A-arm suspension, reinforced rear axle and battery casing in the trunk area.
Changing the front suspensionAfter an unsuccesfull attempt to make this car hop with a full A-arm suspension I went with a shaft and slider setup.
front suspension and shaft setupThe altered front suspension with four poles that acts as guides keeping the up and down sliding setup in place. I added lower A-arms still giving it an authentic look.
chassis with hopper and drive motorThe hopper motor sitting on top of the drive motor to keep all the weight on the front down and creating enough slack for the hopping string to unwind.
Electronics and Remote
I modified the Hobbyking 6 channel radio by removing the turning pots adding joystick like switches still keeping full proportional control on all servos.
A momentary DTDP momentary switch controls the dual RC switch with relays bought at modelradioworkshop to make the hopper motor spin forward and reverse.
The receiver and drive motor is powered by a relative simple and cheap esc bought on Alliexpress and proved to work flawless.
Two 7.2V 2200 mAh lipo batteries lay in the back/ trunk of the car one provides juice for the ESC and the other one directly to the RC switch with relays giving it full power to hop the car.