How does the LIP package which is standard on the A320NEO enable to approach at a slower speed?

Question

Could someone kindly explain as to how the lift improvement package on the A320NEO enable it to approach at a slower speed compared to the IAE CEO. I have the list of the modifications which is done but it doesn’t explain how it helps.

They are:

1. Slats (de icing slay/track shutter modifications and stiffened slat/track seals)
2. Slat 1 enlarged horn
3. Adding an outboard nacelle strake
4. Fuselage wing fairing root fillet aerodynamic improvement
5. Wind shroud close to flap 1 and 2 junction
6. Introduce extended trailing edges on spoilers 1 and 2 and on fixed wing box trailing edge between spoilers 1 and 2.

These modifications mainly allow the aircraft to approach up to 5 knots slower than our CEOs. But how exactly do the modifications work in reducing the approach speed?

Answer 1

On first impressions, all of those (except the nacelle strake and the fillet) seem to modify the high lift system (slats/flaps), presumably to optimise air flow in the gaps between slat and main wing or main wing and flaps. This is probably done to increase the maximum attainable angle of attack or lift coefficient, which will reduce stall speed and thus allow a lower approach speed.

The nacelle strakes normally are used to optimise flow around the engine nacelle at high angles of attack, either to prevent premature wing stall around the nacelle or to at least improve aircraft handling qualities by preventing localised flow separation at the nacelle. Adding another strake on the other side will, I imagine, again allow a slightly higher angle of attack to be sustained and thus will lower the permitted approach speed.

The wing body fairing modification most probably, too, will allow a more optimal local air flow.

All of this is my speculation based on the list of changes in the question; I don’t have additional knowledge on this particular aircraft performance package.

Answer 2

This is the A320neo SHARP (SHort AiRfield Package) that Airbus designed at the Filton, UK Plant in conjunction with their engineering colleagues in Bremen, Germany.

It's a package of aerodynamic improvements meant to increase wing lift at low speeds. The original impetus to develop the enhanced takeoff and landing performance for short fields was a desire to operate the A320neo into Rio de Janeiro's Santos Dumont airport, whose runway is only 1,300m (4,265'). In addition to the short runway, there is a mountain to one side and a long bridge on the other to add to the landing challenge.

It would take dozens of pages to describe how each component improves airflow and enhances low speed lift and performance. But the key component of the package is a Kevlar composite panel modification to the wing's Root Fillet Fairing to optimize airflow at the wing root. This minimizes interference drag by easing the airflow transition between airframe components and retards the onset of stall at low speeds. This enables greater lift at lower speeds, both keys to improved short field capability.

Modern airliners have adopted any number of aerodynamic enhancements. Perhaps the most famous of which are the widely adopted winglets. The blended neo winglets have a relative drag reduction at cruise of about 4%. The difference with the SMART package is that the aerodynamic enhancements target low speed airflow management with the goal of increasing low speed lift.

AIRBUS PREPARES “SHORT AIRFIELD PACKAGE” MODIFICATION FOR A320NEO

Airbus Readies Short-field Mod for A320neo

Airbus designs short airfield package

DEFINITION AND DISCUSSION OF THE INTRINSIC EFFICIENCY OF WINGLETS