Well, I've spent most of my life dealing with engines for a hobby, whether model aircraft, motorcycles or cars. I've also been an aircraft nut since I could walk , and I've never seen a yellow exhaust flame like that shown except from a damaged engine, or one with which I've had to fill the air filter with 'eezy-start' to get it running (which usually meant it was damaged anyway). Even then, the yellow flame soon clears unless the motor is really coked up or has badly pitted valve seats/bent valve stems. Even then the effect wouldn't be uniform for all cylinders. Most primers I've come across are methanol based, which also burns blue/violet.

Hence my question about the primer used. If the yellow flame is indicative of the primer, fair enough. If not, the flame should be blue.

(Actually, I just watched Rudolph's video post again, and the bloke is obviously hand pumping the primer, and, oh look, the flame is still blue!!)

The argument about altitude and RPM is also unfounded as the aircraft was on the ground and ticking over, as were the videos posted.

Like Blackdog, I'm also an amateur astronomer and yes red giants are cool and blue giants are hot. White Dwarfs are very hot and quite nasty, but the exhaust flame of a spit at night should be blue.:)

The MkI, II and IV spits had covers over each pair of exhaust stubs which purportedly produced a degree of 'boost'. It's possible that soot could build up in these somehow and burn to produce a yellow flame, but the ground crew should have been put on jankers for poor maintenance.

I'm beginning to think Mr Maddox does this deliberately just to keep us occupied.:grin:

The thought has struck me too :)

...


Around 08'00" , note the many glowing burnt fragments in the prop wash of this mighty Lanc confirming the bad combustion (dull red) of that transitionnal and intermediate engine power.

http://www.youtube.com/watch?v=k9AGb...ayer_embedded#!

...

Thanks for the up-date, the grass moving looks cool:grin:

Apparently a merlin 45,I don't see any flames:

http://www.youtube.com/watch?v=cv0Onh6NzPA

And another one:

http://www.youtube.com/watch?v=wIpgk-1OfFU

I often feel like that when I'm at work! ;)

I realy like the way the spitfires suspension reacts in the first video. That little dip of the wing as as the plane turns and comes to a halt. It really gives the impression of inertia and the mass of the aircraft.

Cheers and thanks for the update!

Well spotted Rodolphe, I skipped that video for some reason. I notice the same red flames as in the other clip but they appear clearer and longer since there was no external lighting this time. I agree that the engines are probably poorly set up in this case. So...blue flames when running efficiently and redder when the mixture is made richer.

I still see no reflections on the cowlings.

I've taken a few more stills to illustrate in the attached piccy.

That depends on how it's started. These are not typical, but show flames can occur:

http://www.spitfirespares.com/spitfi...h%20flames.jpg

http://www3.pictures.gi.zimbio.com/E...9_syXG3asl.jpg

I think the start-up video is ok. If I had one qualm with it, it is that the smoke of that quantity dissipates very quickly. Either the smoke should be much less, or it should hang around longer if it's going to be that big.

Here's an example, but every video shows the same thing:

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

3:05

Regarding exhaust flame at night - I will leave color to the experts. I would like to point out that color doesn't always have to do with temperature. Some flames burn green for instance, or purple. I would also like to say that the ambient light from the exhaust seems too strong. While exhaust flames would have been an important factor in finding your enemy at night, I don't think they would paint the side of an airplane bright yellow (or any color for that matter). The same occurs in IL-2 when firing guns (bright yellow glow on side of plane and in cockpit), which I think is not accurate.

Regarding sounds - even in IL-2 they are good, but one that was missed was speed of sound in air. Explosions a mile away are heard instantly. I hope this feature will be implemented in SoW. Secondly, sounds are modified by air flow. If it's a windy or turbulent day, the drone of an engine is going to fade in and out in a random way, with the degree of rise and fall of volume increasing with distance. Thirdly, low frequencies travel farther than high frequencies. So, when listening to an engine that produces an array of frequencies, you will hear a low drone when it is far, and a higher click-clack buzzing when it is near. I can't decide if this is modeled in IL-2 or not, but I'm throwing it up here anyway.

Those Merlins have those fancy covers over the six stacks though. You can't really see if it's flaming or not. Come to think of it maybe that's why they're on there.

present color would be OK for a cold engine rich fuel startup. does the color change as engine warms and mixture is leaned?
blue with a pointed white center is optimum