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In more recent years, VTOL (Vertical Take-Off & Landing) aircraft have become fairly popular and are used in some notable air forces (such as the USA and the UK). I was wondering if these aircraft could land on something like the helipad many big boats like cruise ships have or even rooftop helipads like what many hospitals have.

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    $\begingroup$ 1969 is a broad definition of "more recent years" :-D The UK introduced the Harrier before Neil Armstrong stepped on the Moon. $\endgroup$ Commented May 1 at 9:48
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    $\begingroup$ There's barely a hundred F-35B's operational... way down from 278 Harriers and 232 Yaks at the 1980s heyday of VTOLs. $\endgroup$
    – Therac
    Commented May 1 at 11:33
  • $\begingroup$ Also a 'notable navy', I think? $\endgroup$ Commented May 2 at 20:31

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Not necessarily

The two key elements are aircraft mass, and how that mass is kept aloft.

You can probably get a Chinook onto the landing pad of a cruise liner, but you would want to check first if the structural supports under it can take the 10+ tonnes rather than the 1 tonne jet ranger it was probably designed for.

Helicopters support themselves by moving air through the rotor disk down, so larger helicopters produce more air movement which may cause damage to surrounding fixtures.

This is relevant for VTOL aircraft since those using propellers like the V-22 Osprey are normally running smaller disk areas at higher velocities, being more likely to damage nearby structures. Worse are jets like the Harrier or F-35 which are heavy (10-20 tonnes) and supported by quite narrow cross sections of air at very high velocity - for the aft stream this is very hot engine exhaust likely to melt or burn plastic or wood surfaces.

One of the early Harrier pilots notes doing an early public demo where intended landing area had been covered in metal planking but during approach a channel was carved into the grass by the airflow, that then caused parts of the planking to lift.

There may also be issues with the more restricted control authority of a VTOL aircraft in hover compared to a helicopter in dealing with turbulence or other effects of nearby structures, along with worse visibility downwards.

In an emergency you can probably land a VTOL aircraft onto an standard helicopter pad (especially if doing so because low fuel eg lighter), but before doing so regularly some non trivial re-engineering would be wise. Noise may also impact feasibility of regular use.

And certainly there will be marginal areas for helicopter landings (eg soft surfaces or enclosed trees) that would not be possible in a VTOL aircraft that you want to fly again.

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  • $\begingroup$ Harriers cool their exhaust with water, so are less damaging than you would expect. $\endgroup$
    – fectin
    Commented May 1 at 13:40
  • $\begingroup$ As a concrete example, news.usni.org/2016/03/22/…; "The aviation-centric big deck was commissioned in late 2014 but required additional work to take the day-to-day strain of operating the short takeoff and vertical landing (STOVL) strike fighters that will operate from the ship." $\endgroup$
    – ceejayoz
    Commented May 1 at 19:09
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    $\begingroup$ for another concrete example of how it can go wrong, see this example where a USAF Osprey taking off destroyed the helipad at an English hospital: cambridge-news.co.uk/news/cambridge-news/… $\endgroup$
    – Tristan
    Commented May 2 at 9:50
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    $\begingroup$ @Tristan You beat me to it! I was here to post the video: youtube.com/watch?v=vSDMzeIOb-8 Strictly speaking, the question asks "Can it land...?" And really in this particular case, the answer is "Yes, although only the one time!" $\endgroup$
    – ThaRobster
    Commented May 2 at 9:53
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You mention air forces but don't specifically restrict the question to current military types, so considering commercial VTOL aircraft this is exactly what Joby and other air taxi companies are planning. These could be employed by the military, though I don't know of any plans.

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