Myself and three other Mechanical Engineering students are in our last year of college and we wanted to go out with a bang.... So we though, what would be fun to build as a senior project?

Well, we decided unanimously on building a heavy lift gas powered quadcopter. It will have a payload of 50lbs, variable pitch to allow quick maneuvers and two 12.5hp two-stroke hobby motors running parallel. Each rotor head will have four 435mm rotor blades making this UAV one big quadcopter measuring roughly 40" in length. The four of us are really excited to finish and watch it fly. If you are interested check out the links below.



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  • all this talk about using a series hybrid setup; Gas, nitro, diesel ICE combined with an alternator/generator to power electric motors for the rotors. Has anyone thought of using small form factor Hydrogen fuel cells in place of the ICE/genny setup? There have been quite a few advances lately in fuel cells and it might be worth the research. At the very least it's a lot less moving parts, so fewer points of failure. Just a thought.

  • Hi Leonard,

    I was wondering if perhaps that was possible, it seemed to me that it could be feasible because of the power densities these motors are already achieving and at pretty high efficiencies as well.

    It would be interesting if the most feasible option is the one already closest at hand.

  • ok everyone is saying switch to electric, but there is a compromise, check out my post:

    the concept is a electricity generator by way of a small nitro engine or other combustion engine that will give the efficiency of electric equipment, to which you could buy generic stuff and not need to modify it, but get the long flight times from the engine


    Scroll down andyou will se a guy who is actually attempting it and has made the generator part.

    if you could do this, you could sell it to Nato etc

  • Developer

    These brushless motors can be turned into a generator with the appropriate circuitry. Although I would need to have a chat to some of my Prof friends at the university to get an idea of the efficiencies that could be achieved I believe that it could be reasonably efficient with the correct circuitry. (My university does research in this area)

  • @MAC: Flight control failures are the point of adaptive control schemes, specifically MRAC (model reference adaptive control) In this type of control system the flight controller in a sense is tuning and manipulating itself realtime to achieve some modeled controllable system that the controller is aware of. I have taken a few courses in this work and the possibilities of this work are incredible, however, computationally require a workhorse to do it (atleast it appears that way to me but I am no CS major). Specifically FPGAs or other real-time processors.

    Check out MIT adaptive control quadrotor on youtube.

  • Hi Gabe, I actually think what you guys are doing could produce a workable multicopter that has operational capability for far longer flights than our electric copters have and in the forthcoming world of actually functional autonomous aircraft, your basic design could have a lot of utility.

    Having to deal only with collective and using 4 rotors instead of one actually let you produce a more robust rotor system than for an equivalent capacity helicopter and it gives you a kind of simple and symmetrical control very unlike a helicopter, it could have huge uses in a lot of applications.

    The motion picture industry would welcome a heavier lifting stable platform that was easy to "dolly" from place to place. 

    Earlier there was a BLOG from a guy who wanted a Multicopter to pick up, and take out to sea and drop (and later recover) a small autonomous UAV submarine.

    At the time, it was really unlikely, electric multicopters could never have the stamina, but your thing could.

  • @Gabe: Hey, nothing wrong with doing it just for the hell of it, especially in this hobby.  Honestly, that's what most of us are doing anyway...  That said:

    >Another significant driving factor while considering a quadcopter was the ability to recover in the event of a motor, rotor head or blade failure.

    Multi-engine helis are just as possible as multi-engine multicopters, and while I've seen hexacopters and octocopters recover from partial propulsion failures, I've never seen a quadcopter or tricopter recover - there simply aren't enough points of lift to maintain balance or yaw authority if even a single prop stops turning.

  • Mac,

    as with anything scaling up will always incorporate a more complex design and in our case significant drive train and power supply issues. I agree that a single rotor head as in a traditional heli would work fine because it's been proven. The team and I wanted to create something new or as you say "because I wanted to prove I could." 

    Another significant driving factor while considering a quodcopter was the ability to recover in the event of a motor, rotor head or blade failure.

    I see your point and we struggled initially with the idea but ultimately decided to peruse our idea because we think we can do it.

  • Gary,

    you are right on the money. We wanted to reduce weight as much as possible and the generates on the market are not efficient enough to produce the power we need. We know using two gas motors is probably not the best option but with whats currently on the market while considering the project goal, our current design is in our eyes the best chance we have to make this idea a reality

  • @Adam Conway:  While this design requires collective blade control on each rotor, it does not need cyclic control, simplifying the swashplate assembly significantly.  That said, I agree with you that this complexity seems to defeat the purpose of a multicopter.

    Multicopters are great because you eliminate a lot of mechanical complexity, and therefor reduce failure points, cost, maintenance requirements, weight, etc.  No drivetrain, no swashplate, etc.    But when you size it up, and need collective pitch control because the larger motors have too much inertia for RPM-based control...  Now you have multiple swashplates to control, a much more complex drivetrain that has to be extra-tough, due to the rapidly-changing loads on each rotor, etc etc etc.  MORE complexity and potential failure points than a regular helicopter.

    I don't understand why a helocopter wouldn't be a better option at these sizes, other than the "because I wanted to prove I could" side of things.

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