Firewall Forward Work

Starting to knock off some of the miscellaneous items firewall forward.  Based on the Rotax 912iS installation manual, the engine ECU must be mounted inside the cockpit.  That means that some fairly large electrical cables will need to be passed through the firewall into the cockpit.  After measuring the connectors and cables a 3"x1.5" hole was cut in the firewall.  This will later be covered and sealed.  Temporarily, some edge protecting plastic was added to prevent any cable damage.  It was a tight fit, but the ECU, HIC and Fuel Pump cables were passed through the hole. 

3"x1.5" hole in the Firewall

The coolant overflow bottle was mounted to the firewall.  A titanium strap was made and riveted to the firewall.  A screw and nut was used to secure the bottle in its holder.  Finally a hose from the coolant reservoir tank was installed with clamps. 

Coolant Overflow Bottle Installed

We discovered that we need a little more clearance at the oil cooler to prevent rubbing on the oil cooler hose lines.  We didn't need much about 10mm (a little over 3/8").  The four lower cowl attach holes were moved giving us the needed space.  The boot cowl will need some modification to fix this.

Started work on the upper cowl modification.  We wanted to add a fairing behind the propeller hub back plate.  We started with clay to get close to the shape we wanted.  Once it was close, some dimensions were taken and the clay was removed.  Now we need to add some foam and shape it so we can add some fiberglass.  A containment chamber for the 2-part foam was constructed out of cardboard and packing tape   Once all the seams were covered the 2-part foam was mixed and poured into the area.  After allowing the foam to cure excess pieces were removed and a rough shape was carved.

Hours 10

Modeling Clay Fairing

2-part Expanding Foam

Expanding Foam in cardboard containment

Foam carved to rough shape