Need help with engine management in winter conditions below zero.

[RealDCSpilot]

I have troubles with the engine dying or losing power on me during starts on a server with -4° celsius. I tried one with +2° without problems, but at below zero temperatures the jug doesn't seem to like it at all. If someone could provide a step-by-step guide and which one of the temp gauges is the most important here, it'll really be appreciated.

[grafspee]

You need to warm it up first, at very low temps you have to watch oil pressure to not exceed 150 pounds per square inch.

I always wait for 40C oil temp, i close oil cooler, cowl flaps you need to leave open to avoid ignition harness burn out.

Cylinder heads temps i much less important in cold weather.

As soon i get 40C on oil i start engine/accessories check, i open up to 2000rpm it is almost 30". Test prop governor twice, then i test magnetos(i switch magnetos L/R and OFF during warm up to be sure that both are working, i don't want to cut my engine off at high rpm while doing engine test.), check if gen is working.  After test i go for take off.

For take off i open oil cooler to normal position. In flight you may need to close oil cooler a little bit more to prevent over cooling.

Yes radial engines will take longer to warm up, For example Spitfire is equipped with thermostatic valves which are cutting out coolers completely, this speeds up warm up a lot.

Fw190 A-8 is equipped with engine driven fan which slows down warm up a lot this bird takes ages to warm up.

Edited February 3, 2021 by grafspee

[RealDCSpilot]

Alright, will test this. Thanks. Cyl temp never reached more than 180/190 if i remember correctly, even after a long wait for warmup with cowl flaps already closed. I will definitely check the oil temp much closer.

Edited February 3, 2021 by Alec Delorean

[RealDCSpilot]

Ahh, what a relief. Everything worked perfectly this time, managed -6° celsius with cowl flaps closed all the time and readjusting the oil cooler shutter at 0-20% to hold the perfect oil temp. Many thanks for pointing me in the right direction.

Edited February 3, 2021 by Alec Delorean

[Diesel_Thunder]

Don't close your cowl flaps to help with warm up. It's does not help the cylinder head temps as much, and the ignition harnesses end up getting baked for no good reason. As grafspee said, CHT is not that important during cold weather ops. The only time I'd be concerned is if you are overheating for some reason.

 

Proper oil temperature is far more critical to get warm before running the engine past 1,000 RPM. Closing the cooler doors does help with this. If oil pressure is spiking too high after startup, you can use the oil dilution switch to bring the pressures down.

[RealDCSpilot]

Thanks, will try. What i find pretty cool, the engine sound details, never recognized this before (wasn't flying at these low temperatures before). You can actually hear if something is not right, a mechanical rattling noise will appear if you raise RPM too early. Seems to appear on all WW2 birds.

[grafspee]

10 hours ago, Diesel_Thunder said:

Don't close your cowl flaps to help with warm up. It's does not help the cylinder head temps as much, and the ignition harnesses end up getting baked for no good reason. As grafspee said, CHT is not that important during cold weather ops. The only time I'd be concerned is if you are overheating for some reason.

 

Proper oil temperature is far more critical to get warm before running the engine past 1,000 RPM. Closing the cooler doors does help with this. If oil pressure is spiking too high after startup, you can use the oil dilution switch to bring the pressures down.

I was testing this oil dilution thing, looks like it doesn't work in P-47. I noticed that for channel map and Normandy map you cant set temps below +8C.