Yep, tunnel finally fixed. Should be an AD.

[glenmthompson]

Originally Posted by dmaib

Are any RV-10's flying with the Sam James cowling, and if so, are they having hot tunnel problems?

I am not aware of any SJ cowls flying in the 10, but lemme tell ya something. this tunnel is a closed area, and I believe that even without the "chin" CONCENTRATING HEAT UNDER THE TUNNEL,, there will be MORE than enough heat to fry eggs in there.
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NOW FOR MY HIGHLY REQUESTED OPINION FOR IF I WERE BUILDING A 10 for myself......
**** The heat shield mentioned above IMHO would be the best, and I would try this, actually, before my previously mentioned internal false floor due to the following.....
##### The heat put into the aft seat tunnel area is immense due to the converging of the exhaust gasses out of both pipes about 5 feet aft, watching the "stains" I know this. We actually GREATLY reduced the fwd tunnel heat problem with extra cowl bottom "gills", this allowed more heat to escape the sides of the cowl, outside the chin area, away from the center, front tunnel area, but due to the converging of cooling and exhaust gasses in the vicinity of the aft tunnel area, well, this area needs great attention.
##### If one puts the "false floor" I previously thought viable, well, that will work great I am sure in the front, but will continue to burn your passengers in the back. The reason I lean now toward the "external" heat shield is due to the aft seat area. There is just NO ROOM under the elev. push tube to install a "false floor" like I proposed in the front. Therefor, one will need to keep the heat from ever getting on the inside of the bottom skin in the back seat tunnel area.
##### I hear rumblings about drag and asthetics in my SS bottom heat shield. Well, I would, I think, have a lip/edge formed in edge the SS, that allows the SS shield to step down the 1/8 to 1/4 inch one chooses ( thicker the better, 1/8 min.). I also think I would have the SS shield ceramic coated with some of that super wambat, fututistic heat reflective mirror like coatings. This can be retrofitted to ANY existing RV 10 for just a few hundred bucks, and installed on the bottom with flush pull rivits. I am open to suggestions as to how to dimple the bottom skin though, if the false floors are already installed and closed up. The dimpling seems to be the only hold up, or just use conventional rivits.
##### Now the firewall. This MUST BE INSULATED ON THE FWD SIDE!!! Jim' mylar healt blanket stuff, although arguably not the most fire resistant, does a WONDERFUL Job, and heck, if it were to ever burn in a cowling fire, there is not much mass there anyway. Weighs just ounces. Your choice obviously, but lemme tell ya something. If you are unable to put your bare feet on the firewall, ...THEN U WILL HAVE FWD TUNNEL HEAT ISSUES, no matter how you insulate the belly!!!! One thing to ponder huys... Every calorie of heat that enters (assumption for argument purposes my fellow engineers) the tunnel, be it from a leaking cabin heat valve pass through, or conducted or radiated heat through the firewall or belly, will raise the temp. in the tunnel. Up to and including the egg frying temp stage. Trust me. this has been my life the last 8 months. we have not finished the paint scheme on jim's plane due to this issue. If your spending 100K on this plane, you need to heed the above, and spend few hundred bucks on this mod. AD or not.
###### Worried about weight? Well then take off those **** heavy and expensive vetterman mufflers and install straight pipes like every other RV. Vetterman's is making them up now for Jim. He wants to get rid of that horribly heavy heat sink in his cowling that is EXTREMELY close to that sensitive fiberglass.
###### Now, for asthetics.... The dimensions ought to be about 14" wide in the front at the firewall to 8" wide in the back, carried all the way to the rear carry through spar area AT LEAST!!!!...A little further will only help aft seat heat problems! Now...nless your are one who scrubs the belly and waxes said same, every flight....well, come on, think about it. You will have actually with SS, a much easier to clean surface. Plus, if one chooses the super wombat shiny reflective heat reflecting coating, one can have a "mirror" on thieir belly! Not unlike many show cars! Sounds like a pretty cool plane to me!
@
@ BOTTOM LINE HERE ..KEEP THE HEAT ON THE OUTSIDE OF THE FIREWALL AND BELLY SKIN.............
Glen

[glenmthompson]

Originally Posted by Mike S

GREAT!!!!!!!

I also thank you for conquering this fire breathing dragon.

I will pass on the info R. E. the heat shield working.

But, now how are you going to cook breakfast on those morning flights??

Mike

Well Mike, we can hook back up the cabin heat finally, and still have plenty to even cook our cake in an oven! The cabin heat works more than well enough for this.!
Glen

[gmcjetpilot]

Originally Posted by glenmthompson

@@@@@@ Demand Vans turn the above into an AD....Remember, this engine on N331JH has quit in me 3 times with the elec. fuel pump off due to vapor lock (read boiling fuel). And there has been at least one dead stick landing that many of us attribute to vapor lock....There have been AD's issued on certified A/C for far less. THIS IS AN UNDENIABLE, VERIFIABLE, FACTUAL, REALLY DOES CAUSE ENGINE FAILURE, NEED FOR AN AD!!!!@@@@@@

@ BOTTOM LINE HERE ..KEEP THE HEAT ON THE OUTSIDE OF THE FIREWALL AND BELLY SKIN.............GLEN

Glen your RV building and reputation are without question, but it seems you have a lot of emotion in this. Also I think the SS external sheet on the firewall and belly sound fine. It may indeed be the optimum solution.

