I flew the Yak 7, Yak 3, Typhoon, and Spit XVI offline recently. I took it up to 7k-8k, shot at the drones, and landed.
During the Yak 7 ride I caught a pair of B24 engines on fire. I attached a screen shot of the burning B-24. Not sure if that is the burning effect you wanted.
During the Yak 3 ride I noticed the engine is variable. The manifold pressure is operated by the throttle slider but does not control the RPM’s as normal. The throttle sound will go up or down if you manually adjust the RPM’s. I tried remapping the slider on the stick but no joy. Also during this ride I collided with a B-24 and it damaged my engine. The damage message reported a failed engine, manifold and rpm’s dropped to 0, and the engine noise quit but I noticed no physical damage to the prop.
In the Typhoon, there was no audible indication when WEP was engaged. You could see the boost jump (not by much) but no greater engine sound. When you spawn from the hanger at A1 the engine gets damaged immediately. I did see a damaged prop.
The Spit XVI ride was uneventful. You could hear when WEP is engaged but the bump is much greater than the Typhoon WEP.