Throwing some light on rates of turn

[MiG-3U]

Originally Posted by Crumpp

The RAE's use of a single chart given the absence of any differientiation between power levels makes perfect sense with the Merlin XX predictions.

The Merlin XX was predicted to maintain similar power from sea level to 20,000 feet.

1020 Hp at Sea Level and 1075HP at 20000 feet:

http://www.enginehistory.org/members...a/Table-04.jpg

http://www.enginehistory.org/members...lysisR-R.shtml

1. The Merlin XX had a two speed supercharger. The first page you refer gives power at high altitude gear at sealevel due to analysis. See the appendix A at bottom of the second page for power at low altitude gear at sealevel.

2. Even at constant KEAS speed and constant power, the resulting force, thrust, decreases when the altitude increases because force is power divided with true speed. To maintain given angle of bank at given KEAS, power must increase with altitude.

[MiG-3U]

IvanK,
Could you please post parts of the report on turning performance at 20k?

TIA

[IvanK]

This is I think the only relevant bit that includes Sustained turn boundaries for 20,000',25,000',30,000', and 35,000'. "Angle of straight Climb" is Ps=0

[MiG-3U]

Thanks IvanK,

So power is higher, 1100hp at 20k, than 1050hp at 12k. Time to turn 360deg is about 30s at 20k, while it was 18.6s at 12k.