Zenith "no hinge ailerons"

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BBerson

Light Plane Philosopher
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I think it's the mindset I referred to earlier, who hasn't flex a material back and forward a few times and had it fail.
Sure, but that is bending it way past yield each time to break it in only six flexes.
For life below yield, look up the S/N curve for aluminum.
 

Mad MAC

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Dec 9, 2004
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Hamilton New Zealand
What is the problem? Fatigue life 120,000 hours (post 31).
.
Its a pity zenith air didn't use standard terminology
http://www.zenithair.com/kit-data/ht-aileron.html
It should be pointed out that the usual scatter correction factor is 1/6 for fatigue data, its not clear this has been applied to get the 120,000 cycles. Plus they don't address the biggest deviation from the standard test data, which is the shear load in addition to the bending.

Interestingly the design would be quite sensitive to where the surface movement comes from i.e. vertical movement of a bell crank, horizontal motion of the a push rod and were that point is on the surface (well away from the ends would make a big improvement).

During flutter it must be a crazy scene with that extra axis of movement.
It may actually help suppress flutter, if the extra degree freedom can be set to result in non liner movement in the critical case.
 

Pops

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The Zenith 600 project that I had ( From first plans) had piano hinges. Plans showed a 1835 cc, VW engine.
 

BBerson

Light Plane Philosopher
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Port Townsend WA
Interestingly the design would be quite sensitive to where the surface movement comes from i.e. vertical movement of a bell crank, horizontal motion of the a push rod and were that point is on the surface (well away from the ends would make a big improvement).
Yes, I would be more concerned with overall stiffness, which could effect flutter if not stiff.
 

Himat

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It's not so much the materials as it is the size that counts. The square-cube law conspires with Reynolds numbers to severely limit how well such solutions scale between m and 10m span aircraft. There's also the matter of failure criticality--having lives at stake has a way of making durability and reliability much more important.
There is also a difference between manned and radio control sailplanes that can be significant. In a manned airplane aerodynamic and/or inertial forces may overpower the pilot and shift the position of a control surface. On a radio-controlled plane with correct sized servos the control surfaces are stick fixed and do not overpower the servos.
 

litespeed

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May 21, 2008
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Aaah, that’s just his mating ritual. Either that, or he saw the bigger Eagle with a tender human morsel in its mouth and it just wanted a piece of you for himself.
I think he noticed the Goat on the side, and having a penchant for the beasts, got hungry. Jack must have figured he got lucky. No need to climb and drop it from height to tenderise.

Just scare the meat bag flying and he will do all the work for you.

Just bloody lucky Emus don't fly and Kangaroos have no wings.
And don't even mention any local snakes on a plane.

Mother nature sure takes a grudge around here.
 

pictsidhe

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Jul 15, 2014
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North Carolina
Heinz's fatigue test didn't account for binding or shear. It's those that make it a lot more complex to analyse. May as well just set up a test rig that does include them than struggle with the maths.
 
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