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Installing the “inlet ducts”?

Pman

Active Member
Regarding installing the upper cowling inlet ducts:
since the #1 cylinder and #2 cylinder are a few inches staggered differently from their respective air inlet (#1 cylinder is closer to the air inlet opening), should this be a consideration when installing the upper cowl inlet ducts?

Another words, should the placement of the inlet ducts also be staggered to allow for a consistent gap/clearance between the top of each cylinder and its respective inlet duct? Installing both the left and right inlet ducts in the same relative position will effectively result in the #1 cylinder being “pinched“ as the gap would be less.

I totally understand how to epoxy and fiberglass them in place, no problem there, I’m just uncertain about the fore/aft positioning of the inlet ducts?
Thanks to all who may respond,

Mike Perillo
 
Yes. Best practice is to stagger the ramps so you don't restrict the airflow on the right side of the engine.

If you search long and hard, you can probably find a sketch Dan Horton posted which illustrates this.
 
Mike, I'm not aware of anyone changing their inlet configuration and flying instrumented "before and after" tests. So, no hard evidence. However, common sense applies, and better performance is often the sum of little improvements.

I think there is some static pressure to be found by moving the upper ramp forward, and flattening the lower ramp angle. Note your cowl is delivered with a fairly long spigot extending back from the inlet lip. Nothing seriously requires it, and shortening it improves the angles.
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Kyle and Dan, thank you both for your replies. Yesterday I drilled/clecoed the inlet ducts to the cowl. I placed the right inlet duct about 3/4” forward relative to the left inlet duct.
I appreciate your input, thank you both.

Mike
 
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