Runner Bean Growing Height

[neuron]

My young daughter asked me the other day how high my garden runner beans would grow if I could add cane after cane to the bamboo cane structure in the garden.

The canes I use have an above ground height of about eight feet and she's noticed that the plants just curl over the top and flop about when they reach the imposed height limit - I never pinch the growing tips out.

Now I really don't think she has meeting Jack in the Beanstalk in mind, but I did'nt know the answer to her question. I've also just noticed curiously that the seed packet of the Suttons Scarlet Emperor has no information on the height of the mature plant nor the length of the canes to be used

Has anyone any experience of growing runner beans to extraordinary heights? I fully understand picking the pods could be a bit of a problem!

Thanks.