[NSRCA-discussion] Lost Abbra
Fred Huber
fhhuber at clearwire.com
Tue Aug 8 11:11:10 AKDT 2006
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
>>
>> ------------------------------------------------------------------------
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>> NSRCA-discussion at lists.nsrca.org
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>>
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