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Yep, tunnel finally fixed. Should be an AD.

Interior Solution

I have been following the heat issue for a while, and now that I am on to the QB fuse, I have been doing some research on products that could be laid on the floor of the cockpit, or inside the tunnel to help keep the heat on the outside of the plane.

I talked with a product manager at Dynamat this week and here is what he suggested:

Use a layer of Dynaplate against the skin of the airplane. This stuff is rated for the heat, and signficantly dampens vibration / noise.

Use a layer of TACMAT on top of the DynaPlate. TACMAT is 1/4" thick and has a better R value than a wall full of fiberglass.

He said that the products pass all the FAA standards for flame and heat.

My brother has used the Dynamat products in cars with astounding results, so I figured it may be worth a try - and the problem is solved from the inside.

Here are a couple of links:

http://www.dynamat.com/technical_specs_tac_mat.html
http://www.dynamat.com/technical_specs_dynaplate.html

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=12660
http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=12656


Greg
 
Cool!

I LOVE the way you think Greg!!!!! This is the kind of discussion we need here
!....IMHO, whatever an individual can do to keep the heat out of the tunnel,..as in hermitically seal out units of heat...calories........will provide acceptable results.
KEEP IT UP GUYS!
Glen
 
Keep it alive.

In the interest of keeping this 1600 plus hits thread alive I am posting a quick note. We are still putzing around with a fuel leak on 331JH, and still have not tried anything with that brush on sample we got at OSH.
Where are the reports hot and cold of the dozens of flying 10s out there!?
Trust me ladies and gentlemen, from the huge numbers of phone calls and responses I have received, being the leading edge of the spear on this subject...There is great interest out there on this topic and people ARE having heat issues. Lemme hear it here!....Or, I have another idea. If yall do not want your name out there, give me your comments and I will copy them here, sterilized of course...
Glen
 
Intresting Thread

After reading this, like all new products, sometimes issues get over looked. I read this throughly, and knowing I will be building an RV-10, can only hope that, and from what I have read thus far, solutions do exist. I only wish I had my kit now so I could take a stab at the problem. I am a firm beliver in simpler is better. But if I understand everything there is no insulation anywhere to keep heat away. Intreresting :confused:
 
May be over blown

szutowiczrv10 said:
After reading this, like all new products, sometimes issues get over looked. I read this thoroughly, and knowing I will be building an RV-10, can only hope that, and from what I have read thus far, solutions do exist. I only wish I had my kit now so I could take a stab at the problem. I am a firm believer in simpler is better. But if I understand everything there is no insulation anywhere to keep heat away. Interesting :confused:
To be fair and no offense to Mr Glen Thompson, who has had lots of RV-10 issues, his or his friends, unfortunately, more than most, lets call it a worst case. Not everyone has had the hot tunnel syndrome to this extream; it has been more of an annoyance than a severe hazard at worst. I talked to Van's aircraft.

Not sure what you are asking or saying, but there are solutions and simple ones. Again no offense to Glen, many have either had no issue or solved their RV-10 hot tunnel issue with far less than a SS sheet on the belly, not that his or his friends idea is not worthy of consideration, which I think it is.

NONE of the RV kits come with any insulation or an interior, that is a builder option / responsibility. It's an experimental aircraft. My RV-7 has the fuel lines are in the belly and the electric fuel pump is housed in cover off the firewall near the cabin heat vent, similar to the RV-10. I know of no issue with RV-7. My RV-4 and RV-6 had "warm floors" but not to the skin melting extent some might lead you to believe.

Relax it's an issue but a small one for most IMHO and that of Van's aircraft. Best of luck with your project.
 
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:( gmcjetpilot My girlfriend burned her leg on the tunnel of a RV10. To her it was more than an annoyance, it was painful. I went back and read the threads about this issue. Please don"t downplay it. You talked to Vans Aircraft, and then said this really is not much of an issue, but the company did issue a Service Bulletin on the subject so they must be aware there is a problem.
 
If even one guy with a built-to-plans 10 has a first-hand report of interior surfaces hot enough to burn human skin I'd say it's a real problem. Saying that it's not an issue based on second-hand, third-hand, etc. reports or comparisons to dramatically different airframes is counter-productive.

There is a ton of great info available on this site, and I love to consider people's hypothetical explanations for unexplained problems, but for me first-hand reports trump all speculation.
 
