Cat launch force

[wilycoyote4]

here is a quote from sprouty on his work-around----
http://www.sim-outhouse.com/sohforums/showthread.php?54718-Moving-Ships-what-s-the-big-deal
reply #38

The best way to explain what my work-around is made of is to start from DeltaLima words.
In one hand you have Acceleration feature that manage positioning and holdback fixation and blastshield animation but launch with far too much strengh for some light plane.
In other hand, you have RCBCO 3.0 that manage a adjusting launch speed but a fixed coordinates positioning.

My idea was to merge both solution taking best part from each feature:
- the positioning, launchbar and blastshield animation is done by FSX/Acc functionalities
- Launch is done by RCBCO 3.0 's dll

I made a small xml code which:
- calculates the launch speed required taking account weight, air speed on the deck, and plane properties (max gross weight and design speed)
- manage the launch process step by step including some control that FSX didn't took into consideration (throttle, flaps) and local variable to help my carrier model to animate the shooter officer.
- Fire the launch with the appropriate speed

With the courtesy of Rob Barendregt and Doug Dawson (thanks again!!) this small gauge has been packaged with the Etendard and the Zephyr, and I'm working on adapting it to Dino's T45c.

There are 2 issues with this solution:
- I don't succed in managing the catapult vapor effects...
- the launch is done by increasing speed but not acceleration so you don't have any G effect during the launch. It seems that FSUIPC and/or Simconnect doesn't overide the acceleration value...
To my own point of view these two points are minor and fully acceptable...

Reagards
S.

This thread has many posts about cat launch.  Sprouty's mention of Dino's freeware T-45C as a project is interesting.

[wilycoyote4]

this test seems to work

only one thing to do----this has nothing to do with spoutys Etendard work-around

in the FSX.CFG add in the realism section---

[Realism]
CatapultForceLimiter=0   //Enables the catapult systems to generate the required force for any type of aircraft.

My cat launch speed for the T-45C at the end of the cat track was 138 KIAS
that is 25 knots of carrier boat speed and a cat track speed of 113 KIAS for the 138 KIAS total.
Full throttle.
Almost max gross weight---see screeny.

Would anyone else like to try this to get realistic speeds on the Goshawk and other carrier aircraft?

[GOONIE]

Interesting find.

I added the line to my fsx.cfg file and then did a cat launch in the hornet using full Mil power (not burner). My end speed was 189kts. Is this better or more realistic?

What I also liked from your post was the xml file discussed, which changes the FSX trigger for the "shooter" animations. It would be great if the "shooter" only gave the cat launch pose/signal (fencing positing/pointing) when you went full power instead of when you attach to the catapault. Small thing, but more realistic.

-Capt.

[wilycoyote4]

FSDeveloper - Wiki - Catapult/Arrestor Operations (FSXA) - Configuring (FSXA)

the above link may help
---------------------------------------

http://www.sim-outhouse.com/sohforums/showthread.php?54718-Moving-Ships-what-s-the-big-deal
A thread here covers many parts of ships and carriers so there are replies regarding cat launch.  Readers must go through the rambling replies.  One of the replies is quoted in the first post of this topic.  It is sproutys explanation of his method to get a more realistic cat launch speed for his freeware Etendard aircraft.
------------------------------------------------
The use of the single line to the FSX.cfg file seems to work for some people.

Does it work for you?  For most people?

Does weight matter much?  Or not at all?

And throttle as a factor?

At the moment, to me, it seems ok, perhaps not perfect, but cat launch speeds for the freeware T-45C are very much better.

[wilycoyote4]

A test of Dino's freeware F-14D. Very high weight, 100% fuel, 69,426 pounds launch weight, throttle N2 99%, no AB as F-14D Tomcats usually launched without AB.

Speed 193 KIAS at end of cat, minus carrier speed of 25 knots gives cat track speed of 168 KIAS.

In another test at that weight but throttle at N2 87% the speed was 189 KIAS.

Not much difference. 

[wilycoyote4]

......I added the line to my fsx.cfg file and then did a cat launch in the hornet using full Mil power (not burner). My end speed was 189kts. Is this better or more realistic?

More realistic than the much higher speeds such as 250 KIAS for the Goshawk or 230 KIAS for the Hornet.

And throttle is at a realistic setting. 

[Sludge]

Fellas...

Personally, I dont think we are gonna get much better than what WILY and CAPT just posted.  It seems that the default catapult was OVER-RATED in its strength for wide-public use and I dont know that there's much we can do to change that, being that the catapult system is hard-coded into Acceleration as-is.  Granted with other aircraft (T-45 and F-14), other tweaks are open, but with the FSX Hornet we are stuck with what we are given.  We can tweak as much as possible, but in the end, we are stuck with staying at less than MIL power for a realistic looking and feeling cat shot.  My feeling about this anomaly is FSX adds the jets engine's thrust along with catapult strength to end speed, when it should be the cat force ONLY, until the jet is off the cat.  To test my idea, perform two cat shots:  one with the throttle about 80 percent and one at MAX power (full A/B), and watch the airspeed during the cat shot and you'll see what I mean.

