Tunnels Tips

ddddsp · #1 06-25-2006, 11:29 PM

I wanted to pass on a suggestion for those looking to keep their RV 10 TUNNEL cool. Take your Black & Decker Wet vac and hook the hose to the blower/discharge air. Then place the hose over one of the heat vents on the firewall simulating hot air blowing into the cabin. Close the vents and see if air is still entering the cabin with the vents shut and the wet vac blowing air into the vent on the firewall side. What we discovered was alot of air was entering the OPPOSITE vent when both were closed. The air was coming in under the hinge on the vent door. When I placed a small aluminum divider between the air vents on the firewall the air ceased leaking into the cabin tunnel. After playing with a few DEFLECTOR designs, I used the inside mounting bolt on the vent box to hold a deflector in place and then also put an 1/8 inch deflector inside the vent box so air could not sneak under the front of the vent door. This should solve the problem with HOT air entering the Tunnel with the vents CLOSED. There still may be a Radiant heat problem but insulation on the firewall and tunnel floor and silicone between the firewall and vent box helps for Radiant heat. I have pics if anyone is interested.

Dean
40449

brenthg · #2 06-26-2006, 04:53 AM

We are certainly interested in your Tunnel Fix. Can you post the photos here? If not send them to brenthg@yahoo.com.

Our louvers on the bottom of the tunnel had no effect on removing heat. Tunnel is still very hot to the touch.

N331JH

glenmthompson · #3 06-26-2006, 06:13 AM

I truly am getting the reputation as one who repeats himself, but please for the umpteenth time. THE VAST MAJORITY, IF NOT ALL THE HEAT IS COMING INTO THE TUNNEL VIA CONVECTED, AND/OR RADIATED HEAT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!! OK?????????????
The first flight in N331JH is the only flight that had the heat muffs hooked up for cabin heat. I repeat, I repeat, I repeat......This plane has ONLY THE FRESH AIR FROM THE CABIN HEAT S U P P L Y ducts installed. As in blowing HUGE amounts of cool air, directly from the plenum into the tunnel. Is anybody listening? CABIN HEAT IS N O T THE ISSUE. Period, end of discussion, please do not distract from an obvious design flaw. I will most enthisiastically entertain objective commentary on this subject, especially anybody who has over 100 hrs in an RV-10 and been working on hot tunnels for months...like myself.
Glen

brules · #4 07-03-2006, 02:15 PM

glenmthompson, You are absolutely correct. You can remove both heat scat tubes entirely and tape over the heat duct valves with stainless tape and fly the aircraft only to get burned literally! I also have stuffed the aircraft I worked on with insulation with only minor success. This is a design flaw that Vans has only provided a bandaid fix for and should be giving utmost attention to before serious consequences occur.

glenmthompson · #5 07-05-2006, 12:15 PM

Quote:

Originally Posted by brules

glenmthompson, You are absolutely correct. You can remove both heat scat tubes entirely and tape over the heat duct valves with stainless tape and fly the aircraft only to get burned literally! I also have stuffed the aircraft I worked on with insulation with only minor success. This is a design flaw that Vans has only provided a bandaid fix for and should be giving utmost attention to before serious consequences occur.

Thanks dude! I thought I was the only one out there who realized there is a significant problem in this area! I also spoke with a fellow RV'r who said a certain 10 driver had a 100% engine failure (to an off field landing), and hhhmmm, guess what? They later could not find ANY engine or fuel problem!! Well, of course except for the fact the boiling fuel in the tunnel can cause this, up to vapor lock/engine failure and has to me on several occasions (albiet mine was just a minor, short, heart pounding event).
Maybe my incessent whining about this will lead to a permanent/professional/safe/easy/cheap solution...As in..hhhmmm..Maybe continuing the false floor under the tunnel too? HHmm, where have I heard that before? lol...hahaha
Glen

Jconard · #6 07-05-2006, 12:32 PM

I understand that the RV10 has the dual muffler setup, and I also understand that they (The muffler/heat exchanger combo) run hotter...providing great heat when you want it.

What about only disconnecting the scat from the firewall flapper valve, and exhausting that air into the cowl exit?

I just wonder if, with both scat tubes disconnected, there is no air flowing through the heat exchanger part of the mufflers, allowing them to radiate more heat. If this is at all happening, I just thought that running the scat from the baffles, through the heat shroud, and then out the cowl exit would remove heat from these, and into the airstream...reducing the radiated heat.

PJSeipel · #7 07-05-2006, 12:45 PM

This might be a dumb question, but what is all of this heat doing to the strength and fatigue life of the aluminum?

PJ
RV-10 #40032

Chickenlips · #8 07-05-2006, 01:36 PM

Why not just put some cold air into the tunnel? Bring a 1 or 2" scat from the baffle down to the firewall and direct it into the tunnel. Thus you have a continous flow of cooling air inside the tunnel. The cold air will just run out the back along with the elevator push tube... and then out the tailcone.

This could be tried temporarily by using one of the heat shuttles by removing the heat to the shuttle and then instead, route cold air to the shuttle from the baffle inlet. Then go inside the tunnel and remove the same shuttle's hose in there thus dumping the cold air into the tunnel. All easily reversed if you are not happy. If it works, rehook up the heat shuttle and then punch a 1 or 2" hole through the firewall into the tunnel and duct cold air to it permanently.

cl

brules · #9 07-05-2006, 03:53 PM

chickenlips, I believe some have already tried this approach by reading earlier posts, and have also installed cutouts below to evacuate the tunnel air with limited or no success. Is the tailcone providing suction and a route for the bleed air you suggest a way to escape, or is the tailcone air under pressure? This is going to require testing, and my question is... did Vans know about this from the start and hurry this aircraft to market? I keep getting the impression that as far as they are concerned this is a trivial matter and it's really not! Has anybody heard if a design change is pending on future 10 kits?

brules · #10 07-05-2006, 04:00 PM

Chickenlips, one item I forgot to mention, before people start cutting 2 inch holes in their firewalls for a scat blast tube as suggested. If there should be a fire this hole is now a direct route for the heat and flame to breach the firewall and enter the cabin with no means of closing the hole.