I’ve got quite a headache at hand. The dimension on the construction drawing says 8.814 m, which is 28’11” in imperial dimensions, while Jane’s All the Worlds Aircraft from 1919 says 26’6″. Which one is correct? Where is the length measured from? The skid or the propeller?

There is also the AVRO 504K Mark II, which is an improved Mark I. The Bjorn Karlstrom drawings are of the AVRO Mk II, and by scaling up the 1:72 drawing, I get a length of 28’6″ for the Mark II.

AVRO wrote in a brochure for the AVRO 504K Mark II:

• A New” Oleo” undercarriage is fitted.
• An adjustable Tail Plane arranged for dual operation, enabling the machine to be trimmed for different speeds and varying loads.
• Altered Centre Section Plane and Wing Roots, allowing a much greater range of upward and forward vision.
• New shape Ailerons to lighten and harmonise the lateral control with the elevator and rudder controls.
• Direct gravity feed for petrol.

From what I see, the fuselage formers are also of a different shape. The length might possible also have been reduced 6 or 12 inches.

From what I can deduct from photos of the Danish AVRO 504K, it is a Mark I. So why did they write 8.814 m on the construction drawings? It just doesn’t make sense. I need more information.