I understand where you are coming from, but as you know these are experimental aircraft. "AD" is a dirty word to start with and does not apply to us at all. Some who don't know as much might misunderstand, so I just wanted to clarify that. I have not built or flown a RV-10, but I do have experience in with Van, heat transfer in airframes and an interest in all things RV and engineering. Your evaluation of keeping the heat OUT in the first place is a sound idea; that is what the space shuttle does with tiles.

As far as vapor lock and HOT floor......hummmm? Vapor lock is a safety issue. Glen, is HOT floor and vapor lock really related? I would say insulate all fuel lines, put a cooling shroud or and air blast on gascolater or fuel pump as needed. I am pretty sure an external SS sheet on the belly will not help fuel vapor lock, which is serious and should be addressed, but it's a separate issue, don't you think? Not sure how the SS firewall shield would improve vapor lock, but imagine it could if it also shields fuel lines from heat. Of course auto gas need not apply to RV-10's.

I think the Vapor Lock be looked at separately and seriously. Just an observation.

[osxuser]

I think the issue was that the fuel lines run through the tunnel, which is where the vapor lock is the issue. But I could be wrong... being a -7 guy myself.

[gmcjetpilot]

Originally Posted by osxuser

I think the issue was that the fuel lines run through the tunnel, which is where the vapor lock is the issue. But I could be wrong... being a -7 guy myself.

Thanks, Vapor Lock does get my attention. I can see that than. From my research most vapor lock happens in the fuel mechanical pump and sometimes in the carb itself, fuel boils in the bowl. Of course lines are on the list, but I would think the ones in the engine compartment would be more critical than the tunnel? If the tunnel is that hot I would insulate and reroute the fuel lines. That is hot!

[glenmthompson]

Originally Posted by gmcjetpilot

Thanks, Vapor Lock does get my attention. I can see that than. From my research most vapor lock happens in the fuel mechanical pump and sometimes in the carb itself, fuel boils in the bowl. Of course lines are on the list, but I would think the ones in the engine compartment would be more critical than the tunnel? If the tunnel is that hot I would insulate and reroute the fuel lines. That is hot!

Ok, for the nay sayers, once again, lets rephrase..... imagine if you will, flying along. tunnel too hot to touch for even 3 seconds. Inside that tunnel are fuel lines, elec. fuel pump, fuel selector valve, FF transducer.... being cooked to oh I don't know, at least 120-140deg? Just as a guess. (Tunnel is MUCH hotter than these temps, but obviously the fuel does not have enough residence time in the tunnel to completely approach tunnel hand scalding temps.) Insulating lines will help, but like Vans says about blowing air into the tunnel, sorry, this is just a bandade for a much bigger wound. Any way, now take this super heated fuel, being sucked by the VERY HOT engine driven fuel pump, and with elec. pump off. Or God forbid elec. pump failure, or just plane failed to turn it on. Add now, line restrictions and gascolator restrictions, uphill sucking of fuel from wings, and you have, maybe several inches below atmospheric pressure worth of vacuum/suction. VAPOR LOCK HERE IS GUARANTEED! If this happens and the elec. pump is say, inop...Unles you are in the flight levels, you're gonna land off field. I guarantee it!.
Lets pose another question...Who wants to be burned, and burn their passengers virtually every flight? Ever fly in Fl or TX or AZ in the summer, with a huge radiating heater next to you?
Things that hurt people and could make planes crash are important to me and hopefully every other pilot and plane manufacturer. I have experienced 3 engine failures due to vapor lock with the elec. pump off in cruise. Once again,..................Lemme say it again..............I have experienced 3 engine failures due to vapor lock with the elec. pump off in cruise. And I am certain at least one RV 10 dead stick is attributed to this anomoly.....IMHO, an AD is justified. Vans can call it what they want, experimental people can call it what you want. Mandatory SB, ...doesnt matter.
Glen

[brenthg]

Originally Posted by dmaib

Are any RV-10's flying with the Sam James cowling, and if so, are they having hot tunnel problems?

Not sure if Sammy James has any custom cowl parts for th -10 yet, but if he does, they'll work.

I happen to of had first hand experience working with Sammy James way back in the late 60's and early 70's when he was the race mechanic and test engineer for Bertram Yacht. He is a clever guy.

Sammy, if you read this, you know how many stories and lies I've told....I learned them all from you.

