Will insulating the FF make the cockpit warmer or cooler?

[ao.frog]

Hi.

I'm looking for a way to make the cockpit warmer and considering to insulate the FF, but came to wonder if that might have the opposite effect? Maybe the FF is getting warm during flight and by insulating it, I'll get a cooler cockpit?

For the record: I've installed ailreon boots, taped shut all those little holes in the cockpit, have a kind of "seal" along the canopy-rail etc etc, but still the cockpit is rather cold when the OAT drops below -10*C.

I'll also install some insulation on the fuse-sides where I can. I have CAD interior so it schould be room enough for that a number of places.

But for now; will insulating the FF give a warmer or cooler cockpit? My gut feeling tells me that the FF gets warm during flight?

Ofcourse I could find a way to crawl or bend over and feel the FF during flight, but why go through that troublesome exercise when a quick post to the great VAF-forum does the same job?

[DanH]

Originally Posted by ao.frog

....will insulating the FF give a warmer or cooler cockpit? My gut feeling tells me that the FF gets warm during flight?

The firewall gets warm in flight. If it is warmer than the existing in-cockpit temperature, insulating it will make the cockpit cooler.

[ao.frog]

.... Dan. Then no FF-insulation for me.

[DGlaeser]

Originally Posted by ao.frog

... but still the cockpit is rather cold when the OAT drops below -10*C.

Those pesky laws of physics do get in the way - again
Insulation slows the rate at which heat transfers, but unless you can add more heat than your aluminum heat sink (the whole plane ) draws it away, it's a losing battle. My son added a second heater muff to get more heat into his cabin. Every little bit helps.
As Dan noted, more than likely the firewall will be warmer so insulation there will slow that heat getting into the cabin.
One convenience of my liquid cooled engine is the heater core in the cabin that keeps things comfortable even at -10C

[trib]

Flip side is the benefit of the insulation. It will reduce noise in the cockpit and will make the cockpit cooler in the summer.

[ao.frog]

... it's very rare that the cockpit is too hot during summer. Setting the cabin heat to off and opening the fresh air-vents partially makes the cockpit nice and cool for about 95% of the normal summer-weather.

Noise is not a factor either, because both my wife and me have Halo headsets and LOVE them. We also have exhaust-turndowns installed to reduce drumming, and finally the 2-blade M/T-prop is rather quitet compared to other props at our homefield.

By the way; I also have a feeling that the dual P-mags makes the engine more quiet, since they fire twice as often as regular mags, thus making noise more "even" (not pulsating)
The X-over Vetterman exhaust-system has a great influence also I think.

Ofcourse, I'm just guessing here, but people on the ground says our RV is more quiet than most other planes. They say the sound is deeper in a way....
When I flew the test for the "Noise Certificate" (required in Norway), the reading said 69 db. (measured at 1000' at max cruise power) and that's pretty good I think.

But thanks for the note; it's always a good thing to consider all aspects of a modification.

[bruceh]

You could certainly measure the firewall temperature while flying with a non-contact laser thermometer. It would be an interesting data point, both in summer and winter.

[JAT]

Alf,

If you haven't already put insulation on the side walls, it definitely helps. I used 1/4" aircraft grade (fire retardant) insulation/sound deadener and then covered it with cloth (also a/c grade). Cut one inch strips of posterboard and make templates of each panel with a hot glue gun, then cut the foam and cover. They will fit perfectly and help with the cold cockpit. I also changed from an internally controlled cabin heat box to the firewall-side controlled box and ran a scat tube to the eyeball vent mounted on the bottom of the instrument panel. It brings much warmer air right to you.

Hope this helps. It was -27 F in Durango, CO last week!

Jim

[rvmills]

Alf,

I don't have any insulation on the inside of the firewall, just some sound deadening paint. I also have a heater system that shares the ducting with fresh air, via a mix valve on the hot side of the firewall, and that air (hot or cold or in between) comes via scat tubes to the Stein vents under the corners of the panel.

So all the warm air comes at the occupants from those vents...end result is that hands and upper body are pretty comfy, but toes and feet sometimes get chilly, with no heat down there from a standard heat box. It was that way at -5C here in Reno today on a quick hop.

From all the above, I'm thinking that perhaps not enough heat builds up in the firewall (in the winter) to effectively radiate much heat into the cockpit, but I haven't placed insulation there to try to measure if there is a difference. Summer may be a different story, when we battle heat soaking of everything, inside and out. FW insulation may prove more effective then, but Dan has a great thread on heat and fire protective insulation on the hot side of the firewall. (And it sounds like summer heat is not a factor for you there).

I did install DIY side panels, and I think that makes a difference in cold transfer into the cockpit.

All this is very unscientific opinion only, of course. Good luck, and if you find a solution that works in Norge, let us know, so us Vikings on this side of the globe can copy!!

Cheers,
Bob

[N15JB]

How about using a cheap indoor-outdoor thermometer with a wired sensor taped to your firewall? They are available here for about US$10, and will record max-min temps. Seems easier than trying to point an IR thermometer at the correct spot on your firewall while flying.

Jim Berry
RV-10