Skippydiesel wrote:OR if wing space does not permit increasing the size of the fuselage header
OR installing an in fuselage auxiliary.
If its the B model tank - I hope they have done away with the fool of a fill point location/system.
Wing space - you can see in one of the photos I posted in this thread about a week back looking at the top of the wing - the aux fuel tanks are in the wing center section that is integral w/ the fuselage. They did this so the fuel system could remain complete with the wing outer panels off for road transportation / long-term storage / reduced need for build space. Simplest place to add fuel capacity would be in the behind-seat baggage area, and they're currently presenting 90 lb (of weight capacity, not fuel weight) available there. Personally, I can't sit as long as the flight durations you're proposing, so if I wanted that sort of range extension, some self-contained fuel cans/bottles back there, land, top off, keep going would work for me rather than installing anything more permanent.
They did say they're using the B model tank - I can think of a couple reasons not least of which is reduced cost on their side having to carry different inventory at reduced quantities + amortizing supplier set-up costs for a new tank. You can see in one of my photos from the front the same fuel fill door surround feature as the B model in the windshield trim. It's maybe not the best in that if they go with polycarbonate windshield material (which I expect they would, as it can be a flat piece that wraps into place) the polycarbonate supposedly degrades if there's contact with fuel, but I never had an issue with my Sonex, even with the occasional drip. Just don't let fuel sit on there and it seems to do ok. Or if the windshield gets stained or something over time, it's just flat polycarbonate - not too expensive and very easy to cut and drill. You should be able to source it locally and not need to ship a windshield all the way from the factory.