Hai-Lee
Old and Bold RC PILOT
Recently I have been doing a lot of crash repairs of aircraft who are otherwise destined to end up in landfill. Whilst many crashed for known reasons there was a small number which were claimed to be as the result of a loss of signal. As it always seemed to be the same aircraft and not the same radio system that suffered from the fatal landings I started to question the whole idea of the validity of the "Interference" claims.
As I test fly the planes after repair I soon got an idea that the radio spectrum was nothing but a scapegoat in most cases. My last test flight program lead me to a conclusion which could have serious ramifications in our hobby/sport. That revelation is that the ESC is normally the culprit or more exactly the BED included in the ESC which is cutting power to the receiver in flight.
How I came to that conclusion was during a post repair test flight of a Durafly P40 which had 4 flights before it crashed yet again and in the exact same manner as it had crashed previously. A little history of the model shows that it was a later production version which had NEVER had a good history. Whilst other versions, (earlier), had flown quite well and without crashing for many flights this particular model never flew without a loss of control. The loss of control almost always occurred at the end of the flight when the flaps and retracts were deployed. At this point the plane would slowly roll left and head for the ground ignoring all stick movements to correct.
Anyway, after I crashed it on its 4th test flight, (post repair), I noted that it was when I deployed flaps in a bank turn that control was lost. BACK to the workbench for repair! This time I did a few measurements on the current drawn from the BEC and how this current capacity is affected by the ESC temperature from running the motor as in a flight situation. Well I found that the BEC could supply plenty of current for operating all of the controls at the same time whilst at room temperature but when the ESC was hot the BEC would shutdown when I tried to operate all control surfaces and the flaps at the same time. BINGO! or should I say Eureka!
It appears that there was a batch difference in ESCs between early versions and later versions of the same model or could it be that the manufacturer changed ESC manufacturers during the model's production? So for my next test flight I will be adding a second BEC to operate the flaps and retracts separate from the motor ESC!
Just thought I would post my findings as it might save someone else from replacing radio gear which is not faulty and keeping a temperature sensitive ESC which will crash their plane again in the future. Please note: The cooling of an ESC can help but a crashed ESC can become temperature sensitive if the heatsink bond is upset during the crash!
Have fun and fly safe!
As I test fly the planes after repair I soon got an idea that the radio spectrum was nothing but a scapegoat in most cases. My last test flight program lead me to a conclusion which could have serious ramifications in our hobby/sport. That revelation is that the ESC is normally the culprit or more exactly the BED included in the ESC which is cutting power to the receiver in flight.
How I came to that conclusion was during a post repair test flight of a Durafly P40 which had 4 flights before it crashed yet again and in the exact same manner as it had crashed previously. A little history of the model shows that it was a later production version which had NEVER had a good history. Whilst other versions, (earlier), had flown quite well and without crashing for many flights this particular model never flew without a loss of control. The loss of control almost always occurred at the end of the flight when the flaps and retracts were deployed. At this point the plane would slowly roll left and head for the ground ignoring all stick movements to correct.
Anyway, after I crashed it on its 4th test flight, (post repair), I noted that it was when I deployed flaps in a bank turn that control was lost. BACK to the workbench for repair! This time I did a few measurements on the current drawn from the BEC and how this current capacity is affected by the ESC temperature from running the motor as in a flight situation. Well I found that the BEC could supply plenty of current for operating all of the controls at the same time whilst at room temperature but when the ESC was hot the BEC would shutdown when I tried to operate all control surfaces and the flaps at the same time. BINGO! or should I say Eureka!
It appears that there was a batch difference in ESCs between early versions and later versions of the same model or could it be that the manufacturer changed ESC manufacturers during the model's production? So for my next test flight I will be adding a second BEC to operate the flaps and retracts separate from the motor ESC!
Just thought I would post my findings as it might save someone else from replacing radio gear which is not faulty and keeping a temperature sensitive ESC which will crash their plane again in the future. Please note: The cooling of an ESC can help but a crashed ESC can become temperature sensitive if the heatsink bond is upset during the crash!
Have fun and fly safe!
