The main shaft of a micro helicopter nearly always gets bent in a crash. The conventional way to fix it is buy a new one. After buying fifty or sixty dollar's worth of main shafts RC helicopter pilots decide to find a way to fix the ones they have.
Some fliers figure out how to bend the shaft back into serviceable shape with vise grips, pliers, a bench vice, etc. This approach requires you to somehow gauge where the shaft deviates from the desired shape and apply pressure in the right direction to straighten it.
Straightening a main shaft is tricky enough that a fellow named Eisenhard created a special tool that lets you see where the shaft is bent and straighten it rather easily, as illustrated below:
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Eisenhard Tool for straightening bent main shafts. |
The main shaft is held in the lower body of the tool. When you take the shaft out of the helicopter you need to also remove the main bearings. Put the bearings into the recesses on the top and bottom of the tool and insert the main shaft through the bearings. Then put the retaining collar on the shaft and tighten it a little so the shaft stays in the tool, as in the picture below:
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Main shaft in the tool. |
The two screws are used to judge where the shaft is bent and also to apply force to straighten it.Turn the screws until they are close enough to the shaft that you can see the gap widen and narrow when the shaft turns. When you think you know how it needs to be adjusted hold it so it can't turn and use one of the screws to bend it a little. Then keep turning it to decice if it is straight or not. It take practice, but the shaft usually bends in the same place so in time you can straighten it in a few minutes.
This tool is available on eBay from member billbob49. Or you can type in the search string 'Blade CP main shaft tool'.
In the video below Gino CP from RCgroups.com demonstrates how to use the Eisenhard tool:
Using the Eisenhard tool. |