I upgraded to 8S on my F4 from the 6S 12 blade 4068-1835 Kv inrunner, so not sure how the 3668-1960 compares. Had a Camo and Blue Angel F4 on the 1835 inrunner, which was a nice upgrade from the stock 1750 outrunners, but my Camo version had over 150 flights (and had taken a beating) and decided to replace it with the stock grey 8S to do the Jolly Rodgers. That's the 8S 4075-1350 Kv 12 blade with 8S 120 A reversing ESC (which I don't use on grass, only the occasional asphalt flight). If you believe RC Castle's thrust figures, the 2 6S 12 blades (1835 & 1960) are about the same at 4400 & 4200g static thrust respectively, so not sure the 1960 will do it for you. The 8S, on the other hand is around 5300g of static thrust.
After I flew the new 8S F4, I was so impressed that I bought the same fan/ESC for the F4 Blue Angel and my old F16 (which also had the 6S 1835Kv inrunner) and it was a drop in fit for both. On the F4, what a huge difference it made, now arguably one of my favorite EDF's. On 6S, the best balance point for me was around 192mm (close to manual) and it was soft in the corners and needed full throttle for loops. No longer! I found that the 8S flies better around 202mm and I'm rarely at full throttle, except getting off the grass, which now is almost immediate. The 8S fan has plenty of punch and is much more responsive around mid throttle than the 6S. I rarely even go to full throttle doing Cuban 8's, loops or Spit S's. At that balance point, it also seems to land much easier and almost floats in, allowing me to get and keep the nose up about 10-15% on landing without worrying about stalling (which I occasionally did in the corners on landing approach). This F4, IMO is absolutely made for 8S. The battery bay is huge and using a 930gr SMC 8S HiV 5900 gives me at least 5 minutes while I still have about 1 1/2 inches that I could (but won't) move the battery back, with no lead added to the tail. The little extra weight in the fan and battery seems to make it fly even smoother.

I also got the same setup and upgraded my FW F16 and that was a very nice upgrade. Almost as nice as the F4, but not quite. This is the same fan that's in my 8S Eurofighter as well, but the F4 actually flies better IMO. Was thinking of upgrading my F18's, but they seem to fly very well on the 6S 1835Kv fan and I suspect any extra weight in that airframe would not be advisable. Heard someone put that fan in their F18 but haven't heard any update.
So I highly recommend you upgrade your F4 to the 8S instead of trying the 6S 1960Kv fan. You will not regret it. If you do, I'll always take it off your hands for a small fee!




Hugh, are causing me consternation.... 8s set up will empty my wallet.. new motor, esc and batteries..
(usual reaction for a Scotsman when money is mentioned) But, seeing how you and Aussie like the set up I suppose I have to go down that route. Keep up the good work, I have to spend a few weeks getting the garden back into some semblance of order..Have four lawns and six high Leyland hedges to cut so might be a while before I get the beast up again....but the will is back 

Best, LB
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