Yep, tunnel finally fixed. Should be an AD.

[glenmthompson]

Well here is is, we finally did it. Proved what was causing, and found a fix. I was right all along, the fix is in preventing the heat from entering the tunnel through radiant/convective heat transfer through the firewall and belly skin.
Jim called me last night and said he had an idea of insulating the bottom with his super wombat mylar heat shield on the outside, to prevent the tunnel cooking, per my persistant whining and screaming.
So, poor Glen spent an hour degreasing the yet to be painted belly (primer for now) to allow the 18" heat shield to be applied with super duper carpet tape and my heavy duty al. duct tape.
***** Results, the tunnel on the flight we did today was just as cool as it was before we started the engine! My theory has been proven. Whew,... finally, no more screaming and IM's to tone it down.( not quite done screaming yet on this subject...read on)***********
This is what IMHO, yet more experienced than ANYBODY in this area on the RV 10, needs to be done to ALL 10's.:
.
@@@@@@ Install a stainless steel heat shield as suggested by an extremely intelligent 10 builder about ready to fly. Needs to be at least as wide as the tunnel, all the way back to the rear spar carry through. Stand it off, say, oh 1/8" or so, and add fiberfax as a further insulator.
............###Trivia here..Did you know that the abladable heat shield on the Apollo and Mercury spacecraft was mainly fiberfax? Yep.
@@@@@@ No fresh air is necessary in the tunnel after this is accomplished.
@@@@@@The firewall needs to be insulated very well ON THE ENGINE SIDE too, by the above mentioned mylar, SS shield or whatever you want,... the prevent heat introduction through the front is waht needs to be accomplished.
@@@@@@ Call Vans and tell them to [snipped by dr] pay attention to this thread. Listen...How does tis sond to you....? Insulate the inside of the tunnel and blast copius amounts of precious, drag inducing, engine life blood, fresh air, into the tunnel for cooling? Per their SB? Are they nuts? IMHO, nope, just maybe lazy, and not touching their tunnels inflight...Or possibly, some people, tired of Glen pointing out dangerous/annoying things about the RV 10.
@@@@@@ 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!!!!
@@@@@@ Retrofit on flying or substantially completed 10's will be pretty easy. Say, a weekend's work.
@@@@@Scrubbing/cleaning the belly of exhaust stains will be a piece of cake with SS on the belly.
@@@@@ Further fire protection will be awarded to fragile fuel lines in the tunnel area in case of cowling fire.
.
Jim and I will be in the Vans tent at the predesignated 10:00 AM meeting time on 27 and 28 July.....Also, when you look at "The Monarch", please remember she is a flying testbed right now and, yes, we will wash it, finish interior work, and finish the Monarch's spots now that the tunnel problem has been identified and temporarily fixed.
Gawd, what a battle this has been...Good luck and if you treasure your unburned skin and fuel in a liquid state prior to the carb....., take heed.
Glen

[VHMUM]

OK a lot in your post....please just the facts....are you saying you put a heat insulating material on the firewall engine side?
I am getting confused with the other heat shield....are you saying to put it on the outside on the belly in the airflow and stand it of 1/8??

And thanks for all the work you have done.

any pictures

regards Chris 388 Melb AUS

[glenmthompson]

Yup, you understand me correctly on both parts. The well deserved reason I have a lot of info, is due to the immense amount of mine and Jim's life that has gone into this @#$%$#@ issue.haha...And to 100% dispell the many nay sayers (Vans included BTW) to my observations and theories.
I hope this is the "hot" topic with Vans this OSH. It needs to be. This plane is sooo cool, and industry leading, "we" don't need this kind of problem out there when there are soon to be hundreds of 10's flying. Can you imagine how many potential future engine failures/scalded bodies there will be out there in a year or two? The mind wanders and does not like the possibilities.
Glen

[glenmthompson]

Brent, can you take your comp. guru pic skills and get a pic of this before OSH? Maybe I can email one from my phone and you can post? Or anybody else with more patience than me to get the pics to take?
Glen

[dmaib]

Thank you for all of your work on this problem. Much appreciation for photos or sketches when they are available. I will try to find you on the 27th or 28th at Van's. I'll bet there will be quite a few people wanting to talk to you.

[Deems Davis]

Glen, Great work work!!!!!!!, thanks for verifying the theory. Did the problem go away with just the mod to the belly or did you also do the firewall??? (Trying to determine whether or not to make the ff mod)

Deems

[VHMUM]

I think what you have done is just great ......I wonder what can be done about under belly as having someting there wouldnt look the best (better than engine falure) and would cause drag with 1/8 off the belly. Did you try a shield over the rear part of the exhaust to help stop radiating onto belly.

Chris

[glenmthompson]

Will respond to exactly what I would do personally when I have a few more minutes. I have though, explicitly said several times in the tunnel tips section about my suggested fixes, false floor, etc. If one cares to look there until I get a little bit of time to be very specific, it might be worth looking there in tunnel tips.
Glen...(breathing easier now.)

[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

[dmaib]

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