Nosebowl & Exhaust

Extending and repairing the nose bowl..

Visualizing pipe lengths with rolled paper...

11/30/2013

The nose bowl is of carbon fiber material. Ironically, it was purchased from my old home town in the UK, Leicester. On initial dry fit, as expected, the nose bowl would sit a little too low, about 1.5 inches. This would cause the visual line from the bowl to the front instrument panel to have a dip - something I don't want. This dip happens if you build the firewall to the plans! The correct way to approach this in hindsight, is to mount the engine without a firewall, mount the nose bowl, fit the front instrument panel, then snap a line from end to end; build the firewall up to that line. Of course, my firewall is long completed and installed. My fix is to increase the height of the nose bowl.

The bowl is a horizontally split type. I have epoxied it together, with an increase in height to lose the 'dip' along the nose of the plane. The intake apertures are now too big, so I am in the middle of reducing the apertures by 1.5 inches. There are also a lot of flaws in this bowl, and I am having to fill and sand many dips. I am not great with fiberglass, and it is starting to mentally wear me down, so I am going to send this bowl off to a buddy, who will prep this bowl to use as a plug, then he will make a new carbon version, split, flanged, and rearing to go. Someone from biplaneforum.com gave me an exhaust system! This was a $1200 saving. It is a 4 into 2 system, fits perfect, and is now on the engine. I had to extend one of the tail pipes, and I decided to ceramic powder coat these tail pipes satin black. I was tempted to ceramic coat the whole system, but that's not wise, since once it is coated, nothing can be weld-repaired. I stabilized the two tail pipes by making a bracket that paired them together as one unit. This will help during the shaking engine starts/stops. I made some flexible exhaust hangars from an automotive muffler kit.

Pic showing stabilizer bracket, tail pipe heat shields, and hangers...