Printing TPU (or other flexible filaments)

Does anybody have any experience, and hints and tips, on printing with flexible filaments such as TPU?
I have searched the Mendel90 forum and have not found anything.

I want to make a flexible nose cone for a slope soaring model glider to absorb some of the impact stresses on a not so perfect landing. It would appear that the Mendel90 is capable of printing the material but I wondered how the Wades extruder would handle it, i have thought of removing the guide tube from between the spool and the extruder to stop any pulling of the filament, and whether retractions would need tweaking. I normally print exclusively in ABS and I was looking at using those settings in PrusaSlicer as a starting point.

I print TPU on my Huxley90 that has a direct drive extruder feeding a 1.75mm J-head hot end, see [hydraraptor.blogspot.com].

The path between the hobbed drive and the hot end is lined with a PTFE tube for printing TPU. I think that was the only mod I made. I print on glass heated to 95C for the first layer and off on subsequent layers. The hot end temperature I use is 230C and I print slowly at 20mm/s. My retraction distance is 3mm. The steps per mm is reduced compared to PLA because it rides lower in the hobbed drive.

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[www.hydraraptor.blogspot.com]

Thanks for the info.
Is there any reason why you did not use one of your Mendel90 machines to print with TapU?

They all have 2.85mm hot ends and Wade's extruders, which have a longer filament path, and I haven't bought any 2.85mm TPU, although it does exist.

It might work with perhaps just the addition of a PTFE liner in the lower filament path.I think stiffness is the fourth power of diameter, so that probably compensates for the longer filament path.

I think for the best filament control a different hot end / extruder combination to keep the filament path as short as possible would be better. I get quite a lot of ooze and stringing, although recently I think drying the filament would be beneficial as I reprinted something with the same g-code and got much worse results from the same spool of TPU.

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[www.hydraraptor.blogspot.com]

Another issue is because the printed part is flexible you can't print tall thin things as they start to bend away from the nozzle.

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[www.hydraraptor.blogspot.com]

I did wonder how the Wades extruder could handle flexible filaments and you have confirmed my concerns that compression and stretching would be a major concern.
Thanks for the information. I think that I will stick to printing hard plastics with my Mendel90.