[NSRCA-discussion] Serious Torque on the Nose of the Model - RESUBMITTED

[Charlie Barrera]

I torqued the nose off of the fuselage of my WindS Pro. I have a 2 meter
WindS Pro which I recently acquired from a good friend. The model is
probably 2 years old and has close to 200 flights. The model had a contra
rotating propeller power system installed before I acquired it. The nose
section had been modified to accommodate zero degree down thrust and zero
degree right thrust. I installed a new Hacker Q80 motor on the nose,
attaching it to the nose ring. I did not reinforce the rear of the motor to
the fuselage. I re-modified it for 2 1/2 degree right thrust and 1 degree
down thrust.  I reinforced it amply and was confident in the installation.

 

I made a normal takeoff at about half throttle. As I turned to a right
downwind, I powered up to about 3/4 throttle for my usual trim pass. I was
in a right bank, and was rolling to the right. I heard a very loud "whack"
noise. I continued my turn and only then did I realize that something had
changed. I managed to land the model, not realizing that I had lost the
motor. It was difficult landing because of the resultant aft CG. The
fuselage was missing the first 4 inches.  It was also very apparent that
torque had sheared the motor off the fuselage.  I theorize that the
combination of the right roll and the power up caused a gyroscopic effect on
the model, shearing the nose off the model.

 

I wanted to share this to possibly alert others to a nose ring installation
of their high power motors. Be aware of the forces that can be produced by
these high torque motors. I don't know whether providing a rear brace on the
installation would have made a difference. I don't think so. The fuselage
was "torn" well behind where the rear brace would have been.

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.nsrca.org/pipermail/nsrca-discussion/attachments/20121204/a0fe64fb/attachment.html>