Joined: Mar 29, 2006 Posts: 289 Location: Scotland
Posted: Mon Feb 23, 2009 10:48 am Post subject:
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..... _________________ Generally wrapped in rubber, be it in the air or on the water.
Joined: Mar 29, 2006 Posts: 289 Location: Scotland
Posted: Mon Feb 23, 2009 12:03 pm Post subject:
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......... _________________ Generally wrapped in rubber, be it in the air or on the water.
Joined: Mar 29, 2006 Posts: 289 Location: Scotland
Posted: Mon Feb 23, 2009 12:16 pm Post subject:
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
Plenty of work to be done on the house still, after that I will be touting for free-lance again. _________________ Generally wrapped in rubber, be it in the air or on the water.
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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