VAF Forums

VAF Forums (https://vansairforce.net/community/index.php)
-   RV-10 (https://vansairforce.net/community/forumdisplay.php?f=4)
-   -   Tunnel Insulation (https://vansairforce.net/community/showthread.php?t=158579)

Mike S 03-18-2018 12:30 PM

That and prevent belly burn through in case of engine fire.

lr172 03-18-2018 12:40 PM

Quote:

Originally Posted by Weasel (Post 1246644)
If I remember used 0.005" SS



I am going to order an SS sheet to do this on my 10. Do you recall what size sheet you used? Also, did you find the .005" sheet to be rigid enough for a good installation?

Thanks,

Larry

9GT 03-18-2018 12:44 PM

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?

Kyle Boatright 03-18-2018 01:14 PM

Quote:

Originally Posted by 9GT (Post 1246699)
Then again, how many of our certified GA aircraft have SS belly skins?

Not many, but it ain't a bad idea and you get three for one - a cooler tunnel, less noise, and fire protection.

The great thing is that on an experimental, you get to make choices to fit your mission and the set of compromises which are most important to you.

DanH 03-18-2018 02:57 PM

Quote:

Originally Posted by 9GT (Post 1246699)
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?

Let's ignore all fire concerns, as you have, and merely consider comfort. By insulating inside the metal structure, you're allow the structure to heat. The structure conducts that energy very well (it's aluminum, after all), from component to component, by-passing insulation placed against the inside of the skin. It's a very inefficient method.

It's sorta like wearing your raincoat under your clothes.

9GT 03-18-2018 04:26 PM

And again I reiterate that we can get carried away with the ?what if?s? fixes. I?ve done my share I will admit but there comes to a point where I just want to make real progress. I decided to do the double SS firewall with fiberfraxed insulation sandwiched in between, along with SS fire stop pass throughs. Had to remove the mounted engine and the install of the double firewall is really snowballing into a time consuming ?fix?.

mfleming 03-31-2018 10:05 PM

Quote:

Originally Posted by Kyle Boatright (Post 1245556)
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)

Kyle Boatright 03-31-2018 10:24 PM

Quote:

Originally Posted by mfleming (Post 1250066)
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)

I purchased a 24"x48" sheet from either Grainger or McMaster Carr. I don't remember which (I was shopping on delivered price). Off-hand, I don't remember which alloy I used, either. I used half of the sheet on the belly and half of the sheet on the bottom center of the firewall.

The 0.008 didn't pillow and was easy to cut with snips and drill with regular bits.

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

az_gila 04-01-2018 10:46 AM

Quote:

Originally Posted by GregMac (Post 1250088)
..... 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?


All times are GMT -6. The time now is 09:03 AM.