Crash new electro glider 3,2 meter span (10,5 ft)

Dec 18, 2003 2 Replies
F

This is my first post in this group.


Yesterday I crashed a brandnew "Last Down XXL" Electro glider : Total loss of control.



The plane has 2 aileron mini servos, 2 flaps mini servo's, 1 servo for height and 1 for left-right. Electro motor was a brushles Phasor 30/3. Specs as follows :



Maße: 36x52 mm, 220 gr, 7-8 Zellen, 3 Turns, 1200 UpV, max Drehzahl: 11520 UpM, 0,034 Ohm, Motordurchm.: 36x52 mm, Wellendurchm.: 5 mm, empf. Propeller bei 8 Zellen: 10x6 - 11x6, empf. Propeller bei 10 Zellen: 9x7 - 10x6, Stromverbr.: 26-35 Ampere, empf. Brushlessregler: Jes 40-3P BEC, Brushless-Regler ohne BEC: Jes 40-3P OPTO, Gewicht des empf. Reglers: 28 g, Maße d. empf. Reglers: 52x27x10 mm



I used 10 cells NIMH 3,3 A and the brushless regler Jes 40-3P BEC. Specs as follows : E-Regler für brushless Motoren, 6-12 Zellen, 40 A, 52x27x10 mm, BEC.



Is it correct that it is a bad combination while using 6 servos's and BEC together ? I heard that 6 servo's is too much when using BEC: the BEC circuit becomes too hot and the 5 Volt can disappear ? Is it a better option to use Opto-coupler and an extra receiver battery for this situation ?



Thanks



Felicien


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D

In a word, YES. Here is the wording on Hobby Lobby's site, regarding the Jes 40-3P....

JES 40-3P: 2 x 1 x .4", 1 oz., for current to 40 Amps, 6 to 12 cells, and BEC sufficient for 4 or 5 servos.

Notice that it says "4 or 5 servos". You were over the servo count, especially at 10 cells. The BEC is current AND heat limited - pull too much current and the regulator IC limits, causing the voltage to drop off, overheat it and it will SHUT OFF COMPLETELY to protect itself !

With 6 cells, 5 servos is possible - with 12 cells, 4 servos would be ' iffy '. I would not do it.

Now, check this out....

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Lastly, the easiest thing to do is use a separate radio system battery

- it adds a few more grams weight, but it is more reliable and safer.

David

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T

Could have been your problem yes.

A better solution than sperate reciever pack (no need to opto ESC -

just cut teh red wire from teh ESC to receiver) is to use a

UBEC or SBEC from the motor pack. Thse are seperate high

current regulators of the switching sort.

seee

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for SBEC pricing. I can't remember who does UBEC.

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