I've been reading through many of the posts. Those of you who followed Dan Horton's method of insulating the firewall, how did you insulate the tunnel and/or belly? Did you insulate the belly on the outside?
I have a 24"x24" piece of stainless on the belly. I rolled the edges, placed a 1/16" fiberfrax blanket under it, sealed the edges with pro seal, and pop riveted it in place with stainless pop rivets.
I have a 24"x24" piece of stainless on the belly. I rolled the edges, placed a 1/16" fiberfrax blanket under it, sealed the edges with pro seal, and pop riveted it in place with stainless pop rivets.
How thick is the stainless sheet?
I have a 24"x24" piece of stainless on the belly. I rolled the edges, placed a 1/16" fiberfrax blanket under it, sealed the edges with pro seal, and pop riveted it in place with stainless pop rivets.
While Dan H has convinced me this is the only way to go for insulating the firewall, I would not do this for the belly. If the fire gets so bad that it is needed on the belly, the plane is already gone.
The downside of pop riveting this sandwich to the belly is it will tend to collect all the oil and grime that tends to end up there.
I used this insulation (double sided and edges sealed with aluminum tape) in the bottom of the tunnel and never had a hot tunnel: http://www.aircraftspruce.com/pages/cs/insulation/insulator3.php
I did install a belly shield too, using 0.010" SS sheet, which is plenty thick (i.e. it behaves like sheet stock, not foil). Using 1/16" Fiberfrax and securing with rivets and Fire Barrier 2000, the total assembly turned out to be fairly flat and well transitioned. I primed the aluminum skin underneath the belly shield too. See picture on my builder's log below.
http://www.mykitlog.com/users/display_log.php?user=mikrettig&project=803&category=10711&log=222385&row=99
There wasn't much pillowing at all, and I assume that, after final paint, it will all but disappear. After seeing pictures of the RV-10 that had a fire event, with the gapping hole through the belly into the tunnel, I figured it was good insurance. Additionally, shielding the firewall and belly should keep tunnel heat down too; an added bonus. My $0.02.
If I read your blog pictures correctly, the 1/16 Fibrerfrax is sandwiched between the two skins (SS and original belly aluminum) by the same rivets that attach the skins to the fuselage ribs.
Wouldn't having this layer of Fiberfrax in the assembly screw up the structural integrity of the skin to rib riveted joint?
I don't know how either Mike or Kyle assembled theirs, but I would not use the rivets in the plans to ensure no compromise to structural integrity. I would off set rivets lines dedicated to the stainless plate.
Do this ^^^^^
Dan,
Do you have any pictures of what that looks like?
Jeff
If it was me, I'd want to be sure the underlying skin was carefully prepared and corrosion proofed before riveting a plate on. Once you install it inspection will become impossible, and there is a good chances of moisture getting in between the 2 skins and with the dissimilar metals it could be a problem down the road. It would be more work but maybe worthwhile if you're building to use screw/nutplates to intall the sandwich.
Dan,
Do you have any pictures of what that looks like?
Jeff
If I remember used 0.005" SS
Then again, how many of our certified GA aircraft have SS belly skins?
I thought about this when building my RV-10 but could not bear the thought of riveting an ugly/pillowing SS sheet to the underside of the nicely flat and finished belly. I opted to insulate under the floor and in the tunnel. Its easy to get carried away with the "what if (fill in the blank) should happen" issues. If I were that concerned about an engine compartment fire melting the belly skin, I would incorporate a SS skin in that area instead of the per-plans aluminum. Then again, how many of our certified GA aircraft have SS belly skins?
Here you go (I think)...
What stainless did you use? Aircraft Spruce sells 301, 302 & 304 and .016 seems to be the thinnest . (in a previous post I think you said .008 was the thickness)
..... 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. ...
Can you give us pictures of this?
Gil, Greg is speaking of something like the standard exit radius on an -8. You've seen the idea adapted to other models.
The -8 has an exit ramp inset into the belly, so the inset has sidewalls. The stock ramp is aluminum. A stainless overlay for a 10 could be curled at the cowl end, very much like the ramp in the foreground (here upside down on the bench), a one piece SS panel with integral sidewalls for an -8.
...
Thanks, but I was wondering about the work fitting around the -10 nose gear, which is different from the -6A I'm familiar with. I'm also guessing that the lower cowling "bar" referred to was for the alternate screw (not hinge) mounting, but it wasn't quite specific.
I'd bet it was for the bracket that ties the cowl to the bottom of the fuselage. None of the other models (except maybe the -14) have that.
There's a lot to work around down there on the -10.
But, isn't that the U-620 and U-621 stuff on my -6A? Plans sheet 61.