[NSRCA-discussion] Lost Abbra Battery
Jay Marshall
lightfoot at sc.rr.com
Mon Aug 7 13:54:53 AKDT 2006
Don't forget to check for vibration failures. This can be simulated by
placing components on an orbital sander.
-----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: Monday, August 07, 2006 3:50 PM
To: NSRCA Mailing List; NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Lost Abbra Battery
No, we didn't have scanners. Your assumption is very valid. I was aware of
the pilots that were there. I know that I would like to check in two cases.
However, I still believe that there was another problem since I lost control
of the plane just after the snap roll. I am thinking more that was due to
the high g's. Of course, someone could turn the radio exactly when I was in
the middle of the snap roll since the plane responded to my commands to
execute the snap. The chances for this to happen are very small. Tonight I
am going to try to check the wiring and switch looking for something
evident.
Questions:
1. Can a switch be forced to move to the off position due a violent
maneuver? The switch in the Abbra was turned on by by moving to the back
back of the plane. In the crash the switch could have been moved to the on
position due to the sudden stop. However, I have to discard this theory
since the plane stopped the snap and went straight to ground. This tells me
that the plane went to fail-safe. Fail-Safe was programmed to go to control
surfaces in neutral position and engine at idle.
2. What is the voltage that will cause a JR receiver to go to fail-safe
mode?
Thanks,
Vicente "Vince" Bortone
-------------- Original message --------------
From: "Del K. Rykert" <drykert2 at rochester.rr.com>
> Not to belabor the obvious but I have routinely checked what other pilots
> were on my freq. at a contest just to keep me aware of the potential
> conflict. Granted that don't protect you from the casual or sport flier
> showing up or someone turning on in parking lot. I wonder if anyone was
> running a scanner at time of crash and if it detected dual freq. use
during
> the crash? Just a thought. As all other variables have been addressed it
> appears.
>
> Del
> nsrca - 473
> ----- Original Message -----
> From: "Pat Hewitt"
> To: "NSRCA Mailing List" ; "NSRCA Mailing
> List"
> Cc: !
> Sent: Monday, August 07, 2006 12:25 PM
> Subject: [NSRCA-discussion] Lost Abbra Battery
>
>
> >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"
> &! gt; To: "NSRCA Mailing List"
> > Subject: Re: [NSRCA-discussion] 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 lo cked 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 rule 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.
> >
> &g! t; Keit h 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 lo w 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 K! AM 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 the
> > second > & gt; 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.! .. Peop le have found the have a
> > steep
> > drop off when going bad..
> >
> > scott
> >
> > ----- Original Message -----
> >
> > From: vicenterc 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
&! gt; > ; 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 h! ave tha t
> > 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: vicent! erc at com cast.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 i!
nverted
> > 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 serv! os. I c hecked 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 ma h 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 t! o the g roup 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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> > NSRCA-discussion at lists.nsrca.org
> > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >
> >
> >
> >
> > ------------------------------------------------------------------
> >
> >
> >
> > No virus f! ound in this incoming message.
> > Checked by AVG Free Edition.
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> > Date:
> > 8/5/2006
> >
> >
> >
> >
> > ----------------------------------------------------------------------
> >
> >
> >
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