i bought both RP and fX and there is a slight difference, at least to me, and that is FX is a bit heavier, and heavier by a very tiny bit. so i was able to get a tiny bit more power with my clears and smashes. but both are so light. i have the nanospeed 9900, 9000s, and 9000x, and in my opinion the lightest is 9900, but the most difficult racket to play with is 9000x because the shaft is so stiff. they are all stiff rackets, just that the 9000x is very very stiff. i was able to general more power on the 9900 than the 9000x for some reason, even tho i still think the 9900 is the lightest racket in the Nanospeed series. both nanorays are even lighter than the 9900 in my opinion, so it took a while to correct the speed of my swing to even generate power. but then again i'm not a strong smasher, so it takes a lot longer to get my swing up to speed
Tank you for your response.
Just to clarify:
E.g. the Nanoray RP feels a little bit more light than Nanospeed 9900. And the stiffness is similar.
For though the Nanospeed has a smaller frame, the Nanoray goes faster throug the air?
Regarding the balance: I saw it on the Yonex chart: The Nanospeed 9900 is more even balanced, ant the Nanorays mote headlight...
Yeah, the Nanoray is also available in the 4U weight, which is the one I'm using right now. I used to have a Nanospeed 9900, I feel that the 4U weight really makes a difference in speed! Can't wait for the Nanoray 800!
in my personal opinion, the lightest is the 700rp, then 700fx, then ns9900. i trained seriously for a few months so i got used to the lightness of 9900 and had a decent smash, and by decent smash means my opponent can return my smash easily with the other hand picking his/her nose
anyway, i find the nanoray series too light for my because i am not strong enough to get power thru the racket for a smash. it's great when i play for fun and have super quick response, but when i'm being pushed in the back it's quite hard to get any power onto the racket...but it's just me lacking in power. if you have good form/technique, i'm sure you'll do fine