Hot tunnel again

[Lan Vinh Do]

Hi. I have a hot tunnel. I bought the airplane in november. Didn't fly much during the winter. The builder installed a fan to vent the tunnel but since it wasn't working, i just removed it ( he said that he didn't had a hot tunnel with the fan)

I made a cross country last week end and the tunnel was really hot. It was hotter when i was using the heat. My concern is that when all heat wws turn off, there was still a small draft of really hot air that was comming to the rear heat hoses. The exit hole was burning hot to the touch. So it's probably the hot air of the other heat box that enter the opposite hot air box. I will do all the fix that are suggest on previous post and i already put a new fan to vent the tunnel but didn't had the chance to fly with it yet.

My concern with this setting is that if my carbon monoxyde detector go on, my only way to stop the leak would be to turn off the engine since if i just close the heat, it will still come inside the cabin.

Maby not a concern now with all our relatively new engine and exhaust muff but in 10yrs!!


Lan Vinh Do

 

[dmaib]

It might be worth checking your heat box on the firewall and make sure that the doors are closing all the way and are not letting hot air get by. Also look and see if the heat box is isolated from the firewall by some kind of fire/heat barrier material.
How old is the airplane? I am curious if it has the shorter exhaust stacks that were shipped on the earlier kits?

 

[Lan Vinh Do]

exhaust

hi.
the kit was pourchase in 2005 and the plane first flight in 2008.
I've put the link to a photo album so you can tell me what type of exhaust.
I will check if the door of the heat box close completely
It really seem to come more from the hot scat tube more that the exhaust.

link:
https://picasaweb.google.com/lanvinhdo/HotTunnel?authkey=Gv1sRgCMSD-unW2YnAzwE&feat=directlink

Lan Vinh Do

 

[Lan Vinh Do]

one of the problem found

I've made an inspection today and found a part of my problem
There is a pin in the hinge of the heat box that is missing. ( see last photo of the photo album. So the hot air was constantly going in the rear scat tube.

I also send an email to vetterman and there was his answer if i want to take out a muff

"If you remove the shroud, you will get quite a bit of heat on the cowl so suggest you install a heat shield by this method. Measure length of muffler and measure @ 1/3 of the distance on one of the end rings. Cut a piece of .025 alum. and use the muffler shroud clamps to hold it on the bottom side ie. closest to the cowl. this will allow air to flow @ it and still shield the cowl.

larry"

https://picasaweb.google.com/lanvinhdo/HotTunnel?authkey=Gv1sRgCMSD-unW2YnAzwE&feat=directlink

 

[Lan Vinh Do]

muff removed

I removed the left muff and have put a heat shield as recommend by Larry vetterman. I use the left scat tube and connect iy directly to the left heat (cold) box. I hope to resolve the hot tunnel and bring more fresh air in the 10.

I wil go fly this week and let people know.

( since i repair the left heat box, the tunel is more warm than hot)

https://picasaweb.google.com/lh/photo/QYEcfxJB4uNyrm7JMPK8lw?feat=directlink
Lan Vinh DO

 

[Bill.Peyton]

Lan,
I plan to split the right side heat valve with a "y" and provide heat to the front and rear with just one heat muff. I am using a heat shield as you have, and running cold air from the left side cold air hose thru the the heat valve and down the tunnel. I may also put a small vent on each side directly from the tunnel to the floor area to bring in cool air. I also replaced the Vans provided aluminum heat valves.

 

[Lan Vinh Do]

Cool tunnel

Hi
Since i remove the left heat muff and replace it with a heat shield and redirect the left scat tube directly to the left " cool " box, my tunnel is cool. No heat at all, no even warm. So my problem was coming by some hot air entering the left heat box from the right scat tube even when it was close. Not the exhaust under the aircraft at all. My tunnel is not insulate at all.

I can also have good fresh air for the back seat. I just wonde if i will have enough heat in he winter. Let enjoy the summer before.

Lan Vinh Do

 

[Geico266]

My 10 was built with 2 heat muffs also. After a few winters I figured out that all I needed was one heat muff to heat both the front and rear via a "Y" connection. I have flown in -5F quite comfortably. One heat muff is plenty.

 

[Lan Vinh Do]

avionic cooling

Hi
Since i remove the left heat muff and replace it with a heat shield and redirect the left scat tube directly to the left " cool " box, my tunnel is cool. No heat at all, no even warm. So my problem was coming by some hot air entering the left heat box from the right scat tube even when it was close. Not the exhaust under the aircraft at all. My tunnel is not insulate at all.

I can also have good fresh air for the back seat. I just wonde if i will have enough heat in he winter. Let enjoy the summer before.

Lan Vinh Do

I modified a little bit my heat system since passenger didn't find funny to have cool air at freezing temp.
I put a Y pipe to divide the HOT air for the front and the back on the cabin in the tunnel.
I add a eyeball vent to the top of the tunnel do direct fresh air of my left COOL BOX upward behind the panel ( i can close it if i want)
I flew at -15 deg C and the cabin was ok with only one heat muff, enough heat for the back seat and i will have cooler avionic in the summer.