Alex Madsen wrote:



Last week I finished my concept drawing for a tuned carbon fiber intake manifold which I may eventual start producing. After three designs I finally got
something I liked. There are several things I sill need to change (clearances, remove flat surfaces, move plenum entrance to side, and further reduce

height

above engine ect). The engine block is a sketch I roughly scaled from a drawing with calipers.  If anyone has a solid model of the 13B they could send to

me

it would appreciate it. The runners are flattened 2 in. tube with a hydraulic diameter of 1.8 in and a length of 30 in. . I think the 30 in. is a bit long

but

I need to start somewhere. The height of the manifold above the top of the engine is about 3.5 in.   The plenum has a volume of 1.12 L.



I am in the middle of finals at the moment so I have not had time to refine the drawing.



Comment Questions



Alex Madsen

Jr. Mechanical Engineer

Rose-Hulman

Nice 3D work Alex. I did something similar awhile back. Kind of tough
to get the primary tuned length short enough to use the dynamic
chamber principle at 7500 RPM. Never know for sure unless we tried
one on a dyno. The last 3D is one I did.

The stock Mazda dynamic chamber is tuned for 6000 RPM for the long legs
and 3000 RPM in the dynamic chamber mode. You can see the torque hump
at 3000 RPM in the NA HP charts. Something we really don't need in
an aircraft engine.

Ed Anderson and I went around and around on this. He is currently
flying a version that is cockpit adjustable. However without a dyno
it is hard to prove it is working or not working.

A lot of systems also add a tuned length pipe from the dynamic chamber
to the air cleaner. The RX8 uses this principle with multiple dynamic
chambers to fatten the torque curve throughout the RPM range.

BTW IMHO there is no replacement for displacement when it comes to low RPM
torque. That is why I am pushing Mazda management for a 3 rotor in the RX8 :)

Paul Lamar

Nice drawing.  With the flexibility of 3-D routing, you could also run the intake tubes beside each other (horizontally, instead of vertically) at the dynamic
chamber.  This would allow a top or bottom placement of the throttle-body.   True, the inner tubes would be a tad shorter, but not by much.  Either version
would fit in my plane 8-}

With a solid set of standard specifications, I don't think that building the plug and molds by hand would be that terribly difficult.  Could be wrong,
though!  CNC would obviously be much more accurate.

Scott Gettings

BTW A lot of airplanes don't have room on top for an over and under dynamic chamber.

Paul Lamar
 
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