what are the modifications required for flying a 3d heli with airplane radio,
is it possible to fly both airplane and heli with the same radio ?

You cannot modify a radio to fly heli. You need a radio capable of supporting the different swash types and need switches to change normal and idle up modes. It is not possible to add these to a radio yourself. If it didn't come with support for heli, then you could use a CCPM mixer in the heli like the TT TG6100. However this is not as flexible as programming in the radio and is a less preferred approach.

I guess the important question is, what radio do you have ?  If you tell us the make and model number, we can provide responses that are specific to your situation.

And the reason for asking the question is that now most radios (6 channel or above) from major manufacturers all support both airplanes and helis in the same radio.  So we need to be clear on why you are calling your radio an "airplane radio".

dear sir i have futaba 6exhp with 136hp rx so i can fly airplanes? so what can i do my e-mail  is

Quote from: arpith on July 10, 2011, 10:22:02 PM
dear sir i have futaba 6exhp with 136hp rx so i can fly airplanes? so what can i do my e-mail  is

First I would suggest you to get the question correct.

hey...you can fly Heli & plane Both....you just read your Redio manual...every question will solved.
If you dont have manual just downlode...Google jindabad

Quote from: arpith on July 10, 2011, 10:22:02 PM
dear sir i have futaba 6exhp with 136hp rx so i can fly airplanes? so what can i do my e-mail  is

my tx is heli version futaba t6exhp how can i fly airplanes and with flaps or two ailerons

radio modification futaba t6exhp to fly airplane with extra flap knob and extra switches for two aileron flapron mixing

pls post a pic of your tx
& there are settings in the tx 
where you can convert it from heli to plane or glider