SonexBuilders.net

Watched the EAA Homebuilders Week video linked here: https://players.brightcove.net/62700807 ... 3553347001

Mark starts talking about the One Week Wonder Waiex B project which will have a Rotax 912is engine installed at the 57 min 10 second mark of the video. Their install will maintain the clean cowl with no extra cutouts for radiator like most Rotax powered aircraft (such as my RV12). I really like the split Radiator design as well as the Exhaust/routing... Simple. While the cockpit is small, you could conceivable have a passenger and pilot side heater controls. Pulling heat of the radiators and using an louvred baffle to vary the amount of air that passes through each radiator. Search 'Bender Baffle' on the Van's Airforce RV-12 board to get an idea. The bed mount does pretty much prevent a turbo install, but I'm not too concerned about that. You could always do a big bore and get about 120hp.

I'm temped by the B Model, but patiently waiting for the High Wing. Of note, Mark also mentioned no Waiex version of the high wing. It'll be a Sonex tail only. I'm good with that as I prefer less complexity and less weight on the tail.

Would like to have seen the proposed, all important, cowling exit air set up.

I think they said they planned to use the side exits as is to help ‘suck’ air out through the radiators. Of course there will be a bottom exit for exhaust tubes too

Most people focus on the cold air in side of the equation (the "look"), without realising the warm/hot air exit is arguably the more important from a drag minimisation perspective.

Not suggesting the design of the cowling front end isn't important, just highlighting the need to address air in& out for optimum efficiency (function over form every time for me).

Agree. Watch the video. Mark addresses this

killerfish72 wrote:Agree. Watch the video. Mark addresses this

Yeah! Sort of - in passing.

Has some similarities to the Europa cooling system design.

Will be interesting to see how this cooling system works in practice - quite a bit of extra cooling hose & connections but sometimes you just have to "bite bullet" of increased complexity & weight to get a greater "pay off".

My Rotax powered Sonex cowl, which is the standard horizontal split.

Is this an A or B model? What exhaust did you use? Motor mount? More pics? I am seriously thinking of going with the 912

Gary's looks like an 'A' model. Sonex Inc's in the video is a B model. I would expect the same cowl on the high wing so any install on a B model from Sonex should be easily re-applied there.

A model Sonex standard Rotax round exhaust, I built the mount which is a hybrid of the Aerovee, Jabiru3300 married into the Rotax ring mount. The cowl was opened up for more cooling but after flying it for 180 hours I decided to restore it back to stock as I did not need the extra cooling. Also I like the look of the stock Sonex cowl. As you can see I had to put some bulges on to clear the oil filter and exhaust elbows. The prop is a 68" GT Propeller from a Tecnam P2008 which could do with slightly more pitch. Cruise is 120kts burnning less than 15 litres/h. 5200rpm. Has 190 hours Airframe and 1025 hours on the engine.