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Landing - Carrier speed


Taz1004

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33 minutes ago, Pieterras said:

Oh my god,,,

I should detach myself from this conversation.
This will only add to the confusion and has nothing to do with the question. Having flown for a living many years, I have rarely noticed much difference in crab angle caused by approach speed and have flown cessnas, fast birds and airliners.. all the roughly same irrelevant of your speed. Equally there is hardly crosswind on the boat. You are making corrections to compensate for the drift of the centreline not really to correct for crosswind. Equally we should talk apparent winds as we are talking moving object.
 

Equally the boat speed is irrelevant as they keep a constant WOD. To me none of what you wrote makes much sense in relation to carrier ops. Or it does but it is hardly noticeable.

 

That was my whole point.  It’s hardly noticeable.

if you think fast birds and Cessnas hold the same crab angle for the same winds, then then you are missing something fairly fundamental.  Your crab is your component of forward airspeed, that you direct into the wind.

More forward speed means I need less crab angle to counteract the crosswind. Period.  
 

And on the contrary I think I’m the first guy to answer the actual OP’s question.  
 

Not sure what you’re so up in arms about…

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2 minutes ago, cw4ogden said:

That was my whole point.  It’s hardly noticeable.

if you think fast birds and Cessnas hold the same crab angle for the same winds, then then you are missing something fairly fundamental.  Your crab is your component of forward airspeed, that you direct into the wind.

More forward speed means I need less crab angle to counteract the crosswind. Period.  
 

And on the contrary I think I’m the first guy to answer the actual OP’s question.  
 

Not sure what you’re so up in arms about…

Well done you 👏🏻

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49 minutes ago, Pieterras said:

Equally the boat speed is irrelevant as they keep a constant WOD. To me none of what you wrote makes much sense in relation to carrier ops. Or it does but it is hardly noticeable.

Boat speed is not irrelevant because if you have to manufacture the wind i.e. if you have to drive the boat to make that wind, it’s not coming directly down the runway, it’s coming directly down the ships bow.

 

You may have flown for years but It sounds like you’re making the same case that moron I had for an instructor made 20 years ago. 

let me be clear where I disagree besides your initial tone of voice with a total stranger, which I find personally offensive, is are you asserting forward airspeed has no relationship to crab angle?

Go fly a wright flyer in a 40 knot cross wind and tell me it holds the same crab angle as an F 16 at 400 knots.  It doesn’t.  


Edited by cw4ogden
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16 minutes ago, cw4ogden said:

Boat speed is not irrelevant because if you have to manufacture the wind i.e. if you have to drive the boat to make that wind, it’s not coming directly down the runway, it’s coming directly down the ships bow.

 

You may have flown for years but It sounds like you’re making the same case that moron I had for an instructor made 20 years ago. 

let me be clear where I disagree besides your initial tone of voice with a total stranger, which I find personally offensive, is are you asserting forward airspeed has no relationship to crab angle?

Go fly a wright flyer in a 40 knot cross wind and tell me it holds the same crab angle as an F 16 at 400 knots.  It doesn’t.  

 

We aren’t talking Wright flyers but ac that land all within 20kts if IAS, anyway no point of arguing. Glad finally someone answered his question 
 

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6 minutes ago, Pieterras said:

We aren’t talking Wright flyers but ac that land all within 20kts if IAS, anyway no point of arguing. Glad finally someone answered his question 
 

I think we tend to agree the OPs numbers are flawed.  That was what it took me a whole lot of words to say.  I only took issue with the nature of your initial response, and I'm still unsure what you took issue with?  The wordiness of it maybe offended your something, I don't know. 

I saw a whole lot of people not answering his question because, and I think this is where it all got off track - his question was flawed.  It was based on erroneous assumptions of what the factors discussed would actually produce, in terms of crab angle and pilot response.  Which you and I, ironically are both saying is going to be negligible. 

So all that said, sorry if we got off on the wrong foot.   


