Different types of TRDS containment
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Different types of TRDS containment
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.
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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.
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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.
If the TRDS fails, then flailing will be the least of your problems 
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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.
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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.
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.