Let me repeat

When a new RV builder writes he has doubts about the safety of his RV-10 as he works on his tail kit and is contemplating whether finishing it, it concerns me. My goal and mission is to support aviation, safety and building experimental planes, RV's in particular. I think we all have that common ground to work from. Its not about down playing or sensationalizing, it is about helping each other build and be safe. For all newbies these are experimental planes and on occasion you need to engineer a solution to an issue. This is the fun of building, learning and solving issues with your own ideas. I feel all RV's are very very safe planes. Keep in mind EVERY RV is unique, one of a kind, especially then systems. There are similarities, but they're amateur built and workmanship varies. Small variations result in possible large change in results. That is why following the planes is important, but in the end they're called experimental for a reason. The 40 hours Phase I is for working out issues like HOT TUNNELS, and IMHO it can be worked out satisfactory without major modification or effort. Don't accept less than 100% for safety sake.


caitlinRV said:
:( gmcjetpilot My girlfriend burned her leg on the tunnel of a RV10. To her it was more than an annoyance, it was painful. I went back and read the threads about this issue. Please don"t downplay it. You talked to Vans Aircraft, and then said this really is not much of an issue, but the company did issue a Service Bulletin on the subject so they must be aware there is a problem.
I am so sorry for your Girlfriends injury, but let me repeat, not everyone has the same level of problem. I never said it was not a problem nor that it was not hot enough to burn in some cases or trivialize you lady's injury. OK. Reading Mr Glens account, I agree 100%, not touching or wearing long pants is not acceptable or a solution.

My opinon from research is it's not a universal or unilaterally a problem for all builders. This is not wild conjector on my part. You asked nicely if I would not down play or basically shut up. I will respectfully say I'll continue to express my opinion, which obvioulsy is not as severe as others and feel is well thought out and researched.

I have talked to Van's senior staff and RV-10 builders who are not on this forum. Repeat some have a problem to a greater degree than others. I do care and that is why I have looked into it. I am not down playing anything, I am just saying: 1) Not all RV-10's have the issue to extream skin damage; 2) There is more than one solution. Bottom line the RV-10 is safe. New builders and want-a-be builders should NOT be afraid to build a RV-10. Have a good one and be careful.


szicree said:
If even one guy with a built-to-plans 10 has a first-hand report of interior surfaces hot enough to burn human skin I'd say it's a real problem. Saying that it's not an issue based on second-hand, third-hand, etc. reports or comparisons to dramatically different airframes is counter-productive.

There is a ton of great info available on this site, and I love to consider people's hypothetical explanations for unexplained problems, but for me first-hand reports trump all speculation.

No one ever said it was not a problem, did they? Again if you are writing to me than say so. I'll assume you are. I don't think I need to burn my leg personally to know it happens and also several builders don't have a problem as severe as others. Your milage may vary. There are a lot of folks that don't participate on this list I talk to that are RV-10 builders or work for Van's. Just passing info on.

However let's make it clear, I don't approve of burned girlfriends and vapor lock.


rv6ejguy said:
The tunnel structure on the 10 is not like any other Vans design to date. It carries the cabin heat ducting and major part of the fuel system, totally enclosed. Comparisons to other RVs are hardly valid. The fact that there have been burned legs and engine stoppages due to vapor lock plus a Vans directive on the issue proves that this is a really problem. Downplaying the significance of it serves no purpose other than to compromise safety.
Let me say the big difference is the RV-10 has a 6 cylinder engine (more heat) and two large heat muffs. Most two seater RV have one heat muff off of one or two cylinders, not the full heat of 6 jugs. I think the cabin heat leakage and hot firewall from the twin heat muffs is one of the prime issues.

"It carries the cabin heat ducting and major
part of the fuel system, totally enclosed."


You are only part right and you apparently are not familiar with RV-7's which do have the fuel and cabin heat (not ducting but hot air) and major part of the fuel system enclosed together.

I don't think you understand the point of my comparison of the RV-10 to the RV-7 in particular (much different than your RV-6 fuel system). The intent was not to say the RV-10 does not have any issues or there's a direct correlation. My point is the RV-7 does have fuel lines in the belly (center-line) and fuel pump housed in a small box with cabin heat blowing right on it. The point, may be we, RV-7 and other like RV builder's, should see if our fuel is too hot as well. If not why? Why is a RV-7 belly so much cooler. Frankly a lot of the heat is coming from the cabin heat in my opinion (see my previous post).


As far as vapor lock, apparently Glen had 3 occurrences to figure it out, so I am sure he is right, he had vapor lock. He is a brave test pilot, since one vapor lock occurrence would have prompted me to not fly until trying to solve the problem, but that's just me. Again many have not had a problem. I want to know why.

Glen's problem's clearly are quite severe; We all know that, since he said it many times. I believe him, but am I wrong to ask others like Tom Green at Van's or other RV-10 pilots what they think and pass the info on? Q: Have you heard of such severe RV-10 hot tunnel symptoms?

I'll say one more time and politely, may I suggest we all calm down, stop being sensational and just solve the problem with polite discussion. If you disagree fine, but please allow room for more than one idea. More ideas the better. Not all will be jewels. There is clearly a problem but it's not a universal problem with all RV-10 builders; prove I am wrong without attacking me as uninformed. Inform me don't try to discredit. For those who have severe problems, like Glen, I empathize and wish all the best.

