The Thrilling Fried Chicken in the Queen's Flying Field Tracing the Roots

1. Origin

There are many reasons for this fried chicken, but the end result is similar.

If the root cause can be found well, relatively speaking, the probability of fried chicken will be greatly reduced in the future.

This article focuses on combining several fried chickens that the author has encountered to sort out the root cause.

ArduPilot Mark4 H743 BIM270 Royal Fried Chicken

2. Analysis

Analysis of possible reasons for fried chicken:

1. Firmware version issue

Due to the BUG problem of the firmware itself, the stability is abnormal, which leads to fried chicken.
Generally speaking, using a stable firmware version, it should not be a big problem.

2. software configuration problem

Because the firmware needs to run correctly, different configurations are required, such as: PID, filter, rack, etc.
If the above software configuration is incorrect, it will also bring fried chicken.

3. hardware failure problem

Hardware failures are more complicated, such as: chip failures lead to abnormal data; wiring failures cause signal or sensor data to fail to transmit, etc.

4. human manipulation problem

No matter how good the aircraft model is, if the controller makes a mistake, fried chicken is inevitable.

This fried chicken, in the case of the simple elimination method, the whole understanding process is like this.

1. ArduPilot 4.3.7 stable version, rule out firmware version issues
2. The aircraft can fly normally, and the problem of configuration error is ruled out
3. Simple Pitch-Flip operation is not a complicated operation. From the perspective of video and control experience, it should not be a problem of human operation

Based on the above troubleshooting methods, the final problem seems to be mainly [hardware failure]. After frying the chicken, turn on the power again, and there is no obvious abnormality in normal flight. Eliminate wiring, chip failure and other problems.
From previous experience, it seems that whether the blade is slipping or not can not be ruled out immediately. But before take-off, after all, it has been confirmed twice (confirmation method: swing the propeller by hand to see if it is slipping, and if it slips, lock it again).

3. Evidence

All doubts must be proved by evidence. The lack of a chain of evidence will undoubtedly lead to rootcause relying on speculation instead of actual proof, leading to the recurrence of the same problem in the future.

The paddle is fixed by a locknut and fixed by a "barb" on the motor shaft.

Historical blade usage:

1. DALPROP T5046C 5 inch three blade propeller

1. The first set of paddles has been used for a long time;
2. Two of the propellers have been damaged for various reasons;

2. Broken TMOTOR T5146 5-inch three-blade propeller

1. The second set of propellers was also damaged to varying degrees;
2. According to the actual review, after the second set of paddles are used, the probability of frying chicken increases;

3. Qianfeng GEMFAN 51466 5.1-inch three-bladed propeller

1. The third set of paddles used;
2. The number of times of use is less, and it is only used when verifying the second sound of the "monster" of BetaFlight Mark4 and the sound of "monster" of BetaFlight Mark4 ;

The above three sets of propellers, each propeller and the motor bite are similar. The engagement between the motor and the paddle is fixed through the "barb" engagement, and no slippage occurs.

The damage to this part of the three sets of blades is very obvious:

Slipping degree: Pofeng TMOTOR T5146 > DALPROP T5046C > Qianfeng GEMFAN 51466
Pofeng TMOTOR T5146 The fixed position of the "barb" is not just a mark, but a slideway has appeared.
Once the slideway exists, even if the nut is pressed tightly, if the force is greater than the frictional resistance, slippage will occur. And if it is a "barb" mark, it is not frictional resistance, but stuck like a "gear", and it can withstand greater force at this time.

Based on the above situation, we can clearly know that when making larger flight movements, when the torque of the blade rotation increases, due to the "barb" slipping, the frictional resistance cannot resist the torque, resulting in slipping.

4. Summary

According to the above analysis and the chain of evidence, it is a situation that cannot be ignored due to the slippage of the paddle. Even if the tightening is manually confirmed, the propellers are subjected to a very large force during high-speed rotating flight, and it is possible to shoot the propellers, not to mention slipping.

Therefore, in terms of propeller blades, please take seriously the following situations and recommend replacing them to ensure safe flight.

1. Bumps cause defects;
2. External stress deformation;
3. Slippage "track" marks in the bite

5. Supplement: BetaFlight Mark4 + self-locking nut blade loosening + instant frying

BetaFlight Mark4 + Self-locking nuts and propellers are loose + instant frying