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AirLander take off then 2nd Flight Mishap

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AirLander take off then 2nd Flight Mishap

Old 1st Sep 2016, 20:36
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Originally Posted by CaptainSandL
1. If it slows down sufficiently will it actually stall or simply sink; or are they the same thing?
If the wings are rigidly attached to the body, then for them to reach the AoA for a stall in level flight would presumably require the entire aircraft to be pitched up correspondingly.

Otherwise, as it slows down, it simply stops flying and becomes an aerostat, albeit a heavier-than-air one, with only the downward thrust from the vectored fans to (partially) offset the negative buoyancy.
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Old 1st Sep 2016, 20:41
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Airships were traditionally lighter than air which meant you had to permanently lasso them down with an army. Airlander can effectively make itself heavier than air, hence minimal groundcrew requirement and a more rugged proposition out in the wilds.

It can hover at 0kts without stalling - there are pictures of it floating in the hangar for testing prior to opening of the doors.

It makes a rolling takeoff V1/VR 30kts:

Pilot published this big feature recently
http://www.pilotweb.aero/features/the_airship_redrawn_will_this_revolutionise_air_travel_1_463 4083

How it takes off with an extra 10T payload I don't know. You don't use the ballonets for this to suddenly make it less dense, only for trimming and controlling the internal pressure of the envelope.

We're all scratching heads a little over this. To be fair they've had decades to understand the theory and we're all playing catch up.

An earlier question related to the bow thruster above the nose, this is on the Airlander 50 CGI image but not on the 10.

The unusual attitude that was adopted prior to the incident was deliberate. I'm told by airship guys that they do this to punch through an inversion, which can critically affect the buoyancy. I wasn't there but did they go around off the first attempt & tried this second time round? Or maybe it was on the test flight plan.

The speed was low but there just wasn't a flare, only HAV will know why.

Fingers crossed to see it back up there this winter.
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Old 1st Sep 2016, 20:52
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............Although how it uses this airfoil shape to get airborne from a static start is a question I have not seen answered.
Presumably, they use the vectored thrust fully upwards to lift the aircraft off the ground, at almost no forward speed.

At a suitable height, I guess they progressively move the vectored thrust rearwards to start the aircraft moving forward, and at a certain forward speed the body produces enough lift to take over from the vectored lift, so in full 'flight' the vectored fans only need to provide forward thrust - like a Harrier I suppose ?

Using the vectored fans at max power to produce lift must consume fuel at a huge rate though, so I guess they only do this to get airborne - the transition to forward flight and body lift then radically reduces the power required and therefore the fuel consumption?

.
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Old 2nd Sep 2016, 06:10
  #304 (permalink)  
 
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Latest from HAV:

https://www.hybridairvehicles.com/ne...st-august-2016
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Old 2nd Sep 2016, 06:36
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It'll never work...
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Old 5th Sep 2016, 21:12
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In the latest (October 2016) issue of Consumer Reports magazine, investigative journalist Edward Humes opined that within 80 years, "...giant solar airships and airliner sized drones will move other cargo across the globe."

So perhaps the future for airships maybe bright after all, at least for solar powered ones...

Last edited by evansb; 6th Sep 2016 at 06:38.
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Old 8th Sep 2016, 09:04
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operating envelope

"The high approach resulted in the aircraft hovering 120ft above the ground, something that was “outside the normal operating envelope”."

https://www.flightglobal.com/news/ar...flight-429124/
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Old 8th Sep 2016, 14:34
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Quite windy in my part of the country today, should be interesting to see its performance on anything but a calm day. Perhaps they should have one of those nets, that you see at golf ranges, surrounding the airfield.
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Old 8th Sep 2016, 17:53
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Hybrid Air Vehicles (HAV) said repairs will take about three to four months to repair and test and were confined to the hull and the front part of the cockpit, but specialist tools needed for some of the repairs had been scrapped by the US Army and needed replacing, which would "contribute significantly to the estimated overall time required".
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Old 8th Sep 2016, 20:47
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There might be some work for these airships airlifting those huge windturbine blades to remote windfarm locations without close access roads. Airship would spend a few weeks or a couple of months on location setting up a whole bunch of windmills, bringing the blades in from a shipping or air transport hub, so the ferry time in getting the airship to the general area would be amortized.

Edmund
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Old 8th Sep 2016, 21:20
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Good thinking, but there is a lot of preliminary work needed (installing a concrete foundation) then intricate positioning using cranes which seems to need at least a gravel road.
The best use would be lifting the towers from the dock to the installation site (which often needs careful planning of highway routes for long vehicles).

We had a vehicle that ran off a country road and fell into a ditch (due to the length of the road vehicle negotiating a bend):-

Wind turbine recovery from Northumberland road 'hurting trade'.
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Old 9th Sep 2016, 00:05
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If it can't hover at low level would it really be suitable for errecting turbines? Can it maintain station laterally? Eg in wind that change direction?
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Old 9th Sep 2016, 19:13
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Why wouldn't it just turn to point into wind?
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Old 9th Sep 2016, 19:17
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I think edmundronald was just suggesting transporting the wind turbines to the site rather than lifting them into place.
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Old 9th Sep 2016, 19:46
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Originally Posted by G-CPTN
You are all wrong.
When the pilot applied the brakes before landing, the helium all rushed to the front, causing it to be heavy and causing the nose to droop.
While you might jest here, a similar thing does happen. If you have a helium balloon floating in a car, and you brake hard, the balloon goes backwards. The same happens with brains - if you have a car crash the brain hits the back of the skull, not the front.

Why? Because with the floating balloon, the heavier air moves forwards and pushes the lighter helium balloon backwards. Same with brain fluids, which are heavier than brains. Not sure if any of this applies to airships, whise ballonettes should constrain the differential gas mixtures.....

Last edited by silverstrata; 9th Sep 2016 at 21:45.
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Old 10th Sep 2016, 01:26
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Originally Posted by G-CPTN
I think edmundronald was just suggesting transporting the wind turbines to the site rather than lifting them into place.
Yes, I was thinking of a wind-turbine *farm* when a bunch of them may need transporting from the nearest river, port, or heavy access road. Of course the site needs infrastructure, but maybe even cranes etc could be brought in in pieces by airship.

I had no opinion on an airship replacing a heavy lift crane; in fact in view of possible wind gusts at a site selected for wind, the idea makes me nervous
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Old 11th Sep 2016, 17:24
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Originally Posted by Tourist
Yes, if the Germans and US can't manage it, what chance have some Brits got?

Nice attitude.

see WW2.
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Old 25th Nov 2016, 19:53
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The Airlander is being reported on CNN as 'fully assembled' and ready for flight...!


World's largest aircraft prepares to take off - CNN Video


Some interesting footage (albeit small), inside the cockpit and the test pilot talking about it.
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Old 25th Nov 2016, 20:27
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...old video of pre-1st flight launch
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Old 25th Nov 2016, 22:13
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Sorry, I should have realised that I didn't mention the 'weirdness' of why CNN is running this article now...
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