The most likely cause is a bad battery.I have a Sainsmart Jr mini DIY drone kit. It has 4 rotors and they all spin but the drone simply does not take off. Any suggestions appreciated.
Title correctedSorry for the typo- should be Sainsmart not Sinsmart
Hoe do you know that the batteries are good? There is obviously not enough power there to become airborne. Have you measured them under load?It is new, batteries good as the 4 rotors really turn at full speed, but does not take off.
Anyone know where I can get spare propellers? Buying a new drone too costly.As suggested somewhere above, check you propellers
https://dronesgator.com/how-do-drone-propellers-work/
Edit: re reading, I found it
View attachment 271945
/Edit
Every drone is different and uses different propellers.Anyone know where I can get spare propellers? Buying a new drone too costly.