More Winglets?
 

Flew 737 this week and observed that the particular aircraft had not only the substantial turned up wing tip but also a small winglet canted down about 45 degrees.

Does the added winglet make a substantial difference?

The flight was also ready to go a few minutes early and then it was delayed to "move baggage from forward bay to aft bay." I'm guessing this was also in their efforts to balance the aircraft for best fuel consumption.

Sure seem to be getting down to the wire on efficiency these days.

'Scimitar winglets'

Downwards-pointing winglets have generally been avoided due to the risk of damage to the aeroplane and to ground personnel, the Arava being an exception with its high wing. But at a certain point the structural load of taller winglets reaches a limit and one option for continuance is to build downwards.

More likely, the aircraft was Out Of Trim! :)

ie. The aircraft would be unsafe to depart; as had been loaded and passengers boarded so that it was outside of the allowed limits. Therefore, weight and balance adjustments were necessary to bring it back into trim. :ok:

Whilst the Blended Wingtip has become the most common, there is the Airbus double fin winglet and the new 737 MAX double finned winglet that is called (I sit to be corrected) a Sharklet.

When an aircraft is out of trim does instrumentation on board alert the pilot or is it picked up by calculation??

The Airbus winglet is the Sharklet, the 737 winglet is the Scimitar and is being fitted/retro fitted to earlier models than the MAX. You may remain seated!

Calculation

CC is correct because it is too late when it is picked up by the pilot. You might also be pleased to hear that when an aircraft departs, its centre of gravity is such that an allowance is made for people and bar carts to be moved about. The OP also suggests that the holds are loaded to minimise fuel burn (aft C of G). If possible, they are however you rarely delay a flight to get optimum C of G. It is more likely that the flight was delayed to get an acceptable position.

PM

Many thanks..