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Rancho San Antonio 05/31/2019 Modified FMS XF6F-6 Hellcat 1100mm
Blog Post Entry#7,
Serial Number: Aircraft#8 of the Tengarang Fleet
Type: Tail Dragger
Application: Military/Fighter
Designation/Identifier: FMS XF6F-6 Hellcat 1100mm
Nationality: USA
Motor: Eflite BL15 880KV
Propeller: FMS 10.5x8x4
Power Source: 4s 2200mah
Radio/Modulation: DX9/DSMX
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Since the Black Horse Heinkel He-111 1750mm (68.9") Wingspan model will be my first balsa model, I want to make absolutely sure there is plenty of security features in the event of any possibility of battery failure to the ESC and motor load. I will be building a supercapacitor network circuit to charge and if needed in emergency cases, discharge the high capacitance capacitor network in series by utilizing a couple of external components. The key here is to pick optimized resistance values for the charging and discharging circuitry which will be toggled by a high power automotive relay rated at 100Amps with a 12V coil voltage. It's unfortunate that there aren't any relays that accept 5V coil drive, which means I'll need to put in a 5V to 12V DC to DC step-up converter to mitigate this issue. The 5V input will be driven by the hobbyking Dr. Mad thrust UBEC with 2A output load at 5V, I will be sourcing this module with a 2s 2200mah lipo for driving the ubec driver as well as powering the receiver via the ubec itself. I chose the 2200mah 2s pack because of the high torque servos I plan on using for the ailerons and the high accuracy digital elevator servo, as well as the B-17 1875mm, retract setup. and will utilize a 4800uF cap or this one will work (bind port) to decouple the output SBEC 5V to the RX in conjunction with the Dr. Mad thrust regulated 5V out as well, in case any set of BEC's fail there are sure to be more that are going to be active to ensure a brownout will not occur.
Note: there will be two relays and two Dr. Mad thrust UBEC's which will be sourced by the single 2s 2200mah pack, the relays will need to be individually switched for the supercapacitor circuit to proper charge and discharge as I do not want the battery connected during the discharge phase, and also during normal non emergency operation, I want the capacitor to be an open circuit condition after it is fully charged at 16.2V.
Note: in place of the Dr. Mad thrust UBEC module a DR. Mad thrust On-off switch may also be incorporated in place as a substitute but this also means an external BEC such as the Castle Creations BEC 10A will be used as the main BEC module in conjunction with the integrated BECs of the ESC's
The output of the 5V driver from the Dr. mad thrust module will be the input voltage of the 5V to 12V DC to DC step-up converter which will drive an automotive relay mentioned above. I will set the driving circuit to the AUX2 for the main supply relay, and AUX3 will control the supercapacitor relay. Therefore a Lemon 10 Channel RX with Satellite will be incorporated for this operation, with an external eagle tree stabilizer.
For starters, I plan on using a 0.1 Ohm 1% tolerance resistor and a series (Capacitance is the same and voltage gets added, just like a battery) network of six 2.7V 1Farad capacitors to achieve the desired RC time constant in order to quickly charge the capacitor in about ~3.3 seconds before the flight begins. After the capacitor is done the charging, the current across the R1. With a charging characteristic of Seven, RC time constants will essentially have zero voltage drop across it which will terminate its way across R2 into the active load ESC and Brushless motor loads.
Now for the discharging part of the circuit:
If should the discharge circuit ever be needed, in case if a battery happens to be bad or if the runway is too crowded or if its too windy (and therefore multiple attempts to land is needed requiring emergency energy); an act of God determines that the battery is gonna quit and there's nothing left, beyond Low voltage cut off for the ESC's to suck on, then we will simply hit the AUX2 switch to open the battery relay, and immediately close the AUX3 switch to close the capacitor relay which by now is fully charged, via the Dr. Mad thrust unit modules to and energize the relay coil by driving 12V to it via the DC to DC step-up converter. The supercapacitor initially is at 16.2V terminated by R2 (50ohms this value will be calibrated upon experimentation) with a wide tolerance resistor which was chosen to achieve an RC time constant to reach a ~3minute discharge (theoretical at 50Ohms) characteristic. But this being an active load with variable throttle should keep enough to buy enough time to bring the aircraft down safely should a battery network give up.
I will create a debug board and simulate which R1 and R2 values will really be feasible. Because the active load is going to be variable with throttle input, it might be noteworthy to increase the value of R2 to 70ohms (or more) to reach a higher RC time constant and discharge time, but I will stick with these theoretical values to start with to see what might happen until I get a debug session going.
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That sounds... involved. What's your target weight and noise for this apparatus?Live Q&A every Tuesday and Friday at 9pm EST on my Twitch Livestream
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Originally posted by Alpha.MotionRC View PostThat sounds... involved. What's your target weight and noise for this apparatus?
If the input/signal to this circuit was a function then some filtering would have to be considered however this is more of a backup circuit "Spare very lightweight battery" .
There won't be much weight penalty but could eat up some real estate, as the power relays are 1.6oz each and there are two of them and the capacitors are less than 1/2 ounce. The significant weight would be the 2200mah 2s pack and the external Ubec's which are apart of my standard setup anyway for all of my planes that have sufficient real estate. Id say the wiring of the circuit will be some significance in terms of weight added but nothing I implement will be affecting the all up weight by too much. I'd be very surprised if more than 10 oz of weight is needed after all is accounted for.
