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RC Radios, Transmitters, Receivers, Servos, gyros Discussion all about rc radios, transmitters, receivers, servos, etc.

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Old 06-28-2011, 05:06 PM   #1
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Default OrangeRX brownout caught on tape

So that's what a brownout feels like. A couple of seconds into the video.


I always thought the "brown" in "brownout" referred to the color of your underwear and now I got that confirmed.

No, but seriously, it wasn't that bad (especially since I was probably 400" up). Also, I'm not even going to put all the blame on the OrangeRX. I may just have had the antenna in an angle that hid it behind the battery. But it's an interesting feeling of being completely powerless against Mother Gravity...

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Old 06-28-2011, 05:13 PM   #2
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Weeee!

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Old 06-28-2011, 05:16 PM   #3
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Nice recovery. Very glad you had a happy ending on this one. This is one reason I am afraid to move to 2.4. My old FM stuff seems rock solid. I just won't be able to fly any events, because most of them are requiring 2.4 now.

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Old 06-29-2011, 05:17 AM   #4
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Originally Posted by tarheal63 View Post
This is one reason I am afraid to move to 2.4. My old FM stuff seems rock solid. I just won't be able to fly any events, because most of them are requiring 2.4 now.
I've got 7 Spektrum AR7000 receivers and a DX7 transmitter. They are on their third year, and performance on all of them has been flawless. The AR7000 uses dual receivers, so 'blanking out' your receiver behind the battery pack won't happen. Just think of the very short 2.4 Ghz antennas as miniature TV rabbit ears. You must align them with the TV station to get reception. And in some orientations, you loose signal. That's where the second receiver comes in. Its "rabbit ears" are positioned in a different position, so at least one receiver will receive a solid signal.

As for range, the old RCReport magazine did tests on this issue, and found the Spektrum/JR units had about a 3 mile range in the air.

You absolutely must have adequate receiver batteries for this stuff though. That rules out those 5 cell "AA" 2700 milliampere hour batteries for a giant scale model airplane!

I've tested the seven Hitec 645MG servos for maximum current pulled while spinning the sticks on the transmitter. That peak current checked out to be 14 Amps, as measured by a $350 Fluke 87V digital multimeter. Those "AA" size Nih batteries can not put out that kind of current.

Check out the Castle Creations 10 Amp Switching BEC for your models. Less weight, less cost than a 5 cell Nih AA size battery, and far outperforms them.

Spektrum/JR has much of the market on 2.4 Ghz. In fact everyone in my RC club that has gone to 2.4 Ghz has either Spektrum or JR.

Nice thing about the Spektrum/JR radios is their "Model Match". If you've used a radio with multiple model airplanes, you may have taken off with the wrong model in the transmitter, and tried to take off with reversed ailerons.

Model Match prevents this. If the selected model in your transmitter does not match the model, the model receiver is dead. It will not respond. Period.

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Old 06-29-2011, 11:29 AM   #5
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Default

Originally Posted by NJSwede View Post
So that's what a brownout feels like. A couple of seconds into the video.


I always thought the "brown" in "brownout" referred to the color of your underwear and now I got that confirmed.

No, but seriously, it wasn't that bad (especially since I was probably 400" up). Also, I'm not even going to put all the blame on the OrangeRX. I may just have had the antenna in an angle that hid it behind the battery. But it's an interesting feeling of being completely powerless against Mother Gravity...
Glad you were able to save your plane if your not using a UBEC, get one and use them, its cheap insurance against a low voltage Brown out condition, and it could have been a masking problem too, good thing it happened way up there , Take care, Chellie

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Old 06-29-2011, 12:02 PM   #6
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Originally Posted by kyleservicetech View Post

You absolutely must have adequate receiver batteries for this stuff though. That rules out those 5 cell "AA" 2700 milliampere hour batteries for a giant scale model airplane!

Check out the Castle Creations 10 Amp Switching BEC for your models. Less weight, less cost than a 5 cell Nih AA size battery, and far outperforms them.
OK gotta a question about this as I have yet to use a separate BEC for anything, but I have pre-ordered E-flites new Super Cub that comes out in July and was thinking about using a separate battery pack for the receiver and have seen where some people still use just their regular battery but have a separate BEC.

