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1867 Otto & Langen 1/2 hp Replica

Wayne Grenning builds a replica of an Otto & Langen atmospheric engine.

| June/July 2017

  • 1867 Otto & Langen 1/2 hp replica.
    Photo by Woody Sins
  • An original Otto & Langen belonging to Rough & Tumble on display at the Coolspring Power Museum in 2015.
    Photo by Woody Sins
  • Wayne Grenning and his wife, Tracy, with the replica on the occasion of its start-up, March 4, 2017.
    Photo by Woody Sins
  • The slide-valve on the original Otto & Langen.
    Photo by Woody Sins
  • The slide-valve on Wayne’s replica. His workmanship is stunning.
    Photo by Woody Sins

1867 Otto & Langen 1/2 hp replica

Manufacturer: Wayne Greening, Lockport, NY (Originally N.A. Otto & Co., Cologne, Germany)
Year: 2017 (1867)
Horsepower: 1/2 hp @ 100rpm
Bore & stroke: 5.9in x 38.7in
Flywheel dia: 50in x 2-3/16in
Weight: 2,300lb (approx.)
Cooling: Air
Ignition: Flame, slide-valve
Governing: Exhaust

Recently, I had the unique opportunity to watch the start-up of an equally unique project: a full-scale replica of the first generation of the Otto & Langen atmospheric engine, made by Wayne Grenning on the 150-year anniversary of the original engine.

The Otto & Langen engine was conceived by Nikolaus Otto in Cologne, Germany, and was the first successful production engine. This engine was offered in production quantities starting in 1867, and was the precursor to the 4-cycle engine we all know and love.

This was an atmospheric engine. It did not compress the fuel/air charge. As can be seen in the photos, the cylinder is the ornate column, with the piston inside, its connecting rod attached to a rack gear. This engaged a pinion gear, with a one-way clutch on a shaft. The piston starts at the bottom of the cylinder. An elaborate set of cams on a gear-driven secondary shaft lift the piston up a bit, which draws in a charge of gas and air. A second cam moves a slide-valve, which closes the fuel/air supply, and ignites the charge using an open flame within the valve. This ignition throws the piston up in the cylinder. The clutch is disengaged at this time. The piston is heavy, and its momentum, along with the cooling of the burnt gasses, causes the piston to recoil back toward the bottom of the cylinder. The rack and pinion gear engages the clutch during this time, transferring the downward power of the piston to the main shaft, spinning the shaft. The piston settles back to the bottom of the cylinder, and the process is repeated. The descent of the piston after the initial recoil is controlled by a governor, which controls how quickly the gases in the cylinder are expelled. The slower the descent of the piston, the fewer times it fires, and the slower it goes.

This model is the result of Wayne’s lifetime fascination of engines, and the culmination of his studies of the Otto & Langen engines during his adult life. He has built and sold many 1/7-scale models of this engine, as well as a 1/14-scale version and a 3/4-scale version with flame ignition. This latest effort combines many features available on the first-generation engines, such as a secondary slide-valve to close off the gas supply, tall guides for the piston rack, and the governor. The column was machined on a CNC machine from a solid block of cast iron. Many of the other parts, including the flywheel, are custom castings, as well. Alex Grenning helped with the design work, using 3D modeling software. This engine will be on display at the Coolspring Power Museum starting in May 2017. To view an instructional and start-up video of the engine, go to


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