2 piece vs pressure recovery wheel pants

Reading info about the evolution of the van's wheelpants, it seems that their were 3 different design types (1 piece, 2 piece, and pressure recovery )
I believe I have the 2 piece wheelpants and not the pressure recovery type.
Anyone change their 2 piece for the pressure recovery wheelpants and if so what performance change, if any, was observed?
I have read the change from the one piece to the pressure recovery was significant but did not see any comparison between the 2 piece and pressure recovery type.
Also did the leg fairing design change 3 different times as well?
Thanks
Craig

csgj said:

Reading info about the evolution of the van's wheelpants, it seems that their were 3 different design types (1 piece, 2 piece, and pressure recovery )
I believe I have the 2 piece wheelpants and not the pressure recovery type.
Anyone change their 2 piece for the pressure recovery wheelpants and if so what performance change, if any, was observed?
I have read the change from the one piece to the pressure recovery was significant but did not see any comparison between the 2 piece and pressure recovery type.
Also did the leg fairing design change 3 different times as well?
Thanks
Craig

Click to expand...

There has only been two versions of the leg fairings... metal ones and composite ones.
The metal fairings were used with the one piece and the early two piece.
The composite leg fairings where introduced when the two piece pressure recover wheel pants were introduced.
The pressure recover wheel pants were good for about 4 - 5kts faster than the early one piece. I would estimate that the early two piece fall in between the one piece and the pressure recovery wheel pants so is 2 - 3 kts better than the one piece, leaving a delta of about 2 kts between the early 2 piece, and the pressure recover two piece.

The way to tell the difference?

The early two piece are not symmetrical... there is a left and right fairing.

The pressure recovery fairing is symmetrical... same fairing is used on both sides.