Article on adequate radio power
06-28-2007, 10:18 PM
#52
RE: Article on adequate radio power
ORIGINAL: Chris Smith
Thanks Bob.
Is there a reason you went with a regulator for that set up and 5 cell battery?
Thanks,
Chris
Thanks Bob.
Is there a reason you went with a regulator for that set up and 5 cell battery?
Thanks,
Chris
I like the fact that the regulator keeps the voltage to the servos constant - thus you have the same "feel' throughout the flight regardless of the actual battery voltage. The regulator is set at about 5.7V, so the servos are getting a bit higher voltage than with an unregulated 4 cell pack, so they are faster and have more torque. However, they are getting less than an unregulated 5 cell pack (over 7 volts right off the charger) so the current draw is not excessive...
In addition, with the "reliswitch" regulator, you have the "failsafe" functionality that means that you have to actually close the switch to turn the unit OFF, so if the switch fails, the unit simply stays on...
Bob
06-28-2007, 10:54 PM
#53
Senior Member
Join Date: Nov 2005
Location: Henderson, NV
Posts: 2,778
Likes: 0
Received 0 Likes
on
0 Posts
RE: Article on adequate radio power
ORIGINAL: Chris Smith
C2,
Both the Oracle and BNB DPR have minimum input voltages of 5V and 7V respectively. How are they going to record receiver batteries especially when voltage is dragged down in flight?
Thanks,
Chris
C2,
Both the Oracle and BNB DPR have minimum input voltages of 5V and 7V respectively. How are they going to record receiver batteries especially when voltage is dragged down in flight?
Thanks,
Chris
Chris,
Actually they are both 5 (BNB is 5.2) volts input. More than low enough for my 7.4V lithium packs. They come off the charger at 8.4 and even after a full day flying, are at 7.3-7.5.
06-29-2007, 01:20 AM
#54
RE: Article on adequate radio power
Sorry, guys really pushed for time as I leave for london tomorrow WITH my Hawk so I'll pick up this thread later (and reply to your PM Chris)
Regards, David Gladwin.
Regards, David Gladwin.
06-29-2007, 02:50 AM
#55
Join Date: Jun 2006
Location: Gold Coast, Queensland, AUSTRALIA
Posts: 1,469
Received 26 Likes
on
24 Posts
RE: Article on adequate radio power
ORIGINAL: rcguy!
Take this to the bank....
I have a DX7 with the 9ch RX in a KingCat. Servos are 4pc 8611A and 4pcs 8411 on the aerodynamic surfaces. The other 3 servos handle the steering, retracts, and brakes. The KingCat is powered with a Titan SE at 34 pounds of thrust. I'd say this is a potent combo...
I power the Rx with 2pcs 3600NiMh 5 cell packs each with its own switch harness. These plug into the RX at the battery port and at an unused servo port. Thats it. No regulators, no power centers, no nothing! Don't need 'em! I can fly this combo for over 15 flights without a recharge. The batteries are low impedance type rated at 5mhn each. So in parallel the RX sees them as 2.5Mhn. No voltage drop with high servo loads using these batteries and setup.
I have an on board monitor and have yet to see even a single frame loss yet alone a single hold. Antenna fades are well under 100. Trust me on this....The KingCat has been flown to a very tiny dot at the top of an extremely huge loop. Range is not a problem.
So....The setup is easy....
2qty 5 cell packs (6V) in 2 different ports on the RX thru 2 switches. Period. Forget the power busses, regulators, and whatever else someone wants to sell you.
Forget Lipos too. IF you really need to save weight by going to a lighter pack, well you've already lost the game. Learn not to ADD weight during the build.
It amazes me to no end to read all this about RX power loss, etc. Just get good Nicads or Nimhs of low imoedance and fly the crap out your setup. Save the rest of your time reading about others crashing....
Dave
Take this to the bank....
I have a DX7 with the 9ch RX in a KingCat. Servos are 4pc 8611A and 4pcs 8411 on the aerodynamic surfaces. The other 3 servos handle the steering, retracts, and brakes. The KingCat is powered with a Titan SE at 34 pounds of thrust. I'd say this is a potent combo...
