Fitting the cooling plenum to the engine. Note that the rear-most set of two ignition coils from the previous pictures had to be moved forward to clear the plenum and cowling. Note that once the plenum was fitted, and the runners where sanded slightly to allow them to slide into place, we started to fit the attach points. First the firewall and top three sides of the plenum where masked off with duct tape, and the runner was sanded to accept 2 BID layups for flanges. Once cured, the mating surfaces were drilled and clecoed together, then the bottom of the runner was masked, and the plenum sanded for its flange. Putting this flange on the plenum makes it much easier to install and remove the runners.

Cooling Plenum Fitting	Runner Fitting
Runner Fitting Pilot and Co-Pilot Sides	Runners from NACA Inlets to Cooling Plenum
NACA inlet to Runners and Plenum	Laying Up Flanges on Plenum
Finished Lower Flange and Plenum Opening

Here I’m making a notch on the front of the plenum for the LSE ignition coils to fit into. With all six coils mounted on top of the engine, this was required. However, I never really liked how this worked out, since to get to the bottom spark plugs the ignition wires would have to pass through the plenum with a grommet, so I changed the mounting (see next section).

Another late addition to the bump out, at Jerry’s recommendation, was to create yet another piece of glass mated to this surface (in the usual duct-tape over top way), then join them with nut plates, cut opposing slots in them for the wires and hose for removal, and then silicone the lower section to the engine “permanently”. Here is how it turned out.

Lower Plenum Half Caulked down	Lower half of split with nutplates and wires/Hose
Finished Plenum

Here I’m creating holes in the plenum to allow access to the sparkplugs for maintenance. Once I’d created the holes and fiberglass covers, I drilled screw holes and mounted nut plates to secure them with.

Drilled Holes with “Universal Release Agent”

Laying up the cover

Posted By: Brett Ferrell
Friday July 4th, 2003 at 2:43 PM

Categories: Cooling
Tags: Building Cooling Engine Fuselage Magnum