Norm,
I just checked the manual to my 46FX, the part # listed for the pressure fitting is 22681957. Here is a link to it at tower.
http://www3.towerhobbies.com/cgi-bin...EARCH=22681957
Or you may be able to use one of these,
http://www3.towerhobbies.com/cgi-bin...&I=LXD623&P=ML
http://www3.towerhobbies.com/cgi-bin...&I=LXD624&P=ML