I power the Rx with 2pcs 3600NiMh 5 cell packs each with its own switch harness. These plug into the RX at the battery port and at an unused servo port. Thats it. No regulators, no power centers, no nothing! Don't need 'em! I can fly this combo for over 15 flights without a recharge. The batteries are low impedance type rated at 5mhn each. So in parallel the RX sees them as 2.5Mhn. No voltage drop with high servo loads using these batteries and setup.
I have an on board monitor and have yet to see even a single frame loss yet alone a single hold. Antenna fades are well under 100. Trust me on this....The KingCat has been flown to a very tiny dot at the top of an extremely huge loop. Range is not a problem.
So....The setup is easy....
2qty 5 cell packs (6V) in 2 different ports on the RX thru 2 switches. Period. Forget the power busses, regulators, and whatever else someone wants to sell you.
Forget Lipos too. IF you really need to save weight by going to a lighter pack, well you've already lost the game. Learn not to ADD weight during the build.
It amazes me to no end to read all this about RX power loss, etc. Just get good Nicads or Nimhs of low imoedance and fly the crap out your setup. Save the rest of your time reading about others crashing....
Dave
In fact I go even more basic - I use only one 4 cell 1700mah Nicad up to 7 servo's, 2400mah upto 12 servo's and 3600 mah for more servo's. The reason I use 4 cell - many servo's and some receivers don't like 5 cells and even though more power and in some cases quiker response can be had from a 5 cell pack - it also discharges quiker than a 4 cell pack. I maintain my battery packs perfectly and check their condition - under load - before every flight. Furthermore, I don't use ultra high power servo's unless the flying surface, style of aircraft and anticipated flight envelope dictates their use.
I have been flying for 35 years, turbine jets since 1997, and have never lost an airplane due to battery failure. In fact the only losses I've suffered have been due to finger trouble .....
Cheers
Springbok Flyer
06-29-2007, 01:15 PM
#57
RE: Article on adequate radio power
Simple is good. Would that include regulators, 2 batteries, 1 battery, fromecos, etc?
Here's what started the thread.
BVM posted an article as part of an admirable effort to further awareness and safety.
A very experienced sponsored flyer at a show crashes an otherwise fine performing and proven aircraft after making some component changes.
I, and some others want to know what he had on board, and what he changed to fix it.
Article says what happened, however offers no specifics. It is apparent no one involved checked the power system using a measurable criterea. Had always worked for them.
I'd like to assure myself and others that my own jet's power needs are met. Not just guess at it.
Chris
Here's what started the thread.
BVM posted an article as part of an admirable effort to further awareness and safety.
A very experienced sponsored flyer at a show crashes an otherwise fine performing and proven aircraft after making some component changes.
I, and some others want to know what he had on board, and what he changed to fix it.
Article says what happened, however offers no specifics. It is apparent no one involved checked the power system using a measurable criterea. Had always worked for them.
I'd like to assure myself and others that my own jet's power needs are met. Not just guess at it.
Chris
06-29-2007, 01:21 PM
#58
RE: Article on adequate radio power
So tommorrow, I upgrade my servos on my 200 flight, 3 year old Flying Umpty-Frump jet, then add a different receiver and go flying. Sure I whipped out the Vexa and smoothed out the linkage. I even bumped up the battery capacity some arbitrary amount, and fired it up.
Out of a loop at the end of flight 2 I yell I ain't got it, and pancake on the sod adjacent the approach end of the runway right next to BV's latest. Peanut runs and hides under the impound table. Can you imagine the look I'd get? And not just because it was an Umpty-Frump jet either.
Prior to flight:
1. Did I calculate each servo's average current draw? Was it within acceptable range?
Answer Maybe. But I had no clue what acceptable is. So that's a NO.
2. Did I account for peak loads?
Answer NO. I had no clue the new stuff drew that much current, Nor how to find it.
3. Did I insure there was a power margin above that new receivers minimum voltage number?
Answer NO. I have no clue what the manufacturer knows it is. (I hope he knows what it is)
4. Did I know the receivers warm boot, cold boot, or bit check times so I know how to set failsafes?
Answer NO. Had not considered that nor could I have found the data.
