Helicopter physics discussion

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Re: Helicopter physics discussion

Postby admin » Mon Jan 14, 2019 6:34 pm

Hey John, thank you so much for your feedback. I've been reading the heck out of it! Talking it over with some pilots and we're doing our best to tune it up in response :)
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Re: Helicopter physics discussion

Postby John Hargreaves » Sat Apr 20, 2019 5:06 pm

Hi chaps, just had a quick blast with the Bell 407 in the 0.5.6.0 version and I think you have done an excellent job with the physics and handling compared to where we were before. I think your time spent with the experts has paid off, and this helicopter feels much more natural and intuitive all round.
Great stuff, keep up the effort.
i7-7700K/MSI RTX 3080/Win10 64bit/64Gb RAM/Asus Xonar DX+Beyer Dynamic DT990 Pro headphones/LG 34" UM65 @2560x1080/TM Warthog+VKB MkIV Rudder pedals/OE-XAM R22 collective/Reverb G2
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Re: Helicopter physics discussion

Postby John Hargreaves » Mon Apr 22, 2019 5:40 pm

I've taken my January feedback (in italics) and addressed each of the points I raised before, (updated feedback in bold).
John Hargreaves wrote:Leaving the ground: the point where the helicopter goes light on the skids and starts to tell you where it wants to go seems to be quite brief. It currently feels that the collective comes up to 'biting point' and you are straight off the ground. I'd expect a small period where you feel the aircraft go light but still stay on the ground, then a little further pull on the collective brings it up into the hover in the cushion of air you are creating. It might just be due to lack of g-force in a sim.
The 'biting point' period is certainly more subtle now, and you get a sense of where the helicopter wants to go just as it goes light, that gives you chance to balance it with the pedals and stick so that when you give that little haul up into the hover it stays settled. Good stuff.
Hover: feels not bad at all. I got into a pretty stable hover first try, it just felt quite natural. The pedals allowed me to rotate and I could taxi around quite happily.
It is happier hovering into the wind, and there is more lift when facing into it. Turning against the wind you lose lift as expected. From a stable hover a slight tilt of the rotor disc from a collective input sends the helicopter in the right direction and there is a loss of lift, you add a bit of collective to compensate, which increases the torque through the main rotor therefore you need a bit of left pedal to balance it. Just how it should be, excellent.
Moving forward: nudging the cyclic gently forward and adding a tiny bit of collective got the 407 going in the right direction and did generate a bit of translational lift, but I felt the effect was a bit weak and I didn't feel like I was picking up much momentum, almost as if the density of the air was too thin. Also as I picked up speed, I would expect the weather vane effect to start to keep the fuselage going a bit straighter, but the torque effect of the main rotor seemed to be present, then disappear abruptly at a certain speed rather than being a gradually decreasing effect. Once up to 60 knots or so I was able to come off the pedals, so the effect is there.
The translational lift feels much better now, comes in at about 20kt or so and the weather vane effect is gentle and progressive. Great stuff.
In forward flight I was feeling a general lack of lift, and lowering the collective, even at quite a fast airspeed, the helicopter seemed to drop quite quickly rather than cut through the air. Again it felt like the air was very thin.
It now feels like the air has mass and substance, that you are actually flying through a fluid medium. Dropping the collective, you feel resistance as if the helicopter is a parachute on your back resisting the mass of air under the rotor blades. Big improvement.
Cruising along and pulling the collective up without doing anything else, the 407 just gained altitude rather than screwing itself over my right shoulder, so there was no torque effect from the increased power going into the system. I'd expect raising collective > increased lift > increased power to rotor to maintain rpm > increased torque > left pedal to balance it.
This (admittedly something you would generally not do) still felt like the main rotor didn't have as much torque as you would expect when you pull hard up on the collective. Even as slow as 20kt or so, a big tug on the collective didn't need any pedal to compensate. This is more of a 'test' type manoeuvre, not really something done while flying normally, but I guess it helps to tweak the physics.


I only tested the 407 ( as XP11 has a very good one to compare) so the sim allowed me to land on top of buildings. Doing this, if I was just in a ground effect hover, if I moved away from the structure into free air, I lost the ground effect and the helicopter descended. Equally, coming in to land on top of a tower block, I could feel the increased lift from ground effect as I got over the roof of the building. Excellent.
I think I also got myself into VRS by coming over all Tom Cruise at one point, so I did a quick Vuichard manoeuvre by flicking the heli sideways into clean air and lo and behold it worked, I picked up lift from the still air and saved myself from certain sim death. Very impressive.
Overall, if I had just paid out £25 for this helicopter in X-Plane I would be happy with it. I think it's really good and on as blind a test as I could do, I'd say it's able to stand alongside DCS and XP11 in terms of the flight model, certainly in my experience. You would need someone with much more experience than me (there are plenty out there who fit the bill) to pick any serious holes in it I believe.

Hope this helps to keep improving, overall it's another massive step forward and again very encouraging, but even though there will be far more experienced and knowledgeable guys than me who you can draw upon, I think you are doing a great job.
i7-7700K/MSI RTX 3080/Win10 64bit/64Gb RAM/Asus Xonar DX+Beyer Dynamic DT990 Pro headphones/LG 34" UM65 @2560x1080/TM Warthog+VKB MkIV Rudder pedals/OE-XAM R22 collective/Reverb G2
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