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MTA Hobbies . Model Rectifier Corp . PowerHelis

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Flybarless Rotor Head Systems > Power consumption with vbar
 
 
creightoncarr
Key Veteran
Location: Missouri City, Texas - USA

On my Vibe 50 with the new V-bar system I'm pulling approximately 750 mAh per 6:30 minute flight using 8717's at 8V and a BLS251 on the tail. This is close to triple what I was pulling before the v-bar.
09-30-2008 07:55 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

Ouch!

Whats your gyro deadband?, Just a guess, but it can have some to do with it


Team Autopartner - Team pilot
09-30-2008 08:19 PM
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

creightoncarr

what battery are you useing , a lame 4 cell nicd pack?
something just dont add up here.
I have a probar flybarless Joker 3DD 90 , 8717s on swash , Bl 251 on the tail with a spartan gyro. and running off my kontronics Jive HV 80 on 12S for power to the servos and electronics. Im getting a solid 6 min flight time of power like I have never seen before on the head. I put back into the 12s 3850 packs around 2700 ma . I know 750 ma aint going to the radio gear. maybe 250 is being tapped off it .

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
09-30-2008 08:22 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

Misskimo, your using a effective BEC, i.e. your 12s pack dont need mucho mah for the cyclic since the BEC is switching down your voltage.

a 7.4 2s setup will require alot more.
All motors requres watts, and watts = amps * volt, so when you raise the volt, amp goes down, as long as you have the BEC inbetween.


Team Autopartner - Team pilot
09-30-2008 08:29 PM
 
 
marked23
Key Veteran
Location: Lynnwood, WA

flyingfitz
I'm using a 2s A123 2300. I could get four 500mah flights on a charge, but I recharge after three.

I use a VoltMagic to confirm my flight counting. If the VoltMagic PLV kicks in when I pump the collective, that's my no-fly indicator.

-Mark

Edit: Oh, but I'm not using a v-bar.
09-30-2008 08:30 PM
 
 
creightoncarr
Key Veteran
Location: Missouri City, Texas - USA

I'm using TP Extreme lipos. My draw is not completely out of line. I talked with Daniel at Mt. Pleasant and he said that the power consumption if the new v-bar is about double that of the prior units. He was not using the new unit I believe for that reason. He said they were hoping to resolve the problem with a firmware update in the future.
09-30-2008 08:39 PM
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

hey, I know thats most of the case , but 750 ma
on a normal system like my razor I once had, I use nimh 1900 ma batteries. Yes I noticed alot of juice being taking out during the first flight. 2 second flight took more out because the voltage dropping and amps going up.
then I went to a trex 600 with the same setup I had in the razor. except I used the stock align bec with a 2s2p 1400ma thunderpower rx pack and used 250 ma out of each pack.
thats why Im asking if he is useing a nicd pack. but useing the new Vbar is taking that much , why???

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
09-30-2008 08:46 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

read my post on previous page, Mr Mikado didnt even recommend a 5amp bec for the new Vbar & 8717... as I wrote I havent tested it yet, but Ive seen 500mah/flight on 8v systems using 8717 before, so 750 on a vbar isnt out the window, thats why I asked about the deadband...

Actually a NiMh pack and the draw would be less, using 8v -> servo makes the servo go faster and draw MORE current then 6v...


Team Autopartner - Team pilot
09-30-2008 08:49 PM
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

hey , yeh! I know the 8717s can be a gas hog. and it seams JR just made the circuit board beafer to get more amps through it. And now Vbar has made a heater. huh?

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
09-30-2008 09:09 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

If the VBar moves the servo all the time yep, thats why I suspect gyro deadband to contribute since the lower deadband you have the more "chatter" on the servo.


Team Autopartner - Team pilot
09-30-2008 09:20 PM
 
 
misskimo
Key Veteran
Location: Alaska 12 years before , mississippi for 31 y

is the default setting something like 7 on all ?
I remember HC telling me to set all to 0. it seams to get rid of the wobble take off or landings

Do-Yo-Thang! !:~) Team ThunderPower, Minicopter & Spartan Gyros
09-30-2008 09:24 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

I run 2-4 on electrics, 7-8 on nitros.


Team Autopartner - Team pilot
09-30-2008 09:29 PM
 
 
flyingfitz
Senior Heliman
Location: Edwardsville, IL - USA

I would love a firmware update to resolve the issue but who knows.

All of this makes me wonder if direct voltage to the swash is really needed. The speed and power to the servo on direct voltage is obvious but is it overkill. The Vbar enhances the flying qualities of the machine so much maybe there is a balance between a lower voltage system and a little less draw.

On paper the A123 seems to me to be the obvious choice. A slightly lower voltage, still no need for a regulator, and the ability to quick charge in 10-15 minutes for another 3 flights.

Marked23. Is there any drawback to the A123 that you can tell? Does the Vbar work ok? Is the cyclic power there?

Maybe some of the issues with the new Vbar outlined in other posts are a result of the higher voltage and draw of the LiPo/8717 combo?

Anyone else running A123?

Fitz
10-01-2008 04:25 PM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

My servos aren't high current ones (futaba 9255) but the vbar is working them hard and pulling 500-600mah per flight. The rotor gain will directly affect how much power is used to stabilize the heli. I hope Mikado comes up with a software solution without giving up any performance advantage.

Charles

Please stand by for faster service!
10-01-2008 05:09 PM
 
 
MrMel
Elite Veteran
Location: Lidingo, Sweden

I doubt they will, since you get more exact heli from the new hardware, thats why they redesigned it... cost of it is increased powerdraw, specially if you run hv setup.


Team Autopartner - Team pilot
10-01-2008 05:48 PM
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

I talked to Curtis about the flight control system in his Vibe, the one his father designed and built. The sensors are Solid G gyros. His system is not using any more rx power than with the flybar setup. Makes me wonder how the systems differ in software.

Charles

Please stand by for faster service!
10-07-2008 06:14 PM
 
 
jbdww
Senior Heliman
Location: Round Rock, Texas

The servos have to use more power as now they are working more to stabilize the heli, and they are now directly driving the blade grips. The only question is what could be tweaked in the software to keep the draw down and what do you lose.
Joe

Skids Up
10-08-2008 04:30 AM
 
 
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