What servo does the Engineering say you should use on each surface of your large model?

Well there is an Engineering answer....here is a calculator which when you estimate a speed, control surface length and chord, deflection angle then it will tell you servo power needed on oz-in or Ncm ( ~Kgcm * 10 )

http://www.mnbigbirds.com/Servo%20Torque%20Caculator.htm

So, on my 2.6m Breitling it shows for an:
Aileron of 36x4 at 25deg deflection needs about 160oz-in or 12kg ( HS5645MG ) http://www.hitecrcd.com/products/digital/digital-sport/hs-5645mg.html

Elevatorof 18X5 at deg deflection needs about 130oz-in or 9kg ( HS5645MG ) http://www.hitecrcd.com/products/digital/digital-sport/hs-5645mg.html

Rudder 18x7 at 25deg deflection needs about 250oz-in or 18kg (HS805BB ) http://www.hitecrcd.com/products/analog/giant-scale/hs-805bb.html

Oops, the rudder is set up for a servo in each side of the Fuzz near the tail...so that will be two HS5654's instead of one HS805 with cables.

Servo count = 6xHS5645 and one ordinary for throttle.
AR9100 rx with built in power control, 50 amp buss and two Eneloop 2000 batteries controlled by a failsafe FET switch in the RX and a Spektrum " Flight Log".

AR9100 DSM2 9-Channel PowerSafe Receiver

http://www.spektrumrc.com/Products/Default.aspx?ProdID=SPMAR9100


Spektrum Flight Log ...can plug it in after landing and before you power the RX down...use one log diplay for several aeroz.

http://www.spektrumrc.com/Products/Default.aspx?ProdID=SPM9540

Hey Lonz,

25 degrees hey? Come on man, if it aint at 45° you're not even trying

What is the current draw capacity for the 2000mah Eneloop cell? Do yo think it's man enough?

I use the Spekrum data logger as well, but it only shows the current state of pack voltage. It won't record the minimums so the first you know of your cells not providing the voltage you need in that KE snap is when the RX browns out. I've seen a large scale aircraft go down using this type of power supply, and so prefer A123s for servo power myself. Eneloops are great in a 4 cell pack for ign.

michael

Good point...I meed to get some....where do you get yours from.

I also have and Eagle Tree for current and voltage logging etc.

Just thought I would mention the Flight Log to help some people get going.....

What do you think of inserting this in the battery line.....?

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=10080

It records peak and min ( current/volt/power ) with very low insertion resitance...
I have one for my electric things
=====================
The TURNIGY watt meter is a very accurate R/C amp/watt meter.
Predict model airplane flight time with any given propeller.
Ensure peak currents are safe for motor, ESC, wiring and connectors
Check battery health and performance.
Evaluate R/C battery charging efficiency.
Choose the best propeller or gearing and the most efficient motor
Check for wiring and connector power losses
Measure power and energy consumption of ANY device with a battery


Spec.
Operating voltage: 4.8~60V (0V with optional auxiliary battery)
Measures;
0~130A, resolution 0.01A
0~60V, resolution 0.01V
0~6554W, resolution 0.1W
0~65Ah, resolution 0.001Ah
0~6554Wh, resolution 0.1Wh
Screen: 16x2, backlit LCD display
Size: 85x42x25mm
Weight: 82g

I last bought A123s about 14 months ago from rclipos.com:
http://www.rclipos.com/A123_Packs.htm Packs from these guys have free postage. There are probably cheaper options around now.

For a 50cc plane you can use one 2300mah 2S1P pack for $44.90, or use 2 x 1100mah 2S1P packs for $26.96 ea. This is what I did. I use them in parallel through two switches.

If I did it again, I'd just use one 2300 mah pack I think. It's just simpler.

I have the E meter you linked below. It's pretty big, but it would work for recording min pack voltage. If you have the Eagle Tree though I would use that. I have one on the way that I will set up in my yak as soon as it arrives, so I can have a check of current draw and voltage. It will record and graph the voltage for the flight.

I had a Spektrum RX go into low voltage brown out on my edge a while back because the NImh could not keep up with the servo draw in a knife edge. I was high over the ridge, and it came back! I was using a generic brand Nimh 5 cell pack, but still, never again.

michael.

I just ordered:

6x 2 cell 2300 A123 ( 2 for each AR9100 Rx

3x 2 cell 1100 A123, one for each spark motor.....

Paypal...Free Shipping worldwide!

Specs look great.

Hi guys, at the moment i am pondering the same subject as i am about to commit radio to my new P47D.
First i would say is that whatever you do, have 2 batteries and 2 switches for the receiver and servo power one is courting disaster.
I had a one 5000mah battery and regulator in my TA 152, the regulator fused out and killed the battery with no back up battery redundancy, down it went full bore and at 45LB and 85cc in the nose there was not much left you could not fit into a match box.
The new P47D will have 11 servos none digital as hopefully i will not be doing aerobatics with it.
I will be using mostly Hitec 645 with 6 volts.
I have been asking around on Enaloop batteries as i wanted if possible to eliminate the death dealing regulator, you need with Lipo's.
Lipo's are 7.2v and Enaloops are 6v so would not have to have the regulators with the Enaloops.
Stan has them in his large Warbirds and swears by them but i am not convinced that even with 2 X 2200Mah Enaloops going into my smart-fly that that they can handle the amp drawer on 11 servo,s so i am back to 2 X Lipo,s 2 switches and 2 regulators set at 6 volts going into my smart-fly.
In the shot attached you can see the burnt out regulator the 2 naked wires were the charging jack it had a connector at the end that you put the charger on it had nothing else attached to it and as you could charge the battery through it, the wires had direct access to the battery somehow the wires touched and shorted out the battery.
Dave.

And I rekon the best part is you can hammer them with a 5C charge while at the field. Fly 2 - 5 flights (depending on your MAH appetite) and charge again in 20 minutes. You could use the field's charger station, but I just use the world's best value charger http://hobbycity.com/hobbyking/store/uh ... oduct=7028 and run it off a common 2200mah 3 cell lipo. Each lipo has enough capacity to charge the batteries in my 50cc Yak twice.

Good news dave:
the A123's are only 6.6v with all of the good atributes of Lipos...so no regulator for Rx or Servos or RCEXEL ignition!

The Spektrum AR9100 ( see link above ) comes from the factory with two EC3 ( blue ) connectors for batteries, it has a built in battery selector and uses a FET to control the battery on/off without the current going thru the switch and it fails safe to ON.

Ring me if you don't get it all....no RF in the main RX box, just power management and servo bus and management logic...RF is in the 3 satelite thingies...most elegant design around for a DM2 system!

.......and with Mikes A123 badderies you are home and hosed....at last.....I ordered the in lin badderies..easier to fit in...like a pencil...

Hi Mike and Gary what are A123 batteries?
Dave.