Rx Battery Placement.
05-08-2011, 05:11 PM
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Rx Battery Placement.
Is there some rule of thumb as to how close to the rx the rx battery can be? Best rx battery for the spectrum AR 7000 using six DS 821 servos? Plane is a 1/4 scale BUSA Fokker D-VII. Zenoah G-26 for power and an optical kill switch attached to the gear servo location. Will be installing a 2700mAh NiMH for the ignition module. Have the standard 4.8v,1100mAh NiCd that came with the receiver and a 6v 1400mAh NiCd. Any help for this nubbie appreciated. John
05-08-2011, 05:21 PM
#2
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RE: Rx Battery Placement.
I usually use the Rx battery as ballast and put it in a convenient place that helps achieve the proper CG. If that happens to be right next to the RX, it isn't an issue at all.I would run 6 cells with that Spektrum receiver.
05-09-2011, 05:53 AM
#4
RE: Rx Battery Placement.
As an FYI about that servo.....
I personally wouldn't run them in a gasser.
•Manufacturer Warning: "Not recommended for planes over 1.20-size or helicopters over .30-size. Loads and vibration in larger models may cause premature failure of the servo, resulting in damage or injury to property and persons
05-09-2011, 06:10 AM
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RE: Rx Battery Placement.
2700 MaH on the ignition??? Be sure that the igntion can handle six volts. The ones I have on my gassers are 5 cell 1500NiMh 4.8 volt NiMh for the ignition and 5 cell 2300 NiMh, six volt for the Rx. six volts will fry some ignitions, or at least it will fry the ones that I own.
05-09-2011, 06:39 AM
#7
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RE: Rx Battery Placement.
Another heads up. You flight pack battery is nothing I would use in your plane. This is a topic of conversation I just had last week with one of the JR sponsored race pilots. Some years ago when JR/Spektrum came out with there 2.4 systems planes were falling out of the sky way too often. This became known as the BROWN OUT. Then Horizon came out with an on line up-date stating you should be using 6 volt batteries with the new 2.4s. To this day they still give you a 4.8 with any new radio or flight pack. For myself I wouldn't think of flying such a nice big plane with a single 4.8 volt battery pack powering my controls. I would be running two large 6 volts with two switches just to remove the worry factor. Where you locate them isn't a big deal but a single 4.8 sure is. Just me thinking out loud, when I looked at the photos it set off a few bells and whistles. Sorry if I spoke out loud, it isn't my plane.
05-09-2011, 08:52 AM
#8
RE: Rx Battery Placement.
That's good advice, Gene.
I have parallel 6 volt 1800 mah NiMh packs in my Venus II and my Excelleron 90 (both pattern planes). I have a sign le 1800 mah 6 volt pack in my Skylark, but that may change this year by adding parallel NEW 1800 mah LiFe packs to everything, well, almost everything..
CGr.
I have parallel 6 volt 1800 mah NiMh packs in my Venus II and my Excelleron 90 (both pattern planes). I have a sign le 1800 mah 6 volt pack in my Skylark, but that may change this year by adding parallel NEW 1800 mah LiFe packs to everything, well, almost everything..
CGr.
05-09-2011, 09:02 AM
#9
RE: Rx Battery Placement.
Dick and Gene,
While the need for having ample power is always a concern, the brownout issues that plagued early JR/Spektrum systems are pretty much a thing of the past. The problem was that if the receiver voltage dropped below a set level (3.8v if I remember correctly) the receiver would actually "reboot". The reboot on those older receivers took 3-5 seconds and of course that amount of time is an eternity in an RC airplane and would usually result in a crash. Since they have have re-engineered the software so that a reboot now takes less than a second. So if you do get a brownout chances are that you will get control back before the plane crashes.
Like I said, you always want to make sure that you have plenty of juice for the radio on the plane. I just wanted to make sure that the info got out that it's not as big of an issue as it used to be. Other manufacturers have different cutoff voltages for their receivers. I don't know what it is for Futaba, but I know that Airtronics 2.4 systems have a cutoff voltage of 1.8v before the receiver shuts down.
Hope this helps
ken
While the need for having ample power is always a concern, the brownout issues that plagued early JR/Spektrum systems are pretty much a thing of the past. The problem was that if the receiver voltage dropped below a set level (3.8v if I remember correctly) the receiver would actually "reboot". The reboot on those older receivers took 3-5 seconds and of course that amount of time is an eternity in an RC airplane and would usually result in a crash. Since they have have re-engineered the software so that a reboot now takes less than a second. So if you do get a brownout chances are that you will get control back before the plane crashes.
Like I said, you always want to make sure that you have plenty of juice for the radio on the plane. I just wanted to make sure that the info got out that it's not as big of an issue as it used to be. Other manufacturers have different cutoff voltages for their receivers. I don't know what it is for Futaba, but I know that Airtronics 2.4 systems have a cutoff voltage of 1.8v before the receiver shuts down.
Hope this helps
ken
05-09-2011, 01:34 PM
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RE: Rx Battery Placement.
