BOS...Exhaust Animations

[ATAG_Lewis]

I just wanted to bring up the issue of the exhaust animation in this sim....No biggy but something that's been bugging me a bit....I notice this on all the aircraft ingame and it kind of annoys me as something the devs have included because it looks nice and not for any other reason...I could be wrong and that's why I thought I'd run it past this great historian and boffin community as to whether there is any evidence for this to be seen originally during the war

What we see is unspent fuel firing from individual exhaust stubs which usually happens on startup for a few seconds......Now I realise that the fuel would have been different in the 40s so maybe there is some scope for this to have happened but I have never seen this effect in any aircraft in the air at the numerous airshows I have been to..Moreover a large engine like these aircraft still is fast enough that the pistons would be a blur on tickover so how would this effect stagger like it does in the sim?..

Anyway...As I say I could be wrong and I'm sure there are folks out there that know the whys and wherebys so I thought I'd throw this out there for discussion and see what the concensus is..


Below will show you what I am talking about...From 1.15..to 1.21....will show you both aircraft doing this animation


https://www.youtube.com/watch?v=vpqtoE6XMZk

[ATAG_Colander]

http://www.youtube.com/watch?v=eTkatOz_mC0

[1lokos]

Spitfire night startup:


https://www.youtube.com/watch?v=ubCG0Y4A0Os

Well, you can use then to check if mixture settings are OK: :D


https://www.youtube.com/watch?v=UoADOlgfW6Q&list=PLnyigzFtHeNrhK2RjtLNkRyhu9oDWJlAt

Sokol1

[RAF74_Buzzsaw]

Most of the intermittent nature of the exhaust flames shown in the videos is a function of the digital recording devices used.

What was recorded is not what is seen by the human eye.

Change the framerate to a higher one and the flames will appear more continuous.

Regarding BoS's graphics for exhaust flame, from my observations, they do not change with rpm. This is obviously incorrect.

In my opinion the graphics for exhaust flames are more accurate in CLIFFS OF DOVER. ;)

But feel free to register your own opinion. :salute:

[Hood]

In my opinion the graphics for exhaust flames are more accurate in CLIFFS OF DOVER.



Agreed. Thankfully I am mostly in-cockpit so it doesn't bug me.

Hood

[ATAG_Lewis]

All the videos posted above are at night and on startup....We also already know that the mosquito night attack version had guards to stop this so as the aircraft could not be seen at night so there was either unspent fuel or exhaust stub glow from heat and if it was the later then its not the flame from post ignition.....

As the aircraft in BOS still show this effect in daylight....Here's a video in daylight...


https://www.youtube.com/watch?v=e1mh99ZLXcw

[RAF74_Buzzsaw]

All the videos posted above are at night and on startup....We also already know that the mosquito night attack version had guards to stop this so as the aircraft could not be seen at night so there was either unspent fuel or exhaust stub glow from heat and if it was the later then its not the flame from post ignition.....

As the aircraft in BOS still show this effect in daylight....Here's a video in daylight...


https://www.youtube.com/watch?v=e1mh99ZLXcw

In the same way that the digital recording device incorrectly freezes the prop position and shows us what appears to be a stationary prop, the recording device also incorrectly records the flames from the exhausts.

It also has the typical blue blindness of a lot of daylight balanced cameras, so the flames are not as visible.

On a different observation... I wouldn't stand in front of this engine/prop... people are trusting a primitive set of braking devices are going to work and the whole contraption is not going to suddenly roar forward and decapitate/sever various parts from those who are in its path... :stupid:

[ATAG_Lewis]

In the same way that the digital recording device incorrectly freezes the prop position and shows us what appears to be a stationary prop, the recording device also incorrectly records the flames from the exhausts.:

This is a regular at Duxford Legends airshow and I have watched it numerous times from 10 to 20 feet away with our group of diehards....and see just what the video shows here.....no flames when the engine is running hard....If there is unburned fuel making it to the exhaust stubs I don't see any in the daylight until the engineer throttles down and the engine over rides, the engine pops and bangs and even then its only small..and nothing like BOS

I just wondered if something like the fuel was different in 1940s...and that the devs know this and therefore have made the exhaust flames more visible as they would have been originally...?..That could be the case right?

[Hood]

I wouldn't stand in front of this engine/prop... people are trusting a primitive set of braking devices are going to work and the whole contraption is not going to suddenly roar forward and decapitate/sever various parts from those who are in its path... :stupid:


I always think the prop will fly off and keep going forward for a while.

Hood

[Mysticpuma]

I shot this as the FL Air show this July. Video of over primed engine shows lots of flame. Then the running engine shot at 1/500th of a second (video) you can see the faint blue flames but not as bright as BoS.