Brent
N331JH - The Monarch

[gmcjetpilot]

Originally Posted by glenmthompson

Ok, for the nay sayers, once again, lets rephrase..... imagine if you will, flying along. tunnel too hot to touch for even 3 seconds. Inside that tunnel are fuel lines, elec. fuel pump, fuel selector valve, FF transducer.... being cooked to oh I don't know, at least 120-140deg? Just as a guess. (Tunnel is MUCH hotter than these temps, but obviously the fuel does not have enough residence time in the tunnel to completely approach tunnel hand scalding temps.) Insulating lines will help, but like Vans says about blowing air into the tunnel, sorry, this is just a bandade for a much bigger wound. Any way, now take this super heated fuel, being sucked by the VERY HOT engine driven fuel pump, and with elec. pump off. Or God forbid elec. pump failure, or just plane failed to turn it on. Add now, line restrictions and gascolator restrictions, uphill sucking of fuel from wings, and you have, maybe several inches below atmospheric pressure worth of vacuum/suction. VAPOR LOCK HERE IS GUARANTEED! If this happens and the elec. pump is say, inop...Unles you are in the flight levels, you're gonna land off field. I guarantee it!.
Lets pose another question...Who wants to be burned, and burn their passengers virtually every flight? Ever fly in Fl or TX or AZ in the summer, with a huge radiating heater next to you?
Things that hurt people and could make planes crash are important to me and hopefully every other pilot and plane manufacturer. I have experienced 3 engine failures due to vapor lock with the elec. pump off in cruise. Once again,..................Lemme say it again..............I have experienced 3 engine failures due to vapor lock with the elec. pump off in cruise. And I am certain at least one RV 10 dead stick is attributed to this anomaly.....IMHO, an AD is justified. Vans can call it what they want, experimental people can call it what you want. Mandatory SB, ...doesn't matter.
Glen

Ok Glen thanks I get it, I did not know the fuel lines and fuel pump where there; clearly now that you explain it, the hot tunnel could contribute to vapor lock, but you don't have to be condescending about it.

You took this defensive attitude when you said your 3-blade MT prop was not slower than a hartzell a while back and chewed me a new one. I suggest that your highly modified, high HP, engine running at a higher MP, might make up some of the speed difference. I guess you owe me an apology, since it was also Van's conclusion, in a RVator article he wrote a month later, regarding the fly off he had with your plane Vs. the factory RV-10. His conclusion was your engine made the difference not the prop, which was slower than the hartzell by a significant amount. Sorry just our opinions and we are entitled.

Thanks for straightening me out about the hot tunnel, clearly you are right. I just though all those years in engineering school and study of heat transfer I could help. Sorry. I don't know how structural the tunnel is but I would cut large vent holes in it, but like I said I like your idea of keeping the heat out in the first place.

Good luck with your SS sheet solution and AD's. Van's pretty stubborn and will be pleasantly surprised if he makes your mod a standard feature. I hope your solution works and he does incorp it. You can't possibly call me names or chew me out for agreeing with you. Cheers George

[glenmthompson]

I never heard of any flyoff with the factory plane. I am also now the only one who flys Jims plane, and I have not flown off with any other 10.
Also I am on record many times in this forum, that we now have Jims plane actually faster than the factory lyc. powered plane!
And sorry Mr. George, but it gets pretty tireing to write countless times what the problem is, then have someone write here that I/we are clueless and don?t understand vapor lock, when the someone pointing their finger at us, does not have a clue as to the layout of the infamous tunnel. HHHHMMMM
Also,..... passionate about an airworthiness issue with Vans newest, most awsome plane to date???? OF COURSE!!!!!!
Glen.

[gmcjetpilot]

As far as the tunnel I have lost interest, good luck. You need to calm down. No one is pointing fingers. I believe you, there is a problem, got that and never doubted it. I made it clear that I was asking a question and did not know the routing of the fuel and pump. When someone puts "?" after a sentence, it's a question not a pointed finger.

Sounds like re-route of fuel lines and insulate the tunnel to keep the passengers from dying by combusting and catching on fire would do it; that's if your friends heat shield idea does not work as well as first thought, no offense. Geeeee, the RV-10 sounds like it sucks. Is that why you are so angry? We are just having a conversation; no need to attack me. If you don't like or agree that's fine just say you don't agree. It sounds like a workable problem to me, but again what do I know. I no longer care, but sincerily wish you the best luck. May be you should bring lawsuit against Van's, that's the ticket. He can always just raise the kit cost to pay for leagle fees. Or you could just modify your own RV-10 as you see fit and let everyone else decide how to solve the issue.

BTW: to answer you question, this fly off: (RVator flight test, "RV-10 Comparison", page 6, 5th issue 2005.)



*(N610RV posted a 198mph speed at 8280ft and 2251 lbs, -3 mph from spec, and 3.7mph to 5.1 mph slower than the factory N410RV. RV610RV used a standard Hartzell. The factory plane N410RV, uses a Hartzell BA prop. That would account for the +3 mph difference. The other plane, N64ME had a Hi-compression engine and should have been much faster. It was only 1 MPH faster than the factory RV-10 and was hindered by the 3-blade MT prop, which I (and Van) estimate cost at least 6 to 8 mph in speed verses the faster Hartzell BA prop. The customer built RV tested, N104ME was well over spec at 208.6 MPH!!!! That proves a 260HP/Hartzell BA prop RV-10 will do better than spec.)

I guess I got Vic and you mixed up, oh well. I truly regret trying to understand the problem and think I might be able to help.