RCU Review: E-conversion the Hyper 7 PBS

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    Contributed by: Keith Hilderbrand | Published: January 2005 | Views: 166590 | email icon Email this Article | PDFpdf icon

    Review by: Keith Hilderbrand 

    Have you noticed how much the RC world leans more and more towards nitro and pushes electric to back stage? Most people will tell you that electric is slow and just can't keep up with nitro powered RC's. This is because they have not experienced the extreme power of brushless. 
    Nitro powered 
    Hyper 7 PBS
    Convert a 1/8 scale nitro powered buggy to electric brushless

    When working with off-road electric applications, brushed motors do not have enough torque to give it the speed and the power that people want. This is why we chose a high quality burshless ESC and Motor for our application. Using a brushless motor you only need one instead of the two motors that a brushed setup would require. One motor will deliver enough power to give us the low end torque and top end speed we expect from a nitro buggy.
    To show that electric can be just as fast or powerful as a good nitro powered RC. In our project we took a nitro powered 1/8 scale buggy and converted to electric. 

    Nitro powered Hyper 7 1/8 scale buggy before the from nitro to electric conversion.


    Picture of the shop - Lathe and CNC Mill for making custom RC parts.

    1/8 scale buggies are very strong, durable, fast and can not be purchased as an electric RC on the retail market. Therefore some of our parts we had to either modify or make ourselves.

    Needed items for conversion:

    • Brushless ESC
    • Brushless Motor
    • Motor mount
    • Steering servo tray and servo
    • Pinion for electric motor


    Since 1/8 scale buggies only come in nitro form, we need to make a custom motor plate to mount an electric motor. Start off by removing any parts that had to deal with the nitro engine and disk brakes. The throttle brake servo is no longer needed anymore. Electric RC's use the motor for brakes.

    Next step will be to measure the mounting holes on the center diff. We will design and connect a motor plate onto the center differential to allow us to mount an electric motor. We will be doing all our measurements in millimeters (mm). We want 100% accuracy so we will design the motor plate on the computer and cut it using a CNC-Mill. 

    Hyper 7 buggy with all unnecessary parts removed.. Leaving only what we need.

    Shows  measurements and design of the new motor plate to be made on our CNC mill. This will allow a single electric motor to be mounted on our Hyper 7 PBS.

    Motor plate being cut out from 6061 aircraft quality aluminum on our CNC-Mill in our work shop.

    CNC'ed motor plate that will be used on our brushless conversion. After it was cut out we trimmed the thickness of the plate from 6mm to 5mm allowing enough room for our pinion gear to sit properly on out motor shaft.

    For the steering servo we will just modify the stock servo tray. We will cut away the part that holds the brake servo and keep the part that holds the steering servo only.

    Draw a line where you want to cut away the steering servo from the brake servo.

    Cut the servo tray where you drew the line.

    The servo tray should look similar to this picture once it has been cut. Again this could have been done with a dremel tool, but would not have been as clean or straight if we did that.

    Once you have the motor plate and servo tray ready, mount it on the buggy to make sure everything fits. If things do not fit correctly, you will have to remake the parts until you get them correct. It is very important to have the bottom of the pressed up against the bottom of the chassis of the buggy. This will prevent any damage to the center differential, pinion gears or the motor shaft from the torque of the motor.

    Now mount and fit everything onto the buggy and start trying to figure out how you want to setup your batteries. I plan on running with 12 cells and will try to balance them by placing 6 cells on either side of the buggy. Also take not that I used a cheap brushed motor when I am sizing everything up to make sure everything will fit.

    Even though we designed a motor plate from scratch and CNC'ed it. This can also be done by modifying an EMaxx motor plate and using it instead. The following will show how to modify an EMaxx motor plate instead of making on from scratch. Using an EMaxx motor plate is good for those who want to run 2 motors on their converted buggy. This is also good for those who can not afford a high end brushless system. One could get two EMaxx motors and a Novak ESC and run a dual brushed motor setup if they would prefer to do so.

    First get yourself a motor plate from an EMaxx.

    Hold the center differential support up to the motor plate for making measurements for cutting.

    Cut motor plate where you marked and drill the proper screws for mounting. Even though we used a CNC Mill for cutting, when modifying an existing motor plate one could use a dremel tool or something similar to cut for a tight fit.

    Size everything up and mount it to make sure it fits. It is good to try to fit your motor and pinion as well. When we are sizing things up we use a cheap brushed motor and pinion as shown in the picture.

    Once everything has been fitted and installed. Now is the time to make changes if necessary. We started off by making the plate from cheap aluminum and then after test fitting we resized a couple of areas and then remade the plate from 5mm thick 6061 air craft quality aluminum. 

    Many things to decide when doing a nitro to electric conversion like this. Need to decide what motor, ESC, gearing, batteries, how to mount the batteries, where to mount the ESC and receiver, where to put the antenna and many other items alike. 

