Brushless Motor not Reaching Max RPM
 

Hello,
I just built an rc aircraft out of cardboard and I have used all the electronic components from a larger model I crashed, the problem is that it seems like the motor(Sunnysky 3120) is not giving it's full power and the aircraft barely moves on the ground. I am using a 4cell lipo battery with an ESC that came with the other model(FW190 from hobbyking) and amde sure the Throttle was calibrated with the ESC. I have tried a smaller motor I once bought and that one makes the aircraft roll faster but still, not enough thrust to make it airborne.

Any suggestions on what I am doing wrong? What I might be missing?


PS: I can't add any picture of the model yet as the forum doesn't allow me

Wow , so many issues here ... First and foremost , are you SURE the parts your reusing from the crashed model are any good ? I won't go into all the ways crashes can damage things like electric motors and speed controllers since no one here wants to read a 12 page report , but it's something to be strongly considered . Then we have to look at things like weight , was the HK FW190 made of lightweight foam and how much did it weigh (flying weight) VS your cardboard creation ? If your plane is any much more than a little bit overweight compared to the FW190 the excess bloat is likely keeping it grounded . Next we move onto the propeller , presuming the other electrical/mechanical stuff is good , the one that came with the FW190 was likely destroyed in the crash , yes ? If so , what propeller are you using to replace it ? And this is all without getting into things like airfoils and such , since you say it won't move fast enough to get airborne could perhaps a lack of good wing design be wasting any forward speed your creating ? (as in , could it be that the rolling speed isn't as much the limiting factor as the design of the airframe is , since you say a different motor got it rolling faster with still no takeoff ?) .