Category Archives: Firewall Forward

Custom Cowl Mounting Strips – Trial Fit

The upgraded cowling strips fit remarkably well. Clecos are in many of the holes at this point and that’s without having to drill anything out. Ultimately, holes will need to be lightly ‘dressed’ with a #30 reamer. This will allow the rivets be positioned and set easily in the 3 and 4 layer stack-up of parts without a fight. The good news is, it’s all a pretty decent situation to begin with.

Earlier I did a little priming of the underside and edges of fastening tabs for the galvanized steel firewall. It’s winter cold outside, and I can’t really do spray painting just now. It was a small hidden area so I brushed on the gray 2-part epoxy primer. It took several days to cure fully. I’ll probably paint the entire firewall, mostly for aesthetics, when the weather warms a bit.

Care will be needed to address some gaps between layers of the parts stack-up. I believe that by removing most (or all) of the clecos across the top edge of the firewall and then riveting around the corner, fitting and pulling one rivet at a time while the pieces are free to move and pull together will allow the gap to close where the rivet is pulled.

I’m planning to install the ballistic parachute and that means I’ll be needing to accomplish some dimpling for most of the holes across the top of CF-RIB-003 and actual countersinking with a 120 deg pilot-cutter, along the top edge reinforcing pieces of the firewall, to accept 3,2 x 8 mm countersunk rivets. More on that in a future installment.

We’ll see how it all goes. Warmer days are ahead.

Engine, Propeller and Firewall Forward Kit – Ordered

I can see the end of the airframe assembly down the road and setting the wheels in motion to have the engine group arriving in 3 months or so, will keep me motivated to accomplish tasks in order to be ready when it all gets here.

The engine is the BRP Rotax 912iS Sport. It’s state-of-the-art. I’m absolutely set on having a 21st century engine for a 21st century airplane. It’s a mere 100 horsepower, but it’s the engine for the Sling 2 – IMO.

Yes, there is a 115 horsepower turbo engine option – which offers more performance to be sure, but it’s significantly more money, it’s got a turbocharger to maintain, not quite as high-tech – doesn’t have FADEC (computerized engine management system), plus – it demands a constant-speed propeller that costs 4 or 5 times as much as the fixed-pitch unit I’ve decided on for my machine.

Speaking of propellers – the propeller of choice for the 912iS powered Sling 2 happens to be the very sharp-looking, carbon fiber, 70 inch diameter, 3-bladed, ground-adjustable Whirlwind GA-RW3B, dressed with the perfect spinner.

Sling 2 Aircraft Fitted with Whirlwind Composite Propeller

The engine comes from BRP Rotax in Austria, through their South African distributor – Sling Aircraft and then to the USA. Eventually, it all has to make its way to the Upper Left Corner, where I am, in out-of-the-way Sequim, Washington. It’s a roundabout, slow-boat process – no doubt about it.

Because the engine and aircraft are of African decent – I’m expecting the engine fittings are going to be metric, as opposed to UNF – more typical for aircraft in the US. The engine itself is metric, but I understand that they can be had with UNF fittings for oil and fuel lines. However, the firewall forward kit is going to be for a metric engine and I’m not going to try to swim upstream. Go with the flow. Someday, if it really bugs me I could probably convert it from metric fittings. In the meantime, I’m going to put it all together and go flying – as it comes.

It’s pretty darned exciting and really something to look forward to.