[NSRCA-discussion] Lost Abbra Battery
White, Chris
chris at ssd.fsi.com
Mon Aug 7 09:05:48 AKDT 2006
Hi Vince,
I had a battery pack come loose from mounting back in May on an upline.
I lost control of the airplane and finally got the power off and the
airplane level. I did a 180 degree gliding turn to a landing. After
touchdown, I had full battery power, good range check, good engine
running range check. I pulled the canopy, finding the battery
dangling. I then hooked up the tester and tested while shaking the lead
which revealed an intermittent connection. Are you sure you don't have
an intermittent plug connection???
Chris White
________________________________
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
vicenterc at comcast.net
Sent: Monday, August 07, 2006 11:49 AM
To: NSRCA Mailing List; NSRCA Mailing List; NSRCA Mailing List
Cc: gld-sad at hughes.com
Subject: Re: [NSRCA-discussion] Lost Abbra Battery
Pat,
Initially, I believed that the force of the snap disconnected the power
from the receiver because the battery became loose inside the plane.
However, at the crash site the servos had power and I had to turn the
switch off to avoid possible smoke. I just was confused after the
shock. At home, I realized that all connections between the battery and
switches and receiver and servos were intact (I secure all plugs wiht
fishing line). The only loose plug was the throttle servo that was
destroy in the crash. I was confused by that loose plug. Actually, I
just turned the TX and RX on and the system came alive without
disturbing any connection. Only I unplugged the aileron servos to carry
the mess.
I agree, it is going to be difficult to find the cause. Thanks,
Vicente "Vince" Bortone
-------------- Original message --------------
From: "Pat Hewitt" <phewitt at farmersagent.com>
> I am sure we had a battery problem BUT it was not to loss of
power BUT I think
> it departed from its hold down and pulled the switch wire
lose. Remember you
> questioned your material a couple weeks ago and thought of
chainging how you
> had it. THE ONE THING WE KNOW IS WE WILL NEVER KNOW THE CAUSE.
You have a good
> point regarding the two new pilots we had at the fied we need
to find them and
> check them out.
>
> Pat Hewitt
>
> PS I did give you a 10 on the down line.
>
>
> ------ Original Message ------
> Received: 11:11 AM CDT, 08/07/2006
> From: "Keith Black"
> To: "NSRCA Mailing List"
> Subject: Re: [NS! RCA-dis cussion] Lost Abbra
>
> I've been reading this thread and I serously doubt the NiMH
batteries had
> anything to do with the crash. NiMH batteries aren't new on
the market for
> goodness sakes and they've been working very very well on
probably billions of
> flights. Sure we have digital servos, but in truth our loads
aren't really
> very high and certinally not for and extended draw.
>
> I would think if low voltage had caused the loss of control
then once the snap
> stopped, even though you had little time before hitting the
ground, you still
> would have had enough time for the RX to come back to life.
Remember, the
> battery did discharge 1540 mah on the ground.
>
> As to the servo that was locked at full throw, if this had
occurred in the air
> the plane would have been spiraling on it's way down and your
other surfaces
> would have still worked. Therefore, you can ru! le out the
jammed servo, that
> most certinally happened upon impact.
>
> As to the IMAC guys having low impedance problems I can buy
this, but keep in
> mind these guys have two to three servos on each surface,
their planes weigh
> 40 lbs, and they slam the controls like crazy doing blenders
and such. The
> usage by pattern planes isn't even in the same galaxy.
>
> Most likely this was a simple case of lock-out due to
reception. There could
> be some other factor, but I would hate to see anyone go back
to NiCADs due to
> this incident.
>
> Keith Black
> ----- Original Message -----
> From: vicenterc at comcast.net
> To: NSRCA Mailing List ; NSRCA Mailing List
> Sent: Monday, August 07, 2006 7:44 AM
> Subject: Re: [NSRCA-discussion] Lost Abbra
>
>
> Thanks Chris,
>
> You are right. The event was so fast. Going down hill at 45
degrees! didn't
> give me too much time.
>
> I went to NiMh two years ago. Looks like I am going to go back
to NiCads.
> Several fellow pilots are telling me about the voltage drop
problem of the
> NiMh. Probably, the battery was not the cause of the crash but
I think I am
> going to feel more confident going back to NiCads. I went to
NiMh because
> they are lighter for a given capacity. I agree that there has
been a lot of
> comments in regard the low impedance. However, I really don't
want to use
> NiMh after having this problem.
>
> I am planing to send the radio to JR for a complete check out.
