PPRuNe Forums - View Single Post - Shipboard Rolling Vertical Landing - The saviour of Dave-B?
Old 12th Sep 2008, 22:55
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DBTW
 
Join Date: Jul 2008
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Sorry to come so late to this thread and maybe it's already been raised.

Haven't seen it in my quick scan so I'll just make the point most vertical landings on carriers are made with the ship steaming into wind, so the wind over the deck is often quite high. This means, whilst the piloting technique used is definitely VL, the effect and benefit relative to the stationary planet is that of an RVL. IE any wing lift from wind is always aiding jet lift and therefore potentially increasing bring back loads.

This is particularly noticeable if you compare the Harrier I (less wing lift) approaches to the Harrier II approaches. The big throttle movement during the final transition from wing borne to jet borne flight in a Harrier I happened around 90 knots, whereas it was much later in the approach in a Harrier II. That's why the Harrier II youth used to enjoy the rudder inspection in their early approaches because they missed the throttle up with all the excitement of seeing the pitching/rolling boat!

To my mind, along with deck space issues, creeping and running VLs are avoided in both Harrier models because of weak brakes and slippery flightdecks. There is also the issue of manoeuvring within the 30-120 knot speed range with the Harrier's intake momentum drag stability issues. In a normal ship board VL, where you could be seeing indications of 60 or 70 knots anyway, those problems were avoided simply by keeping the vane straight and the AoA under control. If these problems are overcome then there should be no issue for the replacement jets doing CVLs and RVLs if it helps. It is slightly less flexible because more deck space will get taken up during the landing phase.

Remeber most innovation is brought on due cost. STOVL came about because countries couldn't afford conventional carriers. It could be said that because everybody is so rich now there is no reason why we shouldn't all go back to them. Having lived with both types of carrier though, I believe the desire to return to conventional carriers or "semi" conventional with catapult or arrester gear options really only complicates something that is very simple. And to my mind, innovation is moving forward whereas going back to something is not. STOVL, including CVL and RVL techniques, adds flexibility to the launch/recover options. Adding launch/recover machinery reduces flexibility by making the aircraft more dependant on mum. (IE if the machinery doesn't work the aircraft don't fly/become scrap metal)

Let new aircraft technology close the gap on the perceived (by some) performance benefits of conventional over STOVL aircraft and then move towards shorter runways on land as well.
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