How Natural Laminar Flow (NLF) shaped Airbus’s BLADE (Breakthrough Laminar Aircraft Demonstrator in Europe) project under the EU’s Clean Sky programme ?
What was the outcome ?

✔Controlling the Laminar airflow over the wing surface to push transition point is the key.

✔NLF is the advanced leading edge technology, applied on the wing for fuel efficiency & emission-reduction efforts by reducing wing drag upto 50%.

✔Airbus’s A340 laminar-flow “BLADE” test demonstrator aircraft made successful test flights with modified Outer wings in september 2017.

✔The experimental wings, which fitted a 30 ft metallic outboard section each side, had:

A CFRP upper laminar flow surface.

Isolation from the inner wing.

Two Ailerons on each side.

Wing sweep of 20° for a Mach 0.75 cruise (instead of regular 30° for a Mach 0.82–0.84 cruise).

✔ ‘BLADE’ Outcome :

Both outer wings with their Upper-CFRP continuously generated the desired effect.

However, the CFRP LH wing leading edge & Metallic RH wing leading edge showed small differences in aerodynamic effects.

Surprisingly, Laminar flow demonstrated 50% of chord length instead of just aft of the leading edge.

It Reduced the overall aircraft drag by 8% & up to 5% fuel saving on a 800nm range.

Author – Tanmay Palei
Sr. Aircraft Structure Engineer