So far my set-up is going to have a 60amp Turnigy Plush ESC on a Turnigy 32 Motor, six servos (flaps) and nav lights (going as scale as possible), all using a 4S 3300mAh battery.

Now the Turnigy 60amp Plush has a built in 3amp BEC which I have been told is great and don't worry about getting a separate BEC but with this being my first "real" expensive airplane I just wanted to get some opinions from here and you guys always help with that!

Thanks,
Bob
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Old 06-29-2011, 12:12 PM   #7
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Originally Posted by RCFlyer44 View Post
OK gotta a question about this as I have yet to use a separate BEC for anything, but I have pre-ordered E-flites new Super Cub that comes out in July and was thinking about using a separate battery pack for the receiver and have seen where some people still use just their regular battery but have a separate BEC.

So far my set-up is going to have a 60amp Turnigy Plush ESC on a Turnigy 32 Motor, six servos (flaps) and nav lights (going as scale as possible), all using a 4S 3300mAh battery.

Now the Turnigy 60amp Plush has a built in 3amp BEC which I have been told is great and don't worry about getting a separate BEC but with this being my first "real" expensive airplane I just wanted to get some opinions from here and you guys always help with that!

Thanks,
Bob

A Castle BEC, or a separate receiver pack, if you have the space and can handle the weight, is the way to go.

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Old 06-29-2011, 12:30 PM   #8
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Let's just keep things in perspective: My setup is pretty much a joke. We're talking a dirt cheap knock-off receiver in an equally dirt cheap Chinese plane. I don't think it would be wise to see this incident as a testament to the lack of reliability of 2.4GHz technology. It's more a testament to what kind of glitches you can expect if you go dirt cheap...

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Old 06-29-2011, 12:48 PM   #9
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Originally Posted by firemanbill View Post
A Castle BEC, or a separate receiver pack, if you have the space and can handle the weight, is the way to go.
I meant to put in my original that I was not that impressed with Castle, we had a guy out at our field last friday who had a brand new Christian Eagle using a 100amp Castle ESC and it was bench testing on our table fine but when he started his take off run the ESC smoked. Not saying it is the ESC's fault but his first reaction was that was the last Castle ESC he was purchasing so guessing he might have had some other issues with them.
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Old 06-29-2011, 12:52 PM   #10
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Originally Posted by firemanbill View Post
A Castle BEC, or a separate receiver pack, if you have the space and can handle the weight, is the way to go.
So guessing a NiMH receiver pack, and you disconnect one or more of the wires coming from the ESC to the Rx now?
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Old 06-29-2011, 01:03 PM   #11
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Originally Posted by RCFlyer44 View Post
I meant to put in my original that I was not that impressed with Castle, we had a guy out at our field last friday who had a brand new Christian Eagle using a 100amp Castle ESC and it was bench testing on our table fine but when he started his take off run the ESC smoked. Not saying it is the ESC's fault but his first reaction was that was the last Castle ESC he was purchasing so guessing he might have had some other issues with them.
Even Rolls Royce has a service Department... I guess everything can have issues. I blew out the capacitors on a very old Castle HV85 that I bought used from another guy. I called Castle and they said they would replace it with a brand new ICE HV 80 for less than half the cost of a new one.

Generally I have had Excellent results with Castle products, and tremendous customer support.

Originally Posted by RCFlyer44 View Post
So guessing a NiMH receiver pack, and you disconnect one or more of the wires coming from the ESC to the Rx now?
Yeah, remove the red wire and you're in business. I typically run ESC's that do not have internal BEC's on my larger stuff, in that case you just plug it in and don't have to worry about removing a wire

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Old 06-29-2011, 01:04 PM   #12
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OK answering some of my own questions, but just looked at Castle's website and you basically disconnect the red wire from the ESC to the throttle plug on the RX if you are using a BEC. What then is the real advantage of a separate BEC vs. one built into the ESC? Only thing I am seeing is this one has a 10amp draw vs. a 3amp on the built in one, probably a good thing considering I will have 6 servos going, but is that it or is there something else I am not thinking about?

