(The Grand Tour; episode 2) SAS unit fast roping from a Blackhawk.
Why is the helicopter pitched-up? Actual scene footage have it like that for a few seconds while holding steady over a building. How come it's not flying backward?
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1$\begingroup$ Could there be a headwind? $\endgroup$– BillDOeCommented Nov 29, 2016 at 0:54
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9$\begingroup$ Tail wind. Head wind would be nose down. $\endgroup$– SimonCommented Nov 29, 2016 at 6:24
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1$\begingroup$ @ymb1 Yes it would be very strong to hold that apparent pitch up, which leads me to suspect that Pete has the right answer. Approaching, then hovering over a building to do a rope-out with a tailwind like that would be unthinkable. I agree that this is likely nothing more than perspective in the image you grabbed. $\endgroup$– SimonCommented Nov 29, 2016 at 15:51
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$\begingroup$ @757toga -- with a tailwind, the "hovering" helicopter must actually be steadily translating (moving) backwards relative to the airmass. With a headwind the "hovering" helicopter must be steadily translating forwards relative to the airmass. So the first sentence of your comment above appears to be incorrect. Not to say that that's the actual explanation for what we are seeing, but the logic seems sound at least. $\endgroup$– quiet flyerCommented Nov 17, 2021 at 21:05
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$\begingroup$ @quietflyer your use of "translating" in the context of the remaining information in your comment is difficult for me to understand what you are describing and its relationship to a helicopter's pitch attitude. $\endgroup$– user22445Commented Nov 17, 2021 at 21:38
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4 Answers
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This screen grab is from a few seconds before yours was taken. No pitch is evident here.
Sketched above is rope angle and camera position (based on the staircase in both frames).
I think it's just the camera angle used that makes it look pitched combined with the rope's angle in the wind.
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1$\begingroup$ TV production teams and the military are generally risk-averse. I kind of doubt they'd put personnel at risk just for filming a TV show. Hovering above a building while pitching backwards into a tailwind doesn't really sound like a good idea. Even in combat situations, you'd want change that tailwind into a headwind to maintain optimal control (since you can see what's ahead of you a lot easier than what's behind). $\endgroup$– user12007Commented Nov 29, 2016 at 13:18
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1) The 60 has a natural nose up, left wing down hover attitude. I want to say 3, and 1.5 degrees, but I'm going off memory. Given the angle of the shot, I would venture to say that it's more optical illusion of a excessive nose up angle than it actually is.
2) Given the nature of fastrope operations, and without opportunity to observe the video in entirety, it is possible the aircraft is still stabilizing its hover. I would guess that SAS guys are only going to wait around just as long as they need to before they're out of the bird. Or has already been suggested, gusting winds may be forcing the pilot to make adjustments since that building appears to be in a sort of valley which could make winds interesting.
- MH-60S driver
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When in forward flight, the rotor will be pitched down to convert some of the lift vector into forward motion. This also results in the fuselage of the helicopter pitching down. Therefore the fuselage is designed to be pitched up in a hover so that during forward flight it is level or close to level with the airstream for efficiency, and to maximimize pilot visibility to the front, and passenger comfort during the forward flight portion of a flight.
answered Nov 29, 2016 at 11:26
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5$\begingroup$ Not true for any helicopter I know of. The deck is designed to be level in hover (it would be tough to hover otherwise). The horizontal stabiliser is designed to produce an upforce on the tail which levels the nose in cruise. Actually, everything I've flown is slightly nose down at anything much above translational lift speed anyway. Additionally, the rotor attitude has little to do with the stable state of the deck since the fuselage acts as a pendulum hanging beneath and will swing back to it's stable state. In cruise, helis are statically stable but dynamically unstable. $\endgroup$– SimonCommented Nov 29, 2016 at 14:28
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1$\begingroup$ @Simon When I flew the SH-2F, the typical hover attitude was 3 deg nose up. When they converted to SH-2G, and the CG changed a bit, that variant had a nearly level flight attitude. (Made night deck landings a lot easier, according to the TP's who flew it). $\endgroup$ Commented Nov 30, 2016 at 15:52
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Just about every Helicopter has a forward tilt angle to the main rotor mast to allow for zero control force in forward cruise flight. Faster ships have a greater angle.
