Erwin XL medium elektro

Mikko

User
I am helping a friend to finish his new Erwin XL medium elektro version.

PCM at is confirming in a mail that correct CG is located at 100 millimeters.

1) I've always seen the ballast tube located on the CG and not forward as in this case. If i add ballast the CG changes, or ?

2) is it possible that with motor, Esc and 3S Lipo to match the CG indicated by PCM hw has to add 140 grams near the motor in the nose?

Both these points seems to me not clear. point 1) is probably my lack of knowledge and point 2) ??

There is also NO space to add such an amount of weight in the motor area, fuselage is very thin !

Help me to understand and ...my friend to enjoy his new model.
(photo of the wing with ballast tube in the left -steel bar- and wing joiner tube in the right - carbon rod)

Thanks
 

Anhänge

  • Erwin XL .png
    Erwin XL .png
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Hi,

what motor and what batteries do you use? With a Kontronik 480 Motor and a 3s1600mAh from SLS i was able to get the CG at 100mm without additional ballast in the nose.

You are right, putting ballast in the ballast tube changes the CG, but this change is very limited. If needed you can compensate this with a extra trim of the elevator, or by butting some duck tape an the end of the fuselage or you can gently ignore this change (That is what im doing ;-) ).

Best regards
Peter
 

Mikko

User
Set up Erwin XL elektro

Set up Erwin XL elektro

Peter
thanks for your answer.

Motor Poly-Tec 480-23XL mit 4,4:1 Getriebe weight 220 grams, ESC Poly-Tec Control 70-18 Pro weight 60 grams, Lipo Hacker TopFuel Power-X 2400-3S 206 grams.

I don't think it's a very light set up, I suppose is more or less same as yours.

Servo in the rudder are grappler DES427 weight 9 grams each ......

But 140 grams to find CG at 100 millimeters seems a lot, as fuselage is too short........or too long in the back !
 
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