investigating Should Catapult Acceleration Rate Be Slower to Be More Realistic?

[Dr. Anti-Vehicle]

When comparing real life videos with DCS clips, I have reasons to believe DCS catapult acceleration is much faster than what it is in real life. After sampling random clips from Youtube, I noticed it takes about 2.2 seconds for a hornet to run through the catapult, whereas the time in real life videos is about 3.2 seconds.

In game, it feels especially "off" at the very beginning, when the plane literally gains speed immediately upon launch. It is more like a bullet from barrel instead of slingshot.

I hope this is an easier optimization for developers. Btw I really love new catapult sound in 2.7.

For everyone's reference, here is Wag's DCS clip from Youtube, and here is a real life cockpit video for comparison.

[Frederf]

Interesting observation. I assume in reality there is an adjustment of launch power due to wind over deck, airplane weight, etc. A stationary carrier would require a more aggressive launch than one into a strong headwind for example. DCS have have elected to have a single launch acceleration.

 

Anyway, here is a synchronized video comparison. https://viewsync.net/watch?v=3ztrv_ZML8w&t=332&v=oxE04HT9iqw&t=61&mode=solo

[Dr. Anti-Vehicle]

1 minute ago, Frederf said:

Interesting observation. I assume in reality there is an adjustment of launch power due to wind over deck, airplane weight, etc. A stationary carrier would require a more aggressive launch than one into a strong headwind for example. DCS have have elected to have a single launch acceleration.

 

Anyway, here is a synchronized video comparison. https://viewsync.net/watch?v=3ztrv_ZML8w&t=332&v=oxE04HT9iqw&t=61&mode=solo

That’s amazing work. I also compared other real life videos of F35 and F14 launching, and they are also around 3.2 seconds.

I noticed how violent DCS launch was the first time I hopped on, but I didn’t have enough confidence to point it out until now.

I also noticed catapult compressing landing gear during shooting in real life resulting negative AoA, but in DCS jets seem to have a perfect 0 degree AoA while accelerating. But I guess that might be too much to ask from ED for now. So I thought the acceleration thing could be an easier improvement despite that it’s not critical. But it can certainly make carrier ops even more immersive.

[randomTOTEN]

26 minutes ago, Frederf said:

I assume in reality there is an adjustment of launch power due to wind over deck, airplane weight, etc.

 

I believe the catapult performance has already been adjusted since that video was released.

 

[Dr. Anti-Vehicle]

45 minutes ago, randomTOTEN said:

 

I believe the catapult performance has already been adjusted since that video was released.

 

Thank you for pointing that out. I think you are correct. I timed more recent DCS clips and it's now around 2.8 seconds. Strangely I've barely noticed it personally. I think maybe it's because of the beginning of shoot. If it can be a little more "gentle" at the first 0.1 seconds, that can make up the additional 0.2 - 0.3 seconds. Anyway, I am not going to ask for more at this point. It's a little quicker than it should be, but still an amazing experience as I previously said.

[Nealius]

Might be related to the known issue of the catapult end speed being higher than normal in DCS.

[RWC]

 

[obious]

I raised a similar post a little while ago to which they released a ‘fix’ for although I didn’t see any change. 

 

After doing some experimentation recently, I launched a fully loaded F-18c in full AB (3 ext. tanks, two GBU-38s, two AIM-9X, ATFLIR & 1x AIM-120) off the Abraham Lincoln which in ME I set to be steaming 25kts into the wind and I consistently got around 200-220 knots coming off the bow. I even tried without any throttle and was only seeing around a ~10kts reduction in end speed

 

Something just doesn’t seem right with the amount of force being applied to whatever aircraft is hooked up to the catapult. 

[Jackjack171]

IRL, the way it works is the Pilot/Aircrew will give a Weight chit to the Shooters in Flight Deck control! This contains the weight, loadout, asymmetry and other things that I have forgotten. The Shooters take this info and calculate WOD requirements, wet bulb, dew point and some other things. In the bubble they work the magic to get the correct amount of steam for each aircraft. That's the short version as it's been a while! 

I think the problem in DCS is that the CAT Shot is a "one size fits all approach, which is fine considering the complexity of such a thing! 

[Dr. Anti-Vehicle]

On 7/25/2021 at 2:59 PM, Jackjack171 said:

IRL, the way it works is the Pilot/Aircrew will give a Weight chit to the Shooters in Flight Deck control! This contains the weight, loadout, asymmetry and other things that I have forgotten. The Shooters take this info and calculate WOD requirements, wet bulb, dew point and some other things. In the bubble they work the magic to get the correct amount of steam for each aircraft. That's the short version as it's been a while! 

I think the problem in DCS is that the CAT Shot is a "one size fits all approach, which is fine considering the complexity of such a thing! 

Yep. I don't think many of us want to go thru that realistic approach before launch. But a smoother and slower cat shot would be good enough

[Gierasimov]

It would be good to find Hornet cat shots and compare them, here is what fighter pilot says aabout the two:

 

"(...) the procedures are nearly the same as they were in the legacy Hornet, except now the catapult launch is in full flaps and there is no selection of afterburner mid-catstroke. There can still be afterburner shots for certain weights and configurations, but some of those procedures have slightly changed."

 

So, full flaps, no AB, bigger jet... Not too good of a reference Rhino is. 

[Dr. Anti-Vehicle]

On 9/13/2021 at 11:01 AM, Gierasimov said:

It would be good to find Hornet cat shots and compare them, here is what fighter pilot says aabout the two:

 

"(...) the procedures are nearly the same as they were in the legacy Hornet, except now the catapult launch is in full flaps and there is no selection of afterburner mid-catstroke. There can still be afterburner shots for certain weights and configurations, but some of those procedures have slightly changed."

 

So, full flaps, no AB, bigger jet... Not too good of a reference Rhino is. 

I agree with you 100%. I should have thought about that. So created this one using a recent DCS video and the only legacy Hornet cockpit video I can find. As I mentioned above, I think the differences might lie in both the beginning and the end of cat shot. There is too much acceleration at the moment of holdback bar release, and I feel the speed at the end of cat shot in DCS is higher than real life. Again, I know there is weight and wind playing some factors, but regardless how many videos I compare, cat shot in DCS is consistently faster.

http://viewsync.net/watch?v=w5qhYKFXl8U&t=233&v=bmbbUVdDZVI&t=37.88&mode=solo

@BIGNEWYSorry I wasn't very rigorous when first wrote up this topic, but comparison above may be more convincing.

[Dr. Anti-Vehicle]

I tried MIL power take off yesterday, and the end speed feels really good which is around 140 - 160 knots. However I did feel the plane sink at leaving the bow. With AB the end speak is above 180 knots, and the plane still sinks a little.

With that being said, the moment when hold back bar is released, acceleration is still a bit too “abrupt” regardless of AB usage or not.

I hope the new flight model can prevent the plane from sinking to some extent.