Rotary Valve Induction

ben_beyer

Junior Member
I have a question for the engine gurus. I ran across a thread where someone was using a ZDZ motor today. ZDZ is one of the manufacturers that uses rotary valve induction and I think the XYZ 50 a few years ago used it as well. What are the advantages of rotary valve inductions and what changes in terms of throttle response, top end, torque, etc. if you had two engines where one was a reed valve and the other rotary valve?


Just curious.
 

psycho-patch

Well-Known Member
I have had both. No real difference to speak of in power (~) in comparable sizes. It is just a difference in design to accomplish the same function. Both work well.
 

red7fifty

BadAss Member
My only experience with a ZDZ40.....is my last experience with a ZDZ40.
Stubborn SOB to start up, took 3 guys turns flipping the prop to get it to fire up.....dead stick, cost me an airplane......sold the engine cheap.
Now, something like a DA, where they test each one before leaving the factory......both my DA100 and DA150, I bolted up and flew right out of the box.....after only setting the idle speed on the throttle servo.

Others' might have better luck.......but, I'll pass.
:prrr:
 

Tired Old Man

Staff member
Rotary valve engines are a little better suited to racing or high rpm applications. As for the ZDZ 40, if it wasn't primed to the point of flooding it wasn't ready to start yet. They like to be wet. Treat it like a gal you want to see more than once.
 

red7fifty

BadAss Member
Rotary valve engines are a little better suited to racing or high rpm applications. As for the ZDZ 40, if it wasn't primed to the point of flooding it wasn't ready to start yet. They like to be wet. Treat it like a gal you want to see more than once.
We used to smack the hell out of that prop and yell "Start Bitch!" :prrr:
 
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