One for the geometry heads.

[LeadingEdge28]

Yesterday we had a sloping ground landing our limitations are 12 deg nose up. Now because we landed across the slope approx 45deg between left skid low and nose up it felt like we had more room to play with. I think if we went left low or nose up we wouldn’t have been able to land due to limitations. I would like to know the geometry behind it if anyone can help?

Tedge

[Ascend Charlie]

Most low-tail-rotor aircraft will hang left skid low, due to the couple between the T/R thrust and the left-pointing M/R thrust. So, a slope to the left is easier than a slope to the right.

But a 45 degree slope is getting a bit brave??

[Kulwin Park]

Pictures to indicate what you are describing might help us

[The Nr Fairy]

Originally Posted by Ascend Charlie

But a 45 degree slope is getting a bit brave??

I read it as "45 degrees between nose up the slope and nose left or right"

And the Gendarmerie seem to manage 45 degrees or steeper

You Tube

[albatross]

Originally Posted by The Nr Fairy

I read it as "45 degrees between nose up the slope and nose left or right"

And the Gendarmerie seem to manage 45 degrees or steeper

https://www.youtube.com/watch?v=EC2v...hannel=BBCNews

I think the phrase he is looking for is “Diagonally across the slope” or perhaps “On the Bias”.
Most machines have better limits nose upslope than downslope and cross slope.

Found this from a 2014 discussion on the subject. https://www.pprune.org/newreply.php?...eply&p=8675618

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Compound slopes -ie a combination of lateral and nose up are an acceptable way of managing a sloping ground landing whilst staying within limits.

Lateral limits will be due to cyclic authority and avoiding dynamic rollover conditions - nose up will be to do with mast bumping/bending or clearances on the underside of the nose (aerials etc).

The Lynx had a 12 degree lateral slope limit but the fuselage also had an arc of freedom about the skids of 4 degrees either side of the mid point so it was possible to do a 12 degree lateral slope landing and then roll to the 'bottom stop' so you saw 16 degrees on the AI - that felt bloody uncomfortable if you were in the down slope seat!

[Ascend Charlie]

Nr Fairy, I am talking of having both skids / all wheels flat on the ground.

All of us have done toe-in, one-skid-on, heels-on landings / hovers.

One of the ugliest feelings I had was in an A109 on a slope, with the fuselage going lower with the compression of the oleos. Had all wheels on the ground, but lowering the lever made the further roll very uncomfortable.

[The Nr Fairy]

Originally Posted by Ascend Charlie

Nr Fairy, I am talking of having both skids / all wheels flat on the ground..

I did get that - I was being facetious. Apologies for any offence.