Talk:Tumansky R-15

MiG-25 supercruise?

The MiG-31 is able to supercruise but I don't think the MiG-25 was. It was certainly capable of sustained supersonic flight - Tumansky rated the R15B capable of continuous afterburner for 40 minutes - but I don't think the MiG-25 could do it without afterburners. . Flanker235 (talk) 09:40, 24 March 2014 (UTC)

References

Speculation?

Just wondering how much of this is speculative:

"However, a more probable series of events would be the eventual destruction of the engine as the suction force of the compressors began to pull various engine parts through the ignition chamber and turbines."

There's no citation for it. Does anyone else think this should be removed pending further research? Flanker235 (talk) 14:21, 6 October 2014 (UTC)

Yes, that sounds a little unlikely, especially if it's not referenced. The compressor doesn't create suction, it creates accelerated airflow at each stage, which is then slowed by the stator blades which create a high pressure area. There is nowhere within the compressor where the is suction created; in fact the pressure grows as you move through it. I'm not sure of the context of about text, but if it refers to above the compressor, in the inlet tract, then there is no reason it should be "sucking parts in" unless the thing is poorly built. And there isn't any suction in the intake either; there is fast-moving air that has a low pressure, and which moves across a pressure differential. The compressor first stage draws air into the compressor, leaving a pressure differential, which has to be filled by the air in the tract...but at high speed, there should be plenty of air ramming INTO the ducts to even make it slightly positive pressure. AnnaGoFast (talk) 20:23, 9 May 2016 (UTC)

Few stages

It seems strange that such a hugely powerful engine has only 5 stages and a single turbine; that seems very ,very few for an engine of that era. Is that something to do with it being intended for high altitude/high speed flight, and the reason it's so inefficient at lower levels? AnnaGoFast (talk) 20:25, 9 May 2016 (UTC)

Effects of flight beyond Mach 3

This uncited line is echoing a widely repeated myth that keeps getting reprinted without citation or justification and I'm not sure why it's even needed. It gives the impression that there's some magic line which will destroy the engine if passed, yet not catastrophically enough to prevent the aircraft returning to base and landing... there is enough misinformation in the world about R-15s blowing up/turning to slag/whatever after a Mach 3+ dash already. No such situation is supported by the engine's technical documentation, the aircraft's technical documentation, even a basic understanding of metallurgy or turbine construction, or reliable pilot/engineer accounts - didn't this story about the engines being replaced after the Sinai dash start with Belenko? It's bad enough when this story is reprinted uncritically by English-language sources, but here it doesn't even cite said reprints. Even a cursory inspection of the MiG-25's aerodynamics manual describes stability reasons and friction heating of the aircraft structure as being the reason for the M 2.83 service limit, not some mythical sensitivity of the engine. 157.211.12.220 (talk) 02:01, 2 August 2023 (UTC)