March 20, 2016

Some recent news articles on the Ruixiang RX1E got me to do some digging and I think the latest real news is’s 12/4/15 China’s first electricity-powered aircraft gets production approval. That means that the RX1E’s airworthiness certificate from the Civil Aviation Administration of China in February 2015 (see China Daily’s China’s first electric plane ready for sale) didn’t mean that the RX1E had production approval at that time.

So the June 2015 “sale” of two RX1Es reported in spinoffs of the Shenyang Aerospace University announcement Handing over ceremony of RX1E aircrafts and pilot training inauguration ceremony held in Shenyang was really more of a ceremony for student training and sale or transfer of two RX1E prototype airplanes before production would begin.

The good news is that apparently RX1Es can now be manufactured and sold in China and the manufacturer supposedly plans to build 20 this year and ramp up to 100 per year within 3 years. Maybe we’ll hear more from AERO Friedrichshafen in April.

I updated Ruixiang RX1E accordingly.

February 22, 2016

Miles Per Kilowatt Hour is the new Miles Per Gallon


Courtesy of

Vehicle energy efficiency–you know this as Miles Per Gallon (MPG)

A gasoline-powered vehicle’s range is the product of fuel efficiency and fuel capacity. E.g., an internal combustion engine (ICE)-powered automobile with 25 miles per gallon (MPG) fuel efficiency and a 10 gallon fuel tank has a range of 250 miles.

EV energy efficiency–will become known as Miles Per Kilowatt Hour (MPkWh)

An electric vehicle’s range is the product of energy efficiency and energy capacity. E.g., an EV with 3 miles per kilowatt hour (MPkWh) energy efficiency and a 24 kWh battery pack has a range of 72 miles.

Typical EV energy efficiency (miles per kWh):

  • Electric automobile: 3-4 MPkWh (miles/kWh) (combined city/highway)
  • Electric motorcycle: 13 MPkWh city, 6-8 MPkWh highway
  • Electric bike: 62 MPkWh

What energy efficiency do you think electric airplanes have?

e-airplane energy efficiencies

Although some people “joy ride” in automobiles, we don’t generally care about an automobile’s time endurance on a tank of gas. But many pilots joy ride in aircraft and want to maximize their time flying around the patch. I.e, we pilots care about hours per gallon as well as miles per gallon.

With that in mind, we should think of two types of energy efficiency for electric aircraft: range efficiency and endurance efficiency.

Range = range efficiency (distance/energy) * energy capacity (energy)

Examples of e-airplane range efficiency:

  • GW280 eSpyder range efficiency: 8.5 MPkWh (miles/kWh) (at 38 MPH)
  • ElectraFlyer-ULS range efficiency: 10.4 MPkWh (miles/kWh) (at 40 MPH)
  • e-Genius range efficiency: 13.8 MPkWh (miles/kWh) (at 93 MPH)

Endurance = endurance efficiency (duration/energy) * energy capacity (energy)

Examples of e-airplane endurance efficiency:

  • GW280 eSpyder endurance efficiency: 0.225 hours/kWh (= 13.5 minutes/kWh) (at 38 MPH)
  • ElectraFlyer-ULS endurance efficiency: 0.260 hours/kWh (= 15.6 minutes/kWh) (at 40 MPH)
  • eGenius: endurance efficiency: 0.148 hours/kWh (= 8.88 minutes/kWh) (at 93 MPH)

Are you surprised at the range efficiencies of e-airplanes vs electric automobiles, motorcycles, and bikes?

February 22, 2016

Great Expectations


Courtesy of Gartner

Last month, a prototype manned multicopter was touted as an autonomous air taxi, now this: Musk Moving On Electric Jet.

I don’t know how sustainable SuperSonic-VTOL flight can be, but I’m pretty sure the current slope of the e-flight expectations curve isn’t sustainable.

July 17, 2015

Pipistrel needs multiple suppliers of electric motors


Courtesy of Pipistrel

Pipistrel needs multiple suppliers of electric motors. After the English Channel crossing incident (Electric cross-Channel flight: official statement), Pipistrel can’t count on Siemens for motors to power the Alpha Electro or Panthera Electro.

Ideally, Pipistrel should obtain and offer electric powertrains from multiple suppliers so that no problem with a single supplier can interrupt production of Pipistrel electric aircraft.

Siemens electric propulsion systems
Pipistrel Alpha Electro
Pipistrel Panthera Hybrid and Electro
Pipistrel Taurus G4

April 11, 2015

Signs of life at FlyNano


Courtesy of Fly Nano Oy

The FlyNano seaplane was developed by Fly Nano Oy in Finland during 2010 through 2012.

They updated their FlyNano homepage and posted to Facebook on 4/11/15.

They say they’re preparing for production. They’re at least testing the market for interest. I signed up for emails.

–Read More–

March 26, 2015

Siemens develops 260 kW aircraft motor


Courtesy of Siemens

Siemens develops 260 kW (348 HP) continuous power, direct-drive aircraft motor!

Siemens is going after the EV electric powertrain market in a big way with their Inside e-Car Business Unit. In addition, Siemens has worked several projects in the sport aviation market.

–Read More–

February 9, 2015

Ruixiang RX1E certified by the Civil Aviation Administration of China on 2/6/15


Courtesy of China Daily

The Ruixiang RX1E is a prototype two-seat electric airplane certified by the Civil Aviation Administration of China.

As reported by China Daily, the RX1E was developed at Liaoning General Aviation Academy by a team led by Yang Fengtian. The company Ruixiang General Aviation of Shenyang is slated to begin production of the RX1E by June 2015.

China Daily also reports that Yang Fengtian intends to market the RX1E in Europe and the US as well as China and achieve annual production of 100 RX1Es within three years.
–Read More–

February 7, 2015

2011 Eco-Eagle is a proof-of-concept, mild hybrid electric conversion of a Stemme S10 motorglider


Courtesy of CAFE Foundation

The aircraft is powered by a Rotax 912S internal combustion engine (ICE) with 74 kW (100 HP) peak power and an electric motor with 30 kW (40 HP) peak power.

The motor is mechanically connected between ICE and propeller, making the configuration a “parallel hybrid”. Because the motor has lower power than the ICE, the configuration is also called a “mild hybrid”.

–Read More–


February 6, 2015

Available now: TM4 PMAC motor with 50 kW max continuous power


Courtesy of TM4

TM4 Electrodynamic Systems produces liquid-cooled PMAC electric powertrains with 15-180 kW max continuous power.

TM4’s HSM60-MV270 motor and matched CO150 inverter have:

  • Max continuous power: 50 kW (67.0 HP)
  • Peak power (30 sec): 90 kW (120 HP)
  • Total weight (motor+inverter): 45 kg (99 lb)
  • Max continuous power/weight (motor+inverter): 1.11 kW/kg (50 kW / 45 kg)

–Read More–