Seems the one advantage of this is a 10gram BEC vs 97gram NiMH pack.
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Old 06-29-2011, 01:15 PM   #13
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Originally Posted by RCFlyer44 View Post
OK answering some of my own questions, but just looked at Castle's website and you basically disconnect the red wire from the ESC to the throttle plug on the RX if you are using a BEC. What then is the real advantage of a separate BEC vs. one built into the ESC? Only thing I am seeing is this one has a 10amp draw vs. a 3amp on the built in one, probably a good thing considering I will have 6 servos going, but is that it or is there something else I am not thinking about?

Seems the one advantage of this is a 10gram BEC vs 97gram NiMH pack.
Generally the BEC found in an ESC is a linear voltage regulator (or linear mode bec), quite simply the way these work is to take the input voltage (11.1V on a 3S lipo) and outputs 5V to the rx. The problem is that it has to dispose of the excess 6.1V and to do this it converts it to heat. Generally these linear mode BEC's are rated at 2-3 Amps, however what the manufacturers do not tell you is that this rating is only true with a 6V input. Using a 3S (11.1V) input the BEC will only deliver around 0.5A before it starts to overheat. Linear BEC's rarely reach more than 50% efficiency and can run as low as 10-15% efficiency.

Generally external BEC's are switching voltage regulators (or switched mode bec), these do not care about input voltage and can run up to around 30V+ input. A switching regulator works by taking small chunks of energy, bit by bit, from the input voltage source, and moving them to the output. This is accomplished with the help of an electrical switch and a controller which regulates the rate at which energy is transferred to the output (hence the term “switching regulator”).

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Old 06-29-2011, 03:12 PM   #14
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This has been an interesting thread to follow since I have a similar issue going on with Yak 54 foamy I picked up from 2 Dog RC. Came with a DualSky 25 a ESC which has a linear BEC built in with a Spektrum 6110E and four HS-55 clones.
http://www.2dogrc.com/product/dualsk...-brushless-esc
Thought about it awhile and decided ( against the warning I heard going off) to go ahead and try it. Saw the first brown out and did not recognize what was going on as I was spinning the plane pretty hard and it did recover in time to keep it out of the ground. The second episode (same flight) was not so lucky, but minimal damage. Did the repairs and put the plane back up, just flying easy circles and came down after one slight bobble to check it and found the indicator light flashing. I have previously checked the draw on the system and found a max static draw of 18 amps

Have replaced the DualSky ESC with a Heads Up 32 ESC with a Heads Up UBEC set up I had sitting at home but have not had a chance to test fly it as yet.
http://www.headsuprc.com/servlet/the...-32-Amp/Detail
http://www.headsuprc.com/servlet/the...iversal/Detail

If this does not resolve the issue, I guess I will try to reposition the receiver to see if it is getting masked, but there does not seem to be much near it that I would think could hide the receiver that well.
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Old 06-29-2011, 04:37 PM   #15
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Originally Posted by RCFlyer44 View Post
OK gotta a question about this as I have yet to use a separate BEC for anything, but I have pre-ordered E-flites new Super Cub that comes out in July and was thinking about using a separate battery pack for the receiver and have seen where some people still use just their regular battery but have a separate BEC.

So far my set-up is going to have a 60amp Turnigy Plush ESC on a Turnigy 32 Motor, six servos (flaps) and nav lights (going as scale as possible), all using a 4S 3300mAh battery.

Now the Turnigy 60amp Plush has a built in 3amp BEC which I have been told is great and don't worry about getting a separate BEC but with this being my first "real" expensive airplane I just wanted to get some opinions from here and you guys always help with that!

Thanks,
Bob
Don't know about the Turnigy BEC, if its linear or "Switching". At any rate, IMHO, a 3 amp switching BEC is not nearly enough for six servos and nav lights.

