Whelp, another one in the books. The arrival Sunday morning was smooth and easy with not much traffic and in the blink of an eye, camp was set up next to another RV-10 piloted by Troy from Alberta. Heck Sunday’s arrivals were 80% RV-10s so there was lots of fun looking for RV10 pilots I have met in past years. I had another big group friends arrived from my home (Steamboat) and who flew in, all told there eight of us – not bad for a town of 13,000!
With my wife joining me this year, less time was spent in seminars but I did get to a few and had some good chats with folks who supplied parts for my build.
Mike Busch
Only one seminar this year but it gave me a chance to ask Mike and Paul (of Ask the A&Ps) about an abnormal tag following a recent borescope analysis on my #3 cylinder exhaust valve head. Looking at my image and discussing my concerns they relieved my anxiety explaining all is good.
The one takeaway, was that Mike advocates for a preventive solvent ring flush every 500 hours. This clean the rings before they reach a point when it might not be possible to get the solvent past the rings. Savvy’s Analysis solvent flush procedure: Link
Brad @ P-Mag
Yep, Brad is on the way out and following Airventure he will be completely retired. He was so appreciative of the experimental community and the comradery that we all share.
I asked about new firmware versions for the 6 Cylinder version of the P-mags and there is a version V59 (I’m running V58) but Brad didn’t have the details on the change log and suggested I reach out to Trent. I’m happy with how mine are running so I’ll hold off for now on doing more research.
Van’s Safety Notice 00108 (Aircraft Limitations with Aftermarket Extended Range Fuel Tanks Installed)
Released in May, this service letter drew a lot of discussion on Vansairforce and led to more questions than answers as to why it was worded so strongly and had an oddly specific 2.8 knots reduction of VNE for each gallon of fuel in aftermarket extended range (ER) fuel tanks. Top on my list for Airventure was to talk with Rian (Chief Engineer at Van’s) and Ken (Chief Engineer at Sky Design, manufacturer of a version of ER tanks for the RV-10 and RV-14).
Rian was difficult to track down mostly because of the new changes with Mosaic 2.0 and his involvement with various meetings and press conferences, but after four or five trips to the Van’s booth I found him. He was rushing to his next meeting but I managed a short conversation – while mostly it was him giving a boilerplate spiel, I pushed for how the speed reduction is exactly 2.8 knots for both the Sky Design and Hotel Whiskey ER tanks given that the method of holding fuel is completely different (extending the stock fuel tank versus tip tanks) – to this he avoided the question. The only thing of value was telling me that Ken was included in the discussion following the flutter testing analysis that Van’s had performed by an outside company.
Ken on the other hand was easy to connect with and I spent a good hour talking with him and his wife Susan. During our conversation, Ken freely brought out binders of notes (taken during telephone conversations), calculations, and emails between himself and Van’s staff (Rian and Greg). He was 100% transparent and I walked away beyond impressed with his obvious engineering talent and knowledge, and I was further impressed by he genuine care, concern, and confusion over why Van’s has not worked with him in good faith.
Key takeaways:
1. Van’s did reach out to Ken when their outside flutter analysis showed a few scenarios (out of I think over a hundred test scenarios) where there could be a reduction in flutter margin. During that conversation Van’s appeared to be willing to work with Ken to address any potential issues but after the initial call and Ken’s request for details on the testing Rian stepped back and Greg (marketing) responded a couple times, but then went radio silent – Van’s never provided the analysis they told Ken they would provide.
2. During the design phase, Ken had modelled and analyzed the changes that his ER tanks make on the flight characteristics and performed ground vibration testing (GVT) and had not been able to identify any adverse flight characteristics – once Van’s shared the results of their analysis with Ken, he stopped selling kits until he completed additional testing to assure himself that he didn’t miss anything.
3. The ER tank flutter analysis was completed two years ago – yes you heard that correctly 2 YEARS ago, and yet Van’s waited to release the Safety Notice until May of this year – it begs the question of why the delay if it is such a dangerous issues that this must be added to the Maintenance Manual (from the Service Letter “Place a copy of this notification in the back of the maintenance manual for your aircraft. Add the name and date of the service information to the Addendum Documents List at the front of the Maintenance Manual.”).
4. In the Sky Design, the weight of the fuel is in front of the wing’s elastic axis – the Hotel Whiskey tanks I have, part of the tank is behind the wing’s elastic axis which puts it at a higher risk of flutter.
5. The RV-10 and RV-14 tail feathers are a much more robust design than earlier models – There have been 14 incidents of flutter resulting in loss of the tail feathers (I can’t remember if all were in RV-7s or only most of them) – Ken is perplexed as to why Van’s would not address the current design to improve safety, more so since the RV-10/RV-14 tail attachment could easily be adapted for the other models – NOTE: the concerns with the RV-10/RV-14 are for aileron flutter NOT tail feather flutter
6. There has never been a flutter event on an RV-10 or RV-14 (with or without ER tanks) and the Hotel Whiskey tanks have been sold for 23 years for all models (RV-4, RV-6, RV-7, RV-8, RV-9, RV-10 and RV-14) and yet the service letter ONLY addresses the RV-10 and RV-14. Judge for yourself but I believe Van’s has a vendetta for Ken
I want to close out that is was clearly painful to Ken that a past employee attacked him, suggesting intellectual property theft in designing his ER tanks. At the time it was posted online, I found the claim laughable given how simple the fuel tank skin part would be to recreate. Especially for the guy who developed the pre-punch skin method that Van’s uses on their kits. Even in this silly case, Ken explained how he literally took a ruler to take the measurements from a flying RV-10 to generate his engineering drawings.
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