Propeller plane testing

Question

I know they do test on jets where one of the fan blades brakes off... and the caseing must contain the fan blade, protecting the passengers (video available upon request) but what would stop a propeller blade from going through the skin? (if possible can you provide a video)

Thanks in advance,

Lighting Tech

Answer 1

Well, first the answer.  Nothing that I am aware of is added to the fuselage to protect the cabin from a propeller separation.  At that energy, there's not much you can do without a huge weight penalty anyway.  

Next, I'm not so sure the compressor and turbine housing actually IS designed to contain a shed blade.  It certainly will NOT contain a failed rotor or turbine hub, as seen in several instances, killing passengers on board.

I just took my DoT accident investigation course last month, and the engine specialist said he prefers not to sit in the rows next to the engine.  Eh, perhaps a little bit of "shock value" in that, but turbine engines do send rotors through the cabin every so often.

Answer 2

Nothing, if it separated at the right (or wrong!) moment. Considering the profile dimension/s of the fuselage, and the distance from the fuselage the propeller is, you have roughly a 45- to 60-degree arc or area for the propeller to strike. In other words, just because it's spinning off of its hub or bracket does NOT necessarily mean that it will strike the plane, since it has 360-degrees of a possible 'flight path (no pun intended).

I bet if you Googled 'airplane propeller accidents' you'd see a bunch of sites to visit.

Answer 3

There have been cases of breaking propellers bringing aircraft down.

-- search MU2 + propeller separation and you'll see a number of articles about this. (the MU2 was for some reason notoriously susceptible to problems)

Generally if a propeller separates, the severe (underline severe several times) vibration from the out of balance condition is going to be more of a concern than the blade going through the fuselage.

I know of one incident where a C172 threw one blade of a prop. The  pilot made a decent landing following this, but reports were the airplane was nearly shaken apart.

The database is down, at the moment, but you can search the NTSB accident reports at the link and I'm sure you can conduct a search for accidents involving "propeller separation"

Answer 4

The seating is so designed that the probable area which can be hit by a 'thrown' blade is kept clear in line with the spinning disc of the propeller.