Problem with those linear voltage regulators with a "3 Amp" rating, even with a two or three cell Lipo battery, pulling three amperes is an INTERMITTENT rating! Pulling three amperes continuously will overheat them and they will shut down. (You can only get the continuous 3 amp rating if the linear regulator does not overheat. And without a big heat sink, they will overheat on a constant load. That heat sink has to be about 2 inches square with fins on it.)

The Castle Creations 10 Amp BEC will handle a peak current of 10 amperes, and a continuous current of something like 1/2 of that. I've checked several of my CC 10 Amp BEC's, they put out 13 or 14 Amps momentary before they shut down to protect themselves. As soon as the severe overload over its rating was removed, they instantly returned to normal voltage output.

These uBEC's are easy to hook up. Just connect their DC input to the input of your ESC. And connect their DC output to your receiver. Be sure to unplug the red wire from your ESC's BEC, you don't want the two BEC's fighting each other.

If you've got a really big model, you may want to go to dual receiver supplies. My giant scale Extra 330 has both a 10 Amp CC uBEC, and a backup two cell 2300 Mah A123 battery. The A123 battery is isolated from the uBEC with a 10 amp silicon diode. The model now has 35 flights on it, and my built in undervoltage alarm has indicated that the 10 Amp CC uBEC has NEVER dropped below 6.0 volts DC during those 35 flights.

Take a look at my final version in post #19 per below:
http://www.wattflyer.com/forums/showthread.php?t=58310

Nice thing about this setup is it has dual battery inputs to the receiver, so that helps reduce failures from receiver switches and so on.

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Old 06-29-2011, 06:17 PM   #16
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Originally Posted by firemanbill View Post
Generally the BEC found in an ESC is a linear voltage regulator (or linear mode bec), quite simply the way these work is to take the input voltage (11.1V on a 3S lipo) and outputs 5V to the rx. The problem is that it has to dispose of the excess 6.1V and to do this it converts it to heat. Generally these linear mode BEC's are rated at 2-3 Amps, however what the manufacturers do not tell you is that this rating is only true with a 6V input. Using a 3S (11.1V) input the BEC will only deliver around 0.5A before it starts to overheat. Linear BEC's rarely reach more than 50% efficiency and can run as low as 10-15% efficiency.

Generally external BEC's are switching voltage regulators (or switched mode bec), these do not care about input voltage and can run up to around 30V+ input. A switching regulator works by taking small chunks of energy, bit by bit, from the input voltage source, and moving them to the output. This is accomplished with the help of an electrical switch and a controller which regulates the rate at which energy is transferred to the output (hence the term “switching regulator”).
Great info thanks! Stuff I didn't know at all and would never have thought of. And overall you would still recommend a separate battery pack vs. the separate BEC?
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Old 06-29-2011, 06:25 PM   #17
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Originally Posted by kyleservicetech View Post
If you've got a really big model, you may want to go to dual receiver supplies. My giant scale Extra 330 has both a 10 Amp CC uBEC, and a backup two cell 2300 Mah A123 battery. The A123 battery is isolated from the uBEC with a 10 amp silicon diode. The model now has 35 flights on it, and my built in undervoltage alarm has indicated that the 10 Amp CC uBEC has NEVER dropped below 6.0 volts DC during those 35 flights.

Take a look at my final version in post #19 per below:
http://www.wattflyer.com/forums/showthread.php?t=58310

Nice thing about this setup is it has dual battery inputs to the receiver, so that helps reduce failures from receiver switches and so on.
I was going to ask if you plugged both inputs into the receiver and how that could possibly work, but obviously you are a well seasoned electrical engineer after seeing your set up. Definitely not going to have problems with that kind of redundancy. You did this for NASA too I bet .

The info really helped. I think between you and Bill I have definitely made my mind up to not just use the built in BEC on the ESC and kind of leaning towards the CC 10amp BEC, because the Super Cub is not a HUGE plane, but it is a larger investment than I have on my other planes, almost combined so I think a $25 BEC is a wise investment and doesn't add the weight of another battery pack and something else to charge up, check the charge at the field etc.

