What type of plane? Balsa, composite or carbon fiber fuselage?
You mount the active part of the antenna outside (whiskers), very common in sailplanes.
http://www.espritmodel.com/antenna-2...xit-guide.aspx

If you keep the antennae inside, remember to keep the ends of the antennae (the on,y active part of the antenna) away from large dense objects (batteries, CF wing tubes, etc)
You can use small pieces of pushrod tube or tape to hold the antennae in place inside the fuse.
I use this in all my 2m F3A pattern planes to mount the Rx and antennae makes it simple and clean
http://www.f3aunlimited.com/gator-rc...eiver-tray-kit

90 degrees between the tips is recommended for best reception vs. airplane orientation
If you run 2 Rx (4 antennae...very common in turbines), then you would have 2 in the horizontal plane and 2 in the vertical plane

As always, please perform a full and proper range test before flying to verify antenna performance.