Electric/Piston Skymaster Tested In Scotland (Corrected)


A California company is testing a hybridized version of a Cessna 337 Skymaster on a short-haul route between Wick on Scotland’s mainland and the Orkney Islands town of Kirkwall. Ampaire’s push-pull twin has an electric motor in the front and the piston in the rear and the two powerplants share duties during different phases of flight. The electric motor is powered by batteries in a belly pod. 

The Skymaster won’t be put into commercial service but its seven flights over open water are part of a test and demonstration program to see what it would take to use hybrid aircraft commercially. Kirkwall, the site of the Scottish flights, is aiming to eventually have all of its flights operating emissions free. It serves six towns on islands off the coast, all of them short duration. After the Scottish tests, the aircraft will be moved to southern England to fly between smaller cities there.

An earlier version of this story misidentified the standard make and model of engine in a Skymaster and transposed the geographical locations of Wick and Kirkwall.

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.

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  1. Judging from the proud Tartan pattern, it’s hard to read the 2nd and 3rd sentences without thinking it’s a double entendre.

  2. Just to set the record straight, Wick is on the Scottish mainland and Kirkwall on the Orkney Islands, not the other way round as stated in the article.

    • The larger engine has to be there to carry all those depleted batteries around when the motor has no go juice for it. Nice plaid pattern, too.

  3. I think a Skymaster is usually powered by O-360’s.

    So a better way to accomplish this mission would be to leave the IO-540 and delete the electric engine and belly pod of heavy batteries. Useful load is greatly improved and performance will likely be similar to the original powered by two 4 cylinder powerplants and the need to recharge for God knows how long is obviated.

  4. Wrong Headline. Please Change to:

    “Experimental, Electric Engine to Be Used on Passenger Flight. Women and Children to Suffer the Most as World Ends”

  5. The engine is reported to be a Continental IO-550.

    What’s with shipping this thing all over the world for “testing”? Flown in California–shipped to Hawaii to “test” overwater flight–now shipped to Europe to “test” whether it can fly there. Sounds more like marketing flights than engineering.

    Yes–the Skymaster CAN fly on one engine–especially when one of the engines has been changed out for a much LARGER one–going from 210 horsepower to well over 300. The aircraft carries NO payload, only the pilot. In flying with a much larger piston engine to do most of the work, what is proved by having a puny electric engine installed in the nose? I’ve never read or heard of them shutting down the piston engine.

  6. Shutting down the piston engine would not be a problem. The electric motor would take the plane directly to the scene of the crash.