Determining Carrier Heading

[svicar]

I was wondering if anyone knows and can explain how to determin the proper heading to set the carrier so that the head wind component on the landing zone is zero degrees.
Thanks in advance.

[neutrino]

The angled deck is oriented 9 degrees left of the carrier heading. So if your wind is coming at 330 degrees (true north), the ship's true course must be 339 degrees. There is one more variable to consider that complicates the matter and it is the magnetic variation (wind direction is magnetic and your heading is gyro). It can be as big as 15 degrees East or West.

In practical terms you can set some arbitrary wind direction in the menu. Then fly against the wind until the velocity vector is more or less in the vertical centerline of the HUD, which means you are flying exactly against the wind. See what direction this is on the heading tape, let's say 270 degrees. Then fly right at 279 degrees and spawn a carrier with AICarriers2. Now the deck will be oriented in the proper direction. In this case you will have to fly a bit right to keep up with the carrier - see the screenshot (wind direction and runway is the same):



There is one more way to do this - instead of 9 degrees, add 33 degrees. This will ensure that the wind is coming from your left when you are headed directly towards the runway and your velocity vector will drift to the right. However in this approach your nose can be pointed directly towards the runway and you will stay on the centerline without any corrections, because the wind will push you to the right just enough (remember the ship is moving). In this example I assume 10 knots of wind. See the screenshot below - I set the wind to come 33 degrees left of carrier heading at 10 kts and this gives exactly 35 kts wind over deck (carrier is moving at 26 kts with AICarriers2):

[Sludge]

svicar...

You asking where to point the carrier (such as AI carrier) to the right heading for landing w/a straight on headwind over the angled deck?

If so, dial in the TACAN (47X/57X) on the UpFrontController TCN button,as required.  Then using JR's HUD Control panel to confirm the ship's course, via NAV1 (carrier's Base Recovery Course, aka ship's heading) readout.   As the angled deck is 10 deg left of the ship's course, make the carrier's heading 10 degrees right of the wind heading.

Also know that Wind-Over-Deck (WoD) is usually 25 kts, but for the sake of FSX playability and the fact that the carrier meatball and ICLS are set for 4.0, a 30-35 knot WoD is the best compromise.

Here's an example:  Carrier BRC is 020 deg, steaming at 20 kts.  FSX Natural wind is 010 deg (meaning wind flows from 010 to 190) at 15 kts.  This setup will give you a final bearing (angled deck) WoD of 35 kts.

Hope this helped.  And not to confuse, but technically JR is right bout the 9 degrees.  I just use 10 degs.  Makes on the fly public math for us knuckleheads easier.

Later
Sludge

[svicar]

Thanks for the info and the screenies, guys.

I typical practice my carrier traps mid Pacific Ocean, (my computer is ancient so I have to do what I can to keep the FPS at a tolerable level) and usually I will add about 20 degrees right for the ships course for 10-15 KTS of wind, (I have weather set at static).

Usually but not always it is fairly close. I was wondering though if there was some sort of table or chart that was kicking around that gave more precise values and I will have to dig and see what I can find.

Never considered magnetic variation though. At any rate thanks again for the detailed and timely responses. Much appreciated.

[sun444]

Here's an example:  Carrier BRC is 020 deg, steaming at 20 kts.  FSX Natural wind is 010 deg (meaning wind flows from 010 to 190) at 15 kts.  This setup will give you a final bearing (angled deck) WoD of 35 kts.

Sorry Sludge, I think you're wrong. This is a vector addition, not scalar. Wind 15 kts and carrier speed 20 knots leads to resulting vector which is closer to the ships bearing than to the angled deck (somwhere around 4 degrees).

It's easier to picture a 90 degree angled deck, then wind 10 kts in landing strip direction and carrier 20 kts doesn't give you a headwind on the angled deck of 35 kts.

Correct me if I'm wrong.

CU
Hans

[SpazSinbad]

sun444, it has been awhile but thinking about all these issues can numb one's brain....    Yes there are theoretical issues but practical rules. It is best to be practical as SLUDGE is suggesting. On carriers there are instruments (often including an actual wind flag or two visible forward from the bridge) to help find the wind to have it going down the angled deck. The LSO will keep an eye on this also with his instruments at his station, wind swirling around the island in certain situations may affect the WOD. There are +/- factors.

Perhaps FSX does not always simulate the real world so well either but I have not tried to investigate that thought. Perhaps lots of experimentation will find an ideal WOD setup formula. Keep in mind that the carrier is moving (relative to the approaching aircraft) away & to the right, so the aircraft has to constantly 'wing waggle' to the right to correct lineup. Perhaps further experimentation could allow for this in the wind setup but by now my brain hurts and I'll stop.    BTW 'drifting' by starting either right or left of the angle deck centreline to allow either ship movement or wind direction or both to move the aircraft to centreline at touchdown is a recipe for a crash and never allowed anyway by the LSO. Why the crash? The aircraft centreline is not parallel with the angle deck centreline and at right angles to the arrestor gear (if the aircraft is allowed to drift as may be the case ashore). Drift and not lined up will cause an arrest crash/tipover (depending).

Keep in mind that the way to do the carrier approach is purely visual looking at the mirror and angle of attack and line up down the angle deck. Within reason (with the WOD more or less down the angle deck) then nothing else matters. Follow all the visual cues staying 'on glideslope, on lineup at Optimum AoA' and you will have a good landing experience. It is essential to start well and to remain on the three parameters to the best of your ability constantly.

[SpazSinbad]

I'll start another thread about WOD.

http://dictionary.babylon.com/wod/

"VFA-13 Aviation Glossary
Wind Over Deck. The relative wind caused by an aircraft carrier's motion. Usually the carrier is turned so the actual wind is aligned down the axial [here I think this definition found online is in error - it should say 'angle' instead of 'axial' but perhaps times have changed] carrier deck during recovery."

