Resurrecting A Totaled Elev-8 Quadcopter

Discussion in 'Build & Tune' started by GlassKnees, Jan 13, 2018.

  1. GlassKnees

    GlassKnees Well-Known Member

    A couple of months ago, I took out an Elev-8 quadcopter that I built and modified for a fun flight outside the front of my house. For those of you who are unfamiliar with the Elev-8, it was a kit that I bought from Parallax, a company in California that sells kits/parts for people who want to learn about robotics. Anyway, I modified the original quadcopter by replacing it's basic flight controller with an APM2 F.C. with GPS and telemetry. The resulting aircraft allowed me to select any of three flight modes at a time (I can choose from a dozen or so and put any three on the aircraft). It had so many features that I won't go into, as many of you are familiar with the APM which has been around for along time. Here is what it looked like:


    I loved to fly this thing! It was stable and fun to fly. Then, one day, a couple of months ago, I took it outside for a short flight. It flew flawlessly as I expected. I decided to give it full throttle to see how well it would accelerate vertically - just as it rose about 20 feet, I heard a loud crack and it pitched over and crashed in the street. I thought there was a mechanical failure, but saw nothing come off the aircraft as it fell.

    It was totaled. I was going to trash it, but decided to gather it up to see what I could salvage. In the meantime, my wife and I decided to sell our house and move to Colorado. I brought the crashed remains with me. After getting settled in our new house, I set up a work area in the basement and unpacked the pieces:


    Looking around, I found lots of spare parts that I had ordered at various times to repair this and two other Elev-8's I had. After conducting an inventory, I decided that I had enough spare parts to rebuild this aircraft But before I begin, I had to try to salvage some things - the wires going through the booms from the motors to the ESC's which were mounted on the center chassis, etc.

    I also decided to remove and replace the ESC's and while doing so I made a discovery. The ESC for the #3 motor had a bad solder connection - the bullet connector came right off the wire. The #3 motor is the left front and it suffered the most damage - it came down on that boom and cartwheeled so that the left rear boom/motor took most of the remaining shock and damage. The other two booms and motors seemed okay but on closer examination, one of the remaining booms was slightly dented.

    Here is the suspect - note the missing bullet connector on the red (power) lead:


    These were 40 Amp ESCs and I decided to replace them with the stock 30 amp devices that came with the kit. But after awhile I began to wonder about changing motors. I have four brand new KA outrunner 1050Kv motors, but I also have a bunch of Tarot 4006/620KV motors. Hmm, maybe I can use these... There is a dirth of information on the Tarot motors and lots of bad reviews. but hey, I've got some and might as well use them. so, based on info I gleamed from other forums, here's what I'm expecting.

    After searching through my bag o parts I think I have pretty much everything I need to rebuild the aircraft. I did decide to order a new set of ESC's - will wait until they arrive. Here are the parts laid out:


    I'm hoping that the all up weight of the final aircraft to be around 5 - 51/2 pounds. At 50% thrust, I'm expecting to get around 700 gms thrust per motor using 13x5.5 props => 6lb 2.75 ou. I'm expecting to draw 3 A per motor, so with a 5000mah lipo I could get over 20 minutes flight endurance.

    This will be a running thread - I hope to add to it as I get into the build and document my progress. At the end, I weigh the aircraft and conduct some endurance tests to see how far off I am with my expectations. Feel free to comment - if you think I'm off on my numbers then please, let me know!
    KentA likes this.
  2. Gyro Doctor

    Gyro Doctor Electronics Tech for 45 years

    That "loud crack" sound could very well have been electrical in nature.
  3. GlassKnees

    GlassKnees Well-Known Member

    I agree. I will have to be extra careful when soldering to insure that I have good strong connections. I also have a parallel project going on - a Tarot 650 Sport quadcopter - it is built and has a Feiyu-Tech mini 3D axis with GoPro camera. But when I powered it up, I'm getting an indication that one of the ESC's has a power problem - I suspect a loose connection; #4 motor is affected. I will have to open it up and troubleshoot. I hope to get it resolved and take it out on its maiden flight in a week or so.
  4. GlassKnees

    GlassKnees Well-Known Member

    Update - 10 Jan...

    It has been awhile but finally have some progress to report. The ESC's I ordered arrived from Amazon:

    I finished soldering bullet connectors and applying heat shrink. I had agonized as to where I would install the ESCs - underneath the motors or in the center chassis as the original kit was built. After considering which wires would need to be lengthened, I decided to mount them in the chassis.

    I decided to use velcro to attach the ESCs to the chassis as opposed to zip ties because the slits on the chassis plate were not conducive for securing with zip ties. Another change I have to make is I have to fabricate a new set of leads (3 per motor) from the ESC's to the motors. The leads I salvaged are too short. I made one and attached it to one of the ESC leads for the #4 motor:

    I will have to custom make the other wires in order to provide enough length to attach to the motor to facilitate motor replacement without having to take apart the whole aircraft. I don't have enough wire to fabricate all the leads I need but I have some ordered - may be another week or so before report again.
    Jackson and Spork like this.
  5. Gyro Doctor

    Gyro Doctor Electronics Tech for 45 years

    :rolleyes: ... Don't forget to allow some length for a slight "service loop".
    You'll want to be able to access or move some things without the need of unplugging them. ;)
  6. GlassKnees

    GlassKnees Well-Known Member

    Absolutely Gyro doctor! This was a problem with the Elev-8 kit - it was a pain if you wanted to replace motors. I plan to have enough slack so that I can easily change out motors if I have to. Just waiting on the wire to arrive so I can continue. I need to double/triple check solder connections also!
  7. GlassKnees

    GlassKnees Well-Known Member

    Status 1/21
    So, last night before going to sleep it occurred to me that I need to solder some bullet connectors to a couple of the Tarot motors I plan to use. Afterwards, I can test them out. Here are the motors I picked out of the pile:

    To test each motor, I pulg it into an ESC, connect the signal servo connector to the throttle port on an R/C receiver and plug the power leads of the ESC into a lipo battery - in this case, the one I will use for initial flight testing. The ESCs have a Battery Eliminator Circuit (BEC), so the red wire on the servo connector will supply power to the receiver. I turn oon the transmitter and move the throttle stick all the way up, then plug the ESC into the battery. The ESC senses that I want to calibrate it, so I get two beeps, I throttle down, get three beeps and the all clear signal and I can then throttle up the motor:

    All four motors are working and the solder connections appear to be good. So now I'm still waiting for the wire that I need to run through the booms to connect the motors to the ESCs that will be mounted in the center chassis. Stay tuned....
    Gyro Doctor likes this.

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