Wind Over Deck: BRC, Angled Deck, Crosswind?

[Nealius]

One thing that has been bugging the hell out of me with my traps in how to set the wind. I typically have the carrier steaming at 20kts with 5-8kts of headwinds. So 25-28kts over the deck. Check.

 

Source of confusion: which direction?

 

1. If I have the winds straight over the BRC, my nose crabs into the wind. So even if I have a decent lineup, once I hit the deck my nose pulls me way off centerline. All real world videos I watch have the nose staying straight down the angled deck.

 

2. I don't think I've actually tried setting the wind 9° left of BRC to go straight down the angled deck. If I did, I've forgotten what the results were.

 

3. I used to set wind 18° left of BRC. Some trigonometry posted in another thread a long time ago. It made things really easy, and I could keep my nose straight down the angled deck during a trap. Looks more like real life. Problem: Because the wind is pushing me towards the ship's axis while I'm in the 180, I need greater than 30° AoB even with a 1.2-1.3nm abeam distance. I'm not supposed to need 30° AoB unless I'm at 0.9nm abeam distance (according to math done by Victory205 in his old CASE I paper).

 

Soooooooooo.......which direction should the wind be going over the deck to:

 

1. Stay aligned on the angled deck (no crabbed nose)?

2. Not need excessive bank during the 180?

[Raven (Elysian Angel)]

Personally, I see bank angles change depending on gross weight, so I don't consider those 30 degrees to be the holy grail. No crab angle has my preference...

[Nealius]

Bank angle should change with your speed, but in comparison with the math done in that CASE I paper, I'm typically only 3-4kts faster, if not at the same speed that was used (137kts) in the calculations.

[David OC]

When no wind the wind is generated by the boat. So it's straight, this is when the pilots talk about the burble, winds created by the behind the flight deck and superstructure. The extra offset was because of the 6deg variation.

 

The carrier will always try and get the wind straight down the deck IRL (When blowing) and or you should correct the crab on landing when the wind is straight down the deck. It's never been really that bad if the mission is setup correctly tho.

 

I know the video's don't show it.

of this (The landing) and imagine being really crabbed and or well offset.:cry: It's more violent then those other videos make it out to be.

 

It should never be this bad lol. But you get the idea.

 

 

Starts at 1:16

 

 

 

The rest is that pilot sh... as they say and you should be dynamic and change the setup on the fly. 30 deg should be max, allow for that, allow that you might be blown in towards the carrier on the downwind and allow for that, offset more to the right etc. so you are in a better position when turning in. If your blown close, by the time you take the turn it will blow you even more off, way out as you go around and try and come out in the groove.

Edited August 14, 2019 by David OC

[Nealius]

Well, I tried wind straight down the angled deck and still had bad crab, but not as bad as straight down the deck. Kicking the rudder right before impacting the deck doesn't sound like a very good idea considering cables and bolters. I guess I'll keep with the 18° left wind and just deal with higher bank angle or wider abeam distance.

[David OC]

I did a quick test and the 9 deg's looks right (Off DCS Flag). 10 wind 20 boat.

 

Try that, you might be blowing yourself way close to much on the downwind. You would need to allow for more to the right etc. It should feel like you don't need to offset. I.E aim at the ships crotch so much.

 

 

[bbrz]

Well, I tried wind straight down the angled deck and still had bad crab, but not as bad as straight down the deck.

That doesn't make sense. If the wind is straight down the angled deck there's no wind correction required.

 

Quick calculation for the WCA. 20kts headwind with a 9° xwnd component at 130kias (110kts GS) = 1° WCA. That's definitely negligible.

Edited August 14, 2019 by bbrz

[Nealius]

I'll run it again, but my nose was still crabbed towards BRC while my forward movement was along the angled deck axis. Doesn't make sense to me either.

 

These shots were with wind straight down the angled deck....velocity vector is showing me moving towards the crotch but my actual movement was more down the angled deck:

 

[Pikey]

I think you've missed the carrier's forward motion in the equation. You are aiming more towards BRC from far out because the carrier is moving the runway from left to right in your HUD. Actually you start out wide, especially in case 3 if you can see it, your FPM would sit starboard of the island.

