Sikorsky S-61 prototypes, projects and license builds

[Caravellarella]

Dear Boys and Girls, here is a picture with a caption in French of what I believe to be the Sikorsky S-61N full-size mock-up brought to the 1959 Paris Salon; it shows an aerodynamic saucer-shaped fairing covering the main rotor hub. The accompanying article describes the Sikorsky S-61N as being powered by three T-58 engines (like the Sud Aviation SE.3200 Frelon); is this correct for the S-61N design at this stage of development?

The picture comes from the 20th June 1959 issue of Les Ailes......

Terry (Caravellarella)

 

[Stargazer]

Slightly enhanced... (wish I could do better... :-[)

 

[Caravellarella]

Slightly enhanced... (wish I could do better... :-[)

Dear Stéphane, here is the same picture without Chicago Helciopter Airways titles added above the cheatline......

http://www.aerofiles.com/sik-s61n.jpg

Terry (Caravellarella)

 

[HeavyG]

I got to fly in one these bad boys when I left my FOB for the long trip back home. Looks pretty much like the one in the picture except without the rotor hub fairing and the inclusion of a thimble-shaped radome on the nose.

 

[RavenOne]

Has anyone got any pics of the H-3 gunship proposal and H-2 Tomahawk?

Cheers

 

[frank]

Unless it's different, I think the H-3 gunship is the S-67 Blackhawk (not Black Hawk, that's the H-60). For the Tomahawk: http://www.aviastar.org/helicopters_eng/kaman_tomahawk.php

Has anyone got any pics of the H-3 gunship proposal and H-2 Tomahawk?

Cheers

 

[RavenOne]

frank,


There was a proper S-61 gunship proposed as part of the AAFSS not just the S-67. According to Harding's US Army Aviation book, the fly off was at Edwards AFB with the H-2, the H-3 gunship etc etc

Cheers

 

[robunos]

There was a proper S-61 gunship...

I've sen an image of this, but I'm damned if I can find it!
ISTR it was an H-3 without the hull bottom, and an
undernose turret with a MG of some sort...
I know it's out there, but where??




cheers,
Robin.

 

[Stargazer]

Been trying to locate that one but I can't remember ever seeing it, myself. :-\

 

[Kiltonge]

Did Westland also obtain rights to manufacture the S-61R or just the boat-hulled 61D?

Just wondering if the 61R was ever proposed for UK requirements.

 

[TomS]

Did Westland also obtain rights to manufacture the S-61R or just the boat-hulled 61D?

Just wondering if the 61R was ever proposed for UK requirements.

I believe they only licensed the baseline S-61; several sources say Augusta was the only foreign licencee for the S-61R. If Westland did have an S-61R license, I'd think they'd have offered that instead of developing the Commando for troop lift.

 

[Kiltonge]

Cheers TomS. Yes, the Commando was the oddity that made me wonder.

As a tangent, found this in Flight whilst digging for info:

The [Westland] Wiltshire, also to fly this year [1960], will be an anglicised Sikorsky S-61 with twin [Napier] Gazelles.

http://www.flightglobal.com/FlightPDFArchive/1960/1960%20-%200065.PDF

There is a January 1960 reference to a triple-Gnome engined S-61 proposal; that shadows a Sikorsky offering for a triple-T58 installation for hot-and-high.

 

[Kiltonge]

Snippet from Flight noting that the S-61R had been evaluated by the Luftwaffe.

http://www.flightglobal.com/pdfarchive/view/1964/1964%20-%203002.html

Interestingly the latecoming S-65 was the one that snatched the contract.

 

[famvburg]

Weren't all of the S-61s boat-hulled?

 

[TomS]

Weren't all of the S-61s boat-hulled?

I guess it depends on how you define a boat hull. The S-61R had the rear ramp and a flatter, squared-off aft hull, rather than a tapered boat-tail as in the original design (It also did away wiht the outriggers in favor of sponsons, and switched up the landing gear arrangement from a tail-drager to a tricycle arrangement). The forward end did retain that boat-like stemline, though. And the R was still able to water-land because the hull was still watertight.

 

[famvburg]

I was always under the impression that even the Jolly Green Giant was amphibious. So it isn't?

 

[TomS]

I was always under the impression that even the Jolly Green Giant was amphibious. So it isn't?