Im sure you've seen this, but this YouTube is visually informative, as far as real world cat shots.

As you can see, it takes about 3 seconds to hit 140 knots INDICATED at the end of the cat stroke (audible THUD and camera shake) and goes past up to 160+ KIAS, assuming the SkyPig (EA-6B Prowler) is on his climbout and clearing turn.

Dont get me wrong though, I could be wayy off on this, so keep looking and searching.  I'm just airing out my opinion from my prior testing... and we all know what that's worth.  A new technique may come up that doesnt involve a whole new set of gauges.  Keep at it, you might dig up something we can all use.  I'd LOVE to cat-shot at MIL power, at the end be at 140 KIAS, and have to stay at MIL on climbout.

Later
Sludge

[wilycoyote4]

http://www.fsdeveloper.com/wiki/index.php?title=Catapult/Arrestor_Operations_(FSXA)#Configuring_.28FSXA.29

Configuring (FSXA)
fsx.CFG
In the [Realism] section.
Add/edit to enable -

CatapultForceLimiter=1 - Only fighter type aircraft can be catapulted.
CatapultForceLimiter=0 - Enables the catapult systems to generate the required force for any type of aircraft.

TODO - Find/add info how FSX discriminates between fighter and non-fighter aircraft.
-------------------------------------
fighter and nonfighter----
The Goshawk isn't a fighter so how does FSX make a decision?

Anyway, that's why I'm testing "CatapultForceLimiter=0" rather than the other way.

[Letourn]

I tried the new setup

FSX.CFG

[Realism]
CatapultForceLimiter=0   //Enables the catapult systems to generate the required force for any type of aircraft

F/A-18 Sludge / Combat v1.2
35 285 GW / 175 knots with carrier speed at 25 knots
Full military power

T-45 v2 Beta Dino
13 310 GW / 140 knots with carrier speed at 25 knots
Full military power

F-14D Dino
69 426GW / 195 knots with carrier speed at 25 knots
Full military power

[Sludge]

Fellas...

Typical, I write something and now have to eat my words.  Still waiting on permission, so I started modding/testing.  Whats new, right?!

Well, I figured out that in the SDK, there is a value called "LAUNCHBAR HELD EXTENDED, bool", so using that as "catapult armed, tension", I used that point to set the brakes (MLG toe brakes, NOT Parking Brake) to max and hmm, sure enough... after killing the wind, I got several launches under 150 KIAS at MIL power.

So now, we have two instances where setting both MLG toe brakes to MAX helps, when the tailhook is down, so you can do a realistic MIL runup even after the "virtual wire" gives way and stops holding.  And now, at "catapult armed, tension", so you can get realistic launch speeds for the Hornet.

Check out these screenies I just made...

Later
Sludge

[wilycoyote4]

letourn -----
excellent, speeds match very well

sludge ----
you're on the scent, how knows what's next ?  You'll track it down, lol.
here's a part of a page out of the Accel SDK that might be a help, might lead somewhere.

[wilycoyote4]

Iris F-14A, max power, full AB, cat weight 65678 pounds, speed at end of cat 203 KIAS,  carrier speed 25 knots, cat track speed 178 KIAS.  

edit--for a second cat launch
slighty lighter at 65,274 pounds, no AB, 92% throttle gives 198 KIAS, so 5 knots slower.

[Sludge]

Wily...

Already done. This update is already implemented as part of v1.2 CHARLIE coming out this week, as soon as I get the permissions. I've written the READMEs and once I get permission, i'll put it out to everyone here.

You'll see what I'm talking about, and its not the HOLDBACK BAR INSTALLED, its the (EXTENDED, BOOL) variable that I use.  From that, I employ two "tricks", one is setting up both MLG to MAX braking to get that "correct cat-shot speed" and the elevators are auto-set to 48 units (however units are measured) nose up.  That way, the entire first portion of the cat-shot is automated, AS IT SHOULD BE for a Hornet.

Simple procedure.  Before lowering launchbar for hookup, do a FULL "wipeout" to include HOTAS (stick and throttle), rudder pedals, and toe brakes.  Lower launchbar and "hook up".  Push throttle to MAX, see the LBAR green light go out on the left annunciator panel... pull back throttle to MIL power. Hit the LAUNCH button. At the end of the cat-stroke, take note of speed as the jet gets airborne and notice the nose pull up as you gain speed and altitude. Once you see the velocity vector approaching 15 deg, take control with your HOTAS and give a slight turn to BRC and level out at 600 ft MSL.  Start the turn to downwind at your discretion and fly the carrier pattern.

The landing procedures in v1.2 CHARLIE are similarly automatic for the most part. No ATC (yet), or true ICLS lock-on, but from the gauges that are available, they come up automatically, and make the landings alot more realistic.

Later
Sludge

[wilycoyote4]

sludge---
the screenshot was just to indicate that part of the SDK, realism-simulation variables, of which there are several parts.

As per usual, you are ahead, lol.