New sounds discussion

Hot or Cold engine

Yes, but why would the sound go away completely if the engine is cold? This is what I don't understand.

Yes, but why would the sound go away completely if the engine is cold? This is what I don't understand.

because large engines dont like rapid throttle movement and it may quit for a split second.

When engine is cold fuel evaporation is low so when you hit the throttle fast you actually leaning mixture because you are introducing much more air in to engine bu because everything is cold fuel injected in to intake don't have time to evaporate(only evaporated fuel can burn) if engien is designed to operate in full range of coolant temp it is equiped this automatic choke which will compensate the lower evaporation rate with increased fuel injection. Engines in spit may not have this so it probably when cold wont respond to throttle at all and if you try add throttle it will just quit.

In spitfire for start up in temps 0 C and below you need special fuel for this it wont do on ordinary aviation fuel.

I'd rather suspect the same bug which affected Dora for quite a while before being fixed - there was a distinctive throttle position at low RPM which made the sound disappear for good even while the engine kept on running. Cold or hot didn't matter.

One would have to do some testing in Spit and Mustang now, in both engine cold and hot scenarios.

Thanks for the explanation. This happens when throttling down too. Has anyone else tried this?

Backfires come from unburnt fuel detonating in the hot exhaust manifold - heat+fuel+oxygen.

The opposite happens to Grafs explanation when you close the throttle; now your mixture is over rich, so either not all or none of the fuel is burnt in the cylinder and is dumped into the exhaust manifold, where it now encounters a lot more air (oxygen) and the heat radiated from the hot metal of the exhaust manifold.

Cold engine, what factor is missing… ?:smilewink:

Does the pulsing in the cockpit happen in real life? I hear what sounds like the volume being modulated at about 4 cycles per second. It's noticeable in Phil's video at 3:35.

It's a known bug with our core sound engine. I hope we will fix it in a couple of weeks.

Just wondering if this is still on the list to fix. Cheers.