Edited by cw4ogden
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And... there's also a simple 'approach' to all this math:  Eyeball.  At whatever speed I come in from initial to break, I look at the boat after rolling out level and just before descending to 600 ft. trying to estimate if flying downwind exactly on BRC reciprocal will get me to 1.2 nm from the boat at 180 point. If I see I might be too close (pulled too tight for too long during break) then I might adjust my downwind couple of degrees out. Too far - I adjust the d/w in.  I always keep my VV caged on initial so when I start rolling out of the break and see my ghost VV pegged to the left, I know the wind is stronger but it doesn't really matter (unless the wind is 99 kts 🤠  as I demonstrated in my recent silly YT vid). I start 180 turn when abeam the ramp, preferably at 1.2 nm and fly instruments to get to 'around' 450 ft. at the 90. Quick peak at the boat becomes part of the scan. If I see the wind pushed me a second or two behind and below G/S, it's easy to catch up. The rest of the visual approach 'stuff' has been discussed countless times on these forums, including input from RW naval aviators. With practice you'll notice if your lineup corrections are excessive or insufficient immediately, even w/o LSO's chiming in.

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All these arguing will be pointless only if the ones who say speed doesn't matter actually provide track.  No, not another video tutorial.  A direct comparison between fast and slow boat with everything else being same.  Only Stearmandriver was able to so far and actually answered my question.

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I think we tend to agree the OPs numbers are flawed.

And I thought I clarified several times that I did that in attempt to simplify the question.  Just as your Wright flyers and F16 example are exaggerated but gets point across.


Edited by Taz1004
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My only question now relates to why there's a difference in burble effect based on natural wind vs apparent wind (manufactured by boat speed).  Does anyone understand that? Is it even true?  Seems to me, the wave created by say 25krs of air flowing over the deck/island should be the same, regardless of whether the air is moving or the boat is moving.  Kind of like how an airplane can takeoff from a treadmill.

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4 hours ago, Stearmandriver said:

My only question now relates to why there's a difference in burble effect based on natural wind vs apparent wind (manufactured by boat speed).  Does anyone understand that? Is it even true?  Seems to me, the wave created by say 25krs of air flowing over the deck/island should be the same, regardless of whether the air is moving or the boat is moving.  Kind of like how an airplane can takeoff from a treadmill.

Natural wind is over the angled deck. Apparent wind is down the BRC. The superstructure is in-line with the BRC, but not in-line with the angled deck.

Less apparent wind = less burble. 

Is there also a possibility that natural wind down the angled deck blows some of the burble starboard, out of the approach path?

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On 11/2/2021 at 8:30 PM, Taz1004 said:

Thanks but again, that wasn't the question.  I don't think you guys are thinking about what would happen with faster carrier and keep telling me basic procedures.

 

I take your point that your numbers were exaggerated on purpose.  
 

This above is what I was attempting to answer.  I avoided procedures, and focused on the “what would happen with a faster carrier.”

if you want to see a scientific comparison, I’d suggest it, or could possibly post two comparisons with the tomcat flying the autopilot coupled approach to the deck.  Eliminate the user from the equation or it’s going to be hard to quantify or eliminate differences in how each approach was flown by the human.  

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35 minutes ago, cw4ogden said:

 Eliminate the user from the equation or it’s going to be hard to quantify or eliminate differences in how each approach was flown by the human.  

Already has been.  No idea why this thread keeps going.  You can continue to discuss other parts of landing but don't have to keep tagging me.


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15 minutes ago, cw4ogden said:

@Taz1004 Maybe it's because you asked for help.  And then went on and on to be vague about what the hell you were even asking.  Call me crazy...  

And color me stupid for trying to read and make sense of all the posts only to get an F you in return.  Have a nice night.

That wasn't F you but sorry you took it that way.  Question was simple one which was answered on first page.  It went vague when few who didn't understand the question started telling me about irrelevant topic and me trying to explain why it's irrelevant.  But continue to tag me and tell me it's "flawed" or "doesn't make sense".  Even referencing "wrong" example I posted to tell me it's "wrong".  But still reluctant to provide any track.

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7 hours ago, Stearmandriver said:

My only question now relates to why there's a difference in burble effect based on natural wind vs apparent wind (manufactured by boat speed).  Does anyone understand that? Is it even true?  Seems to me, the wave created by say 25krs of air flowing over the deck/island should be the same, regardless of whether the air is moving or the boat is moving.  Kind of like how an airplane can takeoff from a treadmill.

