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Old Nov 10, 2013, 10:44 AM
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USA, CA, El Dorado Hills
Joined Apr 2008
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Question
Reliable Large Jet Power

So recently I had brown-out issues on two different large jets likely due to drawing too much power through the receiver.

One I lost on takeoff, the other I managed to get back (barely). I'm starting on a dual-120mm A-10 that has a lot of large servos so I want to make sure I'm picking good components. I'm thinking as we get bigger and more power to bigger servos I need to pick different components.

This is what I'm using:
2 x BVM EVF 120mm Fans
2 x JR DS3711HV Ailerons Servos
2 x JR DS3711HV Rudder Servos
2 x JR DS3711HV Elevator Servos
4 x JR DS3711HV Flap Servos
1 x JR DS3711HV Steering Servo

Gear is Air Up/Down and Air Brakes
The nose door is air open/close.

This is what I think I need:
1 x AR12200 Cockpit RX
1 x EV5U Air Sequencing Unit
2 x 2S-2500mah LiFE batteries

My questions:
1. Is the AR12200 sufficient to be able to power all of these servos?
The Four Flaps with be matched and the 2 Rudders will be matched

2. Is the EV5U a good choice to handle all of the air requirements. Does it handle the door, gear sequencing properly?

3. Is there any disadvantage to running the HV servos vs. the JR DS3421 instead? In other words using higher voltage does that create issues with the amp draw?

4. Do I need to wrap any of the servo wires around magnets given the longer runs and more power?
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Old Nov 10, 2013, 12:56 PM
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United Kingdom, England, Southampton
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Question 4 (don't know anything about the others).

They are not magnets, they should be ferrite rings and you thread the wires through as many turns as you can. 4 or 5 turns is fine. You may have to put the servo plugs on afterwards. Any electronic component store should have suitable ones.

The 'clip on' split ones are useless. As you only thread the wire through once they do not do anything useful.

Use the ferrite rings. They may do good and can't possibly do any harm. But I think they may be more important on the old, lower, frequencies as the servo leads could be about as long as the aerial and thus act as a sort of aerial and take interference to the receiver. As the lengths are very different on 2.4 this should not happen. But why take the risk of not having them?
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Old Nov 10, 2013, 03:08 PM
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Fontana, California, United States
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Sean,
get the X10+ channel expander from XPS. You can use a separate buss to power all your servos and no way it will brown out. It works with most every kind of rx and is what I use in my big stuff. I almost lost my A-4 last year while I was flying and all of a sudden it locked out! Never done that before! It came back in a flash even though it seemed like 10 minutes and I landed it immediately!! I found that my brake valve had shorted out internally and cause the power spike and brown out. With the X10+ that would have never happened. Power goes to all your servos through a separate buss and radio is fed from same buss but not with little wires. It feeds off from the circuit as a parallel (piggyback) so it doesn't matter what the servos are drawing, your radio is still fed all it needs. When your rx power is fed through the rx it doesn't take much but a couple big torque servos to rob it of what it needs.
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Old Nov 10, 2013, 03:10 PM
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Here it is,

X10+ Channel Expander
X10+ Channel Expander

Details




XtremeLink® X10+ Channel Expander

Compatible with XtremeLink®, Futaba SBUS, and Spektrum/compatible Satellite receivers!




Click picture for more details!


The X10+ Channel Expander is a small device that acts as a power expander, channel expander, voltage monitor, and failsafe system for different types of receivers that output a serial data stream. So, XPS Nano (requires firmware upgrade), Nano II, & RFU, Futaba SBUS, and Spektrum satellite receivers are all supported. ALL types of servos are supported, so SBUS receivers can work with non-SBUS servos!






X10+ Specifications:


Input type: serial data stream
Channel outputs: 10 (or 11 with auxiliary port)
Operating voltage: 1.8v - 16v
Servo bus current: >80A
Recognized protocols: Xtreme (fast), Xtreme (slow) Futaba SBUS, Spektrum satellite, PPM
Size: 1.4" x 1.4" x .450"
Servo plug spacing: .113"
Weight: .256oz (7.30g)
Accessories included: two mounting spacers
Recommeneded accessories: XPS Serial Link, UltraTwist cables, EC3 harness pair


Click here for wiring options.
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Old Nov 10, 2013, 07:55 PM
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Brentwood, California
Joined Jul 2007
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Sean you will not like my answer, but IMHO
Get a futaba fasst radio

Skip all the power buses run direct to a 14 channel fasst rx
run your two life packs direct to the rx, sometimes I even skip the switch and just plug in a deans direct.

keep it simple....forget the HV your don't need it. more stuff is more weight and more things to fail

I've been running giant scale high power electrics for many years and this is the setup that I trust. The problems I have seen are almost always spektrum
if you keep it, send in your radio for a check up. Something doesn't sound right if you have different RX's in both planes the one common is the radio
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Old Nov 10, 2013, 08:54 PM
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Mine is plugged directly in as well, just into a dedicated battery lead not using dinky little servo wires. The X10+ has two holes next to each other and that is where you solder battery leads and your choice of connector. No switch just direct to my A123.
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Old Nov 10, 2013, 08:56 PM
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Ron the radio cant cause a brown out. Its not his radio.
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Old Nov 10, 2013, 11:21 PM
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United Kingdom, England, Southampton
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sbritton,

I agree with Ron101.

