There are advantages and disadvantages to use grub screw on a motor. When using grub screw, the CNC shaft hole will be usually larger for people to change the shaft. However, the grub screw may loose during flight so the shaft will then loose out easily. For the motor without grub screw, factory will usually make the hole (shaft housing) smaller so that the shaft will be stuck inside the hole. But after a period of time, the shaft may loose too. So either way the shaft will loose but usually after crash.
Either method, you need to check and maintain the motor just like you do with your car.
Motor is just like a car wheel which maintenance (check-up) is required for safety reason. It makes sense because the Car Dealer won't monitor your usage and condition remotely. For motor with and without Grub Screw, you should check whether both the shaft and grub screw are loose or not. If either is loose, then you should apply some Loctite Glue on it.
For motor without Grub Screw, you can pull the bell hard after installing a propeller, you can easily make a force of over 5KG, if the motor is not loose, then it will be OK for flight because the propeller usually can make a force (thrust) at about 1-2kg at most. So if the bell is not loose when you pull it hard, then it should not be flying off during flight too.
If you apply more Loctite, the shaft/screw will be suck inside so that you are hard to remove it. However, the reverse happens. If you apply less glue, the shaft/screw will loose out easier but it is more easy to remove the shaft/screw. So you can only win one side of a coin and cannot win both sides. We do not have such a magical motor if you are after a motor with no maintenance is required.
There are two types of USB Cables:
- USB Charge Only Cable
- Data Charge Cable
USB charge-only cables are not different than traditional USB cables in terms of appearance, they both look same. A faulty data cable may charge but will not establish a data connection between the device and computer.
So you need to make sure the USB cable you are using is Quality Data Charge Cable. If you have a problem with the USB, you try the followings:
- Use a different USB Data Cable
- Use a different computer with different Operation System (if you have a problem with Win8, then you better try Win7 because Win7 is somehow better than Win8 as we experienced)
- Look into the Device Manager section of your computer to see if all hardware devices are working properly. This is important because you have no way to use the device if your computer hardware cannot recognize it.
Further observed, when a data connection is established a Windows based computer may generate a USB connection sound which may not be heard if the cable used is a charge only cable since no data connection is being established.
The strength of the signal depends on many factors
- if the area you are testing have some influence on signal eg. Other strong magnetic field and radio frequency, as well as blocks (eg. Wall, Steel, Tree, House).
- antenna looks similar but it is hard to distinguish the quality of the law material used. Using a quality antenna may increase the strength.
- It is better to use the same brand for both RX and TX. Although you may use different brands for both but it is not a good idea thought.
- You need try each different channel because different channel may have different strength.
Since MultiRotor is getting very popular in recent years. Lots of people choose to build the Multirotor Helicopter on their own (DIY) instead of buying a RTF (Ready to Fly) package. Since we also build BNF/RTF Multicopters using the same FC daily so we definitely know whether there is a problem with a batch of FC. If a batch of goods has problem, we will simply return back to the factory to exchange at no cost to us, why do we bother to send you a factory defective product? It does not make sense because we know you will come back to complain.
So the problem comes when people who are stuck during Flight Controller ("FC") configuration if they are not familiar with the FC. These are common ("FC") problems:
- USB Data Cable
- Flashing CC3D Firmware
- During flashing the CC3D firmware (it is in the first stage of setting up the CC3D), the OpenPilot CGS may keep telling you that are unable to communicate with the CC3D so unable to flash the firmware. For this case, you need to retry (re-plug the USB and re-flash the firmware again) until it works (it may need many times of try). Do not ask us why because we do not know. This is very common to CC3D.
- Flashing KK 2.1/2.1.5 firmware
- Hardware Defection & Driver Issue
- It is related to issues of computer hardware and operating system. You should seek assistance from a computer professional if you do not know how to confirm whether you have these problems. This is one of the common problem.
- In common case (eg Win 7). There is a Device Manager which you can see a list of hardware devices installed on the motherboard. This should be the first thing you need to check because if the USB is not working properly (eg. no software driver found) then you will normally see an "exclamation mark" next to that hardware.