    Well first person I thought of was Jamie at Starluck RC. Asked him what motor and ESC he recommended. Jamie recommend the BK Warrior 9918 brushless controller with a Feigao 10L brushless motor. The metal differential gears on 1/8 scale buggies are a Mod-1 pitch. Most manufactures will tell you that they are 32 pitch gears on the metal differentials, if you try to do this with 32 pitch gears they will strip very quickly and easily. When we asked Jamie about what gears to use, he recommended a 16 tooth hardened steel Mod-1 pitch pinion gear with a 5mm bore to fit onto our Feigao 10L motor.

    For batteries, we chose to run 12 matched GP3300's provided by Model Electronics, Corp. To balance the buggy equally we mounted 6 cells on each side of the chassis. Long Velcro straps were used to hold the batteries onto the buggy. I do not care for soldering cells, so we used Model Electronics patented (SPT) Solder-less Power Tubes. This way we can re-assemble the cells into different configurations without having to worry about un-soldering or re-soldering the cells back together. Later we will do a setup with 16 or 18 cells and this product allows us to do that more easily. For now we will just run 12 cells.

    Technical Note:
    One of the most important things when running a high end brushless system is your batteries. Using everyday sport packs will cause loads of cogging and hesitation within the motor and ESC. It is very important that you use very high end cells. Also make sure you are using Deans connectors and not the plastic Tamiya connectors. The Tamiya connectors are very low quality connectors and will cause problems or can even damage a high end brushless ESC or Motor. If you are unsure of the quality batteries you have then replace them. Do not take chances. Brushless motors and ESC's are not cheap, make sure your batteries are not either. This is why we asked Pete at Model Electronics, Corp to personally match and zap our cells for us.

    Everything mounted and ready-to- run. Just need to charge the batteries, put the lid on and go.

    Need to make sure everything sits low enough to allow room for the buggy body.

    Hardened steel 16 tooth Mod-1 pitch pinion. Making sure you have a proper gear mesh is important.

    We used Velcro straps for mounting the batteries. Just cut slits using a dremel or similar tool to allow the Velcro to be ran though the rock guards.

    Test fit the body - make sure everything fits under the lid and nothing is rubbing anywhere.

    On the first test run, this thing was amazing. Was zipping down the street in front of my house a lot faster than when it was powered by nitro. The run times depend on how hard you run it. The harder it is ran, the shorter the runtimes. Runtimes averaged 8 - 15 minutes. Performance and runtimes will vary depending on what ESC, motor or batteries being used.

    We took this new electric powered buggy to the stray in Harrogate, England. There we bashed it around pretty hard and did manage to get a short video. The video was cut short because the bitter cold made the plastic parts very brittle. We ended up breaking the wing mount and rear differential case on the brushless powered  Hyper 7. After owning this buggy for almost 2 years, finally broke my first part.

    Final Review and thoughts:
    On the first run of this newly created masterpiece, all I could say was WWWOOOWWW!!!! This thing has never accelerated this fast as when it had the Hyper 21 8 port nitro powered engine. Not only did it make marks through the grass, but it left deep ruts. I just wish I did this sooner. Even the top end speed was just unbelievable. The power delivered from the brushless motor was more than enough for any off-road RC vehicle 1/10 or 1/8 scale. All this without the mess or the hassle for tuning of the nitro engine. 

    Those who are reading this that want unbelievable power and speed out of their 1/8 scale buggy, then this is a must. Personally I love making RC's go fast. That goes for the fastest acceleration and fast on the top end too. This is definitely a lot faster on both than when it had the 8 port Hyper 21 nitro powered engine.


    Click here to play video.


    Buggy Nitro powered 
    Hyper 7 PBS
    Motor & Pinion
    Feigao 10L brushless motor & 
    16t Mod-1 pitch pinion
    provided by Starluck RC 
    Warrior 9918 brushless ESC 
    provided by Starluck RC 
    2 EPIC Monster power GP3300 7.2 volt battery packs using 
    (SPT) Solderless Power Tubes 
    provided by Model Electronics
    JR Racing Metal Gear High Torque Steering servo

    Manufacturer & Distributor Information

    Model Electronics Corp
    11512-155 Ave Se
    Renton, WA 98059
    Phone: (425)255-4269
    Web: www.modelelectronicscorp.com
    Email: mecpete@aol.com

    Starluck RC
    505 Shaded Arce Court
    Pelzer, SC 29669
    Web: www.starluckrc.com
    Email: starluckrc@charter.net
    Comments on RCU Review: E-conversion the Hyper 7 PBS

    Posted by: fathead431 on 08/19/2008
    where can i get spare parst for my hyper 7?, i managed to do the same thing, broke the rear diff case.
    Posted by: studysession on 08/19/2008
    I got my replacement parts off EBay.
    Page: 1

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