General Category > Unofficial F/A-18 Acceleration Pack board
vLSO Beta release
SpazSinbad:
Tregarth your calculations are correct as long as the ship direction makes the wind the ship creates more or less go down the angle deck when the natural wind is factored in. So we always assume this - that the ship 'steams' into the natural wind at a certain speed to make the REQUIRED WOD (down the angle deck centreline).
And congrats to 'Sludge' - sounds like a great job - that area must be amazing scenically and I guess very wet and cold sometimes.
Orion:
--- Quote from: Tregarth on June 03, 2015, 10:56:12 am ---Can you please clarify Wind over Deck? If the carrier is progressing at 25 kts ( I think that is the AICarriers ship speed) and the F-18 landing speed is 175KIAS the the ship to aircraft closing speed is 150kts.
If the wind speed is 20 kts then I think the Wind over Deck is 25 + 20 = 45kts.
So the plane's landing speed on the carrier is 130 kts.
Do I have this right? If not how are the sums worked out?
--- End quote ---
As SpazSinbad wrote, you're correct in the case where the wind direction, runway heading, and carrier course are aligned. If I understand correctly, wind over deck is the effective headwind component along the ship's runway, which should be given by the following equation:
wind over deck = wind speed * cos(wind direction - runway heading) + ship speed * cos(angle between runway heading and course)
Essentially it's the same calculation you did, but adjusted to account for cases where wind direction, runway heading, and carrier course are different.
SpazSinbad:
'Orion' has it.
Another consideration is that when a carrier has to make WOD in NIL WIND, then the wind will not go exactly down the centreline of the angle deck and that is the case under most conditions of low natural wind; because the ship moves the entire angle deck forward on their course always. That is why carrier approaches always require the 'nibble' to the right constantly to remain lined up (if lined up at the start) because the angle deck is moving always from left to right during the approach.
Tregarth:
I appreciate the replies which makes WoD more clear. Thank you for your help.
As I understand AICarriers the aircraft approach course = the carrier's initial Base Recovery course, but this can be varied. Using the weather settings in FSX where the wind vector can be set, what would be a sensible wind speed to set an optimal WoD given that I think the carrier's speed is set at 25 kts , is this right?
The reason I ask the question is because of Sludge's comments "any wind <35kts is not right". When I fly I set the wind vector to say 15/270, turn the plane to 270, then place the carrier and try to land.
Is this the right way to go about things? I could set the wind speed to, say, 40kts but with a ship's speed of 25kts the crew would not last long on the deck!
At the other end of the scale, if I set the wind speed to +15 kts on HMS Victorious and land a Swordfish (not that easy) the combined wind speed across the deck pushes the plane backwards so I have to keep 25% throttle on to stay stationary, but the take off distance is really short!
Best regards,
Tregarth
SpazSinbad:
IF you require 30 Knots WOD and the AI carrier is tootling along at 25 knots - must be more or less into the wind (or slightly to the right so that the combined natural wind and ship speed INTO the wind - offset to the right slightly) gives 30 knot wind down the angle deck centreline - as close as can be fudged (in FSIM).
CVN LSOs discuss the issue a lot in the past in their newsletters (no longer available) and they discovered that only ONE of the three (IIRC) Wind Indicators gave the correct wind speed/direction reliably. Sadly as I recall now the slightly incorrect bridge indicator meant that sometimes the CVN was not heading quite correctly. These are small details in a big picture though. Sometimes the CVN will NOT be on the best course for WOD for operational reasons and another reason for the LSO to give wind speed (and crosswind details if relevant). LSOs quite rightly gnaw this WOD issue constantly to get the best possible outcomes.
As 'Sludge' is saying too much WOD is counter productive. There are a few posts about this issue on this forum.
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