Thank you!
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Old 06-29-2011, 07:06 PM   #18
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Originally Posted by RCFlyer44 View Post
Great info thanks! Stuff I didn't know at all and would never have thought of. And overall you would still recommend a separate battery pack vs. the separate BEC?
Yeah I run a separate receiver pack. I did recently have a bad moment with that even, proof positive that no system is fool proof. I was flying along with one of my rather large planes and about 6 minutes into my flight I lost all radio contact. She crashed and was pretty well destroyed. Upon investigating I found that my 6v receiver pack still had a full charge but when I put a load on it it dropped down well into the 2 volt region. One of the cells in the pack had crapped out I suppose and caused the failure. I had just recently tested that battery too so the fact that it failed just shows that "Stuff happens" I was pretty bummed about the whole deal but overall I'll still use receiver packs in my bigger planes as opposed to the other methods.

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Old 06-29-2011, 07:29 PM   #19
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Originally Posted by RCFlyer44 View Post
I was going to ask if you plugged both inputs into the receiver and how that could possibly work, but obviously you are a well seasoned electrical engineer after seeing your set up. Definitely not going to have problems with that kind of redundancy. You did this for NASA too I bet .

Thank you!
Nope, not an engineer, just a retired senior electronic tech with 50 years of experience in this stuff. And a job that took me to just about every state in the USA (including Hawaii and Alaska) and 29 foreign countries.

Fifty years goes back to where the circuit breaker controls I worked on had vacuum tubes. What comes around, goes around, now those high power circuit breaker contacts are inside of a ceramic vacuum bottle, and handle 38,000 Volts at 800 Amps continuously. They can clear a fault of 16,000 Amps at 38KV. And their size has shrunk down to smaller than a 2 liter soda bottle. Add to that the mechanical stuff and you've got a 38KV 800 amp three phase circuit breaker that weighs about 300 pounds, a fourth of what they used to weigh.

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Old 06-29-2011, 07:33 PM   #20
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Originally Posted by firemanbill View Post
Yeah I run a separate receiver pack. I did recently have a bad moment with that even, proof positive that no system is fool proof. I was flying along with one of my rather large planes and about 6 minutes into my flight I lost all radio contact. She crashed and was pretty well destroyed. Upon investigating I found that my 6v receiver pack still had a full charge but when I put a load on it it dropped down well into the 2 volt region. One of the cells in the pack had crapped out I suppose and caused the failure. I had just recently tested that battery too so the fact that it failed just shows that "Stuff happens" I was pretty bummed about the whole deal but overall I'll still use receiver packs in my bigger planes as opposed to the other methods.
Ouch that hurts.

Did you run a full discharge test at perhaps 5 amps on your recent test? Or just a quick load test? Normally Nicads and Nih batteries just slowly fade away, its unusual for them to just quit. Unless they've got broken spot welds inside the shrink wrapping or similar.

One test unit that works well is the West Mountain Radio CBA system. Not cheap, but far cheaper than a lost model. I use mine to run discharge tests on my A123 packs before using them in an airplane. Also use it for checking other club members receiver batteries. One of them was using a five cell "AA" type 2700 Mah receiver battery in his $$$$ wet turbine. NOT a good idea. He now has a good quality LiFe battery in it.

Take a look at the attached discharge curves for two different Nih transmitter batteries that were rated at 1000 Mah. One of them was less than a year old.


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Old 06-29-2011, 10:28 PM   #21
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Originally Posted by firemanbill View Post
Yeah I run a separate receiver pack. I did recently have a bad moment with that even, proof positive that no system is fool proof. I was flying along with one of my rather large planes and about 6 minutes into my flight I lost all radio contact. She crashed and was pretty well destroyed. Upon investigating I found that my 6v receiver pack still had a full charge but when I put a load on it it dropped down well into the 2 volt region. One of the cells in the pack had crapped out I suppose and caused the failure. I had just recently tested that battery too so the fact that it failed just shows that "Stuff happens" I was pretty bummed about the whole deal but overall I'll still use receiver packs in my bigger planes as opposed to the other methods.
Uggh sorry to hear that, was that a ShoeString I seem to remember reading about?
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Old 06-30-2011, 12:26 AM   #22
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Originally Posted by RCFlyer44 View Post
Uggh sorry to hear that, was that a ShoeString I seem to remember reading about?
No, the Shoestring was a structural failure. That plane was never designed to do 131mph... I did it, but not for long! It's a .60 size plane that I had doing 93 with a .90 size glow motor in it. I made an electric version and it topped out on radar at 131. I flew her for a while but it finally gave way, a spectacular fiery crash at SEFF in front of 500 or so of my closest friends! I know now what I need to fix, and I'll have it back in the air faster and better than before!

