[NSRCA-discussion] Lost Abbra
dwaynenancy
dwaynenancy at cox.net
Tue Aug 8 11:22:07 AKDT 2006
Stand corrected. Sorry. Dwayne
Fred Huber wrote:
>When a switch is open.. no current can flow. Thus a switch that fails in a
>manner that allows current flow has failed CLOSED.
>
>On the other hand... a water valve which is open lets the water flow, but if
>its closed things dry up. ;)
>
>correct explaination of the effect (and safety value) of the mirical
>switch... improper termonology.
>
>----- Original Message -----
>From: "dwaynenancy" <dwaynenancy at cox.net>
>To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
>Sent: Tuesday, August 08, 2006 2:02 PM
>Subject: Re: [NSRCA-discussion] Lost Abbra
>
>
>
>
>>Vincente, have you ever used a "miricale switch"? These are available at
>>serveral sources, Jim Oddino, MPI and others. These switches, when they
>>fail, do so in the "open" position therefore hopefully never losing
>>power because of the switch. One way to determine a switch failure is
>>the inability to turn the system "off". A $50 switch can save some
>>airplanes.
>>
>>Dwayne
>>
>>vicenterc at comcast.net wrote:
>>
>>
>>
>>>Keith,
>>>The crash was so hard that everything was loose. Soon after the crash
>>>I assumed that the battery came loose (snap g's) and the battery got
>>>disconnected because came loose. However, after analyzing the crash I
>>>found that the battery still was electrically connected with the
>>>system since one servo was buzzing hard. Later after checking with
>>>more detail at home I turned the TX on and RX on and the radio worked
>>>fine. Therefore, I the original conclusion that the battery came loose
>>>and got disconnected is not correct.
>>>Last night I checked the receiver antenna using the ohm meter. The
>>>antenna is OK. Also I did a vibration test on the switch and receiver
>>>and checked all wires and everything is working fine. Looks like is
>>>going to be very difficult to know what caused the crash. I also
>>>checked the servos that survived the crash moving slowly and never
>>>found a bad spot.
>>>Thanks,
>>>Vicente "Vince" Bortone
>>>
>>> -------------- Original message --------------
>>> From: "Keith Black" <tkeithb at comcast.net>
>>> Vince,
>>> Am I to understand that the battery was loose in the plane? If so,
>>> do you know if this occurred due to impact or if this occurred
>>> during the snap?
>>> Keith
>>>
>>> ----- Original Message -----
>>> *From:* vicenterc at comcast.net <mailto:vicenterc at comcast.net>
>>> *To:* NSRCA Mailing List
>>> <mailto:nsrca-discussion at lists.nsrca.org> ; 'NSRCA Mailing
>>> List' <mailto:nsrca-discussion at lists.nsrca.org>
>>> *Sent:* Monday, August 07, 2006 9:03 PM
>>> *Subject:* Re: [NSRCA-discussion] Lost Abbra
>>>
>>> Hi Richard,
>>> I said that wrong. It was really a lot more than 90 degrees.
>>> The plane stop almost inverted. Therefore, the over rotation
>>> was close to 180 degrees. You have a good point. That is
>>> reason I always said the it is pilot error unless I can find
>>> the reason of the mechanical failure. Let me explain a little
>>> more. I snapped to the right because we had 90 degree cross
>>> wind. I was flying the manuever left to right and the wing was
>>> blowing out. Probably 10-12 mph. Therefore, I was snapping
>>> into the wind for obvious reasons. When I noticed that
>>> ailerons were not responsive I did apply down elevator
>>> (releasing the aileron first). The speed was high because I
>>> did a large Inmelman turn so I don't see that the plane was in
>>> stalled condition. However, I could be wrong. Charlie was
>>> calling for me I he could give us his opinion in regard the
>>> stall condition. If I did s! nap a wa y from the wind there
>>> could have been more chances of stalling. I use low rates.
>>> Around 10 degrees in elevator, 12 degrees ailerons.
>>> I really new that there was something wrong very early because
>>> I couldn't stop the snap. It was almost instant feeling that I
>>> didn't have control after I did the snap.
>>> Vicente "Vince" Bortone
>>>
>>> -------------- Original message --------------
>>> From: "Richard Strickland" <richard.s at allied-callaway.com>
>>>
>>> I suppose that if the airplane were over rotated by 90
>>> degrees and at least still in a semi-stalled condition in
>>> knife-edge, the controls would potentially be slow to
>>> respond. In a right hand snap, the right wing would be
>>> stalled and if it were pointed toward the ground—still
>>> stalled--and the fuse was washing out the
>>> left—upper—un-stalled--panel, then that would account for
>>> the non-responsiveness of the ailerons. Aircraft can still
>>> be stalled at high speeds and depending on the timing and
>>> amount of input—maybe exaggerated with high rates with big
>>> expo, a secondary stall/spin can take place making you
>>> wonder ‘how did THAT happen?!’. ! Not all that unlikely a
>>> circumstance with as slippery as these critters are…. And
>>> you might have just had some really lousy luck with wind
>>> shear at that precise moment. I am a Charter Member of SAD.
>>>
>>> RS
>>>
>>> -----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 6:52 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. < o:p>
>>>
>>> 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
>>>
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