The wind likely does not blow steadily in force or direction so in any event some averaging out is necessary by carrier to get an average WOD (with other factors). The carrier may deviate from a defined BRC by one or two degrees if conditions require it but probably if WOD is within limits set (from practical experience on that particular carrier) then the carrier remains on a steady course while the sea wind fluctuates slightly so then will the WOD. On old slow carriers finding wind was important while 'searching for wind' by looking for 'wind lanes' on a calm ocean could consume everyone onboard. This will never be a problem on a CVN though. It makes WAVES!  
_____________________

EDIT Did some LSO NATOPS researching to discover this:

http://www.robertheffley.com/docs/CV_environ/00-80T-104--LSO%20NATOPS.pdf

(LSO needs) Accurately calibrated relative wind indicator (RHW). 1997 LSO NATOPS

EXCESSIVE WIND-OVER-DECK OPERATIONS  (RHW=Relative Head Wind or WOD)
Turbulence and ramp burble increase significantly with RHW values in excess of optimum, resulting in an increased frequency of high landing gear loading. Winds starboard of the angle also adversely affect recovery conditions. The burble, aft of the ramp, becomes stronger and moves closer to the ship as the magnitude of recovery crosswind is increased. The airflow disturbance requires corrective pilot technique if the recovery crosswind exceeds 7 knots for all carriers. Even with corrective pilot technique sinking speeds 3 to 6 feet per second in excess of those experienced during normal (no recovery crosswind) operations can be expected. For these reasons, recovery headwind should be maintained as closely as possible to the optimum velocity and the centerline of the landing area. Shipboard aircraft recovery operations with recovery crosswinds in excess of those specified should be avoided.
________________________

http://www.vaw120.navy.mil/NATOPS/UE_Instructions/LSO%20NATOPS.pdf

2007 LSO NATOPS (RHW = Recovery Head Wind)

Wind Over Deck (WOD) Requirements
RHW should be maintained as close as possible to the optimum velocity and the centerline of the landing area.
CAUTION
The LSO shall immediately inform the air officer of any adverse wind
conditions unsafe to aircraft recovery, and the air officer shall inform the
LSO of downwind recovery situations. EMCON conditions permitting,
pilots shall be advised of adverse wind conditions or downwind recoveries.
______________

EXCESSIVE WIND-OVER-DECK OPERATIONS
Turbulence and ramp burble increase significantly with RHW values in excess of optimum, resulting in an increased frequency of high landing gear loading. Excessive crosswinds adversely affect recovery operations. If the recovery crosswinds exceed 7 knots, rates of descent 3 to 6 feet per second in excess of those experienced during normal operations can be expected, even with corrective pilot technique.

Shipboard aircraft recovery operations with recovery crosswinds in excess of 7 knots require the approval of the CV/N commanding officer.

[Sludge]

Sun...

I dont think Im in error on this one.  Either by my practical FSX way (just using 10 deg instead of 9, as is the real offset of the angled deck), or by CV NATOPS, which is "the bible" used in US Naval Aviation.

http://a4skyhawk.org/specials/cv-natops-21oct99.pdf

I know its dated '99, but since modern carrier aviation has been around since the Vietnam era, I think its safe to say this is a valid document.  On NATOPS pg. 5-19 (pdf pg. 87/126), fig. 5-6, the illustration shows a natural wind down the angled deck.  It might be off a deg or two, who is to tell.  Additionally, one of the board posters here, Average Joe (a prior real-world USMC WSO on delta Hornets), gave me some real world info. to work with when I was tweaking the Sludge, as to how the pattern is flown and what conditions exist.

Finally, I have flown this in FSX using this specific technique for carrier landings, setting up the FSX wind 10 deg left of BRC and it has worked like a champ.  Most of the board posters that have flown with me on the weekend multiplayers we did this winter should be more than happy to tell you how my patterns were usually "on the numbers".

I dont think youre entirely wrong, as there is probly some vector addition involved, but from what Ive used in FSX and what CV NATOPS says, it is fairly negligible.  Also, thanks Spaz for the LSO NATOPS pull.  Good info there.

Good question, no doubt.

Later
Sludge

[sun444]

I was just looking at it as a physicist, not as a pilot, and forces from different directions are added by adding the vectors. Of course Sludge you're right considering the real situation or let me say the situation in FSX. I hope you don't take it as me being a wise guy.

No it's just that I was siumlating autopilots for terminal guided weapons at Martin Lockheed and I had to take all kinds of effects into the account.

Now I'm going back and do some more recording tests, doesn't look bad so far.

CU
sun

[Sludge]

Sun...

No big deal, it was a good question, and made me question where I came up with it.  Just made me do some digging and re-verifying where I got my numbers and procedures.

I was wondering if you have used Orion's SFCarrier mission?  That has some good views, the carrier moves and provides good Wind-over-Deck (35 kts), and if using two people, Im sure we could get the views and the action covered.  Heck, I could even add some 30 sec Fraps clips, and then we could "crop out" the "FRAPS" title overhead?  Youd also be able to get me in the "grunge Sludge" w/full effects (ie, smoke "puffs" when LSO calls for power) in the PLAT Cam.  Ill email you my carrier landing video ideas template.

Later
Sludge

[GOONIE]

Just wanted to share a FSX PLAT cam video I saw on youtube which is very well done . Check out the arresting wire effect added using Adobe After Effects and the second PLAT cam angle as the turkey taxi's out of the landing area, note the foul deck being shown with a F flashing on PLAT cam.

[JamesChams]

Nice; Real Nice!

If only we could have the cable animation in FSX as well...