U bend Help

I am currently trying to make a tunnel system on my land. I have created the basic tunnel shape using a cyliner prim but I am having problems when it comes to making the bends in the tunnel.
So far I have tried every combination of prim I can think of. Using the doughnut shape and cutting in to it does not give me the height or depth that I need, Is there any way to make the cylinder shape bend or a new shape created that I have not yet come across?

You could do a transition curve by using lots of narrow cylinders (rings). I am not sure there is a single prim solution for a full size U-bend.

Thank for your help. I will give that a go!
I have visited other areas in SL which have tunnel systems and they all seem to make the curve using one prim.

look for something called a prim finder, i'm not in world otehrwise i'd tell you the name of the person who makes it and slexchange doesn't seem to be working either, but hopefully you can find this thing in search, from memory it's about 250L to buy one or just use there one there, i find it invaluable for things you know can be made from one prim but are unsure how and i'm positive there is a hollow u-bend shape there

there is also one next door to the texture tutorial build in one of the school rooms which is where i first found it

-Crunch

Lex Neva has a free tool in world called PipeMaker.

taken from the notecard :

'Pipemaker helps you easily create continuous lengths of pipe using cylinders and torus segments. The simple dialog-driven interface always lines pieces up perfectly to give you one long continuous pipe. It's useful for creating industrial complicated pipe messes, weird curlicues, and, of course, for writing your name in prims in the air.'

I use it a lot ... basically make the first prim hollow .. then you keep adding lenghs of pipes, including pipes that bend with ease .. great for making bends in your tunnel

Thanks for all your help. This morning I grabbed a copy of the pipe maker and it is a fantastic tool and has made life so much simpler.

Thank you many wasted hours have been saved )