The boat can't generate any arbitrary WOD by its motion because the ship can't sail in any direction except forward. Wind generated by forward motion necessarily has a right-to-left crosswind component relative to the landing axis. The structure of the ship causes a downwind effect which would be blown into the landing path with such a crosswind.

With sufficient ambient wind the ship can sail in a particular direction to produce a WOD which has no cross component or even a left-to-right component. Thus the burble effect is directionally shifted away from the landing path.

Any competent ship will do the vector algebra necessary to calculate the required heading and speed to result in the desired WOD vector. We can even do a practice problem. Say wind is 6 knots out of 270 and it is desired for the WOD to be anti-parallel to the landing axis (-10 degree offset) at 20 knots. What is the track and speed the ship must steer?

True Wind (A) <090,6> plus Motion Wind (B) <???,?> must equal Resultant Wind (C) <B-10,25>. The first requirement is that the lateral components (relative to landing axis) of wind and motion cancel. B*sin(10°)=6*sin(X) or B knots = 6 knots/sin(10°)x * sin(X). The second requirement is that the dot products of the A and B vectors add to the magnitude of C, 25 knots. B*cos(10°)+6*cos(X)=||C||. Solving the system of equations gives one solution of 36.3°, 20.5kt. A track of 36.3+10° more than 090 is 136.3. That's the motion wind effect so track is reciprocal 306.3 for track to steer. Assuming heading=track the landing axis is 316.3/126.3°. The vector addition of the 6 knot wind to 090 and the motion wind of 20.5 to 136.3 gives a resultant of 25(.024) to 126.3(2)°.

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1 hour ago, Frederf said:

True Wind (A) <090,6> plus Motion Wind (B) <???,?> must equal Resultant Wind (C) <B-10,25>. The first requirement is that the lateral components (relative to landing axis) of wind and motion cancel. B*sin(10°)=6*sin(X) or B knots = 6 knots/sin(10°)x * sin(X). The second requirement is that the dot products of the A and B vectors add to the magnitude of C, 25 knots. B*cos(10°)+6*cos(X)=||C||. Solving the system of equations gives one solution of 36.3°, 20.5kt. A track of 36.3+10° more than 090 is 136.3. That's the motion wind effect so track is reciprocal 306.3 for track to steer. Assuming heading=track the landing axis is 316.3/126.3°. The vector addition of the 6 knot wind to 090 and the motion wind of 20.5 to 136.3 gives a resultant of 25(.024) to 126.3(2)°.

Or you can plot it with a compass and ruler, and measure the resultant angle with a protractor, like any competent old-fashioned ships navigator should be able to do. Don't need maths to do trigonometry.

 

 


Edited by AndyJWest
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On 11/7/2021 at 11:29 AM, Taz1004 said:

All these arguing will be pointless only if the ones who say speed doesn't matter actually provide track.  No, not another video tutorial.  A direct comparison between fast and slow boat with everything else being same...

 

The WOD breakdown does matter but I don't really need the trig.,  just have to look outside of the cockpit now and then, watch the rate of change (drift, etc) Let the boat drivers figure out the proper BRC... Oh wait, I'm driving the boat too, at least in SP :doh:

Just to make sure I could still follow my own doctrine, I switched my usual 'Wind 6kts, boat 24kts' to 'Wind 24kts boat 6kts'  Wind is exactly down the angle.     I aimed for 1.3nm at 180, expecting a slight drift toward the boat on downwind. No big surprises there other then the power seemed sluggish again (no scientific proof though) similar to what we had few builds ago, trimming seemed slow as 'usual' and the ghost velocity vector was not using the 'horizon line' as reference... it showed way too high when pegged on the HUD frame. I thought this was fixed already. Well, it's back.

Here's a 'non-instructional' vid. If this is what you're curious about, I can d/l the track too but I'm sure you realize the replay sometimes gets out of whack, especially when a/c did some turning. This one replayed correctly for the vid. Sorry about VR jitters, I don't use motion smoothing. I didn't bother with 'normal' conditions side by side unless needed. 

https://youtu.be/_f8V3eAE4tg

 


Edited by Gripes323
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1 hour ago, Gripes323 said:

The WOD breakdown does matter but I don't really need the trig.,  just have to look outside of the cockpit now and then, watch the rate of change (drift, etc) Let the boat drivers figure out the proper BRC... Oh wait, I'm driving the boat too, at least in SP :doh:

Just to make sure I could still follow my own doctrine, I switched my usual 'Wind 6kts, boat 24kts' to 'Wind 24kts boat 6kts'  Wind is exactly down the angle.     I aimed for 1.3nm at 180, expecting a slight drift toward the boat on downwind. No big surprises there other then the power seemed sluggish again (no scientific proof though) similar to what we had few builds ago, trimming seemed slow as 'usual' and the ghost velocity vector was not using the 'horizon line' as reference... it showed way too high when pegged on the HUD frame. I thought this was fixed already. Well, it's back.

