Dalton computer
Thread Starter
Joined: Apr 2002
Posts: 79
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From: UK
Thanks everybody for the help to what I thought was a simple question. As John has stated, I do know a bit about deck landings having done about 1200 including teaching day and night. I was just playing with the dalton and could not remember how to do the calculation but have figured it out.
Some of the advice and comments, although meant in the best interests was quite surprising. The relative wind is actually very important when carrying out deck landings for a number of reasons.
Firstly, this will be the actual wind over the deck when you make your approach to land/take off. It may actually put you outside the limitations of your aircraft if significantly crosswind or from the rear. It will affect your control inputs and power requirements.
Secondly, any turbulence over the deck will be caused by the relative wind. Therefore it may be preferable to change the relative wind (by manoeuvering the ship) to reduce turbulence caused by the flow of the air. This can include eddies and significant downdraughts.
Thirdly, in the event of an engine failure during T/O or landing, the flyaway would be better flown into the relative wind to give better performance. In fact, the only way you may be able to land is with a relative wind landing thus reducing your power requirements.
There are other bits and pieces but that is a snapshot. Hope this helps and the drift (no pun intended) was hilarious to watch...............
Some of the advice and comments, although meant in the best interests was quite surprising. The relative wind is actually very important when carrying out deck landings for a number of reasons.
Firstly, this will be the actual wind over the deck when you make your approach to land/take off. It may actually put you outside the limitations of your aircraft if significantly crosswind or from the rear. It will affect your control inputs and power requirements.
Secondly, any turbulence over the deck will be caused by the relative wind. Therefore it may be preferable to change the relative wind (by manoeuvering the ship) to reduce turbulence caused by the flow of the air. This can include eddies and significant downdraughts.
Thirdly, in the event of an engine failure during T/O or landing, the flyaway would be better flown into the relative wind to give better performance. In fact, the only way you may be able to land is with a relative wind landing thus reducing your power requirements.
There are other bits and pieces but that is a snapshot. Hope this helps and the drift (no pun intended) was hilarious to watch...............
Last edited by comedyjock; 18th September 2012 at 05:42.
Joined: Mar 2006
Posts: 275
Likes: 1
From: Behind the curve
No doubt you guys are 100% correct in everything you say re wind lanes and probably most of the rest of your advice. But where I work is between 100 and 200 NM offshore, so coastal shape, profile of the sea bed which is over 100 metres beneath the surface in my patch and local barriers like reefs just aren't factors.
At least a couple of you will also have worked far out over the sea, either doing oil-related work or flying off navy vessels. In which case hopefully you will also have seen that proper wind lanes don't appear very often in deep water, until the wind becomes strong and then only after several hours.
It seems that the waves need to form breaking little white tops from which spume can blow to make wind lanes visible. However the waves far out to sea are definitely at right angles to the wind while the wind comes from a constant direction, so those are effectively my wind lanes in the absence of the real McCoy.
Let me state again "No doubt you guys are 100% correct" but I'll still be depending on wave direction as a more easily-seen indicator for my purposes than the occasional days when the proper thing appears.
Thus far in over 16000 deck landings I haven't landed downwind yet, but then again we always get radio weather reports offshore and have windsocks to look at for relative wind.
Your definition of wind lanes is irrefutable, but there are other indicators to ensure landing into the relative wind on a vessel's deck. All this has little to do with the Dalton computer question though.
At least a couple of you will also have worked far out over the sea, either doing oil-related work or flying off navy vessels. In which case hopefully you will also have seen that proper wind lanes don't appear very often in deep water, until the wind becomes strong and then only after several hours.
It seems that the waves need to form breaking little white tops from which spume can blow to make wind lanes visible. However the waves far out to sea are definitely at right angles to the wind while the wind comes from a constant direction, so those are effectively my wind lanes in the absence of the real McCoy.
Let me state again "No doubt you guys are 100% correct" but I'll still be depending on wave direction as a more easily-seen indicator for my purposes than the occasional days when the proper thing appears.
Thus far in over 16000 deck landings I haven't landed downwind yet, but then again we always get radio weather reports offshore and have windsocks to look at for relative wind.
Your definition of wind lanes is irrefutable, but there are other indicators to ensure landing into the relative wind on a vessel's deck. All this has little to do with the Dalton computer question though.
Last edited by Colibri49; 18th September 2012 at 08:30.
Joined: Jan 2001
Posts: 3,008
Likes: 62
From: North Queensland, Australia
Well, Colibri49, your 16000 deck landings is about 100 times more than I've done, so fair enough!
Just goes to show the differing environments we work in give rise to certain rules of thumb and ways of operating that are right for that place and may or may not translate elsewhere.
That's one of the things I like about this forum, how you can connect with experienced people all round the world just about instantaneously and talk like you're in the crewroom.
I see some talk on Jet Blast about how some people are bagging PPrune for deteriorating in some way, but I've found it to be a great source of good gen, bearing in mind the usual health warnings about not believing everything you read on the internet straight away.
Cheers all.
Just goes to show the differing environments we work in give rise to certain rules of thumb and ways of operating that are right for that place and may or may not translate elsewhere.
That's one of the things I like about this forum, how you can connect with experienced people all round the world just about instantaneously and talk like you're in the crewroom.
I see some talk on Jet Blast about how some people are bagging PPrune for deteriorating in some way, but I've found it to be a great source of good gen, bearing in mind the usual health warnings about not believing everything you read on the internet straight away.
Cheers all.
