Episode 2: FAA Regulations, Seriously?!?

[djentangle]

Episode 2 FAA Regulations, Seriously?!?

On this episode we talk about what we've been up to in the last week, our Christmas wish list, and the main topic: FAA Regulations!

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Links:
- Kevin's FT Viggen landing gear article on flitetest.com http://flitetest.com/articles/ft-viggen-landing-gear

To get in touch with us:
Email us at freefallrc@gmail.com
Facebook page - https://www.facebook.com/freefallrcpodcast/

Podcast on iTunes
https://itunes.apple.com/us/podcast/freefall-rc-podcast/id1069759999

See you next time...

 

[bitogre]

Was listening to this Podcast and heard your question with regards to higher voltage and EMF. Voltage has no direct impact on the ElectroMagnetic Field. It is current that directly effect EMF. The higher the current, the more EMF generated. In fact, Hall Effect current sensors use the EMF to measure the current without the use of a shunt resistor allowing it to be more efficient in measuring the current.

 

[djentangle]

Was listening to this Podcast and heard your question with regards to higher voltage and EMF. Voltage has no direct impact on the ElectroMagnetic Field. It is current that directly effect EMF. The higher the current, the more EMF generated. In fact, Hall Effect current sensors use the EMF to measure the current without the use of a shunt resistor allowing it to be more efficient in measuring the current.

Thanks for the knowledge. That makes sense. Would you think servo wires (not sure what gauge) with say 6-8amps would be considered high EMF?

 

[bitogre]

Thanks for the knowledge. That makes sense. Would you think servo wires (not sure what gauge) with say 6-8amps would be considered high EMF?

When you are talking EMF, thing get very complex very quickly as there are many factors. And I am no expert in this area but I do understand the basics.

High EMF is all relative. I often fly planes and Quads with ESCs that are rated for 12-30 amps which is significantly higher than your 6-8 amps. Distance also plays into EMF. Double the distance and the EMF drops by quarter. Also, what current are the other wires near by carrying. EMF fields of the two power wires on the battery/ESC/servo can cancel each other out (especially at distance) as the current is flowing in opposite parallel directions which causes opposing fields.

Generally, on RC aircraft, you are most concerned with EMF at motors or in very close proximity to the ESCs. The motors are designed to create magnetic field that interact with permanent magnets in the motors. They sometimes do not bother to contain those fields leading to EMF outside the motor.

Not sure what you are trying to get at. My response was not trying to address all the issues surrounding EMF but address the question in the podcast on whether or not the EMF was related to voltage. Answer: No, it is related to current. I might be of more help if you are more specific and I do not remember all the details being discussed in the podcast so please repeat and relevant details here if you want more information.

One final thought, 6amps is a lot for a servo. 9g servos used on most Flite Test planes usually have a draw of a few milliamps when not under load to about 0.75 amps under load. If a 9g servo is pulling anywhere close to 6 amps, it is bad and in the process of destroying itself. It is rare for standard servos to even get to half that current. So, for a servo to need that much current, it must be very big. Maybe a servo on a 1/4 scale plane might be big enough to need that much current.

 

[djentangle]

When you are talking EMF, thing get very complex very quickly as there are many factors. And I am no expert in this area but I do understand the basics.

High EMF is all relative. I often fly planes and Quads with ESCs that are rated for 12-30 amps which is significantly higher than your 6-8 amps. Distance also plays into EMF. Double the distance and the EMF drops by quarter. Also, what current are the other wires near by carrying. EMF fields of the two power wires on the battery/ESC/servo can cancel each other out (especially at distance) as the current is flowing in opposite parallel directions which causes opposing fields.

Generally, on RC aircraft, you are most concerned with EMF at motors or in very close proximity to the ESCs. The motors are designed to create magnetic field that interact with permanent magnets in the motors. They sometimes do not bother to contain those fields leading to EMF outside the motor.

Not sure what you are trying to get at. My response was not trying to address all the issues surrounding EMF but address the question in the podcast on whether or not the EMF was related to voltage. Answer: No, it is related to current. I might be of more help if you are more specific and I do not remember all the details being discussed in the podcast so please repeat and relevant details here if you want more information.

One final thought, 6amps is a lot for a servo. 9g servos used on most Flite Test planes usually have a draw of a few milliamps when not under load to about 0.75 amps under load. If a 9g servo is pulling anywhere close to 6 amps, it is bad and in the process of destroying itself. It is rare for standard servos to even get to half that current. So, for a servo to need that much current, it must be very big. Maybe a servo on a 1/4 scale plane might be big enough to need that much current.

Thanks so much for digging deeper and explaining this further for me. The servos I use on my bigger helis are full size all metal gear, metal housing, HV servos with the ability to run 8.4v with high amp draw when they're put with heavy use. My BEC is programmed to push out up to 20amps for the servo and radio system but I doubt I get anywhere near that. I know with this setup, it's very common to see 8-10amp draw which calls for a BEC that's over 10amp.

It's definitely a bit different hardware with these 3D helis compared to FT aircrafts, but I think what caused my issues is more with improper wiring the BEC to the Flight Controller then EMF. This stuff is very interesting and it seems to be something that's not often talked about in the FT community so I'm glad you were able to help me get some insight on this topic.

Thank you so much and Thanks for Listening