Different types of TRDS containment

[ronnie barker]

Hi i am trying to find out different types of containment methods that are used on helicopter TRDS, when failure occurs. Your advice/expertise would be much appriciated.

[Freewheel]

Just tell 'em to sit down and put their seat belts on.

Works for me, most of the time.....

[nodrama]

On most helicopters, I think it's fair to say that there is no method of 'containing' a drive shaft if it fails. They are held in place by their bearing mounts and covered with a composite fairing.....that's as good as it gets.

[squib66]

The engine-MGB bendix high speed shaft on the 332 family is contained (restrained?) by internal stub shafts if the failure occurs at either bellows, the designed weak point.

[212man]

If the TRDS fails, then flailing will be the least of your problems

[ronnie barker]

On the Apache helicopter there is a driveshaft that runs next to the MRGB oil cooler and thus has an anti-flail device that prevents the shaft from whipping out of alignment and this not puncturing the cooler. I am trying to find out if there are any other helicopters that have a similar device or another method of conteracting this.

[nodrama]

......and there we were thinking you were talking about real helicopters

[Thridle Op Des]

C'mon guys give RB a bit of a break here, he is trying to doing some research and would really like to hear from anyone who worked with Hughes/MDD/Boeing in the design phase of the Apache.

It's an interesting q (IMHO) yes losing a TRDS would not be the event I would choose to have as my career challenging experience but loss of TR thrust (without component loss - as Bell quaintly put it) in the cruise MAY have a chance of survival and that chance would not be expanded if the flailing TRDS removed the tailboom for example.

As an apocryphal story I seem to recollect that the BV234 fatal in SUM had an unconstrained synch shaft in the equation.

[ericferret]

Hughes installed a device for maintaining the drive and retaining the shaft on the fwd coupling of the TRDS in the early 80's for the 500 series.

[Dan Reno]

The RH-53D installed containment shields around the #1 & 2 input DS to prevent a flailing DS from taking out the adjacent flight controls.