jdeas
Well Known Member
Ok, so the title has a bit of a double meaning here. Being new to fiberglass and having a building partner absolutely adverse to epoxy, I decided to build my own composite plenum. The only problem is I didn't know anyone versed in composite construction or have the proper tools. I only knew the concept of using a plenum seemed sound. Less distortion in the cowl, less cooling drag and a lack of the sealing issues was my goal. I considered aluminum, after all I have done 10,000+ rivets in the last few years but this task needs compound curves. That I did not want to tackle in aluminum!
The first step regardless was to trim the baffles to the proper height. Using the paperclip trick I assembled the baffles and trimmed them down to 1/2? below the cowl.
At this point I am still on track with Van's instructions so I could abort and make the traditional baffle seals.
The next step was deciding how to mold the plenum. I thought of all sorts of ways to cover the engine and use foam or some other filler to make the part but in the end (thank you VAF) I saw an example simply using the cowl top!
Yes, that is my cowl top, primed, filled, waxed, two layers of epoxy, plastic and a load of sand. It did appear to work. The next day with some careful pulling and swearing I managed to release the plenum cover from the cowl.
OK, not so good. The shape was great but the epoxy was not well distributed, heavy and leaving a less than stellar part. Even with the 4 layers of crossed cloth the part was too flexible for me to trust.
Now I really don't want to lose the ability to retreat to a standard baffle! Time to stop working in an information vacuum!
The first step regardless was to trim the baffles to the proper height. Using the paperclip trick I assembled the baffles and trimmed them down to 1/2? below the cowl.
![34hgt5j.jpg](/community/proxy.php?image=http%3A%2F%2Fi48.tinypic.com%2F34hgt5j.jpg&hash=ab62ba3fd0db1a56750bc4dcd95b64aa)
At this point I am still on track with Van's instructions so I could abort and make the traditional baffle seals.
The next step was deciding how to mold the plenum. I thought of all sorts of ways to cover the engine and use foam or some other filler to make the part but in the end (thank you VAF) I saw an example simply using the cowl top!
![70kols.jpg](/community/proxy.php?image=http%3A%2F%2Fi49.tinypic.com%2F70kols.jpg&hash=f7b2554509e4ed35557566550bab4923)
Yes, that is my cowl top, primed, filled, waxed, two layers of epoxy, plastic and a load of sand. It did appear to work. The next day with some careful pulling and swearing I managed to release the plenum cover from the cowl.
![xo2xdj.jpg](/community/proxy.php?image=http%3A%2F%2Fi47.tinypic.com%2Fxo2xdj.jpg&hash=494ede0b442f56ffc5905e43ce84f728)
![2z3nwx1.jpg](/community/proxy.php?image=http%3A%2F%2Fi47.tinypic.com%2F2z3nwx1.jpg&hash=dc1c72b00db0c8e5c95b46e6dfd611aa)
OK, not so good. The shape was great but the epoxy was not well distributed, heavy and leaving a less than stellar part. Even with the 4 layers of crossed cloth the part was too flexible for me to trust.
Now I really don't want to lose the ability to retreat to a standard baffle! Time to stop working in an information vacuum!