5. Did I insure the system power was regulated so the elevator servo wouldn't fail prematurely?
Answer NO. There's no maximum servo voltage data, and I blew off the recommendation to use only generic 4.8v like the documents say.
6. Did I know I really needed the added battery capacity and weight?
Answer NO. There is no accurate means or rules of safe practice to follow, so I did what my homies do. Guess.
You can bet at KY Jets I'll be walking around looking, asking, learning. If you wear a red shirt, or an orange and black one, I got questions.
If it were to rain a little bit and we're under the big top, wouldn't it be cool if a bull session was started on these topics.
Chris
Out of a loop at the end of flight 2 I yell I ain't got it, and pancake on the sod adjacent the approach end of the runway right next to BV's latest. Peanut runs and hides under the impound table. Can you imagine the look I'd get? And not just because it was an Umpty-Frump jet either.
Prior to flight:
1. Did I calculate each servo's average current draw? Was it within acceptable range?
Answer Maybe. But I had no clue what acceptable is. So that's a NO.
2. Did I account for peak loads?
Answer NO. I had no clue the new stuff drew that much current, Nor how to find it.
3. Did I insure there was a power margin above that new receivers minimum voltage number?
Answer NO. I have no clue what the manufacturer knows it is. (I hope he knows what it is)
4. Did I know the receivers warm boot, cold boot, or bit check times so I know how to set failsafes?
Answer NO. Had not considered that nor could I have found the data.
5. Did I insure the system power was regulated so the elevator servo wouldn't fail prematurely?
Answer NO. There's no maximum servo voltage data, and I blew off the recommendation to use only generic 4.8v like the documents say.
6. Did I know I really needed the added battery capacity and weight?
Answer NO. There is no accurate means or rules of safe practice to follow, so I did what my homies do. Guess.
You can bet at KY Jets I'll be walking around looking, asking, learning. If you wear a red shirt, or an orange and black one, I got questions.
If it were to rain a little bit and we're under the big top, wouldn't it be cool if a bull session was started on these topics.
Chris
06-29-2007, 06:14 PM
#59
Senior Member
Join Date: Nov 2005
Location: Henderson, NV
Posts: 2,778
Likes: 0
Received 0 Likes
on
0 Posts
RE: Article on adequate radio power
ORIGINAL: Chris Smith
Simple is good. Would that include regulators, 2 batteries, 1 battery, fromecos, etc?
Here's what started the thread.
BVM posted an article as part of an admirable effort to further awareness and safety.
A very experienced sponsored flyer at a show crashes an otherwise fine performing and proven aircraft after making some component changes.
I, and some others want to know what he had on board, and what he changed to fix it.
Article says what happened, however offers no specifics. It is apparent no one involved check the power system using a measurable criterea. Had always worked for them.
I'd like to assure myself and others that my own jet's power needs are met. Not just guess at it.
Chris
Simple is good. Would that include regulators, 2 batteries, 1 battery, fromecos, etc?
Here's what started the thread.
BVM posted an article as part of an admirable effort to further awareness and safety.
A very experienced sponsored flyer at a show crashes an otherwise fine performing and proven aircraft after making some component changes.
I, and some others want to know what he had on board, and what he changed to fix it.
Article says what happened, however offers no specifics. It is apparent no one involved check the power system using a measurable criterea. Had always worked for them.
I'd like to assure myself and others that my own jet's power needs are met. Not just guess at it.
Chris
1 Smart-Fly Super-reg
1 Smart-Fly Power Expander
Redundant, safe, simple.
06-30-2007, 10:46 AM
#60
RE: Article on adequate radio power
ORIGINAL: Chris Smith
Out of a loop at the end of flight 2 I yell I ain't got it, and pancake on the sod adjacent the approach end of the runway right next to BV's latest. Peanut runs and hides under the impound table. Can you imagine the look I'd get? And not just because it was an Umpty-Frump jet either.
