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HeliTorque :: View topic - Secondary Effects of Yaw - Why?
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HeliTorque Forum Index » Flight Dynamics

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Heliwhore
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PostPosted: Mon Feb 23, 2009 10:48 am    Post subject: Reply with quote

I'm going to retract my previous argument, as I wrote it over a glass (or so...) of wine. After a nights sleep: we can't change the C of G, and the centre of force I'm referring to is just the new resultant force that has pitched the aircraft to its new attitude.

Think I may need to draw this up for myself before I continue this, and WhirlyGirl, once again I blame you for starting it all.....
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WhirlyGirl
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PostPosted: Mon Feb 23, 2009 11:27 am    Post subject: Reply with quote

Heliwhore wrote:
WhirlyGirl, once again I blame you for starting it all.....


Why not... I'm good at getting the blame for things. Rolling Eyes

Sarah
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Heliwhore
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PostPosted: Mon Feb 23, 2009 12:03 pm    Post subject: Reply with quote

Alrighty, so I've made a couple of drawings up, which seem to support my theory 1, but they possibly have some relevance to theory 2.

Image 1


In image one I've covered two bases: 1. It shows the aircraft attitude at the lower speed and sitting quite level. 2. It shows also the forces and vectors of an increase in speed before the fusilage pitches forward to resolve and align the resultant vectors. This image shows the arm that the tail rotor forces act over to create its rolling moment.

Image 2



Quote:
What changes is the magntude of those forces but they do not move around the center of gravity they remain fixed in relation to it, so their moment arms remain the same and its the moments that change due to the change in the size of the force.

In image two I have pitched the fusilage fwd to align the resultants, now the tail rotor has a greater moment, but without increasing the magnitude of the force.

Currently keeping head down and bracing for the flak.........
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haggishunter
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PostPosted: Mon Feb 23, 2009 12:12 pm    Post subject: Reply with quote

I am going to start helping you job hunting for you HW, you have too much time on your hands clearly...

...it's for you own good. Hehe.

Any luck by the way?

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Heliwhore
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PostPosted: Mon Feb 23, 2009 12:16 pm    Post subject: Reply with quote

Quote:
you have too much time on your hands clearly...

It's that obvious huh?

Well, now they're landing the things in the water it doesn't help my cause Rolling Eyes

Plenty of work to be done on the house still, after that I will be touting for free-lance again.
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PostPosted: Mon Feb 23, 2009 6:59 pm    Post subject: Reply with quote

Tried HeliPortugal?

HH
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berphead
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PostPosted: Fri Aug 30, 2013 12:50 am    Post subject: Reply with quote

By putting in left pedal the sideslip and hence, lateral velocity increases. The disc responds to this by flapping away from it, just as it does during translational lift. In this case the flapping away from a right sideslip would cause a left roll. Without this phenomena the helicopter would be laterally unstable. It's called Lv. L being a rolling moment caused by v - a lateral velocity. I hope this helps.
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