kemp83

Hi guys! I am building a Great planes extra 330s 27%.It is my 1st Giant!I will use a CRRC Pro GF50i, futaba R617 receiver, and 7 Spectrum A6010 digital servos.

Spectrum A6010 Technical details

So, what I need help with, is what kind of receiver battery should I use to be able to fly 3D...hover and staff...
On my 60 size YAK54 Iuse 6VNiMH 2300mAh. Will this battery be ok? I don't want to risk any power loss due to lack of power....
Please help...

Rafael23cc

My Feedback: (6)

I'm pretty sure you can fly at least once with that battery. Making sure that the battery is fully charged, do a 5 minute flight, land and check how many mah it takes to get the battery to full charge. From there, divide by the time you actually flew. that will be your mah per minute of flight. Estimate how many times you want to fly between charges, and estimate how long your flights are going to be. Multiply the number of flights by the estimated time. that is total minutes between charges. Multiply the mah per minute by the minutes between charges add 20% and that is your required battery size.

Keep in mind that the number may be too high (heavy battery) if you fly a lot, so find a good balance.

Rafael

zacharyR

My Feedback: (5)

I'll reply to your post

any battery you can use .. if your useing Nimh packs i'd just use two and battery share

I'll tell you what I personaly use on 50cc airframe


I use ONE duralite A123 2500MAH pack .. and a tech aero IEBC for the motors inigtion .. and i use a good switch smart fly .. or a badger woverine
and I've put this pack to the test I've had a servo bind up on me and catch on fire in the airframe .. it was drawing so much current It melted the servo lead to the bear metal .. I'm talking alot of current i mean alot of current ...
and i was able to land the airframe and save it.. .. if i was flying a NIMAH i'd probably lost a airframe

just a FYI your aiframe really isn't a 3d airframe .. it smore a sport plane granted you can 3D it .. but just be use to the airframe and be ready for it to fall out . thats all i am saying

opjose

Each digital servo can instantaneously draw 2000mA of power at full stall.

In normal flight servo draw is dependant upon several factors including...

- Movement resistance - Binding
- Control Surface area - Larger sufaces produce more leverage on the linkages equating to more draw
- Geometry - Are you set up for maximum MECHANICAL advantage? Few "recommended" setups are.
- Amount of deflection - More current is used as the surfaces move away from center

You are likely to see between 200mAh to 1200mA draw per servo in actual flight.

If you want to play it completely safe take 2000mA and multiply that by the number of servos = 14,000mA or 14 amps!

In lieu of that you can take a median figure... say 1200mA x 7 servos = 8400mA or 8.4 amps.

So in your shoes I would be providing a minimum of 8.4 amps of power to the electronics...

You could hook up a pair of LiFe's (aka A123's ) with high draw characteristics...

I've been using a lot of these lately because the price is right...

[link=http://www.hobbyking.com/hobbyking/store/__23817__Turnigy_nano_tech_2000mAh_2S1P_20_40C_LiF ePo4_Transmitter_Pack.html]Click me![/link]

I hook two to the RX via a Y cable...

No power distribution box nor regulator is required.

This produces... 2000mA x 2 x 20c = 80 amps maximum draw which is far more than my 50cc and up planes will ever need.

The batteries are far lighter than NiMH, LiIon and NiCD packs and can be recharged at 5C, though I only use 2C charge rates.

A pair of these packs and you can fly all weekend with one charge.... recharge and you can leave the plane sitting ( off ) for weeks without having to recharge it again before another flight as there is almost no self discharge.

raydar

Your 2600 mah battery would prob have enough mah capacity to fly your plane for 4 or 5 flights before getting low on charge HOWEVER it most likely does not have a high enough C rating to provide more than 7 or 8 amps EVEN fully charged.

Conclusion, it could brown out your rx at any time so a single 6 volt nimh is not suited for your application.

And your servos are a bit weak for a model this size at 7 kg torque, I would not fly a model this size with them, they will lack the power required for good performance.

BarracudaHockey

My Feedback: (11)

Interesting.

By point of reference, my 50cc planes with a single 2500mah pack and 5 x 7955's flying 3D, with the same pack split to the ignition, uses 300 to 350mah per flight (6 servos, plus igntion, flying hard 3D)

raydar

2500 mah nimhs or life? Huge difference.

Maybe you have read my post wrong. I have not knocked the capacity, but I do dowbt the C rating of the nimh.

opjose

Yup, but power consumption is not the same as instantaneous draw.

I'm measure about 350mAh per flight on our Giant Scale club trainers ( 7 digital servos ) but instantaneous draw WILL top 1200mA easily especially during hard flying.

As Raydar says, many people are risking brownouts by not properly sizing their packs.

That said NiCD and NiMH packs are fairly good at sustaining high momentary draw rates over their rating, while other technologies are not, e.g. LiPo.

