• Jun 15th 2009 at 2:08PM
  • 11
During a flight that only lasted about eight minutes, the SkySpark managed to set a world record for the fastest speed attained by an electric airplane. The craft, piloted by astronaut (STS-75) Maurizo Cheli, achieved an airspeed of 155 mph (250 km/h) last week at the World Air Games in Turin, Italy. Specifically modified for the project, the battery-powered Pioneer Alpi 300 is thought to be capable of 186 mph (300 km/h).

In partnership with engineering firm Digisky and the Turin Polytechnic University, the plane has been in development since September of 2007 when successful flights of a fuel cell powered craft were completed. It is equipped with a liquid-cooled 65 kW Valentino synchronous motor by Sicme Motori that weighs in at 55 lbs (25 kg) and powered by lithium polymer batteries. The success of the flight is said by the SkySpark team's website to be only an intermediate goal. They will next re-visit their past and concentrate their efforts on a "hydrogen fuel cells powered engine." Hit the jump for video of some friendly Italian sky flying action. Although the sound is missing for the first minute and a half, when it does come on, you'll notice the inside of the plane is eerily quiet. Bonus video from an earlier unveiling (in Italian) has some shots of the craft with the hood up. Thanks to "mister nomer" for the tip!

[Source: EAA]

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    • 1 Second Ago
      • 8 Months Ago
      Very nice, but not not the fastest. with 155mph, it's quite slower than this, for example:

      Plane is plane, no matter the size.
      • 8 Months Ago
      You're comparing apples and oranges. The SkySpark needs 65 kW to go 186 mph, seats 2 and flies like a normal airplane. Care to show us the specs for your record setting car? I've read about Killacycle's record setting runs, putting out something like 500 HP (375 kW), so I imagine a car would need more than that.
        • 8 Months Ago
        Electric motors are capable of incredible torque output for their size and weight. The reason the cars and motorcycles are so fast or quick is because they dump a buttload of amperage to the motors quickly for really high HP (Killacycle is dropping a few thousand amps for 7-8 seconds), but they can only do it for a very short amount of time before either the batteries run out of juice or the motor windings overheat.

        For a plane, the motor needs to deliver the needed HP range for extended periods of time to be viable (what good is an airplane that can fly for only 8 minutes at a time?). Also, there is more to it than the weight or balance. Even the best designed propellors are only about 30-35% efficient, that means only 30-35% of the motor's HP is converted to thrust. For pure aerodynamic drag, planes are sometimes rated in what is called "wet plate" area. In other words, the drag rating would be equivalent to a flat plate held into the air flow flat side into the wind. One of the slickest planes ever built is a homebuilt that has a "wet plate" area of less than one square foot. Drag coefficient for aircraft change drastically throughout the flight regime. It isn't linear.

        Propellors also have a maximum RPM they can be rotated before the tips exceed the speed of sound and the efficiency totally goes to crap or the blades begin to flutter and snap off. The only way to increase thrust for any given propellor diameter is to change the airfoil shape, the pitch, the chord, the number of blades or all the above at once. Each change has it's own trade off. A two-blade propellor is generally more efficient than a three or four (or more) blade propellor. The blade efficiency also changes as the airflow speed increases or decreases, so a variable pitch prop is required for more efficiency (and this adds a level of complexity to the mechanics of the device).

        For a land vehicle, it is far easier to increase traction (i.e. friction drag) proportionate to the HP applied, than it is to find or create the right propellor that can convert motor HP to thrust. It's also far easier to clean up a land vehicle aerodynamically than it is an aircraft because the land vehicle isn't dealing with the same stresses as an aircraft.

        The plane's weight is only important in two areas, that it stays within the design specs for take-off and landing as dictated by category and that the airframe isn't stressed to the point of failure. So, although that little plane here says the design weight limit is 1100+ lbs, it probably could take on an extra 1000 pounds (at least as far as the airframe is concerned for takeoff and landing), it would just mean that the takeoff speed would be higher and more distance required (it would also lower the maximum G forces it could take without breaking, etc, but the point here is for speed from an electric motor, not how tight a turn it can fly). A heavier plane, however does not mean faster speed. Heavier means more drag, which needs more power. The only thing the extra weight will do on the plus side is increase wing loading and allow the plane to ride a little smoother in rougher air (which has nothing to do with speed at all).

        In other words, it is far easier to design a land vehicle for speed or acceleration than it is a propellor driven aircraft. Far, far easier.
      • 8 Months Ago
      Looks like they modified a standard piston engine plane for this run. We could be seeing even higher performance in the future from a plane designed for electric flight.
      • 8 Months Ago
      Hm, a successfull electric airplane would probably have to be of a blended wing body or flying wing design. Very cool though.
      They should really concentrate on improving the battery-powered version instead of pursuing the hydrogen pipe dream.
      • 8 Months Ago
      65Kw Motor X 75% power for cruse * 2 1/2 hour range = 121 KwH.

      Tesla's battery pack is 56 KwH and 1000 pounds. So ~ 2,100 lbs for the battery pack alone.

      The airplane used is the Pioneer Alpi 300, which has a maximum takeoff weight of 530 kg (1160 lbs).

      The normal engine for the plane is a Rotax Engine 912 UL 80 hp, is 123.5 lbs.

        • 8 Months Ago
        But the flight only lasted for 8 minutes, about 20 miles or so, so I imagine the battery was quite a bit smaller than the size you estimated. 65 Kw x 75% x (8/60) = 6.5 Kwh. Add a bit for safety margin, say to 10 Kwh, with a similar type like Tesla is using, that would be about 200 pounds, well within the takeoff limit for the plane.

        150 mph for 2.5 hours would be 375 miles...
      • 8 Months Ago
      It's great to see there's finally some serious work being done on designing an electric airplane!
      • 8 Months Ago
      Funny thing to note: electric car speed records are way faster than electric planes! Even if this planes gets to it's theoretical top speed of 186 mph, that's way short of the current 250+mph of electric car speed records.
        • 8 Months Ago
        Unfortunately, we cannot compare land speed records - with air or water speed records. Being a pilot myself I can say there is more to it than the obvious. For example, the design of the plane and wing, the weight of the plane and the distribution of weight within the plane. I can imagine that especially the distribution of the heavy batteries and a light motor created some challenges to keep it similar to a standard plane.
        • 8 Months Ago
        True, but in the general scheme of things, you expect planes to be faster than cars, and cars faster than boats.
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