Receiver power for giant scale planes

[KatManDEW]

What do you all prefer for powering the receiver on giant scale planes? I have two lipoly receiver batteries with a Batshare and regulators, and a Smart Fly power expander on my 34% Extra with Neu 2215, but that seems like overkill for a 50cc plane.

I just helped a friend range check a 50cc plane with Hacker A60-18L and Castle 110HV, and it failed miserably. We couldn't get more than a few steps away with the transmitter while the motor was running, and the servos and throttle went whako. It was better without the motor running, but still unacceptable.

He's using a Electro Dynamics Pow'R Bus Pro, with a RX battery for servo power, and a BEC for receiver power. We tried a Castle BEC and a Hyperion BEC (which I have had very good luck with).

We tried a second RX pack for the RX power, and it was much better, but still far from acceptable with the motor running.

What are you all using?

[K0na_stinky]

I am new to large scale planes and I am also wondering this.

I emailed Futaba asking if I can run 5 Futaba S9157 servos (425 oz-in) on a R617FS 7-channel receiver and the guy that responded said that the receiver will have no problems.

I'm hoping to get a Extreme Flight 88" yak. CC 110 HV ESC, the new Great Planes Rimfire "65cc" motor and 12s 5000 batts.

My question is do you think I will have similar range problems?

Also can you run 2 BEC's?

[KatManDEW]

Koolflight makes a special version of their BEC that allows using two of them.

I forgot to mention that my friend was using 72mhz. He switched to Spektrum today and the system is now rock solid. That's pretty amazing because it was one of the worst cases of radio glitching that I have ever seen.

[dag214]

Koolflight makes a special version of their BEC that allows using two of them.

I forgot to mention that my friend was using 72mhz. He switched to Spektrum today and the system is now rock solid. That's pretty amazing because it was one of the worst cases of radio glitching that I have ever seen.

I was think about saying something, but most the time try to just keep a low profile on other threads, but......

I have six Hacker A60-16L on my B-36D I am building. I tested two of the motors running from one of my old Futaba radios, I could not even get across the shop without everything going nuts. I re-checked all my bolts and nuts and found about 25% had not been tighten properly (my fault), then tested it again, was much better, but still had problems just being 10 feet away. Then I went to my 2.4 gig system and zero problem. Then I found on the back of my test stand all the extra washers had not pulled up tight when I made my test stand, I tightened all of those and went back to my old Futaba and it was great. But in the end I will use my 2.4 gig on my monster. Anything not really tight will make a bunch of noise with these electric motors, not sure why.

Hope that helps.

DAG

[KatManDEW]

Thanks for the info DAG. Your B-36 is an awesome project!

I have had a DEVIL of a time myself sometimes when using a BEC. One more than one occasion, just switching to different receiver fixed the problem. Last year I repaired a plane and pulled the receiver from another plane that needed repairs. That receiver would not range check, no way no how in the other plane. I put another receiver in it and it works. I repaired the second plane and reinstalled the "problem" receiver, and it works fine. Both of these planes use BEC's.

[twest]

I love bec's (in smaller planes), but they do provide a direct path from the power system to the radio. Using optocupled controllers with separate battery power to the radio should reduce noise. You can always use the castle bec between a 2s lithium pack and the radio.

As power goes up, so does possible interference. "Old standby" techniquesfor really pesky problems included wrapping the reciever body in aluminium foil, and using chokes on the leads of the esc, reciever battery, and sometimes on all the servos. The long wires in our radio systems can act like antannas.

USUALLY, if you keep plugging away at the problem, you will find a way to overcome the range problems. Sometimes you might not even be sure which "fix' actually worked.

Good luck!

[KatManDEW]

Aluminum foil around the receiver has never worked for me. But I wrapped aluminum foil around my head one time and that helped more than anything :D

I have a bag full of assorted chokes that we tried yesterday. It was actually worse. I don't think it ever really helped any of my problems in the past.

Given the problems I've had in the past, and the problems with my friend's plane yesterday, 2.4ghz sure seems like the way to go. And he and I have both been wanting to go there anyway.