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I've run some calculations. and determined fully booked 1000mah 4s lipo has an energy density of 16.8 Watt-hours. This should be more than enough to fully operate two 4238 750KV loaded by a 10.6x7.8x3 props. An equivalent circuit consisting of 30 super caps in a network of 500 Farads each at 2.7V will have an energy density of 15.2 Watt-hours. Which is fairly close to a 4s 1000mah pack for emergency purpose in the event of any main supply failure.....
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This will be the equivalent circuit to that of a 4s 1000mah fully charged lipo which has comparable energy density. For an emergency, in the event, the battery will fail or disconnects from the main flight.
FYI for a fully charged 4s 1000mah (C rating wont matter) has an energy density of 16.8 Watt hours
For the equivalent super cap network shown below i have calculated 15.2 watt hours.
Plenty of juice to do what needs to be done to bring her back to the runway safely.
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Since i cannot delete or revise my previous posts, I will be re-stating some updates here as I have made some modifications to the circuit. Mainly removed the charge and discharge resistors and increased the capacitor count to 36 caps to reach a 500Farad capacitance and maintain an energy density of 18.2 watt hours which is sort of equivalent to a 4s 1.1A lipo. However one must keep in mind not to treat this capacitor like a lipo and smaller fluctuations with throttle must be cautiously exercised while containing the emergency situation until the aircraft lands.
Since the Black Horse Heinkel He-111 1750mm (68.9") Wingspan model will be my first balsa model, I want to make absolutely sure there is plenty of security features in the event of any possibility of battery failure to the ESC and motor load. I will be building a supercapacitor network circuit to charge and if needed in emergency cases, discharge the high capacitance capacitor network by utilizing a couple of external components. The charging and discharging circuitry will be toggled by a high power automotive relay rated at 100Amps with a 12V coil voltage. It's unfortunate that there aren't any relays that accept 5V coil drive (for the 40Amp job), which means I'll need to put in a 5V to 12V DC to DC step-up converter to mitigate this issue. The 5V input will be driven by the hobbyking Dr. Mad thrust UBEC with 2A output load at 5V, I will be sourcing this module with a 2s 2200mah lipo for driving the ubec driver as well as powering the receiver via the ubec itself. I chose the 2200mah 2s pack because of the high torque servos I plan on using for the ailerons and the high accuracy digital elevator servo, as well as the B-17 1875mm, retract setup. and will utilize a 4800uF cap or this one will work (bind port) to decouple the output SBEC 5V to the RX in conjunction with the Dr. Mad thrust regulated 5V out as well, in case any set of BEC's fail there are sure to be more that are going to be active to ensure a brownout will not occur.
Note: there will be two relays and two Dr. Mad thrust UBEC's which will be sourced by the single 2s 2200mah pack, the relays will need to be individually switched for the supercapacitor circuit to proper charge and discharge as I do not want the battery connected during the discharge phase, and also during normal non emergency operation, I want the capacitor to be an open circuit condition after it is fully charged at 16.2V.
Note: in place of the Dr. Mad thrust UBEC module a DR. Mad thrust On-off switch may also be incorporated in place as a substitute but this also means an external BEC such as the Castle Creations BEC 10A will be used as the main BEC module in conjunction with the integrated BECs of the ESC's
The output of the 5V driver from the Dr. mad thrust module will be the input voltage of the 5V to 12V DC to DC step-up converter which will drive an automotive relay mentioned above. I will set the driving circuit to the AUX2 for the main supply relay, and AUX3 will control the supercapacitor relay. Therefore a Lemon 10 Channel RX with Satellite will be incorporated for this operation, with an external eagle tree stabilizer.
I plan on using a 14AWG gauge wire to the 500F capacitor network. After the capacitor is done the charging, I will disconnect it from the circuit during normal operation of the bomber.
As soon as the battery fails due to the will of God the discharging circuit will be engaged and the battery will be removed from the loop.
Now for the discharging part of the circuit:
If should the discharge circuit ever be needed, in case if a battery happens to be bad or if the runway is too crowded or if its too windy (and therefore multiple attempts to land is needed requiring emergency energy); an act of God determines that the battery is gonna quit and there's nothing left, beyond Low voltage cut off for the ESC's to suck on, then we will simply hit the AUX2 switch to open the battery relay, and immediately close the AUX3 switch to close the capacitor relay which by now is fully charged, via the Dr. Mad thrust unit modules to and energize the relay coil by driving 12V to it via the DC to DC step-up converter. The supercapacitor initially is at 16.2V terminated by the esc and motor load. But this being an active load with variable throttle should keep enough to buy enough time to bring the aircraft down safely should a battery network give up.
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Looks like The Lightburner has come out with some new innovations Exclusive to The Lightburner. Safety features are added and the
Prices are very competitive and customization possible upon request.
I may end up getting the FW F-22 just to try out one of these new 90mm releases, Dual LED afterburner specifically designed for all dual tailpipe 80-90mm EDF models
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Took the Maule up at RSA she flew great with the new 4 blade 10.5x8x4 setup.
Video can be viewed from my Pinterest link below
https://www.pinterest.com/pin/580542208198003248/
Serial Number: Aircraft#31 of the Tengarang Fleet
Type: Tail Dragger
Application: Civilian
Designation/Identifier: Horizon Hobby E-Flite Maule M-7
Nationality: USA
Motor: Eflite BL15 850KV measured
Propeller: FMS 10.5x8x4
Power Source: 4s 3300mah
Radio/Modulation: DX9/DSMX/AS3X
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