Bill, my 2700mAh is a 4.8 v. What I am now having problems with is the miracle switch I purchased. Each of the switches in the back have two wires and all my spectrum stuff is 3 wire. Wish I knew more about electronic stuff, this drives me nuts!!!!! No problem Grey Beard, think out loud all ya want to. I will use at least the 6v , 1400mAh for the rx and am thinking about the 6.6 v 2100 mAh LiFe packs from LiFeSource also.
05-09-2011, 01:40 PM
#11
RE: Rx Battery Placement.
The switch you purchased will work just fine for turning your Spektrum equipment on and off. For turning on the receiver only the positive and negative leads (black and red on your switch, red and brown on the Spektrum wiring) is used. However, if you need to bind the receiver the switch you have will not work. In order for that to work you will need a Spektrum 3 wire switch. But you can bind directly at the receiver if you need to.
Ken
05-09-2011, 02:08 PM
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RE: Rx Battery Placement.
Hey Barracuda, what issues do you have with the DS 821's, the nylon gears or something else? Will the 6.6v LiFe packs have any adverse effects on the rx or servos?
05-09-2011, 02:30 PM
#13
RE: Rx Battery Placement.
Thats not "my issue", its a manufactuer warning not to use them with large engines or in high vibration environments.
My personal experience is that the output shaft shears off the top of the servo and or the output amplifiers up and die from vibration. Guys that have insisted on using them with 50 size nitro helis have found out the hard way that it's a lot more expensive to fix a crash than to replace a few servos.
My personal experience is that the output shaft shears off the top of the servo and or the output amplifiers up and die from vibration. Guys that have insisted on using them with 50 size nitro helis have found out the hard way that it's a lot more expensive to fix a crash than to replace a few servos.
05-09-2011, 02:36 PM
#14
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RE: Rx Battery Placement.
Ken, I was talking with the JR guy and got all the new info on the upgrade but as he showed me, he is still running 6 volts in his planes and wouldn't use the 4.8. As he pointed out to me, the reboot is pretty fast but if it happens when you are too low that one thousand one is still a long time. He also showed me something else he has done sense the advent of 2.4, he makes up his own 6 volt packs but he is using AAA batteries. He was telling me he hasn't had one go down in voltage any faster then the AA packs. He is also a speed racer and every gram counts. He is also telling people to keep there old radio for a while, with all the problems in Japan they are vending things out to be made and he doesn't know to whom. He is also telling the guys to send in there radios for the free upgrade, it really speeds up your radio. I had to sit through all the new JR stuff talk for about an hour but I did find out a lot.
05-10-2011, 08:38 AM
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RE: Rx Battery Placement.
I'll be changing the DS 821's for HiTec HS 645MG's, hope these will work as I can't afford the $100 + ea. servos.
05-10-2011, 09:02 AM
#17
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RE: Rx Battery Placement.
ORIGINAL: JBryson
I'll be changing the DS 821's for HiTec HS 645MG's, hope these will work as I can't afford the $100 + ea. servos.
I'll be changing the DS 821's for HiTec HS 645MG's, hope these will work as I can't afford the $100 + ea. servos.
05-10-2011, 01:29 PM
#18
RE: Rx Battery Placement.
ORIGINAL: RCKen
Dick and Gene,
While the need for having ample power is always a concern, the brownout issues that plagued early JR/Spektrum systems are pretty much a thing of the past. The problem was that if the receiver voltage dropped below a set level (3.8v if I remember correctly) the receiver would actually ''reboot''. The reboot on those older receivers took 3-5 seconds and of course that amount of time is an eternity in an RC airplane and would usually result in a crash. Since they have have re-engineered the software so that a reboot now takes less than a second. So if you do get a brownout chances are that you will get control back before the plane crashes.
Like I said, you always want to make sure that you have plenty of juice for the radio on the plane. I just wanted to make sure that the info got out that it's not as big of an issue as it used to be. Other manufacturers have different cutoff voltages for their receivers. I don't know what it is for Futaba, but I know that Airtronics 2.4 systems have a cutoff voltage of 1.8v before the receiver shuts down.
Hope this helps
ken
Dick and Gene,
While the need for having ample power is always a concern, the brownout issues that plagued early JR/Spektrum systems are pretty much a thing of the past. The problem was that if the receiver voltage dropped below a set level (3.8v if I remember correctly) the receiver would actually ''reboot''. The reboot on those older receivers took 3-5 seconds and of course that amount of time is an eternity in an RC airplane and would usually result in a crash. Since they have have re-engineered the software so that a reboot now takes less than a second. So if you do get a brownout chances are that you will get control back before the plane crashes.
Like I said, you always want to make sure that you have plenty of juice for the radio on the plane. I just wanted to make sure that the info got out that it's not as big of an issue as it used to be. Other manufacturers have different cutoff voltages for their receivers. I don't know what it is for Futaba, but I know that Airtronics 2.4 systems have a cutoff voltage of 1.8v before the receiver shuts down.
Hope this helps
ken
Dick.
05-10-2011, 02:13 PM
#19
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RE: Rx Battery Placement.
Any idea if Horizon is still taking these RXs back and replacing them?? I was offered four of the old ones at a really good price not long ago. My 2.4 is Hitec though so I gave it a pass. I do still need a big bundle of Hitec RXs if I want to change over completely. I notice they never seem to come up on sale!
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