The minimum capacity NiMH 4.8v battery I've would use in a plane this size is over 3000mAh.... and higher at 6v.

scale only 4 me

My Feedback: (158)

I agree with the servos being minimal. this is really a 40cc plane, but I had a DA50 in mine

I had it set up with.
4-hs5625 ail./ele.
1-hs5955 rud.
1- standard BB servo for throttle
2-2000mah NiMh pack, shared on a Fromeco Wolverine switch (wired 2 in 2 out)
1-1600 pack for the Ign.
R6008HS futaba RX,,

Never had any issues with brown outs or anything else,, used about the same what BarracudaHockey says for juice while flying pretty hard all the time.

raydar

There seems to be a huge missconception that higher mah pack is going to produce more amps than a lower mah pack, thats true if comparing two identical batterys of the same make and chemistry.

However if you compare a 2600 mah mimh 6v pack to a 1100 a123/life 2s 6.6v genuine cell pack I am pretty confident the little life/a123 battery will have a higher C rating than the nimh by far.

The mah is the way you rate the amount of power a battery can store, the C rating dictates how fast you can get it in or out of the battery without damaging /overloading the battery. Completely different things.

Im pretty confident that barracuda and most others do not fly there 50cc planes on a single 2600 mah AA cell nimh.

BarracudaHockey

My Feedback: (11)

LMAO no, I was speaking of A123's

FWIW I don't consider stall current because I don't stall my servos and my testing hasn't indicated flight load current anywhere near that high.

Anything is possible though

zacharyR

My Feedback: (5)

what it boils down to is you can use nimh packs .. but really.. stop buying them and start making your shift to new tech ... A123 .. is probably the most friendly and none complex ..




and back to the orgnial topic.. those servos are kinda sucky as mentioned above 100 once for a 50cc is flyable .. but i wouldn't dare go over 1 " arm

and that machin your going to need long arms to get any 3D going on .. and hell its really a sport plane at best ..


if you could .. you sould really sit down at the computer and do some reaserch .. IMO

raydar

Not exactly, what is important is he understands that one nimh AA 2600 mah pack for his rx is really pushin his luck and frankly insane in a plane this size. Run two in parallel and then if their good batterys theoretically with the servos suggested they should do the job as double the ampage will be available.

Personally I have seen to many false charges in nimh batterys and AA cells really are not that powerful so I would not run them even in a 30cc even doubled up. I at least would want a couple sub C nimhs for a 27%

Sooo what it boils down to is A123 is a great upgrade and now would be a good time to do it.

Of course thats just my opinion.

kemp83

Ok guys! Thank you very much!

opjose

Click on the link of my first post above.

All you need is a Y cable to hook them up, or if you wish you can put them on separate switches for added safety.

NO powerbox or regulator is needed with the 2S LiFe packs, and if anything using these adds unneeded complexity and failure points.

As far as your servos, just make sure you set up the arms and linkages for maximum mechanical advantage and you'll do fine.

kemp83

Hi opjose! 

sensei

These days I use JR Powersafe receiver's, a single soft switch and two 2500 ma lipos to keep weight down on all my stuff.

Bob

jefflangton

My Feedback: (23)

You may also consider making a paperweight out of the crcc and put a dle 55 in it with a xoar 22/10 or 23/8 prop. You'll love it!!!

Texastbird

That plane would be a rocket ship with the DLE55! Kemp, if you haven't bought the CRRC yet, you might want to reconsider this choice. I am wondering how this plane would do on a EME 35 if you kept the weight down. Once you try the LIfe chemistry battery, (and the correct charger), you'll never go back to Nimh, that's for sure.

opjose

Yes you can use two switches wired to the RX, though it does not have to be on separate "channels".

I don't bother with this myself. I just use a good high quality switch, and hook both batteries to a "Y" cable, then the "Y" cable to the switch.

This is cheaper and IMHO better than many other solutions... e.g. the Powersafe's are really nice, but given the price, for a 50cc? eh no thanks.

Other electronic switches do the same thing and default to power on, during failure.... but that is another matter.

If you leave the batteries connected together ( in parallel ), they will equalize with each other.

Failure is never instant, particularly with LiFe's. It happens over time, almost never at once. Just be diligent with your batteries...

You can charge both via one receptacle in the switch which is what I do normally for a "flying the next day" charge.

I also once a season remove the packs from the plane and do a balance charge & cycle with load, to determine their health & capacity. This should be part of your seasonal review... and should go hand in hand with changing out your gas fuel tubing every year or so...

BTW: I did all of this with four of our Giant club trainers and we have gone months in storage without re-charging the packs after their last use, then we pull out the planes for training and just fly them. The packs I indicated above hold their charge very well.

You mean "the closest to the SERVO pole arm"...

Yes that is what I mean.

Set up your transmitter for 150% movement and then your linkages for maximum mechanical advantage.

You may find that this MAY give you slightly less than 3D deflections, though you knew that was a risk with the servos you selected.... but at least this way there is little chance of blow-back. The servos will be able to hold the surfaces effectively at deflection. Your control will also be smoother and more "fine grained" by doing so.

Consider flying the plane this way and as you get better with it, you can change the servos to higher torque ones later... starting with the rudder which typically needs the strongest servo(s).

kemp83

thanks!That's really helpful.Anybody using smart switch?

kemp83

http://www.hobbyking.com/hobbyking/store/__23825__Turnigy_nano_tech_2100mAh_2S1P_20_40C_LiF ePo4_Receiver_Pack.html