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Recent content by Tony Williams

HomeBuiltAirplanes.com

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  1. T

    Electric Powered - High Performance Design

    Two motors are fine, except... 1) It needs a way to reduce propeller speed 2) What if a motor seizes? Answer, with this design, they both freeze apparently
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    Electric Powered - High Performance Design

    Fire is a bigger enemy. Unlike a kerosine or oil fire, lithium batteries (and magnesium metal) can and will burn without oxygen. Those cells need to be in small enough arrangements so that a fire can be contained. The heat cannot get into the spar(s). I don’t want the weight of making the...
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    Electric Powered - High Performance Design

    Yes, that is outlined on the post linked below, with both overpressure and venting to atmosphere for pressure differential while climbing and descending. I suspect that the venting needs to go through an air filter, since air would be going in and out of the battery cells. The overpressure can...
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    Electric Powered - High Performance Design

    Much like gasoline or Jet-A, there is a lot of stored of energy that can burn amazingly well when things go bad. It’s super important to protect the airframe during a fire, especially with the fire in a wing. This picture is cylindrical 18650 cells (18mm diameter x 65.0mm) that caught on fire.
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    Electric Powered - High Performance Design

    This airframe is 2600 pounds with the turbine power plant and prop. Maybe about 2000-2200 without a motor? By the way, it hauls the bacon with 750-1000 hp.
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    Electric Powered - High Performance Design

    The inverter is only part of the noise issues with an inductive motor. There’s enough power in there to wipe out bearings and shafts.
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    Electric Powered - High Performance Design

    I believe the NASA design is: 1) High wing (so the prop blades don’t hit the ground) 2) Low power per motor 3) A dozen motors
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    Electric Powered - High Performance Design

    All the metrics that they proposed were all pie-in-the-sky... range, payload, etc. Snake oil salesmen. Hopefully, burning this one down might have saved a few lives.
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    Electric Powered - High Performance Design

    The 2170 cells fit in “sheets” between the spars, where the petroleum stuff normally goes.
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    Electric Powered - High Performance Design

    The lithium cells have instant power. There’s no advantage with capacitors. Capacitors are not “energy storage”. If there’s going to be a turbine “range extender”, you probably should just get rid of the batteries and power the plane with Jet-A. That’s a LOT of extra weight... engine, gearbox...
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