Blade 200QX - Page 849 - RC Groups
Thread Tools
Sep 12, 2017, 04:04 PM
Luck is my skill
queadlunnrau's Avatar
Quote:
Originally Posted by Norman Adlam
Thinking that it may have previously been loss of signal, I replaced the 'bit of wire' with a Frsky proper coax aerial - and have flown it beyond where it decided to land. It was whilst I was coming back to me that the 'event' occurred.

Have a look at the photo in post #12716 and you'll see it poking up by the square GPS module.
Maybe add a capacitor, could be tripping LVC early from a voltage/current drop?
Sign up now
to remove ads between posts
Sep 12, 2017, 05:07 PM
Official Old Git!
Quote:
Originally Posted by queadlunnrau
Maybe add a capacitor, could be tripping LVC early from a voltage/current drop?
Initially I was thinking of rewiring the OSD so it checks the voltage actually going into the BEC connector (rather than the balance lead). Better would be checking the voltage on the main board, well after the connector, but it's a pig to solder.

Your suggestion is reasonable, and worth considering, though..
Sep 13, 2017, 09:49 AM
Luck is my skill
queadlunnrau's Avatar
Quote:
Originally Posted by Norman Adlam
Initially I was thinking of rewiring the OSD so it checks the voltage actually going into the BEC connector (rather than the balance lead). Better would be checking the voltage on the main board, well after the connector, but it's a pig to solder.

Your suggestion is reasonable, and worth considering, though..
Ah I assumed your OSD was wired on the board. would be good to log the voltage from there.

Although probably not the case on the 200qx, but in other micro drones, hitting LVC (if that is the problem in your case) occurs due to bad connectors or smaller gauge wire, example the Blade inductrix on the stock pico connector gets like 2 minutes of flight before current loss triggers LVC, people just change out the wire gauge and pop on a JST-PH 2.0 connector or micro losi connector and get 4 minutes after.

Just throwing it out there cause I know troubleshooting issues like yours can be brain numbing.
Sep 13, 2017, 10:44 AM
Official Old Git!
Quote:
Originally Posted by queadlunnrau
Ah I assumed your OSD was wired on the board. would be good to log the voltage from there.

Although probably not the case on the 200qx, but in other micro drones, hitting LVC (if that is the problem in your case) occurs due to bad connectors or smaller gauge wire, example the Blade inductrix on the stock pico connector gets like 2 minutes of flight before current loss triggers LVC, people just change out the wire gauge and pop on a JST-PH 2.0 connector or micro losi connector and get 4 minutes after.

Just throwing it out there cause I know troubleshooting issues like yours can be brain numbing.
The previous one would do this often, and it improved significantly - from say 4 mins flight to 8 mins (but wasn't cured) - when I replaced the BEC connector.

The manual suggest flashing white lights are low battery - but I don't believe that is completely true! If you crash at all, then you end up with flashing white lights, so I think it's simple a generic indications.

What has confused me is this strange 'twitch' when flying, and which I have (sometimes) got past by giving it a lot of throttle.
Sep 13, 2017, 12:29 PM
Luck is my skill
queadlunnrau's Avatar
Quote:
Originally Posted by Norman Adlam
What has confused me is this strange 'twitch' when flying, and which I have (sometimes) got past by giving it a lot of throttle.
I also have that twitch once in a while, I was chalking it up to a possible wind gust, but not sure if its a wind gust when in FPV so not sure what it is.

Maybe replace the stock JST connectors? I run XT30's on mine I've had JST's give me throttle studders and got really warm in some 35mm EDFs so I don't trust them for anything over 12a, the 200qx pulling upwards of over 15a when weighted with FPV gear.
Sep 13, 2017, 01:17 PM
What goes up must come down
Bush Pusher's Avatar
Does anyone know the bearing sizes for the stock motors got one that sounds bad and feels rough
Sep 13, 2017, 04:45 PM
Sopwith Camel's Cousin
Quote:
Originally Posted by Norman Adlam
I'm still getting my Rakon 200qx randomly landing when I'm flying. Even though I've swapped over the controller/ESC PCB's with a totally different one!
...
The symptoms - viewing through the FPV goggles - are that it gives a 'twitch' during flight, levels itself, then starts to land. Sometimes if I significantly raise the throttle it gets back to normal, but other times it ignores it and lands. Indication is always a flashing white led (but I think that just means "Houston, we have a problem!').

