That would require a minimum fuselage height (top to bottom) of 430 inches. Given the extreme ovoid cross section of the WhaleJet, that would make for a fuselage width of at least 367 inches. Using the composite technology of the B787, OEW would be at least 600,000 lbs. With four engines, each would need more thrust than a

GE-90-115B for it to have remotely reasonable payload/range.

Also, you show the lowest passenger deck being longer than the middle deck. That's very backwards. The smallest reasonably shaped triple-decker (same ovoid shape as the WhaleJet) would seat 3-4-4-3 on the lower deck, 3-5-5-3 on the middle deck, and 3-4-3 on the upper deck. An 80 meter length would be very stubby. No chance of an 80 meter wingspan unless it's a biplane.

If more capacity were ever needed than provided by the WhaleJet, much larger double deck designs are possible. Keeping the fuselage height of the WhaleJet and widening it until the fuselage is circular at 331 inches would provide 2-4-4-2 seating downstairs and 3-3-3 (or 2-5-2) seating upstairs.