I`ve just finished Rickenbacker`s book "Fighting The Flying Circus". He speaks several times of fellow pilots having the fabric rip off the upper wings of their N.28`s, and how putting the aircraft in steep dives caused the problem.I`ve read of this problem on this aircraft before, but I`ve never read anywhere what in the design of this plane caused this to happen. Could the problem have been corrected once discovered, ala the DR1 and it`s wing spars being re-worked? Any help on this question would be very appreciated-

WW1 Aero #165 (Aug. 1999) featured a very well written article on the Ni. 28, including a detailed analisys of the wing failure problem.
Recommended !

The spars were not the primary problem. The nose of the ribs were breaking off and peeling back. This probably could be corrected by full rib capstrips as it appears that the wings failed at the joint between the leading edge sheeting and the cap strips.

Wolfgang: The doped linen fabric is subjected to tremendous suction forces which over a period of flights gradually separates the fabric which is glued to the airfoil from its attachment points. Once the wind gets under this fabric it completely separates it from the airfoil. The airfoils, if not correctly braced, will flex or torque wooden members, and so help to separate the fabric as the dried glue fragments. Bullet holes in the fabric, and slugs which sever the bracing wires will also set this failure node up. Putting a 20G force on a 10G wing does it every time.

Wiolfgang:
The plywood sheet was only on the upper surface of the wing. The span from the leading edge to the front spar was wider than most wings. In a dive the cenmnter of pressure moved aft on the chord of the wing increasing the upward force on the leading edge of the wing. Without the plywood reinforcement on the bottom surface, the bottom capstrips and ribs failed resulting in the loss of the leading edge and the upper fabric cover.
According to the Gorrell Reports this problem was solved and the Nieuport 28c1 was going to rbe reissued to the USAS Pursuit Squadrons in 1919.
Blue skies,
Dan-San Abbott

The explanations offered on this thread largely track with the info generated during restoration of Doug Champlin's gorgeous N.28 in Arizona. The Type 28 was the first Nieuport design produced in numbers that was not a sesquiplane/V-strutter. Despite the novelty of the 28 configuration within the Nieup. organization, there was insufficient testing of the design, and there were also questions about quality of material and workmanship. In any case, the leading-edge extension was source of the problem rather than EVR's oft-quoted report fingering the fabric attachment.
Builder/restorer/test pilot Jim Appleby opined that a properly arranged 28 could be safely dived at 200 mph.

I don't know if this is relevant to the discussion or not, but Hollywood stunt pilot Garland Lincoln had similar troubles with a rebuilt N.28. If I recall the story correctly, he'd rebuilt the wings using aluminum instead of wood -- and still had the fabric peel away from the leading edge of the upper wing on one occasion. This happened in the early '30s, I believe, post "Dawn Patrol."