[NSRCA-discussion] Lost Abbra

[Jay Marshall]

Vincent, try to move the remaining good servos slowly. I have had one which
shorted the battery, and therefore the other servos, at only one position. I
was lucky and managed to get it back.
 
-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
vicenterc at comcast.net
Sent: Sunday, August 06, 2006 7:52 PM
To: nsrca-discussion at lists.nsrca.org
Subject: [NSRCA-discussion] Lost Abbra
 
Yes, yesterday afternoon I lost my Abbra.  I was doing the 45 degree down
with snap.  After the snap, I could not control the plane.  This is my
recollection of events:
 
1. I over rotated the snap for a kittle more than 90 degrees.  It was clear
to me at that early stage that something was going wrong.  I snapped to the
right.  
2. My friend Charlie was calling for me.  He also noticed and said something
to put it back in position.  I told him that the plane was not responding.  
3. First reaction was to give full left to get it back upright.  The
ailerons did not respond.  When I realized that, I tried to take it out of
the dive by given down elevator since was pracically in inverted position.
It did not respond.  It that aptitude everything goes very fast.  Finally, I
tried to give up elevator but was already too late.  I am aware that I
applied these control input.  It was clear to me that there was no reaction.
I was able to realize that I didn't have control and I could not avoid the
crash.  
4. I did not have time to do anything with rudder and throttle.  Throttle
was at idle.  
5. When we checked the crash site. One aileron servo was buzzing hard.  I
disconnected the servo.  Therefore, my first impression that the battery
flew off and it got disconnected with the force of the snap was not valid.
6. I took the plane home as it came from the crash.  I disconnected only the
ailerons servos.  I checked the radio and everything is working fine.  Only
two servos are not working.  The throttle servo that was practically
destroyed in the crash and one aileron servo that the gears were stripped.
I believe that this was caused by the force of the impact.  There was not
evidence of flutter in the ailerons before the crash or structural damage
after coming out of the snap.
7.  I believe that the plane was well over stall speed after the snap.
Therefore, the plane was not in stalled condition.  However, I could be
wrong.
7. I use JR all around with digital servos.  PCM receiver with fail safe
programmed to cut engine and leave the servos in the last commanded
position.  
8. I use 2300 mah NiMh battery (4 cells AA Sanyo).  I checked the battery
voltage and was at 5.15 volts after the crash.  Discharged the battery and
gave 1540 mah using 250mah rate.  I am planning to cycle the battery with
higher loads.  
9. It was very hot day.  The plane was sitting in the sun and it was second
fly of the day around 2:00 PM.  Easily was close to 100 oF. 
 
At this point, I have to admit that has to be pilot error since I have not
been able to find a definitive cause of the crash.  It is clear that the
snap initiated some kind of failure.  Other pilots think that the NiMh
battery gave up at high currents during the snap and caused the crash.  I
have been flying this type of battery for two years now with no problems. 
 
I am informing this to the group since I would like to have your feedback.
If someone had a similar problem and found the cause of the crash, please
let me know.  I am going back to my backup plane (the old hydeout).  I have
a brand new Abbra so need to put it together.   
 
Thanks and have a nice day,
 
Vicente Bortone
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