There is an expression: “the Best is the enemy of good.” It remains true, however not always. Any Modeler familiar with one of the standard domestic compression motors — KMD-2,5. Although it is designed for racing model aircraft, it is successfully used and air “fighters”, only pilots and beginners.
Gained recognition KMD and avtomodelistov. But the treadmill Assembly engines work in a more intense heat treatment than in the air — worse blowout. KMD starts to “act up”, he shows a tendency to “zadavlivanii” even with a small contraction kontrpartiya. And sometimes, just a single click ratchet retainer adjusting screw to a motor in NC mode at half the distance.
Modification of the system of regulating the compression ratio of the engine KMD-2,5:
1 — adjusting screw microcontrolle with external thread М5Х0,5, 2 — adjusting screw main kontrpartiya with internal thread М5Х0,5 and the outer М8Х0,5 (in the engine head is cut the same thread), 3 — intermediate, thrust washer, 4 — controlling, 5 — microcontroller.
The solution to this design challenges were interesting: serial counter-piston is retained; in this axis rastaquouere hole Ø 9 mm and it rubbed microcontroller. Manage business accounts for only the last. You say: but then why not just put between the main ControlNet and head set of distance pieces, choosing the one on the training of their total thickness? But the motor wears out, changing weather, changing of the model. And you have again and again to disassemble the head to find the gasket. All this is not required, if you do screw in the screw, in the same way as controlling in concorse! Remains the possibility of any adjustment, coarse and fine. Under any conditions it is possible to form the combustion chamber of the advantageous forms.