Im looking to start building my first kit and I have a few questions about servos.

Do the brand of the servos need to match the brand of your radio? For example I have a JR radio so does that mean I need to get JR seros?

Also the plane im going to be building is a sig somethin' extra, so what do I look for in a servo?

Any help you can give would be appriciated, thanks.

No, you can use just about any brand servo you want. There are a few small considerations that may need to be taken, but they are minor. Like the tab on a Futaba servo may need shaved off. Or older Airtronics servos may need wires switched. Refer to the attached diagram as a reference.

Ken

when it comes to servos, is it possible to not use servos arms? and just use the holes in the circular part of the servo if it works well?

I am having a hard time picturing what you are saying, but while it may be possible, and it may work now, under flight conditions, i wouldn't trust a setup like that. JMO. Maybe I could say I approved if you explained it a bit more.

If you mean an output wheel such as http://www2.towerhobbies.com/cgi-bin...?&I=LXH364&P=7

then YES, that would be fine. You can't use a clevis with one of these though or even an L-bend. You will need to use a Z-bend or something like these
http://www2.towerhobbies.com/cgi-bin...4&I=LXE114&P=K

I get it now
For some reason I was picturing you trying to connect the output shaft directly to the control surface and I thought to myself, "well it would probably work but you won't have any way of setting the throws unless you have a computer radio"

So could I also use any receiver I wanted as long as its the same frequency as the radio?

Frequency and "shift" most JRs are positive shift.(I have heard some newer JR radios are shift selectable)
Look for a positive shift, shift selectable or auto shift reciever. I have had good performance from Hitec recievers.
I should go a step further not knowing what JR radio you have.
You cannot use a PCM reciever unless your radio is PCM capable.

I have a JR XF421.

Frequency - matches TX
shift - pos or neg to match TX (may be selectable or autoshift)
modulation - AM or FM - Then if PCM it needs to be the SAME mfg as the TX and TX be PCM capable.
Range - don't use park flyer RX in nitro plane or plane may go bye-bye

http://www.rcuniverse.com/product_gu...smitter_id=147

The only exception to the picture that RC Ken put up is that the newer Airtronics Z servo's have a blue signal wire instead of what is shown. But the power leads are still black and red (black is ground or common, red is the "hot" lead).

Thanks for all the help guys.

Just to be 100% sure how would this setup be?

Radio - JR XF421 FM
http://www.rcuniverse.com/product_gu...smitter_id=147

Receiver - Tower Hobbies 8-Channel DC FM Receiver
http://www2.towerhobbies.com/cgi-bin...1p?&I=LXMFU6**

Servos - Tower Hobbies TS-53 Servo Standard U
http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXUK84

May not work.
JR is positive shift, Hitec and Futaba are negative shift. The JR radio you selected does not list it as being shift selectable so I assume it isn't.
Here is what it says about the reciever you chose:
"Compatible with 72MHz Futaba and Hitec FM or PPM transmitters, or
FM/PPM transmitters with selectable frequency shift"
Here is a better choice and will work with that JR radio
http://www2.towerhobbies.com/cgi-bin...&I=LXKYK3&P=ML

Hi!
During my 32 years in this hobby I have seen many newcomers (and more experienced fliers as well ) that have had lots of trouble when they have mixed their radio systems ( transmitter and receiver).
Why buy a JR transmitter and then not buy a JR receiver??? Puzzles me.
JR makes some of the best (if not the best) radios on the market so why not get a JR receiver as well)
Sevos are OK to mix though.

The receiver you're interested in is not compatible with the JR transmitter. If you look into the receiver's description, it says that it works with Futaba and Hitec transmitters. You're wanting to use a JR. The reason Tower lists what TX the RXs work with is because the RXs either work with Futaba/Hitec or with JR/Airtronics. Some RXs work with all. Most don't.

Hitec happens to make RXs that work with Fut/Hitec and RXs that work with JR/Airtx and some that work with both. Here is one that's the JR model. They've got the same that's a Futaba model.

http://www2.towerhobbies.com/cgi-bin...?&I=LXCXM9&P=7

If you are trying to piece together a package in an effort to save money that is tough to do. Usually cheaper/better to buy a complete package from one of the manufacturers.
Even in the list you gave you didn't allow for switches or RX batteries and some of the other things that may be included with a system that in DESIGNED to work together.

Ok I think I have this down now.

This is a complete package that includes the receiver that Missileman said will work with my Transmitter and comes with the battery and switch.

http://www2.towerhobbies.com/cgi-bin...?&I=LXKYL2&P=0

That is a complete AIRBORNE system but doesn't include a TX of course.
There is also this note:
REQUIRES: Hitec Dual Conversion Crystal, HRCL01**
If wall charger is needed, order HRCP3025

Now you need to find a TX.

The crystal is about $10 and a walwart charger is about $10 (will charge both your receiver battery and your transmitter battery)
I like the 425 servos, I have them in several planes and they work flawlessly.