turbulence
Controversial, moi?
Joined: Oct 2000
Posts: 1,622
Likes: 22
From: UK
Phase slag
Funny you should mention helicopter blades. I remember seeing a documentary showing some film some while ago taken with with a rotor head mounted video camera.
Now that was scary!
In a similar vein to Apex45's question I am always fascinated to think of the loads transmitted through the engine mountings of a 777 in an engine failure on take-off situation at max. weights or are they machined out of rubber too?
Funny you should mention helicopter blades. I remember seeing a documentary showing some film some while ago taken with with a rotor head mounted video camera.
Now that was scary!
In a similar vein to Apex45's question I am always fascinated to think of the loads transmitted through the engine mountings of a 777 in an engine failure on take-off situation at max. weights or are they machined out of rubber too?
Joined: Aug 1998
Aviation Qualifications: ATPL
Posts: 6,623
Likes: 847
From: Ex-pat Aussie in the UK
Hmm, after a bit or research, Slash!
As the Electra became operational, they found some excessive vibration in the centre cabin, and the outboard props were more highly stressed than the inboard ones - this was the reason the outboard nacelles' incidence was raised 3° upwards.
The Vno was reduced from 324 kt to 275 kt, and then a week later to 225 kt (with a Vne of 245 kt) after the second accident I mentioned above, and stayed that way until the LEAP was completed.
As the Electra became operational, they found some excessive vibration in the centre cabin, and the outboard props were more highly stressed than the inboard ones - this was the reason the outboard nacelles' incidence was raised 3° upwards.
The Vno was reduced from 324 kt to 275 kt, and then a week later to 225 kt (with a Vne of 245 kt) after the second accident I mentioned above, and stayed that way until the LEAP was completed.
Joined: Mar 2000
Posts: 8,571
Likes: 3
From: Arizona USA
Considering the bending relief of aircraft wings, it is interesting to note the maximum designed movement (full up to full down) of the wing tip in normal service is....
DC-6/DC-7, 12 feet
L1649A, 14 feet
B707-320, 22 feet
Beyond this amount, skin deformation occurs.
DC-6/DC-7, 12 feet
L1649A, 14 feet
B707-320, 22 feet
Beyond this amount, skin deformation occurs.
Joined: Dec 2001
Posts: 17
Likes: 0
From: Devon
Just a short thought. Not only is it important to not exceed the elastic limit of the material, but it is also V important not to stress the material to its proof stressor beyond. In other words, the material has been bent, but by such a small degree that it may go un-noticed. 1-2% proof stress can cause critical crystal/grain distlocations in some materials which could decrease the ultimate strength of the material by 25-40%. This eats into the Factor of Saftey and even into the normal operating load range, with associated brown pants!
I am sorry if this was boring or incorrect.
I am sorry if this was boring or incorrect.
