Ground effect and sharklet
 

Hi everyone.

I would like to do a little comparison between wingtip 320 and sharklet 320. This is more for the thinking than real application, but I think that it is good to discuss and understand things properly.

Sharklets have less induced drag, because of blocked downwashed/unwashed vortices. When the 320 Sharklet comes into the ground effect, the effect of it should be less noticeable than for the wingtip one. As a result (considering stable approach criteria, same wx, standard flare) the sharklet should be less prone to float, but it is not what I tend to see IRL.

any thoughts ?

best regards

I have no idea about specifics, but it could be that the sharklet gives a reduction of induced drag while in ground effect, that's even bigger than while out of ground effect.

My 2 pc

Agreed:
Some of the extra magic provided by an endplate is lost down low because the ground itself (WIG) provides the same and takes over.

New angle:
Since the sharklet magic is much bigger than wing-fence magic, losing e.g. half of each (the bottom part) still has the sharklets throw harder punches.

If your reference float is the wingfence float, the sharklet one is more powerful. Peldor Joi

You may have to consider the contribution of the tailplane in ground effect and if this would change with improved wingtips, (and for other aircraft, the basic geometry, high-low tail position, i.e. the combined contribution to ground effect)

Sharklets tend to make aircraft slippery due less drag or as Airbus says CEO has strong deceleration quality. So for the Neo, which always comes with sharklets they use a factor of .33 for GSmini. But surprisingly for CEO with or without sharklets they use same factor of 1.0. I am not sure why. Because Neo or CEO, deceleration should depend on sharklets not on engines.

In my experience, sharklets float considerably more.

Exactly! Not only that Neo Vref is 5kts less than CEO but Flap3 speed is same as CEO because it's 10kts higher than Vref instead 5kts as in CEO Flap3. That is to prevent reduction in tail clearence.

Is that what it is? Is that also true for the A321 Neo? I couldn’t find any information on which flap setting provides more tail clearance for the A321 Neo.

Neo Sharklets reduce VS1g so Vref which is 1.23 of that also reduces. Generally Flap3 speed in CEO is appx Vref+5 kts. If they keep that in Neo the approach attitude will increase so instead it's increased by 10kts. making it almost same as CEO. Not sure about 321 because I think 321 uses double slotted flap which may be reducing the attitude.

Vilas, given the detail of your research, have you seen any differences between NEO LEAP and PW? Having done my first flight on the LEAP just recently the nacelle ground clearance is just the bare minimum.