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losing throttle control right after takeoff.

lsherwoodrm

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Hello all,
I've been building a FC model 250 freestyle quad. I have a speedy bee f4 FC, emax2306 2750kv motors, cicada 35amp 4in1 esc, frsky x8r Rx and qx7. My quad appears to be great on the bench but when I put props on and fly as soon as the quad leaves the ground I lose all throttle control and have to disarm to get it back on the ground. I will try to post a video of this happening inf it help troubleshoot the problem. if I left any information out feel free to ask. Thanks for any help.
 

HighTechPauper

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I am having a similar issue too, once I leave the ground the quad will likely go to full throttle and I have to disarm. It is likely the RX to blame or it could possibly be the FC. I know it isn't the TX because no other quad does it and it has individual ESC's so I doubt they could be the problem. Something is telling the quad to go to full throttle and the RX is the most likely culprit.

I plan to throw another RX into mine and test it out sometime in the next week or so.
 
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HighTechPauper

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Also as a side note, I have already re-flashed the RX and FC and applied only the minimal needed config to make it fly and still the same thing, so it isn't just that firware got scrambled. But I would still try to at least reflash the RX to the latest firmware just to be sure it isn't a bug in the current rev. There is no way to tell what rev is on the Frsky receivers so all you can do is flash the latest and test it again.
 
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lsherwoodrm

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Also as a side note, I have already re-flashed the RX and FC and applied only the minimal needed config to make it fly and still the same thing, so it isn't just that firware got scrambled. But I would still try to at least reflash the RX to the latest firmware just to be sure it isn't a bug in the current rev. There is no way to tell what rev is on the Frsky receivers so all you can do is flash the latest and test it again.
Thanks for the info I will try to reflash Rx firmware tomorrow after work and give you an update
 

HighTechPauper

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Smart move, I think it may not fix things and a RX replacement may be in order, if so and you can get one any of the other X series RX would be much smaller/lighter than the old x8r. While the x4r is still popular with the old pros that bought 12 of them back in the day I would suggest an R-XSR as an alternative that is much better for this application.
 
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lsherwoodrm

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Hey guys haven't been able to reflash yet. have to work one more 12 hour day then I can get some to tinker with it. Thanks for all your help I'll keep you posted in the coming days.
 

lsherwoodrm

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Got update for ya guys, OK a confession. I'm not to good at this firmware flasing I tired to flash my qx7 tx firware and then use smart port to flash x8r firmware. Now the tx won't communicate the rx, I tried to rebind but that didn't help. I'm not sure what to do now.
 

dr0nrb0nr

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Have you guys attempted to calibrate your ESC’s through beta flight

 

HighTechPauper

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Yes, if you are running a digital DShot protocol it isn’t needed, but if you run an analog like OneShot MultiShot then you need to do it. Motors tab WITH NO PROPS you Enable then set Master to full and plug in batt, get initial tones, master to 0 throttle and get final tones and then unplug batt and should be done if all works right
 

RENOV8R

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I've always set the protocol to Oneshot125, calibrated ESCs, then set protocol to DShot600. Just a little extra insurance I guess
 
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HighTechPauper

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I've always set the protocol to Oneshot125, calibrated ESCs, then set protocol to DShot600. Just a little extra insurance I guess
I do the same also, when updating the BF on the FC it will be reset to OneShot125 and if somehow it got powered like that I would want the ESC's to have a cal for analog protocols to be safe(r).
 

lsherwoodrm

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Hey guys sorry I haven't been able to update yet, I'm a$$ deep in work for next couple of weeks. Thanks for all the helpful information
 

RENOV8R

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Just reread this thread. A lot of times, loss of control is due to improper flight controller orientation (turned 90 or 180 degrees). Chesck and see that your flight controller is pointing forward and if not you'll have to go into the configurator and change the board yaw alignment accordingly.
 

lsherwoodrm

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Yay, got control again (on the bench anyway) did a firmware reflash for both the qx7 and x8r. Everything appears to work again when I put a battery on and leave it setting on the bench and give tx throttle input it seems to respond correctly, thats without props of course. I'll try a test flight tomorrow after work and see if its good to go
 
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lsherwoodrm

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Nope no good. I just don't get it, on the bench it acts like it should, as soon as I put props on and it gets airborne it wants to flyaway. The quad doesn't respond to tx input. I have a r xsr on the way now to replace it. I'm just kinda bummed, I spend almost $40 on a supposedly top on of line rx and it can't even perform correctly. I hope a new rx fixes this I just want to fly
 

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