Futaba is a VERY reliable radio. You just don't hear of problems with them, and FASST is a superb transmission method. The 14SG (may be called something different is the US) would be fine. Don't go for the expensive 18 channel set - it is only some useless transmitter gimmicks to go wrong. There may be some 'cost cutting' in their low end radios, as in every brand, but not in their 10 channel and up radios.

Note - I am not just praising 'my own radio'. I use neither Futaba nor Spektrum. I use Multiplex. Not because it is better, but because it is European - so am I.

Servos, power distribution.

This plane is not truly 'Giant Scale', it is just 'quite big'. Nor is it particularly fast - we are not talking an Electra or Bandit on 12S (or lately 14S) here. I grant that it is pretty heavy.

That it happens to be an EDF doesn't make any difference.

The Futaba S-Bus system is perfectly suitable. It allows you to 'spread' the power supplies if you see fit. So you don't have to use any 'foreign attachments' made by small, frequently short-lived, organisations with often just an engineer or two and no long-term depth of expertise. Futaba is a large company, lots of quality control, and long experience. Don't mess up all that with small company's pointless over complication. I suggested S-Bus, Ron101 goes for a conventional 14 channel receiver connected direct. Your choice.

Any big metal geared Futaba servos will do.
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Old Nov 10, 2013, 11:32 PM
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Wow. Arrogance knows no bounds. I want you to tell us how a radio caused a brown out? This "small" company makes excellent equipment and the part i was refering to cost $25 and it will absolutely end his issues. It is compatable with most radio systems and eliminates small servo leads from carrying all the current to feed all these high torque servos. It doesnt take much to draw the voltage down to brown out levels with spektrum. This would stop that with spending $500......
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Old Nov 10, 2013, 11:45 PM
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Quote:
Originally Posted by rvincent View Post
Wow. Arrogance knows no bounds. I want you to tell us how a radio caused a brown out? This "small" company makes excellent equipment and the part i was refering to cost $25 and it will absolutely end his issues. It is compatable with most radio systems and eliminates small servo leads from carrying all the current to feed all these high torque servos. It doesnt take much to draw the voltage down to brown out levels with spektrum. This would stop that with spending $500......
Nothing to do with arrogance. Just a safe choice. Futaba is one of the oldest in the business and it works. If it needed any extra bits they would have built them in. I have not made any criticism of Spektrum. You have, with your "It doesn't take much..." And I do not think he is building this plane as a money-saving exercise

I am not on this thread to argue with others. Just to offer my radio experience of over 50 years to the OP. He is free to choose what he likes.
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Last edited by Mark Powell; Nov 11, 2013 at 02:49 AM.
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Old Nov 11, 2013, 12:01 AM
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I use the jr power safe RX's 9 and 12 channel on all my big stuff with a pair of a123 cell packs and solid as a rock. With JR/Spektrum you just have to know how to set it up and check the data ( i like to do it after every flight on the big jets!) On my 42% Extra I have 9) 333oz servos all running hard and I use a smartfly to distribute the power and an AR9100 to connect and it's solid as a rock as well.

Every radio brand can fail and I have seen it or heard of it from every brand.

I have not had the need to use the HV servos, I run the straight 6.6 volt A123 power into the JR and Hitec servos I use and all good.
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Old Nov 11, 2013, 05:24 AM
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Quote:
Originally Posted by bri6672 View Post
Every radio brand can fail and I have seen it or heard of it from every brand.
Sure they can. And some actually do. My first 'proportional' radio was a Dee Bee Quadruplex. A bit crude, but worked fine (and still does, but I don't use it). Look at it sometimes and recall my happy youth. It's real, better than old photos. Followed by a Sampey 404. A few minor funnies but it never crashed a plane. Then a Bonner Digimite. Nothing to say, really - they also made good single channel escapements. Gave up for some years, started again, JR 347, 25 or so years ago. Still in fairly frequent use, never failed, but why did they style it like a 1950's jukebox?