[K0na_stinky]

I know I'm jacking the thread but its a pretty simple question.

For a EF 88" yak can I get away what out a power box for sure? Just use the receiver and a BEC? Or do I need a receiver battery?

Thanks.

[KatManDEW]

I know I'm jacking the thread but its a pretty simple question.

For a EF 88" yak can I get away what out a power box for sure? Just use the receiver and a BEC? Or do I need a receiver battery?

Thanks.

You're not hijacking the thread at all. I'm curious as to what folks think about your question.

[Geoff Dryer]

I use one 2300 mah A123 battery (Duralite) plugged into a Smart-Fly Power Expander Pro and a flag switch in my Hangar 9 33% Sukhoi (electric). It uses about 100 mah per flight. I have no range issues (PCM JR receiver). In a plane this big I wanted a separate battery for the radio gear just in case I have some sort of catastrophic failure of the lipos powering the motor.

[F1 Rocket]

My 87" 300 SHP uses a single 1500 MAH 2s pack and Duralite 7.5 amp 6v reg. Everything runs through a JR 921 rec. Servos are (5) JR 8611A's. After (4) 8 min flights the pack will take 1100-1200 MAH. This setup is simple, light, and has worked without issue for me.


Danny

[dag214]

I should have said what I am using when I am done with my B-36D,I will have 3 JR R922 RX's, each is made to take 2 batteries which will be A-123 6.0 volt 4200 Mha. That is 6 RX batteries, then each motor will have 1 6-cell 5000 Mha ThunderPower battery. She will have 32 servos. But even my small planes I run a separate RX battery. I know it adds weight, but have never had a crash because of RX problems, and yes I just knock on wood.

Cheers, DAG

[E-Challenged]

For my small scale electrics I only use 2.4ghz gear. The close spacing of power and R/C gear always in small models leads to glitching, range problems, and crashing. I have read that mechanical and electrically generated noise not only causes glitching but affects the gain controls in 72 mhz receivers which leads to reduced range. I don't trust anything but 2.4ghz for valued models anymore, and even then you have to watch supply voltage vs number of servos, certain receiver brownouts and resetting issues due to battery voltage drop issues and speed control BEC amp capacity vs use of separate switching BEC devices. I started building my own R/C systems in the early 60's and flying R/C models is still somewhat "iffy".

[Airbus]

I have become a big fan of A123 cells. Some great info can be found at

http://www.hangtimes.com/a123_batteries_for_giants_faq.html

I use 2 cell packs of the 2300ma size. No regulator or additional electronics needed. Fewer things to fail.

A123's have terrific output amperage and are far safer to care and feed than LiPos. If you build your own remember to use heavy gauge wire to carry all that power.

[Smash McCrash]

Interesting question... Anything I have of .90 size or larger gets a battery pack. I have a few .60 sized planes that have batteries, and a couple that have BEC's. I only fly Spektrum for reference, but I don't think I would change anything if I was on 72 still.

Mike

[K0na_stinky]

Interesting question... Anything I have of .90 size or larger gets a battery pack. I have a few .60 sized planes that have batteries, and a couple that have BEC's. I only fly Spektrum for reference, but I don't think I would change anything if I was on 72 still.

Mike
A few questions.

How big is a .90 size plane? I have only had electrics. How many watts, whats the weight and wingspan?

And why after that size do you go to a RX pack?


Also, can I fly a 88", 50cc size electric plane with out a power box?

Thanks.

[BoneDoc]

I run 2S x 2 packs straight to my AR 9100 on my 89" Slick and 87" SHP. It's been flawless thus far.

[Smash McCrash]

I don't know exactly where the cutoff is for plane size. For me, I guess I just put packs in the planes that need more weight somewhere to help balance, as I don't like putting dead weight in something. I would rather have the weight perform some kind of function. The Ultra Stick 60 (66" span, iirc) has a pack in the tail for balance, the Fokker DVII has a pack in the nose for balance. The Funtana 90 and Super Decathlon have packs for safety, at 2000W and 1600W I don't want any problems. Just need to be vigilant with checking the packs before flying. I have a Super Chipmunk 70E from Hyperion, while, about the same size as the Ultra Stick, weighs less. I have a CCBEC in this one as I didn't need any extra weight for balance. So, I guess from my reasoning, it really depends on the airframe.

