If I HADA euro...


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1 February 2007
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...for every high-speed rotorcraft idea...

Spain's national aerospace technical institute INTA has unveiled plans to fly an unmanned prototype of its HADA - Helicopter Adaptable Aircraft - concept.

See the release (in Spanish) here:


Basically HADA is a stopped-rotor design that folds the blades and unfolds a wing for forward flight. The two small images on the INTA site show a notional attack aircraft with two-blade folding rotor, pop-out wing and a propeller at the rear, aft of the fan-in-fin tailrotor.

They plan to fly the UAV version in 2009, it seems.


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LOL - The proverbial pendulum seems to be swinging back toward dabbling with high speed rotorcraft again. It will be interesting to see how it all pans out between the old school "go with what you know" in active operations, or if the potential of 'long war' will see the development of new systems. I remember reading somewhere recently that Bell Helicopter was relooking stop fold. Folding rotor systems are a maintainers pain in the arse when they are not turning. Thats gonna take some interesting hydraulics or electrical work I suspect.
One hates to come over all Dionysus Lardner about this stuff, but when one has reached the advanced age that CN and LO have attained, you start to wonder if The Big Guy really intends aircraft to take off vertically and then do more than 160 knots without breaking a major sweat.

Stop-folds always remind me of somebody trying to open and close a cheap umbrella on Oxford Street on a gale-force day.
It's sad, I know, but I lay awake last night trying to think of a single rotor that has been stopped in flight. I know of one that was started in flight - the Herrick thingy - but stopped? In a windtunnel, perhaps?

Then I spent the rest of the night thinking about what stopping a rotor in flight actually involves.
SOKO from former Yugoslavia (SFRJ) also had a high-speed rotorcraft idea!


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You'll need even more straitjackets, quite a lot only for all those
Sikorsky engineers ...
(from aviationweek 10/1960, 9/1967, 19/1968)

Seems, the idea of the stoppable/stowable rotor found a lot of fans,
at least in the sixties !


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Wasn't the rotor of the Sikorsky S-72 RSRA supposed to be stopped in flight in its x-wing version?

I don't know if it ever did stop, tho...


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AFAIK, it never flew with rotor, just as a conventional aircraft, but
I think, stopping a rotor in flight still is a different story, to folding
and stowing it in flight, not to mention unfold it !
Radeks said:

SOKO from former Yugoslavia (SFRJ) also had a high-speed rotorcraft idea!


That's an interesting project, is there anymore information about it? There are certainly quite a lot of interesting projects from the ex Warsaw Pact nations that we know nothing about.
there is not much information about this project and this picture is from Aerosvet magazine. The project was called ELH (Experimental light helicopter - Eksperimentalni laki helikopter). His speed should have been 410km/h at 4000m and because SOKO was buildnig Gazella helicopters, ELH was suposed to have a lot of parts and components from Gazella. Estimated funds needed for this project were around 14 million dolars and the first flight was suposed to be in 1994.

P.S. Yugoslavia was never a part of W.P.

Thanks for the information. Does the magazine 'Aerosvet' feature unbuilt project aircraft from time to time?
Radeks said:
SOKO from former Yugoslavia (SFRJ) also had a high-speed rotorcraft idea!

Also,here is the whole two pages.


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Hesham already posted this article a couple of years ago, I'll just add some explanations, from said article.
SOKO ELH (Eksperimentalni laki helikopter - Experimental Light Helicopter) was designed in order to beat the Lynx; top speed was supposed to be 410 km/h at the altitude of 4000m. They have manufactured the Gazelle helicopter under license for almost 20 years and they intended to use as much as possible of it's technology in the new design. Main rotor was to be used only in hovering or in low speed (less than 100 km/h) modes. If proven promising, they wanted to implement this design in other types of helicopters. The construction of the first prototype was scheduled for 1993 and the first flight was expected in 1994.

wrong thread, please delete this post.

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