Moki Turbulator

In most cases the reason for unequal operation of single cylinders in radial engines is the generation of an asymmetric fuel mixture ofthe carburetor. Both the lateral inlet of the premix into the intake tube and the slanted throttle blade at partial load are responsible for that.In practice, the rotating crankshaft in the central crankcase is just not a perfect mixer and distributor, as often assumed.Through the intake duct the fuel mixture arrives as fog at the edge of the duct leading into the crankcase. And even before any "mixing"the first cylinder sucks the  “rich” fog of mixture. The engine always fires every other cylinder. However, the next but one cylinder does notreceive the same fat fuel mixture, etc. Thus, the effects depend very much on the distance between the inlet (centrally in the middle ofthe casing) and the position of the individual intake tubes. The larger this distance the better the mix is actually distributed up to "entering"one of the 5 intake tubes. This is the reason that the smaller 150-series engines suffer more from this effect than their larger counterparts. But also with these largertypes the cylinder temperatures are not equal - audible in partially choked flights by very harmful stuttering operation or measurable afterlanding when a cylinder is colder than the others (usually the 7-o-clock one when viewed from the front). Hence the turbulators of the smaller series 150 and that of the 215/250 ones are NOT identical though the latter ones have identicalengine cases. Please, do not use the stator of the wrong engine type (housing is marked).

Top row: note that the bottom cylinders run colder

Bottom rows: using an adjusted Turbulator

Operating the engine with too rich of a mixture will in almost all cases damage the spark plugs. Sometimes this is so serious that theignition coils are also damaged (especially that of the 4th cylinder - the clock-7 one viewed from the front). We recommend replacing at least this one sparking plug (or better all) with new original one(s). Even if the sparking plugs are lit properly, they can always be a cause for trouble. The conversion kit works only when the engine operates correctly. Another effect might happened. After mounting the turbulator the engine might not accelerate when opening the throttle past 2/3rds ofthe way. The reason for this is a simultaneous fuel exchange and/or the membrane is no longer optimal for other reasons. We should remember that with the design inherit to RC class radial engines there are no reserves when it comes to fuel , its atomization and distribution, any deterioration of any one of the part will affect the engines performance! Kunkel has compensated for this by reducing the twist angle of the turbulator, but sooner or later the engine will have a problem, i.e.the engine will run smooth during the first few flights and then might begins to stutter and the performance might decrease. In such a case, a simple test is to blow into the ventline of the tank or better, squeezing the tank together. If the problem is eliminated and the engine is running noticably better that instant you should purchase an APS electric fuelpump available from Vogelsng Aeroscale.The addition of an e-pump removes the vulnerability in the fuel supply. Using the additional fuel pump the engines will run at an optimized compromise in fuel mix distribution and usually gain performance.

Custom Baffles

You will not find a full size radial powered airplane of the cowled kind that is missing baffles. Air is lazy and will find the path of least resistance, meaning it will go everywhere but where it is needed: between the fins of your motor.

Furthermore we need to somehwo achieve a positive ratio of incoming to exiting parting. Meaning, your round opening of you cowl is most if not all cases exceeds the exit port by a multiple, creating a bottleneck design which hinders all heat management.

Our CAD designed and CNC cut baffles not only guarantee that your incoming port (surface area) is now as small as can be and therefore you create a rapid exit airflow inside your cowl, we are forcing the air to travel thorugh the fins at an accelerated speed.

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