Bought a Multiplex simply because I thought it looked nice, and I fancied some 'shopping therapy'. Worked, so I have used them ever since. Never failed in any way. But a couple of bad reports, true or not (how can I tell?) on a make I have never owned crosses them off my consider list. Might be unfair, but it's my money, buy whatever I like. So can you.
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Old Nov 11, 2013, 09:55 AM
Xtreme Power Systems
Lake Havasu, AZ
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Quote:
Originally Posted by Mark Powell View Post
The Futaba S-Bus system is perfectly suitable. It allows you to 'spread' the power supplies if you see fit. So you don't have to use any 'foreign attachments' made by small, frequently short-lived, organisations with often just an engineer or two and no long-term depth of expertise. Futaba is a large company, lots of quality control, and long experience. Don't mess up all that with small company's pointless over complication. I suggested S-Bus, Ron101 goes for a conventional 14 channel receiver connected direct. Your choice.
The S.BUS is perfectly suitable as a control link, but not as a power solution. Futaba would have you believe (giving their examples both in their manual and videos posted by Hobbico) that you can power all of your S.BUS servos through a single power cable, daisy-chained through hubs. Take a look at the datasheets for those servo connectors and pins. Not only will you find an insertion life-cycle (yes, they're only good for some many uses), you will also find a maximum amperage of ~5A. This means that if you are powering your receiver though a single battery connection, the entire servo bus is going to be sharing the same 5A supply. When that bus supply is exceeded several things happen.. a voltage drop and micro-pitting of the contact surfaces, typically at the source connector. Adding a second battery connection (preferably to the opposite end of the bus) will help by doubling the current capability of the bus. For our jets, 10A is probably enough to get by with unless you are doing a bunch of bank and yank maneuvers. People seem to think that servos draw their highest amount of current during a stalled condition and that is not true. Servos draw 2-5 times the stalled current during a direction change - that is when the servo is moving one direction and told to switch directions. In order to achieve the fastest transit times the servo electronics don't stop the motor before reversing its direction. They just reverse it. This results in a tremendous current spike as the gear train is spinning against the direction the motor is now trying to spin. Granted, it lasts typically 25ms-50ms but that is long enough that it can cause a brown out or lockout in many of the systems out there. An example I give for this issue is my Hangar 9 Extra 360 with 7 JR8711 servos. Using an amperage recorder, I see just over 60A of current draw on a snap-to-snap maneuver. This lasts for about 28ms peak and then tapers off to normal amperage over the next 16ms.

Using real power inputs (heavy duty wires) and a multi-layered 2oz+ copper poured bus is a way to achieve solid power for every single servo output on a bus. This is what the X10+ gives you. I pulled 80A @12v across the bus during testing with absolutely no issues.

As far as the 'small vs. large'... XPS has sold millions of dollars of radio systems world-wide since 2006. We introduced full range 2.4GHz to the R/C industry (yes, before Spektrum) and also had the first aircraft modules for R/C. We continue to develop new products that modelers need because XPS is made up of modelers, with myself also being an engineer for over 30 years. That is a big difference between our company and other "large" companies. How many of those engineers at Futaba or JR are actually avid modelers who perform field tests and can tell the difference between something that works on paper and something that works in the real world? I have met with both companies' engineers.

We are selling a lot of the X10+ to Futaba owners because it gives them a way to properly power their system, and they can also use any brand of servo (S.BUS servos not required), set failsafes individually for every channel, change channel mapping, reverse servos, set offsets, etc.

The X10+ outputs up 11 channels, but if you need more channels or would like to have duplicates of channels (even servo reversed duplicates) you could add a 2nd X10+ board.

The X10+ can also be used with a Spektrum satellite receiver. However, until we release the new firmware update that allows a 2nd receiver to be used, I would not recommend flying the Spektrum system on just one receiver.

There will be magazines releasing reviews of the X10+, so you will be able to get the scoop from those... or you can check out our forum area where people from all brands are reporting their results using the X10+.

There is no "complication" with using the X10+. You use a receiver, such as small S.BUS receiver (all of the Futaba S.BUS receivers have the same range) and single cable connected between the receiver and X10+. You can place the X10+ anywhere that is convenient in your fuse, with the servo leads now much shorter than before because there is no need to try to keep a "receiver" out in the open and away from wiring, metal, carbon, etc. because there is no RF on the X10+ itself. You mount the receiver anywhere away from the "noise", such as a vertical stab, wing tip, turtle deck, etc. Most people don't realize that you have to keep all wires, metal, carbon, etc. at least 2" away from any brand's 2.4GHz antenna system. The 1/4 wave length antenna for 2.4GHz is ~27mm long. If you have something conductive too close, it alters the antenna tuning and you can kiss your range and multi-path rejection goodbye. Moving wires are the worse.

So, by using the X10+ you are actually simplifying your installation by reducing the length of the servo wires normally needed to locate a 2.4GHz receiver to an open location, eliminating any type of other power expander solution where the receiver is piggy-backed on to it, providing a high current input for power, and reducing your cost factor by using a smaller/lighter and less expensive receiver. The X10+ (like our receivers) also runs down to 1.8v, which is well below the threshold of where servo electronics stop working, meaning that the brownout is not actually possible since the load goes away when the servos stop working (this occurs at ~2.5v).

BTW, we have a 2.4GHz system for the Multiplex radios, including a module for the EVO that support full M-Link emulation (all versions up to the current v3.46) including telemetry in the display - and its legal in the U.S.
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Old Nov 11, 2013, 10:23 AM
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Thanks for the clarification Jim I know I LOVE mine! It absolutely make the install easy and less complicated. The way installs should have been with these large EDF's from day one. I won't go back for sure.
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Old Nov 11, 2013, 03:32 PM
Xtreme Power Systems
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2.4GHz has been quite the learning experience, for both radio manufacturers and modelers. I wish I would have done it this way from the very beginning.
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