I've been wanting to seal my cowling to leg fairings for a while after reading others tips on VAF, on the side by side RV's the lower cowling pressures push air right down the gearleg to the wheelpants and out intersection fairings.
Not sure why but my starbord side seems to carry more pressure (I've not measured, just an observation), as in my starbord wheelpant seeps a little bit of lower cowing goo and the entire inside of the fairings are 5 times messier than the port side. My oil leaks also seem to manifest themselves on the starbord side of the cowling as well. Could be the starbord side of my engine is just messier....
I was thinking of an intersection fairing addition that closed the gap, but I didn't make it that far. I decided to see what I could do with some leftover baffle material and Ultra Black RTV.
I started by installing the intersection fairings without the cowling and rough cutting 2 pieces of cardboard to fit along the bottom and sides of the firewall and around the gear leg. With the 2 pieces of cardboard laying nicely against the firewall bottom and side, I also pressed them into the shape of the intersection fairing and taped them together to hold the shape.
I then taped the cardboard template to the cowling using the firewall bottom and side as a square reference. The cardboard did not lay flat on the cowling on the forward side, but I laid scrap baffle material on the outside of the cowling and traced the gear leg cutout from the cardboard template as best I could. I then made the required cuts on the firewall side of the baffle material.
My baffle scraps were too small to make a one piece seal RTV'd to the firewall which was plan A, so plan B was to make and RTV a horseshoe of baffle material to the cowling. Plan B worked out well because the thickness of the baffle material made an even surface for the second seal to lay on reference hinge material and nutplates.
Baffle material seal RTV'd to the firewall and gear leg. I fit the seal with the cowling on and used Ultra Black to RTV it to the gearleg where I could with the cowling installed, after it dried a couple hours later I removed the cowling and RTV'd the remainder of the seal to the firewall.
Seems to make a good seal against each other at least in the hangar. I assume a max of 5 inches H2O lower cowling pressure for .18 PSI, seal is approx 3 sq in x .18 = .54 lb, 5 guesstimated lbs of finger pressure just make the seal tighter so it seems strong enough.
Not sure why but my starbord side seems to carry more pressure (I've not measured, just an observation), as in my starbord wheelpant seeps a little bit of lower cowing goo and the entire inside of the fairings are 5 times messier than the port side. My oil leaks also seem to manifest themselves on the starbord side of the cowling as well. Could be the starbord side of my engine is just messier....
I was thinking of an intersection fairing addition that closed the gap, but I didn't make it that far. I decided to see what I could do with some leftover baffle material and Ultra Black RTV.
I started by installing the intersection fairings without the cowling and rough cutting 2 pieces of cardboard to fit along the bottom and sides of the firewall and around the gear leg. With the 2 pieces of cardboard laying nicely against the firewall bottom and side, I also pressed them into the shape of the intersection fairing and taped them together to hold the shape.
I then taped the cardboard template to the cowling using the firewall bottom and side as a square reference. The cardboard did not lay flat on the cowling on the forward side, but I laid scrap baffle material on the outside of the cowling and traced the gear leg cutout from the cardboard template as best I could. I then made the required cuts on the firewall side of the baffle material.
My baffle scraps were too small to make a one piece seal RTV'd to the firewall which was plan A, so plan B was to make and RTV a horseshoe of baffle material to the cowling. Plan B worked out well because the thickness of the baffle material made an even surface for the second seal to lay on reference hinge material and nutplates.
Baffle material seal RTV'd to the firewall and gear leg. I fit the seal with the cowling on and used Ultra Black to RTV it to the gearleg where I could with the cowling installed, after it dried a couple hours later I removed the cowling and RTV'd the remainder of the seal to the firewall.
Seems to make a good seal against each other at least in the hangar. I assume a max of 5 inches H2O lower cowling pressure for .18 PSI, seal is approx 3 sq in x .18 = .54 lb, 5 guesstimated lbs of finger pressure just make the seal tighter so it seems strong enough.
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