r22/r44 rotor-cabin or rotor-tailboom strike

[heliroger]

Hi All,
I find it rather hard to believe that the main rotor of r22 or r44 can impact the tail boom or cabin.Can anyone explain to me how this happens as i think there's more than enough clearance between the main rotor and the cabin.Any explanations are welcome

[manfromuncle]

Basically... there is huge aerodynamic force on the blades. There is approx ten tonnes of forces pulling the blades outward during flight. If the blades wants to come down and sever the tailboom, nothing is going to stop it!

[tegwin]

Think about this scenario...


You are in a hover in an R-22..... You decide it would be fun to fly backwards....so you give it a shot...suddenly you reach transational lift and the helicopter pitches forwards thus lifting the tail boom higher than normal.... An untrained pilot would automatically pull back on the stick to try and correct the forward tilt.... This brings the back of the rotor disk lower than usual.....

If you did it hard enough the rotor would deffinately smack the tail boom....



Those blades are super flexible when they are spinning that fast!

[Practice Auto 3,2,1]

http://www.aaib.dft.gov.uk/publicati...ro__g_taty.cfm

This is a link to the AAIB accident report for G-TATY and R44 that crashed in 2005.

On page 3 (of the 12 in the report) there is a picture from the crash scene.

The M/R blades came down in the impact and took out the front of the cabin and the dual tacho instrument from the panel.

[Nipper]

Low RRPM

With low RRPM/blade stall in an R22 it is common for the balde to enter the cabin or take off the tailboom. There is not enought space here to go into the aerodynamics, however go to the accident sites on most websites (FAA, NTSB, ATSB, CAANZ etc) and have a look at the fatal accidents involving R22's and see how many have entered the cabin. The link below gives just one example, I think there are a few more on this site alone

http://www.caa.govt.nz/Accident_Repo..._17Jan2003.pdf

[DoubleAIm]

Like this close call for a R44
http://www.youtube.com/watch?v=Y73uKsZo4f0

[VfrpilotPB/2]

There is also the possibility of " Blade Sailing" on start up or shutdown when in gusty conditions!

Peter r-B
Vfr

[Chukkablade]

Thanks Nipper. Hopefully by reading and learning from reports like that, a low time Robbo pilot like I can avoid having the ultimate bad day.

After reading 'Fatal Traps', it's unsurprising just how much damage those blades are capable of.

[Drumpump]

I had an accident in an R22 some years ago, The Helicopter was rolling and a pitch-link broke one blade went flat and cut the instrument panel out and the rear of the Helicopter off, The blade missed my toes by inches

[krobar]

In Low-G situations the robbies have been known to suffer cabin impacts rather than having blade seperation due to mast-bumping.
Essentially, when the fuselage doesn't pendulum under the disc, there is a lot of room for a cabin or tailboom strike