Mike

[KatManDEW]

Some good info turning up. Thanks.

Hey Doc - That AR 9100 looks like the sweet setup. Does it have a built-in battery sharing feature? (so one battery doesn't back feed into the other if it goes bad) I can't tell by reading the specs for it... Are you running 2S lipoly, with the 8.4 volt servos?

I think "90 size" depends on the type of aircraft. For aerobatic planes, I always figured 90 size to be in the neighboord of 70 inches, and 8-9 pounds. But you can fly a giant Telemaster with a 90 too.

[Staggerflyer]

Just a note to those of you with glitching/range problems. One of the biggest problems with 72mhz systems, AM and FM bands has always been "electrical" noise, ie, glitches. ANY metal to metal contact, and most long lead/multiple servos on same lead items almost always guaranteed trouble. Thus lots of chokes and rewiring. Since going to 2.4G, all of my glitching/range problems have been eliminated.

Electric models are full of noise. While there are those who do get no problems on smaller models on 72mhz, personally, I wouldn't trust my bigger, expensive planes and helos to anything but 2.4G systems.

[BoneDoc]

Kat,

yes, it has a built in batt share, thus eliminating all that other stuff. That alone IMHO is worth the price of admission :).

[KatManDEW]

Just a note to those of you with glitching/range problems. One of the biggest problems with 72mhz systems, AM and FM bands has always been "electrical" noise, ie, glitches. ANY metal to metal contact, and most long lead/multiple servos on same lead items almost always guaranteed trouble. Thus lots of chokes and rewiring. Since going to 2.4G, all of my glitching/range problems have been eliminated.

Electric models are full of noise. While there are those who do get no problems on smaller models on 72mhz, personally, I wouldn't trust my bigger, expensive planes and helos to anything but 2.4G systems.

Many of us were flying bigger stuff before 2.4ghz became available, so we had to trust our planes to 72mhz. We had to work out the interference problems if we wanted to fly. I have not yet converted to 2.4ghz, but I will soon. Converting is not a quick & easy, or inexpensive proposition, if you have more than a couple aircraft.

[KatManDEW]

Kat,

yes, it has a built in batt share, thus eliminating all that other stuff. That alone IMHO is worth the price of admission :).

Thanks Doc. That's just another nail in the Futaba coffin the way I see it :(

[BoneDoc]

Kat,

If you want, I have a 9C module that I'll let go for a very reasonable price (you have a Futaba Tx that is). I fly my Dx7 mostly. This will help ease you into 2.4 :D.

[KatManDEW]

Thanks very much for the offer Doc! I know where I can get one locally real reasonable, but I've been dragging my feet because of the expense, and the hassle of swapping out bunches of receivers (I have way too many airplanes).

I've been watching 2.4ghz since I saw guys flying the first Spektrum's indoors years ago, and I've been sitting the fence. I've been wanting to stick with Futaba, and a dedicated 2.4 system, without the module and antenna, but many factors, (like the JR Powersafe receiver), just keep adding up and swaying me away from a 2.4ghz Futaba setup. Throw in the electrical noise resistance, and the lack of channel sharing like 72mhz, and 2.4 has just about become overwhelmingly too hard to resist.

[BoneDoc]

That's why the module is so tempting. Just convert one receiver at a time :).

[olivergottlieb]

I am using a Smart Fly Power Expander pro with a Super Reg and 2 TP 2S 2070 for my 27% Edge on Hacker A60 18L with CC Phoenix 110HV receiver AR 7000

Never had any trouble

[davidleitch]

How can you test whether your reciever is getting enough power? I recently lost 2 x 2.4 ghz planes when the radio just stopped working in the air. The tx has been rock solid on several other planes.