Out of a loop at the end of flight 2 I yell I ain't got it, and pancake on the sod adjacent the approach end of the runway right next to BV's latest. Peanut runs and hides under the impound table. Can you imagine the look I'd get? And not just because it was an Umpty-Frump jet either.
"I ain't got it!" Those three "words" say it all, no investigation required [:'(]
07-01-2007, 03:43 AM
#61
Senior Member
My Feedback: (5)
Join Date: Jan 2002
Location: Lakeville , MN,
Posts: 348
Likes: 0
Received 0 Likes
on
0 Posts
RE: Article on adequate radio power
Two big, low impedance NiCads, tested under load before flight.
Two GOOD switches, rated for expected amp load.
Heavy gauge wire to minimize voltage drop.
Result : No crashes due to DC power problems.
Works for me, for years.
Those expecting a perfect system that will never fail are doomed to disappointment. There is no such thing.
Two GOOD switches, rated for expected amp load.
Heavy gauge wire to minimize voltage drop.
Result : No crashes due to DC power problems.
Works for me, for years.
Those expecting a perfect system that will never fail are doomed to disappointment. There is no such thing.
07-03-2007, 05:35 AM
#62
RE: Article on adequate radio power
Well, a bit of time to kill waiting for my Hawk to arrive from Heathrow airport after clearing customs, so:
Yes there is a great deal to be said for simplicity if the individual compoenents are up to the job. For a long time my standard jet install has been :
2 batteries of 2000Mah plus regulators plus 2 heavy duty JR switches one into the batt port, the other y-leaded into a servo output, it all finishes up on the power bus. No problems at all.
For those concerned about regulators, and with Duralites/lipos they are essential, may wish to consider the Mini Hobby units as some time ago I read on the BVM web site that they are dual channel units therefore failure of one channel is no problem. That said I have never had a single reg problem using Mini Hobby or Duralite units.
However models are getting bigger and more complex and things like Powerboxes (Champion) and Weatronics allow programming of servos without matchboxes etc and also eliminate separate regs AND can deliver high currents if need such as on the 20 digital servos on my Mig 29. But what ARE those currents ?
On my Skymaster Hawk the peak current recorded is 2.7 amps on Mick Burrels MB339 its just on 3 amps, well within regs outputs, the big current draw being flap selection. I will soon find the total current on my AirWorld Hawk with its 7 8711/8511 servos plus many other smaller digital servos but I am certain it will be well with the Weatronics huge capability. The good thing is its data recording will TELL me exactly what is going on in the model and THAT is very reassuring.
I agree that NO system is 100% safe but a dual battery system, each capable of delivering, say, twice the max current is, within practical limits, pretty close to it, particularly if each pack is checked under load during refuelling for the next flight !
Regards, David Gladwin
Yes there is a great deal to be said for simplicity if the individual compoenents are up to the job. For a long time my standard jet install has been :
2 batteries of 2000Mah plus regulators plus 2 heavy duty JR switches one into the batt port, the other y-leaded into a servo output, it all finishes up on the power bus. No problems at all.
For those concerned about regulators, and with Duralites/lipos they are essential, may wish to consider the Mini Hobby units as some time ago I read on the BVM web site that they are dual channel units therefore failure of one channel is no problem. That said I have never had a single reg problem using Mini Hobby or Duralite units.
However models are getting bigger and more complex and things like Powerboxes (Champion) and Weatronics allow programming of servos without matchboxes etc and also eliminate separate regs AND can deliver high currents if need such as on the 20 digital servos on my Mig 29. But what ARE those currents ?
On my Skymaster Hawk the peak current recorded is 2.7 amps on Mick Burrels MB339 its just on 3 amps, well within regs outputs, the big current draw being flap selection. I will soon find the total current on my AirWorld Hawk with its 7 8711/8511 servos plus many other smaller digital servos but I am certain it will be well with the Weatronics huge capability. The good thing is its data recording will TELL me exactly what is going on in the model and THAT is very reassuring.
I agree that NO system is 100% safe but a dual battery system, each capable of delivering, say, twice the max current is, within practical limits, pretty close to it, particularly if each pack is checked under load during refuelling for the next flight !
Regards, David Gladwin
