Hi Guys,
Bringing an old thread back to life again, I was speaking with an very experienced A&P yesterday (or Licenced Air Maintenance Engineer as we call them down here) and was bouncing a few questions off him regarding my RV-7's firewall installation. He mentioned that I should use monel rivets in the stainless firewall to limit the intermetallic corrosion risk. He says in the past that he has seen the factory heads of AN470 rivets pop off due to corrosion on stainless firewalls. To be fair, his maintenance facility is located half a mile from the ocean, as are many of his customer's aircraft, so one could say he is in a pretty extreme corrosion environment. That said, although I am based 60 miles in from the coast, most of the places I fly to are on the coast, so I am going all the way with corrosion protection. Today I spoke with a Glasair Glastar builder and he said that kit came delivered with monel firewall rivets from the factory, and strongly recommended the use of them if I have a stainless firewall. He said they were a little tougher to drive, but were manageable with a regular gun and bucking bar.
I have been unable to find any concrete documented use of monel rivets on VAF, however I have found things such as "On my Rocket the FW rivets appear to be stainless." indicating that perhaps there are builders out there using monel in this application.
Just sourcing the required countersunk rivets hasn't been easy, however I think I have found a supplier.
https://www.ecasinc.com/parts/number/MS20427M6-12
I know there are going to be people out there who will say "if it's worked for thousands of builders, then why change" however they probably don't live in the middle of an island and have to fly airfields that butt right up against the ocean. For everyone else, I guess the the question is before I pull the trigger on purchasing these monel rivets, are there any hurdles I have not foreseen, and is anyone who has installed monel rivets in this application able to chime in?
Regards,
Tom.
I would also be interested in hearing Van's Engineers thoughts on the opinions of some of the folks posted here that question the safety of the firewall installation as called out in the plans, based on "their" interpretation of the CFARs...
(Most) RV's say experimental on them, so very few of the CFAR's that regulate aircraft design apply (that doesn't mean that using them as a guideline isn't a good idea).
Because they are experimental, If anyone doesn't agree with a detail of the design they can change it to meet what ever they think it should be.... rolleyes:
Hi Ken, for the record, I am a fully qualified aerospace engineer (RMIT 2002 grad) as are many other active members of this forum. Vans strives to to offer a simple, cost effective and easy to build solution that follows where practicle the FAA certified requirements, but they are not bound to these per the experimental category exemptions. If builders choose to take things a little closer to the certified standards, then that choice is theirs. I can tell you that being an aerospace engineer doesn't really matter in many of these situations, as a lot of them are just basic research of existing certified ideas combined with critical thinking skills, then the willingness to take solutions to peer review (aka this forum) prior to implementation. This has resulted in a number of modifications to later experimental aircraft, so without this crowd sourcing mentality, the experimental market would not be progressing at the rate it is.
My 2c.
Tom.
Hi Ken, for the record, I am a fully qualified aerospace engineer (RMIT 2002 grad) as are many other active members of this forum. Vans strives to to offer a simple, cost effective and easy to build solution that follows where practical the FAA certified requirements, but they are not bound to these per the experimental category exemptions. If builders choose to take things a little closer to the certified standards, then that choice is theirs. I can tell you that being an aerospace engineer doesn't really matter in many of these situations, as a lot of them are just basic research of existing certified ideas combined with critical thinking skills, then the willingness to take solutions to peer review (aka this forum) prior to implementation. This has resulted in a number of modifications to later experimental aircraft, so without this crowd sourcing mentality, the experimental market would not be progressing at the rate it is.
My 2c.
Tom.
Tom, My apologies for the misunderstanding. I wasn't referring to your comments and should have clarified that. My comments were in reference to a previous thread that I will not resurrect, involving someone who is not an engineer.