Anyone seen this/ have an idea what the problem is?
Continuing on the LVC possibility: the 'twitch' may be a momentary drop in voltage, perhaps momentary enough not to register on your voltage monitoring but still sometimes low enough to trigger LVC.

With some ESC's, one can undo/reset an LVC trigger by zeroing the throttle and then bringing throttle back up.
But one needs to do all this throttle movement before the model hits the ground.
My brain and fingers were never fast enough to do this,
but then I also fly pretty low.
Sep 13, 2017, 04:59 PM
Official Old Git!
Quote:
Originally Posted by flying-llama
Continuing on the LVC possibility: the 'twitch' may be a momentary drop in voltage, perhaps momentary enough not to register on your voltage monitoring but still sometimes low enough to trigger LVC.

With some ESC's, one can undo/reset an LVC trigger by zeroing the throttle and then bringing throttle back up.
But one needs to do all this throttle movement before the model hits the ground.
My brain and fingers were never fast enough to do this,
but then I also fly pretty low.
Yep, that's indeed a possibility - although the motors haven't stopped when it 'twitches' so it's not like the quad has actually shutdown, just gone into 'fail-safe'. Based on that, I suspect that it's less the ESC's, and more the Rx/Controller that is affected.

Anyone know the LVC circuit info on the 200qx? Can it be changed in the firmware?
Sep 14, 2017, 12:39 AM
Sopwith Camel's Cousin
Quote:
Originally Posted by Norman Adlam
Yep, that's indeed a possibility - although the motors haven't stopped when it 'twitches' so it's not like the quad has actually shutdown, just gone into 'fail-safe'. ...
Some ESC's have a mode that when they reach "LVC", they do not totally shut-down at first. Rather they go into a low-power limit to force the aircraft to land real fast, but with still a little motor power. This is particularly useful for multi-rotors, which have no steering control at all when the motors stop: even with no motor power, planes can glide under some control and collective pitch helicopters can auto-rotate (with a freewheeling-type of gearing). In those cases, LVC cuts the motor to save the battery power for the servos to control a plane's rudder, elevator, etc. or a helicopter's cyclic and collective controls.
Last edited by flying-llama; Sep 14, 2017 at 01:29 AM.
Sep 14, 2017, 12:52 AM
Sopwith Camel's Cousin
Quote:
Originally Posted by Norman Adlam
...

The manual suggest flashing white lights are low battery - but I don't believe that is completely true! If you crash at all, then you end up with flashing white lights, ....
If a crash involves a propeller striking something, a crash can cause an LVC: a propeller striking something slows or stops that propeller, which causes the
propeller's motor to start drawing more current (possibly a lot more), which can cause the battery voltage to drop below LVC.

An alternative that I have heard of with some control boards is that if a propeller strikes something and slows down or stops, the associated motor will have a current surge and start drawing too much current, and this type of control board is designed to detect this and lock out power to the motors like as if it hit LVC to protect that motor from frying.
Last edited by flying-llama; Sep 14, 2017 at 01:30 AM.


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Drone noob with blade 350qx3, blade 200qx and cgo2 camera projects. nitrodude123 Beginner Multirotor Drones 1 Aug 05, 2017 02:26 PM
Sold Blade 200qx, blade 350qx3 and cgo2gb camera for parts or repair nitrodude123 Aircraft - Electric - Multirotor (FS/W) 0 Jan 31, 2017 06:19 PM
Sold Blade 200qx, blade 350qx3 and cgo2gb camera for parts or repair nitrodude123 Aircraft - Electric - Multirotor (FS/W) 3 Jan 30, 2017 01:57 PM
Sold Blade Mach 25, Blade 200QX, and DXE package KSQuad Aircraft - Electric - Multirotor (FS/W) 3 Jan 20, 2017 08:34 AM
Discussion Dalprops 4045 2 blade and Blade 200QX are not compatible. FredYates Mini Multirotor Drones 0 Aug 27, 2016 07:07 PM