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    Electric power for dummys......

    In terms of hovering efficiency, a light helicopter outperforms any multi-copter out there. The advantage of multi-copters are mechanical simplicity and potential transition to a wing-borne flight with a higher L/D than 5, typical for single rotor helicopters, but I'm not sure I've seen any in...
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    Electric power for dummys......

    It depends ... Similar to fixed wings, the efficiency of rotating blades depends a lot on the blades L/D, which is very dependant on the Reynolds number. Considering similar disk loading, smaller multiple propellers could have the Reynolds much lower than a single propeller. For a small 2-4...
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    Hot wire cutting.

    Actually the whole cnc machine build is presented here: http://aliptera.blogspot.com/search?updated-max=2016-02-17T19:09:00-05:00&max-results=7&start=7&by-date=false
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    Hot wire cutting.

    For compound shapes as in channel wing or lip wings, actually any curved wings, I made a jig where I use stainless steel 16 gauge, shaped as the airfoil, and program the cnc to do the curved shape of the wing. The current needs to be increased between 8-10A
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    Hot wire cutting.

    I converted from nicrome to rene-41 wire. You can go much thinner diameters, more precision, less current and the rene is much tougher than the nicrome, does not break. I buy it from here: Rene 41 Wire
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    Power to weight ratio of fuel cells

    What is the "best" in the sense what system can get the best power to weight ratio regardless of fuel type?
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    Power to weight ratio of fuel cells

    A lot of people are talking about hydrogen fuel cells for aircraft in order to get over the low specific energy of current batteries, but during my research I've discovered the fuel cell stacks are relatively heavy for the power they can deliver. The best numbers I found for specific power are...
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    Why battery-powered aircraft will never have significant range

    The VTOL flight portion is short (maybe 2-3 minutes) and range depends how "clean" the aerodynamics is. If the aircraft can stay in the air for 40 minutes and consume 20KW in cruise and still get to 110kts, that means range would be about 70nm. If not, range will be shorter. Anyway range is...
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    Oh No! Another multicopter!

    If the performance numbers from the theory don't make sense, no amount of practice will fix it. There's this thing with aerodynamics theory predictions - usually it over-predicts performance as there are simplifying assumptions. So performance you got from the theory are an ideal limit that will...
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    Oh No! Another multicopter!

    The rotors/propellers are not 100% efficient and cannot be. At most they are around 80-90%, but this is besides the point. The point is conflicting requirements for the driving parameters of cruise and hovering performance for any VTOL aircraft: L/D drives the performance for cruise and that...
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    quadraplane

    With 4 wings, you'll take a hit in performance, especially low L/D, as it is dependent on wetted aspect ratio, see post here: Ultralight Biplanes
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    Fisher Flying Products Announces New Electric Propulsion Systems

    The reality is that even today, buying of the shelf parts, you can make an electric propulsion system that is even lighter than a comparable piston ICE if you size the system for flights not longer than 30-40 minutes. See this post here: Why battery-powered aircraft will never have significant range
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    Oh No! Another multicopter!

    The transition from hover to forward flight was figured in 50's, but what wasn't figured yet, is how to fly in both modes as efficient as possible. A VTOL capable of transition is a compromise. It has much more disk loading than similarly sized helicopter, so power for hovering it's much higher...
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    Oh No! Another multicopter!

    I'm not sure that will work. If I want to go to another town 200km away, I need to get into my car, get to my town's airport, get through security, wait to get on the plane, fly to the other town, disembark, get to the bus station, and ride the bus to my final destination, all this enchilada is...
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