It would be refreshing to talk facts and ideas than make comment about who is making the suggestions or if their input is more or less worthy. Just advice, you never know where the good info will come from, so listen to everyone, even me sometimes. :rolleyes: We agree to disagree. Just trying to help. There's no need to be combative or emotional. It's just an engineering problem to me; it's not a personal issue with anyone. :D

Any one else want to pile on? So just for the record Glen has some serious and real problems. I think his input should be considered by any builder. I don't argue with success, and if Glens SS belly sheet solution works, do it if you like. I personally would try other methods first as previously outline.
 
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Brush on heat barrier testing

Ok guys and gals, now that we fixed the fuel leak on 331JH,(still have "black death" on my fingernails from last week) and I have like, maybe, 2 minutes between trips to Rio (yep, hard life hehe), it is time for testing of the sample we got from that vendor at OSH.
I am looking for objective ideas on how to test, to see if the product is worth our time. We have been provided a sample of .040 aluminum with about a 25 mil thickness of the black heat barrier coating I previously spoke about. The sample is about 2" by 3" in size. The dude at OSH said the coolest demo they have is to put the provided sample in a frying pan and next to the sample, to be frying an egg. Then have an ice cube on top of the sample, and it sits there not melting. In fact it melts at the same rate as an ice cube sitting on the counter. My idea was to blow air from my heat gun and do a "touch test". Of course I will protect from hot air blowing around the sample to prevent back side heating due to eddies flowing around sample. It is suppose to be good to 500 deg f.
Is there anybody out there interested in this product that would like me to do maybe a different test? Maybe a group buy? It runs like 140 bucks for 2 gallons and numerous RV'rs could possibly benefit. I actually am cautiously excited about the product. Light, brush/roll/spray on....Cheap in a group buy...
I am thinking initially liberally brushing the entire inside of the tunnel to take temp readings to see if I might give all (maybe Vans will sell with kit?????) a possibly very cheap and easy alternative to the unnecessary (according to one any way) Glen SS heat shield. Then, maybe paint the bottom (barrier is paintable) for a double wammy protective barrier...
..
..
. Ideas? Suggestions? Comments?
 
no probs

Just a follow up about the tunnel heat issue. After 50 hours we do have any sign of tunnel heat at all. We have the standard Vans setup.:D

regards Chris VH-ICY
 
my solution

Attached, you´ll see pics of a SS foil with a fiberfax sheet in between the belly.
It improve a lot the lowering of temp in the tunnel, but in very hots days (say 85 and up) the problem still seems uncomfortable.[/ATTACH]
 

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No tunnel heat issue here...

I have no tunnel heat issue on my -10.

Showplanes cowl, SS heat valves, and Custom Aircraft Exhaust...
 
I have no tunnel heat issue on my -10.

Showplanes cowl, SS heat valves, and Custom Aircraft Exhaust...

Love it when these old threads get resurrected for us current builders. Did you do the Custom Aircraft Exhaust for the cold air induction system?
 
No

I did the custom aircraft exhaust because I used the showplanes cowl and CAI. Talking with showplanes, they weren’t sure the Vetterman would fit. I am really happy with the custom aircraft exhaust. Looks great and sounds better!
 
On my RV-3B, a totally different airplane that's similar in this respect: it has the fuel lines and electric fuel pump in the center bay, equivalent the "tunnel" in the RV-10. The bottom of this bay is the inside of the bottom belly skin.

Forward of the spar, I added 1/16" Fiberfrax and overlaid that with .020 grade 2 Titanium that I got from McMaster. I chose that because it was more than adequate as a firewall material; I kept the .040 aluminum forward belly skin becasue that was primary structure. Where there were rivets, I used .063 aluminum spacers. The installation came out looking pretty good.

Haven't flown it yet so I can't say how well it works....

A tip for people who want to assess the temperature of their RV-10 tunnels - use a remote IR thermometer. They are inexpensive and very handy in the kitchen, too.

Dave
 
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I have no tunnel heat issue on my -10.

Showplanes cowl, SS heat valves, and Custom Aircraft Exhaust...

Me either. My setup is completely stock. When I’m running heat, it definitely gets warm, but not something to be concerned with.
 
I have 1/8" of Fibrefrax sandwich on the firewall with SS foil covering that and a SS heat box (singular) on top of the sandwich. Tunnel is reasonably cool at all times. Just flew with a buddy today in his 10 who didn't bother with Fibrefrax or foil or a special heater air box and his tunnel is as cool as mine - barely warm to touch.

I can only say it looks like the "fixes" aren't always necessary. Who knows why.
 
