| GregMac |
04-01-2018 05:02 AM |
When you drill right down to it, the two causes of a hot tunnel are 1/ Two cabin heat scats blasting away diagonally on the firewall just behind the tunnel........and 2/. The exhaust pipes on exit out of the bottom cowl run very close to the bottom of the firewall and that?s just below the bottom of the tunnel. The RV10 is not really any different (apart from size) to all the other Vans models in that apart from these two features they do not normally catch fire or heat the cabin/firewall excessively. Sure if you really have concerns about fire then fit stainless and insulation everywhere. But to simply treat the cause, try fitting butterfly valves in the heater scats so the hot air can be exhausted down at the bottom of the cowl until needed, of course if you don?t normally fly in sub zero temps then doing away with the rear heat scat altogether halves the problem straight away. I?ve done both the above to my RV10. It?s also pretty normal to put a rounded fairing from the firewall about two inches up and down to the flat bar that most folk fit to attach the bottom of the bottom cowl. As the Lancair speed demons have demonstrated, rounding that exit area instead of leaving it sharp improves the Airflow out of the cowl reducing drag and improving speed. That round fairing is pretty easy to fit to a taildragger, a little harder and not so efficient on a tricycle RV10 cause you have to fit the fairings around the nose gear horizontal and allow for the the gear movement, but it?s doable. On my RV10 (250hrs) that fairing is made of aluminium and effectively does two things, smooths the exit Airflow, and it also insulates the bottom of the firewall and reduces any heating of the bottom of the tunnel. Interestingly even though the aluminium fairing runs very close to the exhaust it hasn?t been adversely affected by the heat. To answer the original question by Jeffwhip, Apart from putting some of the standard Vans supplied self adhesive heat shield on the firewall from the heater vents down as far as I could and only caus I had some left over from the cowl, then that?s all that?s been done on my aircraft, it?s been flown in some 40*c Australian heat and no tunnel heat problem. Cheers from Western Australia
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