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Old Jul 13, 2013, 08:57 PM
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Drew - you said you were not using the motor in either crash. How could it be the ESC unless you are thinking it lost power to the receiver. Maybe so but I'm not sure how common that is. I do know I have had a similar crash on my first flights. Flying along and the v-roc just fall out of the sky and noses in. My problem was trying to fly the v-roc to slow. This is a big bird and the air speed will fool you. It is hard to stall but when it dose it will fall straight down and take a lot of room to recover, if you can before the ground. Could this be what is happening?
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Old Jul 13, 2013, 09:08 PM
Lou
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Originally Posted by Tom.MotionRC View Post
All t his data has been on our site since the first day we sold this model. Link:
http://www.motionrc.com/rochobby-220...specifications

Note: SBEC = switched BEC.
My apologies Tom, you are correct. I had looked at the ESC listed under Spares and the specs were not there.

http://www.motionrc.com/rochobby-v-tail-glider-35a-esc/

I had a 'duh' moment concerning component listing for the specs for the plane.
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Old Jul 13, 2013, 09:17 PM
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Quote:
Originally Posted by Petrie View Post
Drew - you said you were not using the motor in either crash. How could it be the ESC unless you are thinking it lost power to the receiver. Maybe so but I'm not sure how common that is. I do know I have had a similar crash on my first flights. Flying along and the v-roc just fall out of the sky and noses in. My problem was trying to fly the v-roc to slow. This is a big bird and the air speed will fool you. It is hard to stall but when it dose it will fall straight down and take a lot of room to recover, if you can before the ground. Could this be what is happening?
Nah, the model simply didn't respond in either case. The first time, I was doing lazy thermal circles in good air for about 3 minutes straight when it just corkscrewed down with no signs of response. The second time was a pretty fast run leading into a turn when it just spiraled in. Again, I gave it all sorts of recovery movement from the Tx and nothing I did altered its dive path. I just watched it helplessly spiral down. Neither case looked like a tip stall to me. Usually you can recover from tip stalls with full elevator and opposite rudder/aileron, but the model simply continued down in a constant steady spiral.

Yes, I was thinking it would have to be the BEC circuitry that was faulty. But I have no proof. I need to measure current draw with the servos operating.
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Old Jul 13, 2013, 10:28 PM
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Originally Posted by DrewV View Post
Nah, the model simply didn't respond in either case. The first time, I was doing lazy thermal circles in good air for about 3 minutes straight when it just corkscrewed down with no signs of response. The second time was a pretty fast run leading into a turn when it just spiraled in. Again, I gave it all sorts of recovery movement from the Tx and nothing I did altered its dive path. I just watched it helplessly spiral down. Neither case looked like a tip stall to me. Usually you can recover from tip stalls with full elevator and opposite rudder/aileron, but the model simply continued down in a constant steady spiral.

Yes, I was thinking it would have to be the BEC circuitry that was faulty. But I have no proof. I need to measure current draw with the servos operating.
Wow, you got me thinking know. When I spiraled in from about 30-40 ft up I should have been able to recover from a stall on any kind of plane at that altitude. But I had no control of it not even to correct the roll. I passed it off as a bad stall or a V-tail thing but, I'm starting to think twice about it. Been on vacation and playing with a new Futaba radio so I only got about 15 flights on the v-roc. I'll try to spend some time tomorrow and repair the nose and try a couple more test flights with it.
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Old Jul 13, 2013, 10:39 PM
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Interesting. Sounds like you had a similar situation. What radio were you using in your V-Roc?

I've had maybe 2 hours total flying on the V-Roc and it's failed twice. Since it crashed last time, I re-arranged the receiver antenna, thinking that was the problem. But in less than 10 minutes of flying after repairing the model, it crashed the exact same way, only even at a shorter range the second time. Moving the antenna around didn't seem to help.