I'm not ready to talk about the other one yet, It still hurts a bit too much.

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Old 06-30-2011, 03:41 AM   #23
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Finally had time to get the Yak up tonight, flew happily with no issues so I hope that means it is filed under lessons learned and now reinforced.
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Old 07-06-2011, 02:15 PM   #24
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See posts 14 and 23

Put the YAK back up in the air Saturday evening, had two uneventful flights, and then on the third flight had a loss of control, glide in landing with only a broken prop with the receiver indicating one data hold, no brown out. The only thing I thought looked out of line was that both of the antenna were pointed in more of less the same direction rather than being at right angles to each other.
Checked the system voltage last night and the UBEC output was rock steady at 5.3 v with the servos loaded and motor at full throttle and as usual I was unable to reproduce the problem.
Thought about trying to change the receiver position, but it worked fine when I first started to fly this plane. The receiver is located under the wing, you can see it in the picture series by using the link below:
http://2dogrc.com/techone-indestruct...-foam-airplane

There are a couple of CF rods located in the fuse and wing but not that much and the rest of the airframe is foam

This receiver has some mileage on it so it is possible there is an intermitent problem. I went ahead and changed it out to a new receiver. Will how that works out.
Tx is a JR 9503 having no issues with other multiple aircraft
Any other ideas to try?
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Old 07-06-2011, 04:00 PM   #25
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Originally Posted by dumo01 View Post

See posts 14 and 23

Put the YAK back up in the air Saturday evening, had two uneventful flights, and then on the third flight had a loss of control, glide in landing with only a broken prop with the receiver indicating one data hold, no brown out. The only thing I thought looked out of line was that both of the antenna were pointed in more of less the same direction rather than being at right angles to each other.
Checked the system voltage last night and the UBEC output was rock steady at 5.3 v with the servos loaded and motor at full throttle and as usual I was unable to reproduce the problem.
Thought about trying to change the receiver position, but it worked fine when I first started to fly this plane. The receiver is located under the wing, you can see it in the picture series by using the link below:
http://2dogrc.com/techone-indestruct...-foam-airplane

There are a couple of CF rods located in the fuse and wing but not that much and the rest of the airframe is foam

This receiver has some mileage on it so it is possible there is an intermitent problem. I went ahead and changed it out to a new receiver. Will how that works out.
Tx is a JR 9503 having no issues with other multiple aircraft
Any other ideas to try?

H'mmmmm
Are you using the ESC's built in BEC? (Battery Elimination Circuit). If so, and if its the typical linear voltage regulator, if that regulator gets to hot, it shuts down, killing power to your receiver. And by the time you've got to your model, that regulator has cooled off, and will restart itself. Those claims of a 3 amp BEC in an ESC are for an intermittent current rating only. Apply a constant 3 amp load to them, and they will quickly overheat and shut down.

Those regulators are designed to work with heat sinks, large ones on the order of a finned two inch square unit. And the ESC's simply don't use heat sinks on their linear regulators.

IMHO, you might investigate one of those Castle Creations 10 amp uBEC (Switching Battery Elimination Circuit) for your model. They weigh in at about 1/2 ounce. I've tested them at a constant 6 ampere load for 10 minutes, with zero problems, or overheating.

I'm using one of them on my giant scale 78 inch 189 pound model with seven Hitec 645MG servos. That model also has a battery backup, but so far, the battery backup has never kicked in. My models have four of them, and so far they've been flawless.

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