Pipistrel Alpha Electro
Updated: Dec 28, 2021
First Impressions: I’m happy to pay for fuel in this plane! Outwardly this plane looks like many new LSA aircraft but trust me, things are different under the hood of the Alpha Electro!
Design Features: Well, if you haven’t figured out already by the name…it’s electric! The airframe is mostly composite and, due to the relatively light weight of the powerplant and “fuel”, the useful load is quite high. The airframe is very streamlined and every detail is designed with efficiency in mind. . This is a two-place side-by-side, fixed tricycle gear aircraft with dual stick controls. The brakes are dual disk style Beringers and are applied with a center console-mounted handbrake, which will take some getting used to if you’ve never used this style of brakes. The flight controls are pushrod-activated with the exception of the rudders, which use cables. The Electro has flaperons which extend the entire length of the wing, providing excellent roll authority throughout the flight envelope. Due to the low-drag airframe, there are electrically-operated spoilers mounted on the top of each wing. The spoilers are activated with a spring loaded twist knob on the instrument panel. As an extra safety measure the Electro incorporates a BRS (Ballistic Recovery System) rocket-propelled parachute for the entire airframe.
About the Electro: The Electro was purpose-designed as a zero emissions and cost effective primary flight trainer to teach students basic flying qualities and traffic pattern work. For private pilot training, the Electro is to be supplemented by a gas-powered aircraft in to
complete cross-country requirements. This plane is certainly groundbreaking in that it’s one of the first production electric aircraft on the market. The lack of fuel burn and low maintenance costs also make this a very affordable aircraft for a student pilot to train in, making a pilot license a more achievable goal for those with less disposable income. The flight school where I tested and occasionally instruct in Alpha Electros is the first (and currently the only) flight school in North America to utilize electric aircraft!
Ergonomics: Dual gull-wing doors provide easy access to the cockpit but you will be required to swing one leg over the control stick once you sit down. The seats are comfortable and have four point harnesses. If you’re around 6 feet tall or greater, after sitting down, you’ll notice that the spar runs just in front of your forehead and wrapped in soft indoor/outdoor carpet. It’s not necessarily in the way, but it’ll getting used to the somewhat awkward position. The BRS activation handle is mounted overhead between the seats, making it easy to find the unlikely event you need it.
Powerplant: This is where things get interesting! Two 400 Volt batteries operate in parallel (for redundancy) to power the motor. The battery power is converted from DC to AC via the inverter. A separate 12V battery powers cockpit displays and instruments. Thrust is generated by a fixed pitch, three bladed composite propeller. Power is not measured by horsepower but by kilowatts (kW). A full throttle takeoff will yield 70 kW and equates to approximately 94 horsepower. Another very different thing to get used to is the “fuel gauge”. The EPSI 570 engine monitoring system shows a color-coded visual depiction of both batteries with a State of Charge (SoC) percentage remaining as well as “time remaining” in minutes.
Pre-Flight: Before flying, you must plan ahead to ensure the batteries are charged and ready to go! The chargers require a 220V hookup and have multiple charging options available. There are multiple options for charging but plan for at least 80 minutes. Ensure all battery and throttle enable switches in the cockpit are off, then walk out front and spin the three bladed prop in either direction to check for binding. It spins smooth and free as there are no crankshaft, pistons, or alternator belts. As a matter-of-fact, the entire motor is in the prop hub and spinner itself! Next, make sure the charging cord is unplugged from the port in the cowling. Open the front battery door and note the State of Charge, battery health and temperature. An outside air temperature of 40° Celsius (104° F) is the limit for Alpha Electro and this is restricted due to the operating limitations of the inverter. The rest of the pre-flight is just like most other aircraft except you won’t have to dip the tanks or drain fuel samples. Also, note how clean the belly of the Electro is!
Start/Taxi/Takeoff: After yelling “clear prop”, the Electro is started by turning four console switches from Off to On. From left to right on the console, the Master, Avionics, Power Enable, and Throttle Enable are turned on, making the aircraft is ready to go, even though there is complete silence! Carefully bump the throttle forward and the prop immediately spins up and the plane starts taxiing forward. Steering is easy with direct link nose wheel steering. If you need to slow down or stop pull the throttle to idle and the prop spins to a stop. Needless to say it is very strange to have your propeller completely stopped and hear nothing but the sound of the wheels rolling down the taxiway! There are no toe brakes but there is plenty of braking control with the handbrake. There is also no run up to accomplish so once pre-takeoff checks are complete, take the runway and add full throttle!
Takeoff: One advantage to an electric-powered aircraft is there is virtually no delay between throttle movement and thrust. This instantaneous thrust, coupled with a light, low-drag aircraft means the acceleration is surprisingly fast! At 70 kW on takeoff you will see your “time remaining” go significantly down but once power is reduced after takeoff your “fuel” will increase! Even with a fuel-conserving 40 kW climb power set, the Pipistrel Electro still climbs between 800-1000 fpm with two large adults on board.
Cruise: The flight controls are extremely light and all inputs can be done with only two fingers on the stick. No death grips required! Typical cruise power is set at about 17-18 kW to maximize time airborne. A local-area flight in the Electro will be about 45 minutes, landing with about 20% State of Charge (SoC). The SoC depiction turns red at 19% remaining but still provide full power if required. At 10% SoC, the available power will be metered back to conserve time aloft. Trim is electric and accomplished with a rocker switch but is rarely needed. Visibility is excellent due to the large front windscreen and full-windowed doors.
Approach and Landing: As previously stated, the Electro is extremely slick and doesn’t like to slow down. To maximize efficiency, a power-off approach and landing is standard. Retard the throttle to idle at midfield and allow the aircraft to decelerate until below 70 kts. Of note, at idle with the propeller windmilling, the motor is acting as a generator and actually charging the batteries! Pull the Johnson bar-style flap handle to the first detent, giving 15 degrees down. When established on final and below 60 kts, pull the handle to the second and final detent which deploys 25 degrees of flaps. Attitude is everything on final. You must resist the temptation to nose over and dive for the runway if you find yourself high. You will rapidly blow through the max flap speed almost immediately. Hold a constant attitude that gives 55 kts and use the spoilers to kill lift until reestablished on glideslope. With the spoilers deployed, the sink rate dramatically increases. While you could slip to land in the Electro, the spoilers do the job and allow for a very stabilized approach. The flight controls are sensitive and the flare and touchdown is relatively easy as long as you don’t overcontrol the aircraft and use the rudders to keep the longitudinal axis tracking straight down the runway. Taxi back to parking, turn the four switches off in reverse order, plug the Electro back in and go grab lunch while your steed charges for your next flight!
Wrap-up: Since the days of Orville and Wilbur, aircraft engines have operated by burning dead dinosaurs! While there are certainly new aviation technologies being developed every day, it’s not often that you get to fly an aircraft with a completely new type of powerplant. I fully expect electric aircraft to continue to develop in the coming years but its certainly cool to fly an aircraft on the leading edge!