 

Around the 1nm mark the FPM will sit around the crotch (not that you should spot the deck), it's to the right of the runway, to keep up with the carrier moving at 4-24kts ground speed slightly to your right. In calm winds the carrier moves faster and that side movement is more exaggerated.

The 10 degrees offset between the forward motion and the runway is enough to make it feel like it's crabbing. Realistically, you are just adjusting your landing point continuously.

[Nealius]

So how would I correct for my nose being out of alignment with the angled deck? If I shoot the exact same approach with wind 18° left of BRC, it tends to eliminate the perceived crab for some reason.

[Pikey]

Surely you've set the wind to come down the runway, as in 11 degrees? Then you set your landing point slightly right, where at 1nm it will be half the length of the runway right of centreline.

 

 

What I think you have done is introduced a countering cross wind of additional 7 degrees for the exact wind so you can aim at the runway.

 

 

Depending on the actual carrier speed for the same wind over deck you might end up having to keep changing that. It would still vary depending on how far away you were. Consider Case III where you have 12nm of running with a cross wind except now you have another 7 degrees of it throughout.

 

 

Best to have zero cross wind at the touchdown point and adjust in the run up.

[ricktoberfest]

I might be missing something here, but instead of crabbing, drop your right wing a degree or 2 to introduce a side slip making up for the carrier movement. Then at the last second you lift the wing again

[bbrz]

I might be missing something here, but instead of crabbing, drop your right wing a degree or 2 to introduce a side slip making up for the carrier movement. Then at the last second you lift the wing again

Nope. For one the xwnd component is very small and you definitely don't use bank to apply a wind correction!

 

Pikeys replies do make a lot of sense!

As soon as the carrier is moving you always have a small xwnd component, since there's the fixed 9deg difference between the carriers longitudinal/movement axis and the angled deck.

[majapahit]

In the groove (600-300 Alt) you point to the 'crotch' of the landing deck where 9dgs offset meets straight to bow, the right upper corner of the landing deck.

You cannot really 'crab' the FA18C but just for a tiny bit, so it is all anticipation and experience of where you'll end up,

When passing the threshold in the middle of the stern, you correct, as you would any plane with crosswind, you yaw left and pitch down a tad,

lower the VV to about halfway and in the middle of the last right hand white box of the landing deck, whilst keeping you AOA WW at the prescribed 8dgs, and making sure when you hit your cable you’re straight.

 

2cts

Edited August 14, 2019 by majapahit

[TonyG]

I use the Airboss script with MOOSE, it takes care of the calculations and turns the carrier to get the wind down the angle at what I want. This way it can handle variations in dynamic weather instead of just dealing with static weather.

 

Fantastic addition to DCS.

 

Airboss

[Jack McCoy]

See my answer, discussion starting at post #34: https://forums.eagle.ru/showthread.php?t=214816&page=4

 

I hope it helps!

[TonyG]

To add to my post.

 

More natural wind, less carrier speed, less right drift and course correction needed.

 

Less natural wind, more carrier speed, more the carrier is moving away to the right necessitating corrections to keep aligned.

 

We like to keep some changing variables in our server so guys don’t get too accustomed to the same solution everytime. Changing wind speed/direction or putting in dynamic weather has kept it fresh for us and made our debriefs fun.

 

As such, having Airboss drive the carrier speed and direction keeps our mission planning simple.

[Nealius]

Surely you've set the wind to come down the runway, as in 11 degrees?

 

Why 11? The angled deck is 9 degrees left of BRC. I'm still trying to find that original thread, but someone did 18 degrees left of BRC and it somehow eliminated the crosswind component over the deck, but introduced crosswind component in the pattern.

 

See my answer, discussion starting at post #34: https://forums.eagle.ru/showthread.php?t=214816&page=4

 

I hope it helps!

 

Ah! There's the thread I was looking for! Now I see what I've been doing wrong with my 18° left setups: My carrier speed and wind speed aren't even close to the same.

Edited August 15, 2019 by Nealius