LF39 6 cylinder 3900 cc liquid cooled engine
D-Motor Engines rely on tried and true Flat Head technology that use Side Valves instead of overhead valves. This allows for a very large displacement and a very narrow overall width. D-Motor engines will fit in aircraft that are designed around inverted inline engines!
The Flathead design used by D-Motor eliminates the complexity of the overhead valve rocker arms and their leak-prone pushrod tubes. One D-Motor Customer wrote: “After fiddling in it’s belly, I have even more faith in the mechanics of the engine. It is so simple, there is not much that can go wrong. This engine will go a long way!”
D-Motor has reduced weight through the elimination of the overhead valve structure and cooling fins. This weight reduction completely compensates for the added weight of the liquid cooling system. The benefits of liquid cooling can then be realized without the weight penalty. Continuous touch and go landings without risk of shock cooling can be performed. Lower emissions and improved fuel economy are also a bonus!
The LF39 design uses a larger displacement than other engines of comparable horsepower. This results in higher shaft torque and eliminates the need for a reduction drive. The LF39 uses the same Nikasil coatings on the cylinder walls as high-rpm motorcycle engines to ensure long life and reliability.
When a valve of an overhead valve engine fails, the engine stops and an emergency landing usually ensues. When a valve of a side valve engine fails, only one cylinder ceases to function and the plane has the power to make a landing at the nearest airport, saving both airframe and passengers!