There are several schools of thought on which tail to use. Basically the short story is the stock motor is inadequate, and it's personal preference between the DD and the dual tail. It all depends on what you are looking for. For fun flying and peice of mind with redundancy I would say the dual tail. For hard 3d I would probably say the DD because that's what the "pro's" seem to be going with. If that's a simple enough and to the point enough explination for you to decide... just stop there =P Otherwise you can read the lengthy part for more info. Just whatever you choose IMPO it's a good idea to heatsink it and fuse it =)

I have read several forums about this because I am trying to decide also. Several of the really pro fliers like nick maxwell use the DD, so there has got to be good weight to power ratio, and good areobatic flight qualities. If you haven't seen it yet, watch this video
http://www.youtube.com/watch?v=lNQeDYpWvEI

SSG Scott over on RC Groups is a military chopper mechanic with 27 years experience, and he has done alot of testing. In short what he has come up with is that the DD setup on average lasts about 2x the regular motor, and the twin tail lasts much longer than either of them because it keeps the motors much cooler (even with heatsinks), which is the main factor for failure. From his estimates the order from the least tail authority to the most is stock motor, dd, and twin tail. The other benifit to the twin tail is redundancy. When you wire the motors up, you do it in parallel (cautions to be explained later), so that when one motor burns out, the other one keeps running, which allows you to land and replace the worn motors. Both the DD and the stock motors will have you doing crazy piro's if you don't catch them going out before you fly. There are also brushless tails, but I am unsure of the exact weight on them, and those if properly taken care of rarely if ever go out.

Either way if you upgrade the tail, you will want to do the fuse mod. I have a pic of the mod I did a couple of posts earlier. This is the short and simple version

And this is the explination why
Basically the explination for this is that the power mosfets on the esc for the tail are rated at something like 6A surge. The main esc has two mosfets and is rated at 12A surge. The normal tail motor draws about 1A continuous at full power, and averages probably around 500mA. The problem is when you crash if the tail gets bound up, the motor goes into a full short current. The stock motor is about 1.7 ohm at 11.1v for a 3s lipo which works out to be 6.5A when the motor is stalled. This part of the reason why many people have fried their 4 in 1's. I'm not sure what the cn12's (gws's DD) resistance is, but it is most likely less than 1.7 ohms which would increase the amperage, so it would be a good idea to fuse that motor too. When it comes to the dual tail, I would say it is a big risk of frying your 4 in 1 if you don't fuse it, because each motor can draw 6.5A in a stall which is 7A over what the tail esc mosfet is rated for, however this logic does not apply for running amperage. Running amps measured on the dual tail motor system run the same as the single motor, or slightly less because the dual tail system puts the motors in a more efficient power curve.

SSG Scott took some nice measurements and found that either the DD setup or the twin tail add 9 to 11 grams. By his estimate, on average, the dual tail setup was slightly lighter (like 1g, but not really something significant). I'm not sure on that weight measurement if he used his custom plastic dual tail mod or if he used a CNC holder. For the DD he used the standard GWS parts.

All in all they basically weigh the same, and either one will get you better tail performance. I would definately go with a fuse, because it's cheap and easy to replace a fuse, and more expensive to replace a 3 in 1. I would also make sure to atleast single heatsink each motor, if not double. If you like redundancy I would go with the dual tail, and if you want to follow nick maxwell and others for hard 3d flying, then I would stick with their decision and go with the DD.

Hope that clears something up without being too terribly long =P (OK, so I know it's long =P, gota work on shorter posts =)

mrasmm

Also see http://www.rcuniverse.com/forum/m_55...tm.htm#5534073