After the first incident I thought maybe the linear regulator and 800 mah 2S lipo pack at 6v was the problem and switched it out for a bigger regulator and 1600 pack. However that system also gave up on its 3 rd flight only 1.30 minutes in. Expensive to be sure. I did have the receiver 2s pack on the second model wrapped up on the motor cage for cg reasons which meant the lead was running say 15" to the regulator, but with 7 + volts going to the regulator don't see how that could be an issue.

The only components in common were the tx, which I'm sure is ok, the receiver and a couple of servos.

I will surely change the receiver out, but would like to know how to test for brownout risk?

[BoneDoc]

What were you flying, and what were the circumstances around it?

Another good option is the data logger to tell you what happens in the flight

[lmopar69]

Hey guys, if you dont mind, let me throw my question into the ring here. Im finishing up a 20lb biplane right now with 10S 4450 lipos, AXI 5345, CC HV-110 and 7 HS 645MG servos.

My plan was to run a seperate 3S 2500 lipo into a CC BEC to power everything. Is there any reason I should not do this, or is there anything that is better/safer for me to use to power all those servos?

Laine.

[KatManDEW]

Hey guys, if you dont mind, let me throw my question into the ring here. Im finishing up a 20lb biplane right now with 10S 4450 lipos, AXI 5345, CC HV-110 and 7 HS 645MG servos.

My plan was to run a seperate 3S 2500 lipo into a CC BEC to power everything. Is there any reason I should not do this, or is there anything that is better/safer for me to use to power all those servos?

Laine.

I personally wouldn't do that. I would use a pair of 123's, or 2S lipoly and a conventional linear regulator, or 3S lipoly and something like a Western Robotics BEC. Although they're not digital, 7 HS645's is a load, especially with 4 aileron servos changing direction simultaneously, and the CC BEC's don't take too kindly to that.

Some will of course dispute this, but there have been enough reports of CC BEC's not just failing, but going up in flames, that I wouldn't use them in anything much larger than park flyer type applications myself. Better safe than sorry with a nice expensive aircraft.

[KatManDEW]

How can you test whether your reciever is getting enough power? I recently lost 2 x 2.4 ghz planes when the radio just stopped working in the air. The tx has been rock solid on several other planes.

After the first incident I thought maybe the linear regulator and 800 mah 2S lipo pack at 6v was the problem and switched it out for a bigger regulator and 1600 pack. However that system also gave up on its 3 rd flight only 1.30 minutes in. Expensive to be sure. I did have the receiver 2s pack on the second model wrapped up on the motor cage for cg reasons which meant the lead was running say 15" to the regulator, but with 7 + volts going to the regulator don't see how that could be an issue.

The only components in common were the tx, which I'm sure is ok, the receiver and a couple of servos.

I will surely change the receiver out, but would like to know how to test for brownout risk?

Which 2.4 Ghz system?

[davidleitch]

Not trying to hijack the thread with my case, really just interested best way to power receiver etc. Bonedoc. Your suggestion of the datalogger is good.

Having said that to answer the questions:

1st plane lost, 69" qq yak, small linear regulator, 800 mah 2s receiver pack, 4 standard digital servos, futaba 14 channel receiver with about 15 previous flights before loss of control. The receiver had been in a couple of small crashs prior to its use in the Yak. The motor gearbox did need greasing so noise and vibration levels were higher than normal.

2nd plane lost Sebart Katana 1.20 3rd flight, 1600 mah 2s lipo receiver pack, duralite digital switch with regulator, 3 standard digital servos and 2 minis in the elevator. Same futaba receiver. Plane lost on 3rd flight. Same motor

The Futaba 2.4 ghz is rock solid in my F5B and thermal gliders and park flyers. I have had total confidence in it. Obviously the gliders are flown at far greater distances than the sports planes and the F5B system goes pretty quick and the planes have carbon everywhere. I've been so pleased with the Futaba setup that it will take a lot more bad experience to make me move away.

I should have switched the receiver out after the first crash but it had a good history.

In both cases there was a lockout in the air, but the system seemed to work on the ground. So it sounds like receiver losing power for reasons that are hard to understand as there should have been plenty of power available.

As I said my issue really belongs in the radio forum, but I was interested in the best way to power the receiver going forward.