>
> Vicente "Vince" Bortone
> -------------- Original message --------------
> From: "White, Chris"
>
> Hi Vince, very sorry to hear about your Abbra loss...not much
time to
> recover or evaluate the problem considering where it happened.
For what its > worth, I've heard of airplane losses due to over-demand
voltage during snaps .
> I also hear many of the giant scale guys are using "low
impedance" nimh
> batteries when using nimh because of servo over-demand during
certain
> maneuvers such as snaps. After hearing the low-impedance story
I went to
> Hangtime Hobbies and am now flying their KAM 1800 6v low
impedance packs.
> Their site is worth a visit just for the read.
>
>
>
> www.hangtimes.com/nobsbatteries.html
>
>
>
> I hope you find closure on the cause.
>
>
>
> Chris White
>
>
>
>
>
>
>
>
>
------------------------------------------------------------------------
----
>
> From: nsrca-discussion-bounces at lists.nsrca.org
> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of
> vicenterc at comcast.net
>! Sent: Monday, August 07, 2006 5:49 AM
> To: NSRCA Mailing List; NSRCA Mailing List
> Subject: Re: [NSRCA-discussion] Lost Abbra
>
>
>
> Ron,
>
>
>
> I checked all servos but throttle and one aileron servo. All
are working
> on the bench fine. One of the aileron servos gears is locked
in maximum
> travel position and I am assuming that was caused in the
crash. However, I
> could be wrong.
>
>
>
> Thanks,
>
>
>
> Vicente "Vince" Bortone
>
>
>
> -------------- Original message --------------
> From: Ron Van Putte
>
> On Aug 6, 2006, at 9:50 PM, vicenterc at comcast.net wrote:
>
>
>
>
>
> The battery was a little over a year old. I cycled the battery
after the
> crash and got around 1540 mah. It was freshly charged and I
was in t! he seco nd
> fly. I use around 200 mah per fly so the battery was close to
2000 mah. I
> always charge at C/10 and never fast charged.
>
>
>
> I am discharging the battery now at 500 mah. I discharged the
first time
> at 250 mah. I will keep increasing the discharge rate to check
if I find
> something wrong.
>
>
>
> I am willing to bet that you will find a bad servo. Maybe Jim
Oddino or
> one of the other radio wizards can explain, but a single servo
can cause the
> whole system to crash.
>
>
>
> Ron
>
>
>
>
>
> -------------- Original message --------------
> From: "Scott Anderson"
>
> How old are the NiMh batteries... People have found the have a
steep
> drop off when going bad..
>
> scott
>
> ----- Original Message -----
>
> Fr! om: vic enterc at comcast.net
>
> To: NSRCA Mailing List ; nsrca-discussion at lists.nsrca.org
>
> Cc: Fred Huber
>
> Sent: Sunday, August 06, 2006 10:19 PM
>
> Subject: Re: [NSRCA-discussion] Lost Abbra
>
>
>
> Fred,
>
>
>
> Usually I called pilot (and/or mechanic) error until I find
the
> cause of the crash. I haven't been in this position in a very
long time. I
> tend to agree with you since it was clear that I didn't have
control. However,
> the radio is working even after such a crash. There was a
comment at the field
> that NiMh batteries can cause this problem. I will check the
battery as much
> as possible (cycle increasing the current draws) but not sure
if the test will
> be valid.
>
>
>
> Thanks,
>
>
>
> Vicente "Vince" Bortone
>
>
>
> --------! ------ Original message --------------
> From: "Fred Huber"
>
> In that case... it may have gone to lock out just as it was
> finishing the snap... rather than your control input to get
out of the
> rotation, the surfaces go to neutral, it over-rotates and then
plays lawn
> dart.
>
> No response at all its very easy to thing failsafe lockout.
Since
> the engine was already at the failsafe setting, you don't have
that indicator
> to confirm (or refute) the lockout.
>
> I wouldn't call it pilot error when the control input attempts
you
> made simply had no effect...
>
> ----- Original Message -----
>
> From: vicenterc at comcast.net
>
> To: nsrca-discussion at lists.nsrca.org
>
> Sent: Sunday, August 06, 2006 7:15 PM
>
> Subject: Re: [NSRCA-discussion] Lost Abbra
>
>
>
> I am wrong! below in regard the fail safe in regard the fail
> safe. The fail safe is programmed to cut the engine and set
the control
> surfaces at neutral.
>
>
>
> Vicente "Vince" Bortone
>
>
>
> -------------- Original message --------------
> From: vicenterc at comcast.net
>
> 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
> disconnect! ed 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
> batt! ery 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 ! togethe
r.
>
> Thanks and have a nice day,
>
> Vicente Bortone
>
>
>
>
>
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