My heater boxes wouldn't close all the way unless I modified the control arm. I'm not flying yet but don't anticipate any issues, I hope... :)
 

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I can only say it looks like the "fixes" aren't always necessary. Who knows why.

When I spoke to Clint at Vetterman when ordering my exhaust, he mentioned that they re-designed the 10 mufflers many years ago to help address this issue. He said that they had so much heat that cutting it back wouldn't hurt anything and likely help the hot tunnel issue. I see old post with folks saying they barely had one of the heat circuits open in the winter. I need both heaters open more than half way in the colder winter days, loosely confirming the reduced heat output from the current vs the original style. It makes sense, as the muff heat is probably the greatest source of heat at the front tunnel wall.

Larry
 
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I finished N810RK in February 2020. I live in Las Vegas and I have flown it in weather up to 110F. I have a Barrett 540-X 290 HP, with a Showplanes cowl and induction system and Vetterman exhaust. I insulated the bottom of the tunnel with 1 inch Soundex and the firewall inside the tunnel. My electric fuel pump sits 1 inch high on a piece of 1 inch square tube. My exhaust pipes are pointed well down and don't leave exhaust stains on the belly. Since the belly is white I would really notice it. All I get on the belly is a little oil mist from the crankcase breather.

My tunnel still gets a little warm in the hottest weather. Not so that I can't hold my hand on it continuously, but warmer than I would like. I think I will mount a small 12 volt computer cooling fan with a grill on the most forward part of the tunnel cover on the inside with the grill covering the outside. There is room for some of the air to exhaust out the back into the tail cone and perhaps some will follow the path out the aileron push tubes into the wing. I don't think I need much airflow to get the job done because it takes quite a while for it to heat up.

Has Anyone tried this?
 
I read this entire thread again and it became quite clear that some aircraft have a bigger problem with tunnel heat than others. I remember that one thing that is quite different about mine is the Showplanes cowl. With the Showplanes cowl there is an inner fairing about as wide as the tunnel that is in two pieces. One piece is attached to the bottom of the aircraft over the tunnel and the other piece attaches to it and covers the nose wheel rubber donut suspension system. Because of this fairing, exit air from the cowl is split in two and the exit air extends much further outboard than the stock cowl. As a result, the exhaust pipes are set wider apart than the stock system. Because of this, the exhaust gasses pass outboard of the skin where the tunnel is. This is almost certainly an advantage.

I would also highly recommend putting something with insulative value between the heater valves and the firewall. I did not do that when I was building, but I wish I had. I am going to look at how hard it will be to do after the fact. Some really good insulation on the inside of the firewall everywhere would be quite helpful, particularly inside the tunnel. I am quite sure that radiant heat is the real problem here and anything that can be done to block it would be helpful.
 
I did the custom aircraft exhaust because I used the showplanes cowl and CAI. Talking with showplanes, they weren’t sure the Vetterman would fit. I am really happy with the custom aircraft exhaust. Looks great and sounds better!

Vetterman makes a great exhaust system for the RV10 with cold air induction and a Showplanes cowl. However you have to tell him what you have. The stock exhaust won’t work. When I ordered mine I called them up and told them what I had. The reply was “RV10 with a Barrett engine with cold air induction and Showplanes cowl. I have already done that. It will fit perfectly”. Of course it did fit perfectly. I was shocked at how easy it was to install.
 
Sceet tubes in RV10 tunnel

The last thing I did was insulate the Sceet tubes for the heaters inside the tunnel. I noticed that the tunnel would get hot when I was using the heater, especially the rear one. (a rare occasion in the Southwest) I insulated it with 2” fire sleeve and that solved the problem. It takes 6 feet to do the job, which included insulating the aluminum T’s the Sceet is attached to. When I test flew afterwards I ran the rear heater full open and both forward vents wide open so I would not get cooked. The tunnel was still barely warmer than the rest of the airframe.
The 2” fire sleeve was $300 at All Hoses in Las Vegas. There might be something cheaper that would work, but the fire sleeve will take the heat, no problem.
 
Robert, the temperature of the airframe components is a function of energy in less energy out. Insulating the inside of the belly skin or firewall guarantees those components will adopt a higher operating temperature, as the insulation slows the energy out path. In the event of an engine compartment fire, the belly skin just aft of the cowl outlet will melt through very quickly.

I realize you have a Showplanes RV-10 cowl with outboard exits. I'm guessing you placed Soundex under the forward floor panels. The rubber foam is very flammable and generates lots of black smoke. Be prepared to jettison the gullwing doors.

None of this is new. We've already seen belly melt, followed by a tunnel insulation fire and jettisoned doors.

Don't care about fire? Insulating the inside also does nothing about the conductive heat path...the metal-to-metal conduction of energy into the airframe. Not much point is heating the airframe, then trying to stop the heat from reaching the humans.
 
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