Check out from 1m 05 secs:


https://vimeo.com/100783834

https://vimeo.com/100783834

[LuseKofte]

BOS got in my opinion a cartoonish way to show effects, I think this is done to please people playing fps.
And to be honest, I find it entertaining and cool, it is really more how you look at it.
I hope for public made offline campaign , and I happily fly along.
I still aprechiate IL 2 and I see a lot of improved stuff from that game, ànd it would not be CLOD if il2 was'nt around

[III./ZG76_Saipan]

ive never noticed the clod animation change for the 110 exhaust. do i need to look closer? is it that accurate to have stuff coming out all the time?

[startrekmike]

The effect in BoS may be a little exaggerated but I don't really lose any sleep over it, to be blunt, as long as it is not DCS, I don't really expect 100% realism, especially from a developer that is trying very hard to walk a fine line between a proper simulator product and a product that non-simulation fans will actually buy.

I mean, we can hop on youtube and look up footage of aircraft being run (a video of a Mustang starting up comes to mind) and we don't see ANY flame coming from the exhaust (probably because it is too dim to see in daylight from even short distance), even CloD tends to always show some flame, even if it is more subtle than BoS.

[ATAG_Bliss]

A 4 stroke combustion engine fires 1/2 it's cylinders every single crankshaft rotation. During a single crankshaft rotation half the cylinders have sucked in air/atomized fuel and compressed (piston up and down) while the other have have fired that fuel and thrown it out the exhaust (piston up and down) (hence 4 stroke). So every crank rotation of a V12 engine, 6 cylinders have fired. So an engine running at 1500RPMs does an entire crankshaft revolution 15 times per second. So that would mean, for instance in a V12, every single second at 1500RPMs, there are 90 cylinders that have fired. At 3000 RPMs, this number is 180 times every single second of run time.

The thing with combustion / vapor burn is, it tends to happen from heat and unspent fuel. So a freshly started engine with a short exhaust header doesn't necessarily throw fireballs out the exhaust. Most cameras highly exaggerate this occurrence. But, as the exhaust header is full of heat soak, the unspent fuel vapor that was ignited in a cylinder tends to stay "lit" until it is all burned out and this is because the heat at the exhaust is hot enough to keep the fuel burning.

Obviously with a longer (normal exhaust such as a modern car) that vapor burn is long over with by the time it starts reaching the emission devices etc. But even with full exhaust (such as a car again) if you were to touch your tail pipe of your car after a long trip, it would still burn your hand in most cases. That's because the heat soak from the "fire" coming out of the cylinders is still heating up the rest of the exhaust. And without this "fire" that heat wouldn't exist in the 1st place. So with the aforementioned 1500RPM scenario with 90 cylinders being fired per every second of revolution, it's easy to see that this unspent vapor that is still burning, will also still be burning by the time that particular cylinder fires again, which makes a continual "flame". So every single cylinder should look identical at RPM/Load with regards to flame etc. As an engine guy, the way it's modeled in BoS makes me cringe and makes me wonder how they could get it soo wrong.

So if there's any flames to be simulated at all. Unless at idle/engine cold etc., when you are normally flying at operating temperature, especially under load, the cylinders with a short enough header, will indeed look like mini flame throwers. I asked for this to be changed in BoS and was quickly shot down by the usual suspects, which of course, either don't care or don't know about the combustion engine in the 1st place.

To give you an idea of what a short header 7000+ horsepower V8 looks like under load, during the day etc., this is pretty close. Turn that around to night, and it looks like one big row of fire out of each cylinder the entire pass.

http://speednik.com/files/2012/08/094-TonySchumacher-BT.jpg

And at night:

http://speednik.com/files/2014/04/dobbo-super3-20141.jpg

[RAF74_Buzzsaw]

Regarding CLIFFS OF DOVER exhaust flames and the complexity of the modeling:

1) The regularity of the appearance of the flames is timed to link with engine RPM's and which cylinder is firing. The flames are combined with exhaust smoke... there is a larger frequency of smoke in situations where engine combustion is less efficient or when there is damage.

2) The colour of the flames are an indicator of how much stress is being put on the engine, or if there is damage. Generally light blue flames indicate normal combustion, reddish flames indicate engine stress, potential overheat or damage.

3) Each exhaust port is handled separately... so if there is damage to a particular cylinder, the flames from only that cylinder will change colour.

It is probably the case the flames are slightly more visible than real life, but that was done to allow the players in the game to more accurately assess the engine state... they also play a part in the ability of a player to see an opposing players aircraft in low light situations, with the limited ability of a monitor to portray the human cornea's ability to open up and register very low light sources.

[ATAG_Colander]

http://speednik.com/files/2014/04/dobbo-super3-20141.jpg


So, if I paint flames on my car, will it go that fast?
:)

[III./ZG76_Saipan]

cool, didn't know the colour was coded for engine stress. ill have to check that tonight. thanks for the info!