You should NEVER cut the Rx antenna. The length (about 39"), isn't random, antenna legth is based on the Radio system's operating frequency (72 mHz). If you only cut off an inch or two you're probably alright, but I'd still do a good range check. With Tx antenna collapsed, you should be able to walk out about 100 feet from the plane without the servos "chattering", and still have good control over them. Much less than 100 feet is suspect.

Some small park flyer Rx's use 1/2 length antennas (about 17" instead of 39"), but the range is reduced to about 500 - 800 feet.
Dennis-