Izzy

I used a water waste pipe fitting which was 90degree right bend, now this particular right hand elbow/bend which I use was also perfect as it was a low profile one so the bottom of the bend was flat.
The diameter of the fitting is 1 1/4" or 32mm (31.75mm) I brought the fitting from B&Q (Home Depot in US) same type of store
I would try and get one for you but cannot get out at the moment :-(
I will sketch you a pic and post how I glued in with Hysol, don't forget water pipe fittings are PVC and Hysol will not attach to PVC even if you rough it up. So I created a fillet around the fitting and glued directly to body of aircraft, came out perfect and looks exactly like 1:1 scale
The holsol fillet 'locks' the fitting to the fibreglass body.

Alan