helipilot12

@kam Just experimentation, wanted to test what happens when pitch is pulled during a 0 knot or below-ETL autorotation. I've done a couple autos in an R44 that started as a vertical descent, then gaining around 30kts of forward speed, and then yanking the collective at the bottom (full-down to the ground and no flare). The Huey in DCS reacts similarly to that, and satisfies what I've seen in the real world. Doing one with no forward airspeed at all in real life wasn't going to be something anyone attempts, so I figured I'd do some testing in DCS.

@cw4ogden Thank you for the diagram and explanation, I assume this is probably something taught in much more depth in military flight programs, compared to a part 61 civilian flight school. I've been researching this topic on-and-off over the past several years, and have never seen that diagram, so it's certainly something new to consider and a good point to do some more research with. I'll bring this up with a few flight instructors when I get a chance, it'll be good to re-visit this topic. It would be neat to test this further in real life, although it's not really feasible given that you'd likely end up as a pancake on the runway. Off to do some more testing in DCS with this new information, thanks again! Mods - Feel free to move this to the correct section.

Hello, I'm not sure if this is a bug or if it's theoretically possible, but it happens often enough for me to question it. I tried searching for previous threads regarding this, but couldn't find something with the exact issues either. Please feel free to move/close/point this thread to an existing one if one does exist. From a theoretical standpoint, helicopter rotor discs have 3 modes of flight: 1: Normal flight (air travels down through the rotor disc) 2: Autorotation (air travels up through the rotor disc) 3: Vortex ring state (air travels down through the disc, and is then recycled around the rotor tips and back through the top towards the bottom) I'm a huge believe in practicing full-down autorotations, thus I use DCS as a good platform to play around with. I am a real pilot (only ~100 hours however), so I'm not an industry veteran, and I'm well open for suggestions, corrections, and others' experiences. The issue at hand essentially seems to be the ability to enter VRS while the engine is idle or off, and the aircraft is already in a state of autorotation. To replicate this, set up at around 2000ft AGL, drop the engine to idle, and enter a direct vertical descent autorotation. Once in a stable auto at 0 knots airspeed, and 1500-2500FPM descent, firmly pull the collective to max pitch. What I would expect to happen is my descent rate being reduced, until the rotor RPM decays enough. What happens instead is a rapid increase in descent rate (Unexpected), along with the rotor bleeding off RPM(Expected). As I understand it and as the industry has been teaching, the following factors must be present to enter vortex ring state: 1: Descent rate of greater than 300FPM (This factor varies widely based on aircraft, rotor loading, etc. The FAA just uses 300FPM as a safe number) 2: Airspeed less than Effective Translational Lift 3: Between 20-100% engine power (essentially some power that's keeping the rotor spinning rather than RPM decaying) I have two ideas as to what could possibly be happening: 1: The firm pull on the collective is enough for the aircraft to enter VRS briefly as if it were still under power 2: The flight model doesn't have this simulated properly I'm at about a 50/50 split between my two theories, and I'm open to what others may have to say. I've done autos in an R44 at ~20 knots with no flare, and the rotor RPM decays immediately and arrests the descent. I'm able to replicate this in DCS as well, and I'm 99% sure it can be attributed with there being enough airspeed to be in ETL. So the only effect I'm questioning at this point is the ability to enter VRS at 0 airspeed. I know the DCS Huey flight model has been particularly prone to VRS in the past as well, based on some other forum posts I was reading. Again, feel free to question, critique, correct, or share your experiences, I've been meaning to ask this for a while and finally had some time to do it.