[lmopar69]

So, just to make sure I have this right, I can hook a 2S lipo direct to my AR 7000 reciever to power my servos? I figured for sure that would be too much voltage. I thought I had to keep it at 6 volts or lower. But, if it can handle a 7.2v lipo hooked direct to it, that seems by far the easiest and safest way to go.

Laine.

[KatManDEW]

Not trying to hijack the thread with my case, really just interested best way to power receiver etc. Bonedoc. Your suggestion of the datalogger is good.

Having said that to answer the questions:

1st plane lost, 69" qq yak, small linear regulator, 800 mah 2s receiver pack, 4 standard digital servos, futaba 14 channel receiver with about 15 previous flights before loss of control. The receiver had been in a couple of small crashs prior to its use in the Yak. The motor gearbox did need greasing so noise and vibration levels were higher than normal.

2nd plane lost Sebart Katana 1.20 3rd flight, 1600 mah 2s lipo receiver pack, duralite digital switch with regulator, 3 standard digital servos and 2 minis in the elevator. Same futaba receiver. Plane lost on 3rd flight. Same motor

The Futaba 2.4 ghz is rock solid in my F5B and thermal gliders and park flyers. I have had total confidence in it. Obviously the gliders are flown at far greater distances than the sports planes and the F5B system goes pretty quick and the planes have carbon everywhere. I've been so pleased with the Futaba setup that it will take a lot more bad experience to make me move away.

I should have switched the receiver out after the first crash but it had a good history.

In both cases there was a lockout in the air, but the system seemed to work on the ground. So it sounds like receiver losing power for reasons that are hard to understand as there should have been plenty of power available.

As I said my issue really belongs in the radio forum, but I was interested in the best way to power the receiver going forward.

Which Futaba 14 channel? The old FS version or the new HS version? There were reports of some kind of overheating problem or something with the older FS version. That shouldn't be a problem if it's used in conjunction with something like a Smart Fly power expander. I know a guy using one of the FS versions with a Electro Dynamics power isolator.

[KatManDEW]

So, just to make sure I have this right, I can hook a 2S lipo direct to my AR 7000 reciever to power my servos? I figured for sure that would be too much voltage. I thought I had to keep it at 6 volts or lower. But, if it can handle a 7.2v lipo hooked direct to it, that seems by far the easiest and safest way to go.

Laine.

I'm not sure myself if the AR7000 is one of the ones that can handle two lipolys (which are 7.4 volts). I think the AR7000 is capable (check to be sure), but you also need servos rated for 7.4 volts. Hitec and JR have some rated for 7.4 volts, and I think Futaba recently introduced some.

Otherwise, you can run two unregulated A123's without the need for 7.4 volt servos. Lots of folks are using two unregulated A123's for receiver power.

[lmopar69]

right right. I talked to Hitec today, the 645s would not like 7.4v at all.

I also talked to Castle. They swear that the CC BEC would take it like a champ. I did run 2 CC BECs in my 3 foot SRT/10 flying wing. It had 8 servos in it and as far as I know, I never had any problems with that set up.

Laine.

[davidleitch]

Which Futaba 14 channel? The old FS version or the new HS version? There were reports of some kind of overheating problem or something with the older FS version. That shouldn't be a problem if it's used in conjunction with something like a Smart Fly power expander. I know a guy using one of the FS versions with a Electro Dynamics power isolator.

Reread some of the Futaba information and I notice that there is a specific advisory about the 14 channel receiver only outputting 2.7 volts.

http://www.futaba-rc.com/faq/faq-receivers-q1060.html

Hmm. Think I'll pick on the receiver output voltage rather than the input voltage and I suppose that's why, for giant planes, its best to avoid the receiver bus.

[KatManDEW]

Reread some of the Futaba information and I notice that there is a specific advisory about the 14 channel receiver only outputting 2.7 volts.

http://www.futaba-rc.com/faq/faq-receivers-q1060.html

Hmm. Think I'll pick on the receiver output voltage rather than the input voltage and I suppose that's why, for giant planes, its best to avoid the receiver bus.

