[NSRCA-discussion] Lost Abbra Battery

[vicenterc at comcast.net]

Pat,

That has been the only time I got a 10.......

VB

-------------- 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: [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" 
> 
> 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 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" 
> 
> 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" 
> 
> 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 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.nsrca.org/pipermail/nsrca-discussion/attachments/20060807/e28233cf/attachment.html