Here's a 'non-instructional' vid. If this is what you're curious about, I can d/l the track too but I'm sure you realize the replay sometimes gets out of whack, especially when a/c did some turning. This one replayed correctly for the vid. Sorry about VR jitters, I don't use motion smoothing. I didn't bother with 'normal' conditions side by side unless needed. 

https://youtu.be/_f8V3eAE4tg

Thanks for making that video but it's not what I was looking for.  I want to compare the location of the carrier after rolling out between fast and slow carrier.  And in this video, you are aware of the carrier speed.  Many don't seem to understand the purpose of original question.  That is if you're expecting fast carrier and encounter a slow one or vice versa.

The campaign I was playing, Looking Glass V2 from User files, had 27kts carrier with 15kts wind.  So I got used to that until Mission 9 where mission designer made the carrier 12kts with 15kts wind.  But I was expecting same condition as prior missions so I had to do what Streamandriver did in page 1.  Zigzag on final leg.  That is what my question was.

Again, sorry for keep brining up Stearmandriver but he was only one so far to do what I asked for and his comment after trying it.

Quote

^^  Haha I just had the same experience when I intentionally slowed my boat down to make one of these tracks.  My pattern timing was all messed up ;).

 


Edited by Taz1004
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2 hours ago, Taz1004 said:

Thanks for making that video but it's not what I was looking for.  I want to compare the location of the carrier after rolling out between fast and slow carrier.  And in this video, you are aware of the carrier speed.  Many don't seem to understand the purpose of original question.  That is if you're expecting fast carrier and encounter a slow one or vice versa.

The campaign I was playing, Looking Glass V2 from User files, had 27kts carrier with 15kts wind.  So I got used to that until Mission 9 where mission designer made the carrier 12kts with 15kts wind.  But I was expecting same condition as prior missions so I had to do what Streamandriver did in page 1.  Zigzag on final leg.  That is what my question was.

Again, sorry for keep brining up Stearmandriver but he was only one so far to do what I asked for and his comment after trying it.

 

 

Well, I only fly carrier ops with WOD between 25 ~ 35 kts., ok, I'll take 40,  The wind component preferably lined up with FB but... I'll take BRC wind any day. The example you gave ~ 42 or so... I wouldn't snicker at it :biggrin: 

Just to finish my contribution... a clip of a trap w/  FB wind 6 kts. and boat 24kts.  If tracks make a difference, I have them.

https://youtu.be/it2olyX9kaE

 


Edited by Gripes323
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58 minutes ago, Gripes323 said:

Well, I only fly carrier ops with WOD between 25 ~ 35 kts., ok, I'll take 40,  The wind component preferably lined up with FB but... I'll take BRC wind any day. The example you gave ~ 42 or so... I wouldn't snicker at it :biggrin: 

Just to finish my contribution... a clip of a trap w/  FB wind 6 kts. and boat 24kts.  If tracks make a difference, I have them.

https://youtu.be/it2olyX9kaE

Track would be better at making comparison but I just played your two videos side by side.  And looking at your bank angle, it looked like you were making wider turn at 24kts.  Which was the question.  Do you turn early, make tighter/wider turn, or correct after 90.  I would change my turn too but if you expect one and encounter another, always seem to make more drastic correction late.

Thanks for making the video.


Edited by Taz1004
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Boat speed affects 2 things.

1. The burble

2. How much costs wind component. The more own wind the boat creates the more this will be. Assuming that if there is natural wind the boat is turned to put that down the runway.

Other than that there is no different between a 30kt natural head wind and a 30 it boat head wind to you it’s the same. Your approaching the boat at the same Ground speed for the on speed air speed your on. Don’t over think it.

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