[NSRCA-discussion] Lost Abbra Battery
Del K. Rykert
drykert2 at rochester.rr.com
Mon Aug 7 10:19:04 AKDT 2006
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" <phewitt at farmersagent.com>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>; "NSRCA Mailing
List" <nsrca-discussion at lists.nsrca.org>
Cc: <gld-sad at hughes.com>
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" <tkeithb at comcast.net>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> 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 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 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.
>
> 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" <chris at ssd.fsi.com>
>
> 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 <vanputte at cox.net>
>
> 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
> 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" <scott at rcfoamy.com>
>
> How old are the NiMh batteries... People 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
> 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" <fhhuber at clearwire.com>
>
> 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
> 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
>
>
>
>
> ------------------------------------------------------------------
>
>
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
>
>
>
> ------------------------------------------------------------------
>
>
>
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.1.394 / Virus Database: 268.10.7/410 - Release
> Date:
> 8/5/2006
>
>
>
>
> ----------------------------------------------------------------------
>
>
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
> _______________________________________________
>
> NSRCA-discussion mailing list
>
> NSRCA-discussion at lists.nsrca.org
>
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
>
>
>
>
> ------------------------------------------------------------------------------
>
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
>
>
>
> _______________________________________________
> NSRCA-discussion mailing list
> NSRCA-discussion at lists.nsrca.org
> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
>
More information about the NSRCA-discussion
mailing list