KMD-SHIFTERThe design of the rear cover of the engine KMD-2,5-made, in our opinion, wrong. The flow of fresh fuel mixture from the distribution node goes directly to the bypass channels of the cylinder, bypassing the area of the crankshaft. And the result is the most loaded part of the Microdrive (neck crank and lower rod cap) remains without grease that enters the motor along with the fuel-air mixture from the carburetor. Responsible node is overheating due to strain fall resource and capacity.

The best option — when the mixture comes from the Central axial holes of the spool in the direction of the crankshaft. So designed domestic motor “Rhythm”. But in most circles to make a new wall for KMD difficult. So we decided to go more simple way: to try to turn the entire back cover of the motor through 180°, changing the direction of input flow of fresh mixture. In this embodiment, on her way to the bypass channels inevitably would meet the crank and the connecting rod cap, cooling and lubricating these parts. For engine work needed (to preserve the original timing in cheek regular spool) new to saw through the groove under the leash of the crank, opposite the existing one.
After the modifications the engine was assembled in the usual way, put on stand and run. The tachometer tweaked for maximum speed and stopped. Then, without changing the adjustment, turned back at 180° (the leash of the crank, of course, have to enter into a new groove cheeks of the spool), and re-started the engine. Measurement of speed showed that in the second case, the shaft speed at 1,000 rpm more. All tests were conducted on a single fuel with a single propeller under the same atmospheric conditions.
Modified engine KMD-2,5 assy, right engine with the removed back cover of the boat.
Modified engine KMD-2,5 assy, right engine with the removed back cover of the boat. Separately shown is crude spool.
Now to increase the power and life of the engine KMD-2,5, we use this innovation.
S. GLADKOV, head. laboratory of aviation technology Republican syut Kazakh SSR

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