85cc plane setup

[cmircman]

Ok guys i am making the jump from 50cc to 85cc. I am going to be using 4 5645's on the wings(I already have them) and 4 7955's in the tail. I already have a 2300mah A123 pack , a smartfly super switch and ignition cutt off, and will be using a a JR921 reciever. After doing some reading I am confused on what would be the best way to set this up. I was looking into a power expander just for how simple it would be to setup but now I think it may be overkill. What would you do? Thanks for any help.

[STLAV8R]

A PE would be overkill. Not necessary and just extra weight.

[cmircman]

Ok so i take it what you are saying is I could use a 2 matchboxes for the wings and have plenty of power so I would not have a brown out on the reciever correct? Also how do you calculate the max amperage you need for a power system?

[f5air]

just a question...one 7955 is not enough on the rudder?. Also for one per wing?.

[cmircman]

I could probably get away with 1 7955 on the ruddder but the ailerons need 2 servos each.

[jamesrxx951]

imo ditch the 5645's they are slow. get another set of 7955's or 7985's. also you can run those a123's into reciever. just use 2 and use 2 different power inputs. you don't need a PE. if you feel that you do sell the 921 and get a 922 power safe reciever and has a built in fail safe switch so it would probably be cheaper and lighter than using a PE. you can get the 922 at cheif aircraft for only $189.

[cmircman]

I was eventually going to ditch the 5645's i was just using them to get the plane in the air. I am looking into the 922 reciever. I would just love to know why the did not just use deans conectors on it. My main concern is having a brown out on the reciever.

[jamesrxx951]

i think it is because they use there own style of connector. they sell batteries that have the same connector. i called them and you can solder on deans, thats what i did.

[crazyjoe]

4- 7955s for the wings
2- 7955s for the elevators
1- 8711 for the rudder
2- A123s for power
Power Expander Pro and fail safe switch is $150.00 plus $20.00 for switch $170.00 total
How much for 2 switches 2 matchboxes and a $189.00 dollar receiver. And none of the benefits you get with the power expander. I have three planes set up like this pic 2- 35% and a 40% 4 seasons and no problems. Smart fly Expanders are inexpensive light and reliable.

[2walla]

	Quote: Originally Posted by crazyjoe
	4- 7955s for the wings 2- 7955s for the elevators 1- 8711 for the rudder 2- A123s for power Power Expander Pro and fail safe switch is $150.00 plus $20.00 for switch $170.00 total How much for 2 switches 2 matchboxes and a $189.00 dollar receiver. And none of the benefits you get with the power expander. I have three planes set up like this pic 2- 35% and a 40% 4 seasons and no problems. Smart fly Expanders are inexpensive light and reliable.

Just use a powersafe receiver... 189dollars and comes with the switch.. forget the power expander it just adds cost.... Set the linkages well mechanically and you probably don't need a matchbox.. Especially if you put the aileron servos one outboard on one inboard on the ailerons. Unless you are doing a comp arf the ailerons will have enough flex to abosorb minor misalignment between the servos... Or buy some decent servos and just go one per wing...

[crazyjoe]

If he uses Hitecs he can program them and like you said he wont need matchboxs. I feel like they are a huge waste of money.

[jamesrxx951]

	Quote: Originally Posted by crazyjoe
	4- 7955s for the wings 2- 7955s for the elevators 1- 8711 for the rudder 2- A123s for power Power Expander Pro and fail safe switch is $150.00 plus $20.00 for switch $170.00 total How much for 2 switches 2 matchboxes and a $189.00 dollar receiver. And none of the benefits you get with the power expander. I have three planes set up like this pic 2- 35% and a 40% 4 seasons and no problems. Smart fly Expanders are inexpensive light and reliable.

i have the exact setup 7955 on wings and elevators,8711 on rudder and using a123's. using a 922 power safe reciever and no match boxes or power expanders. just program the servo's and go. i use the programmer for all my planes it is a very useful tool. you still need a reciever so you have to add that to the $170 you just spent on a power expander. but everyone uses what they think is best for their plane so if you feel you need a expander thats fine they are very nice but imo just not needed.

[cmircman]

I was going to get a servo programmer. TBM lists 2 different ones. Does anyone know what the difference is? Also the plane i am building is a Lanier 94" yak. Everything I am using is overkill on it. I know it is a cheap plane but i figured it is a good way to learn before I spend money on a good plane (and I got a great deal on it).

Crazyjoe what you recomend is what i was planning on doing to begin with but you always see everyone on here say dont use a power expander or you do not need it. So I was tring to figure out how to do it without and save some money. It does look like no matter how i do it I am going to be spending the same amount of money. I dont mind spending money as long as I can use it another plane especially if I move up to a bigger plane.

[jamesrxx951]

you don't need a power expander. i have seen alot of 40%ers fly just lipo-reg-receiever. both jr and futaba. or even simpler is a123-switch-reciever unless the reciever has a built in safe switch then battery-reciever.

[cmircman]

James I looked at chief aircraft today and the have them listed for $209. Is there a speacial i do not see?