So on new builds Robert, and this is true in the main tank in my project since it is just in shells state now, is going to be formed blown insert. Inert to any fuel type (Plutonium excepted in case of the famous Flux Capacitor). By adding this, the possibility
of leaks s near nil. This change does NOT negate the fact that the main tank is primary structure in this design...in fact the header tank is also a carry through of stress loads..though less of than the main.
Take heart that composite structures are remarkably repairable. Just imagine trying this repair on a 747 wing..or for that matter.. a G650 wing when was literally over pressurized on the final pressure test (Boom!). Same thing on a G280 wing at Triumph Aerostructure
in Tulsa. The cause? The tech did realize the pressure gauge was calibrated in different ranges... so instead of 3 PSI the wing was spiked up to 50 or more PSI.
Repair was in fact...way more expensive than just building another wing..each copy of a G280 wing went for just over 6 million (our cost).
I encourage you to continue and do so with confidence. You now know this aircraft better than a second buyer that has never been into the
structure this far. Remember the basis of the EAA....anything you learn in aviation can never be taken away from you and in experimental aviation that I would say is even more a truth.
Today was another chapter in "Duckies" rescue, but the ending of this book isn't written yet despite the set back. So let's start by saying when I bought "Duckie" to rescue, I was happily surprised how little damage there was to the fiberglass and how
well it held up. I thought it was almost too good to be true ... well this weekend proved, it wasn't.
As many of you have seen, I was quite happy with my progress ... the controls were back on and moving super crisp, all the fiberglass damaged looked to be fixed and new improvements from after this plane was originally built went in such as a reflexor. Also,
I had made good progress on putting the O-200 together with the SDS fuel injection and electronic ignition, I even had gone and marked all the components on the firewall.
So now it was time for the fuel system and that's when I checked the bottom sump drain, with some unexpected findings to call it nicely. Per the picture below, you can see the bottom was seriously warped right where the main tank was. What is this warping I
wondered? Did we have a fuel leak that caused this warping asked Jason S?
So while I figured out how to flip the plane on its back, I was still bugging all you with my fuel system questions of where do I put my main tank 3/8 output per fuel injection manufacturer, how do I make my new 1 1/2 in header to main fill pipe etc. I had
fun and was a bit delusional thinking that it was just a little warping. But I knew I needed help so I scheduled a work Saturday with my EAA crew and Sam Kittle came too which was awesome.
We flipped the plane on its back, using the ingenious "Sam Kittle" flip engine bracket and went to work ...
After we cut off the warped part ...
And scraped out all the damaged foam ...
Is was pretty clear right away, well clear isn't the right word, but it smelled pretty much right away to the root cause was a fuel leak. The foam after years of sitting still had lots of blue fuel squeezing out of it when we removed it with a putty knife ...
yuck! But the moment of truth came with a little pressure test ...
... or mayeb this is a new thing instead of smoke pumps, make "Duckie" a soap bubble machine ;-)
Well back to reality, it is clear that this tank bottom won't make it and no patch job will do. Now I am planning on the next steps, such as resealing and making a new bottom. But in good Robert fashion I am trying to see the silver lining in this ...
- Putting in a 3/8 fitting for a pickup won't be a problem anymore
- Putting in a new 1 1/2 fill pipe won't be a problem anymore
- Inspecting the tanks will be done sooner than later
My final unanswered concern is how well the header tank was built and if its sealed. Next immediate step ... pressure test on the header tank.
Hope you enjoyed my little Saturday story update from "Duckie's Rescue". And to quote Chris W, it's pretty clear that the Quickie found me, I didn't find it because otherwise I would have long given up ;-)
Tomorrow is another day, looking forward to your laughs, encouragement and suggestions. Have a great and safe weekend,
Robert "TheFrisco" Schmid
Love building planes almost as much as flying. Latest completed build is "Loki", a Chinook Plus 2 bush plane.