Chapter 23: Forward Baffles
Step 7: Forward Baffles
(In work)
(Updated 4/9/2012)
(Not per plans)
My forward baffles form the front side of my contained plenum under the engine. As such, the baffles extend downward along both sides of the accessory case to completely seal off the front of the engine. This approach is entirely different from the plans.
The first picture shows the 5 baffles that seal off the left side of the engine. The second picture shows the right-side baffles. The third picture shows the sump baffle that seals off the bottom of the engine.
Installing the Left-Side Forward Baffles
The left side of the engine was the toughest part of the engine to baffle. The biggest challenge was getting the baffles to fit and seal securely against the accessory case while also getting around the oil dipstick and the oil sump reservoirs. I tried many combinations and configurations before settling on this 5-panel configuration. I must have gone through a stack of cardboard paper trying to template these baffles.
1. The first picture shows the cylinder #3 outer head baffle and the outer barrel baffle in place on the engine. These must be in place before installing the left-side baffles. Note the brackets on the outer barrel baffle. These will be used to secure the barrel baffle to forward baffle #3.
2. The second picture shows Baffle #3 in place. It gets installed first. The outboard portion of the panel is secured with a fastener screwed into a threaded port on the cylinder head near the intake port. The same fastener holds the outer head baffle in place, too. The four clecos are being used to temporarily secure the outer barrel baffle brackets to the forward baffle. I will install nutplates on the brackets and use screws to attach the barrel baffle to the forward baffle. .
3. The third picture shows the bracket (or brace) that holds the two forward baffles that span across the top of the engine. It is fastened to the vacuum pump pad.
4. The fourth picture shows all the left-side forward baffles in place. I didn't think about stopping to take a picture of each panel. Sorry. With left-side panel #3 in place, the rest of the assembly order is to secure baffle #1 across the top of the engine, install baffle #2, then install baffle #4 and #5. Finish by installing the angle bracket that attaches the left-side baffles to the #3 cylinder baffle that gets installed later on. I used the angle bracket instead of trying to bend up tabs on each baffle panel. it was easier. Please note that the fasteners you see in these pictures are temporary fasteners. They will all be replaced with AN screws and locking nuts.
Installing the Right-Side Forward Baffles
It's really hard to get good pictures of right-side baffles. So, I have only this one picture that shows all three right-side baffles in place. The installation process is about the same as the left side baffles. The cylinder #4 outer head baffle and the outer barrel baffle are installed first. Then the inner right-side baffle is installed. Then the outer baffle. Then the small baffle that seals off an area around the oil sump reservoir.
Installing the Sump Baffle
The sump baffle is what ties the left-side baffles and right-side baffles together under the engine. It is secured in place by two fasteners locations on the bottom of the oil sump and by being fastened to the left- and right-side baffles. The sump baffle will sit into a C-channel fabricated onto the NACA diffuser in the lower cowl.
