Capn kamikaze

Is this in the pipeline?

Until the F/A-18 comes along it will hold the crown as the most useful modern western plane.

Since there is the USAF aggressor side, could we have a Russian one, for a civil war type scenario like a certain F/A-18 Super hornet simulator from days gone by.....

Oorah!

We have the AAV-7, and now that we have the Tarawa and the Harrier to play with could it actually be made amphibious, so we can build missions actually supporting Marines going ashore? Also would it be possible to some day have LCAC's and modern landing craft?

What about using optical guidance after launch rather than "laser"?

To the collective thing, yes, it's irrelevant, but the precession discussion was about retreating blade stall effects, and it is very relevant to that.

It is difficult, but the main mission of the AV-8B is CAS, so a FAC can solve a lot of those problems.

Thank's rep inbound.

Try as much as I can, this doesn't seem to work, unfortunately the one vid showing the method that I can find fast forwards past a bit where it looks like some systems are used.

:beer:

http://navybmr.com/study%20material/14008a/14008A_ch7.pdf http://www.rotorandwing.com/2017/08/04/ray-prouty-rotor-gyro/ http://www.danubewings.com/gyroscopic-precession/ How you can really say it does not act like a gyroscope is frankly astounding.

What? Sorry but the fact is it is a gyroscope, any spinning mass is, it's why precession applies to the problem.

Chic, that is a swash linkage geometry control issue, which is not relevant to what we're talking about, once you get to the upper part of the swash those linkages, or the hub or rotors don't "know" what has gone on below, it transfers the control inputs but still allows the rotation of the disk, and that leaves the problem as being simply an issue of angular momentum of the disk, in other words all that matters when talking about reactions of the disk to aerodynamic forces on it is that the response will be 90 degrees offset from where the force is applied to it. Don't confuse control inputs from below the swash with aerodynamic inputs from the air that it's flying through, they have different effects, that's one of the first things you learn on an aeronautical engineering course.

Jester, the reason why the roll is not directly caused by the retreating blade stall is the coning angle and the oncoming flow....

The fundamental physics are the same, and depending on the heli, scale, 3D, etc, you can have exactly the same type of rotorhead design, eg a rigid, or semi-rigid design, my first one a had a split spindle which was very similar to a fully articulated one. You're right about the RPM, which mostly means lower coning angles, and more force pulling the blades out straight which reduces lead and lag angles to a much tighter range than full scale. The only reason I mentioned RC was because of the fact you can set them up to have negative pitch, with zero in the middle, and that demonstrates that a force from the cyclic in a negative direction on one side of the disk will have the same effect as a positive force of the same magnitude on the other side of the disk, causing one side to precess up and the other down.

That's swash linkage phasing offsets, or phase lag, which is a separate issue, but the gyroscopic precession of a rotating mass is always 90 degrees.

... and I am arguing as to whether it is more significant than the pitch up, and as to the mechanism behind it, and I have studied aeronautical engineering. Consider it from another angle, we can agree that the rotor disk is a gyroscope, like any other rotating mass, so any rotation it makes outside of its plane of rotation HAS to be caused by a force 90 degrees preceeding the observed motion, if the left hand side drops and the right hand side rises, then it is caused by a force, or pair of forces acting as a couple at the 12 and 6 positions. Just because it has stalled already does not mean it breaks the laws of the conservation of angular momentum, and therefore must still be acting like a gyroscope, and it will do that until only one thing happens..... it stops rotating.

In the case above with the CCW disk, you'd get a roll to the right, in the case of the Gazelle it should be to the left.

Let me put it another way, I fly R/C model helicopters, and I am quite good at "3D" flying, the way we set them up is that at centre stick on the collective you're at zero degrees pitch, you can flip them over on the spot because you can generate lift one one side of the disk and negative lift on the other, these manifest 90 degrees around, as a cyclic response, if it didn't work like that it would not be possible to do on the spot flips. Removing a force is similar to adding a force in the opposite direction, if you add more lift on one side, and reducing it on the other you still end up with a 90 degree precessed response, the heli doesn't know if its from RBS or from a cyclic input. When you have RBS and have an abrupt pitch up, that will then also cause a secondary roll, but that roll is NOT caused by the loss of lift as if you'd snapped a wing off a plane, but as a secondary precession effect that only manifests because the nose came up.

NO, in RBS the rotor has not stopped producing lift, a portion of it has, meaning the centre of lift moves to the advancing side, and has the same effect as pulling back on the cyclic.... The side without lift acts like it does when you use cyclic, its force manifests 90 degrees around, at the tail. Gyroscopic precession doesn't just work for applying a force, it works for removing one too...

Also the stalled region is towards the tip of the blades, it does not include the entire side of the disk. What is happening is that the centre of lift is moving towards the advancing blades side of the disk, and it doesn't have to move far to cause a large nose up moment.

It doesn't work that way, the lack of lift on the retreating side causes the lift to drop off at the rear of the disk. Think of it like how the cyclic control works, the control inputs are offset by 90 degrees, the front of the swash plate rising, the rear falling, consider a CW rotating two rotor disk, at zero collective pitch, you pull back on the stick, the front of the swash rises, the rear falls, the linkages translate that through 90 degrees, the rotor at the 9 oclock position pitchs up, and the one at the 3 oclock pitches down, now think about the positions 90 degrees around from that, the blade that was at 9 will rise to a high point at 12, and the one at 3 will drop to a low point at 6.

Jester, that roll is a secondary indirect effect, because the nose of the helicopter is being forced up, due to the extra lift on one side of the disk becoming dominant, that translates to a secondary effect, via gyroscopic precession. The first effect, the nose up force, is caused by the asymmetry of lift, 90 degrees around, the rotation of the blades doesn't matter, either CW or CCW, it always appears as a nose up force, when that abruptly manifests, that motion also causes a further 90 degree shift, and a much smaller roll motion is observed. Hypothetically if the nose never came up, the much less severe roll force would never manifest.

http://www.pprune.org/rotorheads/296643-tail-rotor-position.html