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Old Aug 17, 2014, 01:28 AM
Racing Enthusiast AMA 3557
JetMech2002's Avatar
United States, MO, Sedalia
Joined Sep 2011
675 Posts
Careful!
Issue with DSM2 and Sheriff transmitting tower

I was flying my E-Flite T34 today. One that had 60 flights with no issues. Took off circled the KCRC field at lake Jacomo in Blue Springs, MO, was turning base leg, and nothing. The plane rolled and went to full throttle and planted itself. As it rolled and I realized I had no control, I chopped the throttle to no avail. After recovering the plane, I double checked the batteries and range check and all was functioning and checked good. This field has had several issues in the past on 72 Mhz, and recently has claimed several more, all flying Spektrum DSM2 systems. From a T-28 trojan to a 426 quickie. All experienced pilots, and all reported total loss of control. Is it possible that this Sheriff tower is transmitting at such a high wattage to swamp our systems? Also I have been told that when a CC controller looses signal it shuts down. My plane went to full throttle? Any ideas guys?
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Old Aug 17, 2014, 04:54 AM
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Kambalunga's Avatar
Deutschland, Hessen, LA
Joined Jan 2009
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Failsafe trottle low?
It's looks like for me that you have failsafe WOT.
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Old Aug 17, 2014, 05:48 AM
X-Ikarus
Reflex1's Avatar
United Kingdom, North York
Joined Feb 2003
1,673 Posts
Rather worry about the loss of control first
than the failsafe setting ....

Primary issue is Loss Of Control
Many issues have been posted for DSM2

Consider using DSMX instead

disclaimer. failsafe should also always be set and tested before flight (standard common sense)
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Old Aug 17, 2014, 06:58 AM
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Nashville, NC, USA
Joined Mar 1999
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Consider using another brand. You just don't see these type of complaints nearly as much with other systems.
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Old Aug 17, 2014, 07:13 AM
59 years of RC flying
Daedalus66's Avatar
Canada, ON, Ottawa
Joined Feb 2006
16,115 Posts
If overloading from a very strong signal is the cause, failsafe will likely be irrelevant as there is no signal loss. Rather, the receiver is overloaded with signal. Going to DSMX (which is about as good as any of the current systems in resisting interference and considerably more robust than DSM2) would be a good solution. Check with others at the field who are using DSMX to see if they are having problems.
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Old Aug 17, 2014, 07:27 AM
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Dr Honda's Avatar
Pittsburgh Allegheny, Pennsylvania, United States
Joined May 2004
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Quote:
Originally Posted by Daedalus66 View Post
If overloading from a very strong signal is the cause, failsafe will likely be irrelevant as there is no signal loss. Rather, the receiver is overloaded with signal. Going to DSMX (which is about as good as any of the current systems in resisting interference and considerably more robust than DSM2) would be a good solution. Check with others at the field who are using DSMX to see if they are having problems.
I agree with moving to DSMX. (now) But the overload comment isn't true. The system is digital, and it's looking for a proper signal. SO... if the front-end is swamped with "Junk" the system will go into it's failsafe pre-sets. (that should have been checked, and set by the OP)

I had this happen earlier this season with my favorite gaser model. The tip of the sparkplug came off... and cause crazy interference. It was flying along just fine... and the engine went to idle, and I had no control. All I could do is watch it hit the trees. FYI... it had a DSM2 Rx in it. If it was DSMX, it would at least had a chance, since the reconnect is much faster.

Davecee: ALL systems have issues. The hot system had a nasty habit of getting turned off. And Futaba had issues with the global ID going to ZERO !!!! So, please don't go down that road. I can say... in the +10 years I've been using JR/Spektrum DSM system... this was my first actual issue with RF... and after checking the damage... we knew EXACTLY what caused it. (bad maintenance by me)
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Old Aug 17, 2014, 07:35 AM
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RyanNX211's Avatar
Upper Arlington, Ohio
Joined Dec 2007
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This thread has been going for a few hours and no one has blamed it all on you yet.

I feel your pain
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Old Aug 17, 2014, 08:37 AM
AndyKunz's Avatar
Illinois
Joined Sep 2001
22,879 Posts
Quote:
Originally Posted by Daedalus66 View Post
If overloading from a very strong signal is the cause, failsafe will likely be irrelevant as there is no signal loss. Rather, the receiver is overloaded with signal. Going to DSMX (which is about as good as any of the current systems in resisting interference and considerably more robust than DSM2) would be a good solution. Check with others at the field who are using DSMX to see if they are having problems.
Um, that's not what "signal loss" means, Nigel. It means "no usable control signal" - at least that's what it means in a Spektrum system. If it doesn't detect packets for it, that means a frame was lost.

Andy
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Old Aug 17, 2014, 10:42 AM
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richard hanson's Avatar
United States, UT, Salt Lake City
Joined Oct 2007
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Quote:
Originally Posted by JetMech2002 View Post
I have been told that when a CC controller looses signal it shuts down. My plane went to full throttle? Any ideas guys?
I have a suggestion for future testing:
Buy a 4 cell pack of ELITE 1500ma cells these are 10 C cells
Cheap Battery Packs, batteries sell these and a pack weighs just 3 ounces. 12 bucks
remove red wire from BEC to rx.
plug batt pack into rx a hd Y will work I you run out of ports.
The idea is to cut the BEC out of the circuit
Test model using a inline volt meter before flying - this battery pack - should never drop1 volt under any servo testing prior to a flight.
Now fly around the deadly tower - if there is still an issue with HOLDS- the problem isn't power to the rx - but BEC failures are very common and impossible to prove-for most users, as they cool off and work after the crash.

ratings on BECs are just like gasoline milage spec on cars
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Old Aug 17, 2014, 10:59 AM
X-Ikarus
Reflex1's Avatar
United Kingdom, North York
Joined Feb 2003
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Always the BEC eh Richard ?

No matter how many "good" flights beforehand (60 flights with no issues)
or other issues at his field ...

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Old Aug 17, 2014, 11:13 AM
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richard hanson's Avatar
United States, UT, Salt Lake City
Joined Oct 2007
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Yes - always suspect it first
If you have a better idea -lets hear it .
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Old Aug 17, 2014, 11:22 AM
X-Ikarus
Reflex1's Avatar
United Kingdom, North York
Joined Feb 2003
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Quote:
Originally Posted by richard hanson View Post
Yes - always suspect it first
If you have a better idea -lets hear it .
Read the 1st post
after 60 flights the BEC is clearly eliminated

He is on the correct track
and doesn't need any misinformation from you
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Old Aug 17, 2014, 11:25 AM
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richard hanson's Avatar
United States, UT, Salt Lake City
Joined Oct 2007
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Quote:
Originally Posted by Reflex1 View Post
Read the 1st post
after 60 flights the BEC is clearly eliminated

He is on the correct track
and doesn't need any misinformation from you
Your expertise is clearly of little /no value
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Old Aug 17, 2014, 11:27 AM
X-Ikarus
Reflex1's Avatar
United Kingdom, North York
Joined Feb 2003
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Quote:
Originally Posted by richard hanson View Post
Your expertise is clearly of little /no value
and yours is
just like gasoline milage spec on cars
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Old Aug 17, 2014, 11:31 AM
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richard hanson's Avatar
United States, UT, Salt Lake City
Joined Oct 2007
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Perhaps you should study up on how BECs actually work - and why the ratings vary with inputs and the failure modes
If all you do is read "reports"on line - you have no real understanding of these type failures
it's an open forum sonny, you can say whatever you like.
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