At this point, I don't know what it could be. I will install a different receiver and repair the model, then try it again. If it still fails, then there's definitely something wrong with the ESC, as that would be the only commonality for all of the failures.
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Old Jul 13, 2013, 11:01 PM
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Would be interesting to have a video of what the ails and/or ruddervators were doing when you were 'apparently' browned-out. Got a key-cam or such?
&....that sounds like a classic accelerated stall, what you're calling a tip stall.

Oh, had another thought. Is the Rx you're using capable of & using failsafe settings? (Even if inadvertently set)?
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Old Jul 13, 2013, 11:02 PM
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FYI, it looks like the price just increased on the V-Tail by $25 from $149 to $174.

-Randy
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Old Jul 13, 2013, 11:42 PM
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I just noticed that too. I had my finger on the trigger but now I have to think about it.
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Old Jul 13, 2013, 11:53 PM
Lou
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Originally Posted by Hawk570 View Post
I just noticed that too. I had my finger on the trigger but now I have to think about it.
I got lucky. I ordered mine on Thursday evening at the $149. I think it was Friday evening or Saturday day that I saw the price go to $174.

Keep this in mind though ... the shipping is free. At least it was on Friday. That alone will save you $12 to $25 dollars, just based on the size of the box. All in all it is still a good deal at $174.

I would not shy away from the plane especially if the shipping is free.
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Old Jul 14, 2013, 12:01 AM
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Drew I am currently using a DX6i with a receiver and satilite. I will also change that for another known receiver before the next flight. Just got a Futaba 14SG that I will be using later. I'm also thinking of reflowing the connector I put on the ESC.

The other time I have had a problem was at lanch. After release about 20 yards out she just nosed in the ground. I'm not a novice flyer. Manual says toss the then add power. I have been using more than 3/4 throttle because of fear of another stall. Hope I have time tomorrow to get it out, have lots of questions. However, when it is not diving for the dirt it is a wonderful flying plane. Sure we both just have some silly qurk that we will work out. Hopefully before the fatal crash.
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Old Jul 14, 2013, 03:40 AM
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Originally Posted by StarHopper44 View Post
Would be interesting to have a video of what the ails and/or ruddervators were doing when you were 'apparently' browned-out. Got a key-cam or such?
&....that sounds like a classic accelerated stall, what you're calling a tip stall.

I don't have a camera.

I know what a stall looks like (in various forms) and how to recover from them. That is not what's happening. You don't think I can tell whether or not the plane is responding to stick inputs?? It just goes dead, plain and simple.
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Old Jul 14, 2013, 05:58 AM
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I apologize -- didn't mean to insult your flying skills or knowledge. I had a couple of ideas, but I'll kindly just back away from this one -- I'm sure you can figure it out.
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Old Jul 14, 2013, 07:29 AM
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Drew can we plug a switch in one of the receiver solts and add a flight battery? Be extra weight but with a 1300ma they should both fit. Not sure what it will rule out as a problem but you will know the receiver will have power. Do you turn off the BEC when you add a battery or can you run both?
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Old Jul 14, 2013, 08:13 AM
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When flying mine last week 4 times with 3 flights over 25 minutes I did play with its stalling. With wings level and into a light wind it did stall straight ahead but deeper than I expected. It did drop quit a bit of altitude but recovered fine but would not want to do it at low altitude, say less than 20 to 30 ft. Installing a new receiver will at least narrow it down and tell you it may be the ESC.

Stringfly <>+++++
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Old Jul 14, 2013, 09:04 AM
Lou
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Originally Posted by Petrie View Post
Drew can we plug a switch in one of the receiver solts and add a flight battery? Be extra weight but with a 1300ma they should both fit. Not sure what it will rule out as a problem but you will know the receiver will have power. Do you turn off the BEC when you add a battery or can you run both?
Depends on receiver and ESC and how power and from where power is applied.

Generally, anytime you add external power to the receiver via a separate battery, you will need to remove the red lead from the ESC 3 wire connector that goes to the throttle of the receiver.

Problem is though that without a voltage regulator a straight battery to receiver setup can burn up the receiver if the receiver is not rated for that voltage level. Same with servos, using higher than recommend voltage on a servo will damage it. An external BEC offers that voltage regulation.
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