28 Jan 2024

The Sling-supplied aluminium manifolds for the internal ventilation system are complicated and do not facilitate the provision of fresh air to rear passengers. I have decided to use Aerosport Products NACA control vents which should provide far better cold air cutoff than the factory-supplied units, in conjunction with Aveo Maxi eyeball vents. That being the case, I have decided to simplify the Sling air routing for the side channels and allow for exterior air to pass to the rear passengers as well.

To achieve this, I cut the supplied compound manifolds in half after de-riveting the support brackets and some of the rivets near the cut point. I then gently flared the ends open a bit with fluting pliers and trimmed a U-shape out of the top of the T angle in the side channel where the two parts join. I then joined each half of the compound bracket to the T angle, after applying Flame Master sealant, and then riveted them in place.

The result is a simplified channel which has a Y-shaped input joining to the T on the channel, with the T nicely following the inside cutout profile required where the Y joins. The overall length of the manifold is within 5mm of the original compound duct and at the same angle as specified in the KAI. So by simply positioning this duct structure further aft - in the same position as the original compound manifold - it allows for hot air from the heater to enter the duct from the top, at a Y joint so the flow should be good, and for cold air to flow in at the bottom via the NACA duct cutoffs. Both can then flow directly to the vents on the panel and via the side ducts to the rear. Far simpler and hopefully more functional too.

I will be using additional ducts from the heater for the front and rear footwell areas. I am planning to run SCEET tubes inside the sidewall duct cavities to address the insulation problem which robs warm air of its heat on the way rearwards.