So the problem is in fact with the older FS receivers. And using something like a Power Expander does in fact eliminate the problem. I was right on two counts :)

I have the newer R6014HS receiver, and I'm using it with a Power Expander.

[davidleitch]

I guess the 2.7 volt issue is on the signal wire? So using a receiver with 3 volts on the signal wire, like all the other 2.4 Futaba receivers should get over the problem. I don't want to go to the expense and weight of a separate Power Expander unless I have to.

After all its just 3 standard and 2 mini servos. That's why I couldn't understand the problem in the first place.

Still not sure how the the issue translates into total loss of control but sure seems like the potential culprit.

Hmm this has been a useful thread and I still like the idea of the data logger. I have the excellent SM Unilog, just need to pull it out of the F5B model.

[Tipover]

Apparently some servo's can't deal with the lower 2.7v signal level. This is the pulse width signal that tells the servo where and how far to travel. It's a borderline situation, so sometimes they simply do not read the lower voltage as a valid signal. At that point they see nothing and do nothing on command. Apparenty so borderline that temperature can make all the difference.

Kevin

I guess the 2.7 volt issue is on the signal wire? So using a receiver with 3 volts on the signal wire, like all the other 2.4 Futaba receivers should get over the problem. I don't want to go to the expense and weight of a separate Power Expander unless I have to.

After all its just 3 standard and 2 mini servos. That's why I couldn't understand the problem in the first place.

Still not sure how the the issue translates into total loss of control but sure seems like the potential culprit.

Hmm this has been a useful thread and I still like the idea of the data logger. I have the excellent SM Unilog, just need to pull it out of the F5B model.

[feathermerchant]

My favorite system is the AR9100 on 2 X 2S A123's. I've had over 40 flights on a 17lb 87" 3DHS SHP. After 5 flights I put about 500mAh in each of the 1100mAh packs. No regulator or switch. I use Astro connectors between the batteries and the receiver. I plug them in one at a time to make sure either one will run the plane. The AR9100 will operate from 3V to 10V and isolates the 2 batteries so if one goes dead or even shorts out, the other can power the plane. I make sure the wiring is such that if the main batteries are ejected the receiver will still receive power.

[markepilot]

My .02 cents worth.

I'm flying a 3DHS 50cc extra 260 AUW is 14lbs6oz. I power the receiver/servos off of one of the two 5S packs (10S to ESC/motor). I'm running two CCBEC's to do this. One BEC runs the AIL servos and the AR-7000rx. The other runs the Rud and Elev servos. I originally ran the system off of one BEC but went to two because of the current draw potential of digital servos. I like the CCBEC's because they are easy to adjust and weigh almost nothing. I run them at 6.6volts and have many many flights on this setup. After a 10 min flight the battery that runs the flight controls only takes a few more mah during recharge.

Cheers, Mark

[lmopar69]

Thats good to hear Mark. Your using them and a couple of the guys on Flying Giants are using them in thier big planes too. So, Thats what Im gonna do. I just wish I could afford a nice set of digital servos right now. So, for now, I'll have to just stick with the HS 645s and the CC BEC set at 6 volts.

Laine.

[feathermerchant]

Imopar - Have a look at the Atlas DS20-UMD's. They are pretty heap and have lots of torque.

[lmopar69]

Will do feathermerchant. I like the "Use the 4S Luke"... nice play on words.

[lmopar69]

Did I convert that right? 11.6kg/cm converts to 409oz/in of torque on those servos?

[feathermerchant]

I can't take credit for it. I steal from the best. I think 11.6 is 161 ozin.
I think you use the higher torque value. like 20.9/23.5which is 329 ozin on 6V.
I'm running mine on 2S A123's ut have not actually flown yet. Should maiden Sat.

[markepilot]

Hey guys,

I'm running the Hyperion Altas coreless digitals (DS20X-TMD) in my 50cc Extra and they are holding up well. I just got the Hyperion digital programmer and adjusted the deadband. If you buy the servos buy the programmer. They were jittery at center and now that I've made the deadband wider they seem to be better.

Cheers, Mark