Well hello every one im new into the giant scale and ever since i picked up the first magazine of model aviation i always loved the giants,love the size and sound of them,but now that i moved up after years in the RC cars into planes i think im ready.
(Hold it i know what your asking,a giant wont be my first plane ever) correction it would be my 4th-5th plane, i have a decathlon,edge,avistar and FT spitfires and my favorite has to be the decathlon. so to stop making stuff boring for you guys, im planing on getting a 25 % bell hempel extreme decathlon.

Here's the part i need help, whats the minimum oz you can use in the plane for servos, and im still looking for a affordable 40cc -55cc motor for it. Also ill be getting the parts and motors first then the air frame.

So any way thanks for reading and i hope you are all having a wonderful day or night.

Id recommend you go with some servos that are stronger than what you 'can' get away with. Buy cheap, buy twice is true with many things, but in this case it's buy cheap buy everything twice... Flutter, lack of authority when needed, Ect will destroy a plane in a heartbeat.

If it were my plane, I'd go with something in the 250oz range or greater. Savox makes some affordable ones in that range and up, and many people like them. Ill have some in my next one.

Thanks! what's the model you use?

For 50cc 3d models.. Mostly folks are using equivalent of hs 7954 or savox 1270 or mks777. Smaller control surfaces can go with lesser oz-inch.

I'm using the Futaba 3071HV servo on my 92" (25%) Hempel Xtreme Decathlon. They are 146 in-oz on 2S lipo/Lion and have proven to be both robust and reliable. The surfaces on this plane are fairly large and I even use this servo on the flaps which are large and deflect 50 degrees at full throw.

My 50cc AW Extra uses servos that are around 180 in-oz torque and they too have proven to be more than up to the task. It is not a matter of "what you can get away with" and more like not spending money on torque you don't really need. Personally anything over 200 in-oz on a 50cc plane is overkill.

For me centering is far more important than simply focusing on torque. Unfortunately you cannot easily find those numbers. It is sort of like in the early days of PCs. Everyone focused on the clock speed of the processor. But that was not always the best and most meaningful parameter to determine actual performance.

Thank you! this helps so much,though i was gonna spend all my budget on servos

The Hitec 5685 are HV servos and are about 180 oz-in (the specs are real, I have personally tested them) and are less than $40 each at Tower.
http://www3.towerhobbies.com/cgi-bin...P?I=LXZTZ2&P=8

i wish i could put a 7 V lipo but my receiver isnt rated for that,thinking the HS-5645MG because at 6V they pull around 168 oz

and yea its not a spectrum or JR,its tactic 6 channel but damn is it reliable, flown all of my planes with it and they are cheap and super reliable,sadly because i dont have the 8 channel one i cant put 2 s lipos

Originally Posted by CarribeanSnowFox

i wish i could put a 7 V lipo but my receiver isnt rated for that,thinking the HS-5645MG because at 6V they pull around 168 oz

and yea its not a spectrum or JR,its tactic 6 channel but damn is it reliable, flown all of my planes with it and they are cheap and super reliable,sadly because i dont have the 8 channel one i cant put 2 s lipos

Have you considered LIFE batteries? No regulator needed, more amps than a NIMH, and with a nominal voltage of 6.6v they can be used with any system running at 6v. Also +1 for 5645 servos they will be just fine for the 25% decathlon.

The Tatic RX can easily handle a LiFePO4 pack. A 2S lipo would likely be OK as well, but I'd go with the Life and stop worrying about it. The difference in speed and torque is not worth thinking about, especially on the Decathlon.

THANKS ! I'll be sure to pick up a life battery as well !

Originally Posted by CarribeanSnowFox

THANKS ! I'll be sure to pick up a life battery as well !

Pick up 2
1 large capacity for the receiver & servos
1 smaller capacity for the ignition

What receiver cannot handle 8.5V these days? And I would skip the separate ignition battery, use a Tech Aero IBEC.
http://www.tech-aero.net/ultra-ibec

Originally Posted by scootr

Pick up 2
1 large capacity for the receiver & servos
1 smaller capacity for the ignition

Yes, pich up 2

2 of the same capacity for the RX and an AeroTech IBEC for ignition/kill. No need for an ignition battery and better to have redundant power for the RX.