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Kitfox IV Cowl to Firewall Seal


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Posted

I'm looking for some fabrication ideas from the experts on the forum.  This may get a little long, so be warned...

I am not the original builder of the Mangy Fox.  I am the re-bulder.  During the rebuild I fixed and reworked a lot of different problems with the plane.  One area where I just simply ran out of time was the firewall and cowling.  Both of these items really needed to be redone from scratch, but the clock was running out on me and I had to get the plane finished.  So here's my problem:

The firewall does not seal to my cowling.  The fit is pretty terrible to be honest.  I thought I could overcome this issue by using silicone baffling flap material to make a seal covering the difference.  Well that didn't work worth a darn, so I'm back to the drawing board.

In a long enough timeline, I want to completely redo the firewall forward on this plane with a new design engine mount and cowling.  Something following the design of the model 7SS type FWF.  I have room in the weight and balance to do this, but I'm not to the point of doing it just yet, so this will just be phase two of the bandaid.


There is a crescent shaped gap between the top curved portion of the firewall and the cowl.  I started making a female template today of the outside of the installed cowl in order to get the shape and curve correct (or at least closer).  I plan on using this template to make a sheetmetal crescent to attach to the top of the firewall.  To the edge of this crescent I would like to attach a flange so that a "bulb seal" like this can be added to really seal the firewall to the cowl. 

I'd like some opinions on this idea from the experts here, if I'm on a good track or if there's a better way of accomplishing what I want to achieve.

Fire away with what ever brainstorms you may have!

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Posted

Not sure if this is what you are looking for, but this is what I did on my Avid MK IV firewall.  It's all stainless steel.  The seal  could glue onto the top cap strip.  I have to add a seal on mine as well.  Not sure I want to pay $13 per foot though.  Think  that was what I was seeing.  Then again, maybe 5' is all you need.  $65 or so...... JImChuk

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Posted (edited)

I think I made the cap strip 1 1/2" wide, but cut the cowl so it's split at the firewall.  If you go with a one piece top cowl, you could use a piece of angel and cut/notch one leg of it every 2 inches or so,  then you can curve it around the top of the firewall.  Here is a picture showing how I did that on a different plane.  The angel turns towards the back of the plane.  It would actually be less work and maybe seal better than the other method.  JImChuk

PS  found another picture where the angel was turned forward

New MK IV 048 (Large).jpg

Jab engine pics 006.jpg

Edited by 1avidflyer

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