Hollow bolt design

[bigoil]

Can someone please give me a technical reason for the hollow bolt design?

Like in the wing bolts of some ac and apparently helicopter blade bolts.

Thanks

[AB139engineer]

Originally Posted by bigoil

Can someone please give me a technical reason for the hollow bolt design?

Like in the wing bolts of some ac and apparently helicopter blade bolts.

Thanks

In most cases stress loads on a object such as a bolt are taken up by its surface(s) not the core of the bolt.
Another reason is to save weight and in the case of blade bolts they are used to store additional weight for main rotor balancing purposes.

[NutLoose]

Originally Posted by AB139engineer

In most cases stress loads on a object such as a bolt are taken up by its surface(s) not the core of the bolt.
Another reason is to save weight and in the case of blade bolts they are used to store additional weight for main rotor balancing purposes.

They do not work very well in the PA28 Piper Warrior though, the centre torque links on the undercarriage had a hollow one with a grease nipple built in the end to lubricate the centre off the torque link, unfortunatly when it fails there is no mechanical stop built into the legs so the whole lower leg assembly wheel , strut and brake simply blow themselves out of the bottom of the strut and dangle on the end of the brake hose, hence they now fit solid bolts and inspect them..

[SUB]

Sometimes called fuse pins that are designed to shear so the Eng or L.G can seperate from the a/c without adding any additional damage.

[barit1]

Originally Posted by NutLoose

They do not work very well in the PA28 Piper Warrior though, the centre torque links on the undercarriage had a hollow one with a grease nipple built in the end to lubricate the centre off the torque link, unfortunatly when it fails there is no mechanical stop ...

This is either a design problem, or a manufacturing problem in the bolt. There's no reason why the concept is unsound - it's the attention to detail that counts.