28% Aircraft are both hard and easy to set up.  These planes are basically an inbetween size for just about everything including batteries.  Many who fly this size of Aircraft can speak first hand at how imortant and critial weight is to this size of plane.  

• 1-4800mAh+Reg. for RX, and 1-2400+Reg. for Ign.  This set up provides ample capacity and flight time per charge. In most cases the charge will out last it's pilot in a day of flying. This is the set up that we recommend on this size of Aircraft.
• 1-2400mAhPeerless+Reg. for RX, and 1-2400mAh+Reg. for Ing. This set up requires thorough preflight checks, and load checks before each flight.

Just ordered a Aerotech 28% Yak 54.  Wingspan is 84" and will power the plane wit ha DA 50 Engine.  Will also have 5 Hitec 35955S Servos for the control surfaces producing 333 oz torque at 6 v.  Will also have two standard digital servos for choke & throttle.  Would like a full day of flight without having to recharge.  Would appreciate your suggestion for Rx batteries and iginition battery and regulators(s) if required.   I use JR radio.

For a 28% Yak the 4800 Peerless or Relion for RX, and 2400 Peerless or Relion for Ign. is the perfect set up.  This will allow for a full day of flying in most cases.  A full day of flying would be considered at the least 8 flights at 10 minutes a piece. 
If a Redundant system is needed then 2 2400's in place of the 4800 will also work as well. 

Also remember when flying hard like this it is very important to manage your batteries correctly, proper load checking between each flight.  Please see our links below to other Knowledge Base Articles related to this topic.

I have a 27% EXTRA with 5 HST-5955 digital servos and a DA-50R engin.
For this size plane and digital servos what is the recommended battery, regulator and switch setup.

We would still recommend a 4800mAh pack for RX and a 2400mAh Pack for the Ignition, the 5955 are power hungry servos however the 4800 will still get the job done on that size of plane with that many servos. 

We  do recommend that you monitor you system closely on the first flights to get a good idea of what kind of flight time you are going to get out of your RX battery.

I am running a DA 50 with  5, hi tech 5955 and 1 5625 for throttle and a futaba 3010 on choke, I would like to get 8-10  17 min. flights per charge. will dual 2400 be ok or should i go with the 4800,
thanks.

The set up you mention with the dual 2400mA packs is the perfect set up for this size plane.  We try really hard to NOT quote how many flights you will get on a certain set up.  This is due to the fact that everybodies set is different, some are more efficient than others, and everybodies flying style is different. 

We would recommend the 2400mA packs over the 4800mA packs. 

I am getting a 50cc sized plane and want to know what you guys recommend. Since you dont sell 4800 maH packs any more is it alright to use one 5200 maH for the receiver and one 2600 maH for the Ignition. I am guessing I will need 2 regulators and does it matter if its a reliaswitch or  "The Regualtor".I will need 2 switches and will all the connectors from all these components from Fromeco work in a Futaba Receiver?

Also can you give all the chargers and voltmeters out on the market that I can use?

Yes your set up is a good one, and is what we would recommend if you were to call us. 

The Regulator and the Reliaswitch are built on the same Regulator Platform, the Reliaswitch just has the ability to be used as a switch.  The choice is really up to you.  On thing to keep in mind while making that choice is the Reliaswitch uses power in the off Position, batteries should be unplugged if being stored for long periods of time.

All Fromeco Equipment comes with JR standard for leads that would plug into a RX, this gives compatiblity with all Radio Systems. 

There are Hundreds of chargers out on the Market that can be used, what you are looking for is a charger that can charge either Lithium Ion or Lithium Polymer, it needs to be able to charge a 2S pack or 7.4VDC.  The Triton Line of chargers work well, for first timers, but can only charge one battery. 

Load meters, again lot on the Market.  We make one, Hanger 9, Futaba.......and so on.  What you need is a load meter that puts a 1amp load on the batteries for 7 to 10 seconds.