EDF speed and throttle issue

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Flying_Fast74

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I have made foam board RC F-18 super hornet following Ben Harber's plans. I am using parts listed below. The issue I have is - After connecting the battery, when I increase the throttle on transmitter, the edfs speed up and reach to only about 80% max speed before max throttle position and then slow down to 30-40% of max speed when I shift to max throttle position. If I were to immidietly push the throttle to max speed instead of gradually, the EDFs will go to max speed, but stay at that speed only for a few seconds and then slow down to about 30-40% of max speed. In each subsequent tests with the battery still connected, the EDFs reach their highest speed about 10-20% slower than the time before. E.g. if I reconnect the battery and EDFs go to 80% max speed before slowing down to around 40%, then the next tests it will reach only upto 45% max speed, and then slow down to 30% of max speed, so on and so forth. Once the speed dips to or below that 30-40% mark, the speed remains constant irrespective of the throttle position. My battery is fully charged (though, I would welcome suggestion of a battery level tester). I want to make sure the edf speed gradually increases and reaches the highest at the full throttle position in repeated tests. I have used one ESC for each EDF. Both of my ESCs are connected to one battery, and are calibrated as well.

Connected parts list:
1) TWO Powerfun EDF 50mm 11 Blades Ducted Fan with RC Brushless Motor 4300KV (Balance Tested for EDF 4S RC Jet Airplane).
2) TWO ZTW Beatles Series 50A 60A Brushless ESC with BEC for RC Airplane 4S 6S (Beatles 60A ESC with Connector)
3) 3.5mm Banana Gold Bullet Connector Extension Cable for RC Brushless Motor ESC Extension Cable Wire (16AWG 30CM).
4) Flysky FS-i6 radio transmitter and FS-iA10B 4.0-6.5V/DC 2.4GHz 10 channel receiver.
5) OVONIC AIR 3000 50c mAh battery. 11.1V (Main Battery for ESCs)
6) ONE Blomiky 8.14Wh 7.4V 1100mAh 35C Li-ion-Po Battery with JST Plug (For External BEC)
7) BW RC Servo BEC UBEC 3A 5V Airplane Receiver Servo Power Supply
8) Onkuey T Plug Male to 2 T Plug Female Parallel Battery Connector Cable (120mm)
 
It looks like there isn't enough voltage for these ESCs. They require at least 4s for the ESCs and the 3s doesn't put out enough voltage (11.1 V for the 3s nominal vs. 14.8 V for the 4s pack). I would suggest running at least a 4s pack and using a BEC (Battery Eliminator Circuit) to power the RX and servos and not use the small 2s pack to save a bit of weight.
 
I'm with hamz 3 cell is your issue. id go with 4 cell and a ubec ran off the 4 cell
 
It looks like there isn't enough voltage for these ESCs. They require at least 4s for the ESCs and the 3s doesn't put out enough voltage (11.1 V for the 3s nominal vs. 14.8 V for the 4s pack). I would suggest running at least a 4s pack and using a BEC (Battery Eliminator Circuit) to power the RX and servos and not use the small 2s pack to save a bit of weight.
I'm using a separate BEC (standalone BEC) connected to the 2s battery to power the servos, but I will try using a 4s battery to power both ESCs. I'm using two SBECs, so I had disconnected the red wire from both of them. When I would connect the red wire for one of them, the EDF with the ESC that has the red wire connected spins faster, but it might be because the battery wouldn't be able to handle the current pull.
 
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