That's not what I said. The S-61R/HH-3E could land on water -- the hull was waterproof and would float. But if you look at the original S-61, that hull has a v-shaped bottom with a distinct keel and chines where the bottom meet the sides. That's the boat hull, which makes for better stability and on water, and probably better take-off characteristics because it would unstick more cleanly (like a flying boat). The S61R has a flat bottom and a more rounded transition from the bottom to the hull sides, which made it less suited for water operations.


Of course, in practice, neither type did water landings very often so the difference isn't all that crucial.

 

[famvburg]

Ah, I see now.

 

[Kiltonge]

I assume that much of Sikorsky's hydrodynamic research into the boat-hull was licensed to Sud Aviation along with the gearbox and rotors when developing the Super Frelon.

The keel and chine shapes are pretty much identical, just scaled-up.

 

[Kiltonge]

China has opened preliminary talks with Sikorsky which may lead to the
placing of an order for S-61Ns. It is reported that although China might
have a military application for the helicopters they would be sold by
Sikorsky in standard civil S-61N form.

The company is reported by Reuter to be negotiating also with Romania
which is understood to be interested in licence-production of the S-61N.

http://www.flightglobal.com/FlightPDFArchive/1974/1974%20-%200173.PDF

 

[hesham]

New info for me,thank you Kiltonge.

 

[mil]

Why Sikorsky didn't use the Rotoprop system tested for S-61 by later helicopters.

 

[riggerrob]

Back in 1974, China May have been negotiating to build S-61s, but they never built any Sikorskys. Instead China bought licenses to build several French helicopters: Dauphin, Super Frelon, etc.

 

[riggerrob]

Yes, the Westland Commando always looked odd as a troop-carrier! The sill of the cargo door is waist-high on Akan standing beside it! How did fully-equipped Royal Marine Commandos climb on board? Consider that during the Afghan War, RMC wore 70 pounds of a armour, plus weapons, plus ammunition, plus water, etc. for one-day foot patrols!

 

[Jemiba]

Why Sikorsky didn't use the Rotoprop system tested for S-61 by later helicopters.

That system to my opinion was just a swivelling tail rotor, still using the same drivetrain,
as the conventional tail rotor. So it would have been limited to a relatively low power,
definitely not comparable to the pusher prop à la X2. And in the hover and when flying
at lower speeds, it still would have needed the tail rotor. And a swivelling gear for
really high power output in the extreme tail probably would be a heavy in a position,
where it shouldn't be.

 

[riggerrob]

The West German Navy bought 21 S-61s for search and rescue. I suspect that they bought them from Westland.
Meanwhile, the West German Army bought (twin-engined) Sikorsky CH-53s to haul soldiers. Some German CH-53s hauled NATO soldiers during recent fighting in Afghanistan.

 

[hesham]

Why Sikorsky didn't use the Rotoprop system tested for S-61 by later helicopters.

Nice find Mil.

 

[TomS]

The West German Navy bought 21 S-61s for search and rescue. I suspect that they bought them from Westland.

Yes, the German Sea Kings were Westland Sea King Mk. 41 models. There were actually 22 ordered initially.

 

[TsrJoe]

Sikorsky S.61N (with short fuselage ?) in BEA. markings, manufacturers display model

 

[riggerrob]

Dear Tsr Joe,
Your photo looks like the standard S-61 fuselage length.
Sikorsky built S-61L to carry passengers. Most worked hauling crews to off-shore oil rigs. They were eventually replaced by Super Pumas and now by Sikorsky S-92.
All the extra length is in the forward fuselage between the engines and cockpit.
Ironically, a few S-61L have had the fuselage extension removed o reduce weight as they are now working at heli-logging.

 

[Hood]

They probably just painted up a standard Sea King model for promotional purposes, perhaps they didn't have any correct S.61N promotional models at the time?

 

[LOLCOS81]

frank,


There was a proper S-61 gunship proposed as part of the AAFSS not just the S-67. According to Harding's US Army Aviation book, the fly off was at Edwards AFB with the H-2, the H-3 gunship etc etc

Cheers

 

[TsrJoe]

Sikorsky S.61N mockup, note rotor hub fairing (also displayed at LeBourget, 1959) http://1000aircraftphotos.com/PRPhotos/SikorskyS-61.htm
& retouched image in BEA. markings for press release (Aeroplane, May 1963)

I would appreciate any thoughts as to the colour scheme of the mockup ? a tinplate toy of the period suggests orange and blue cheatline ?

cheers, Joe

 

[Pioneer]

There is a January 1960 reference to a triple-Gnome engined S-61 proposal; that shadows a Sikorsky offering for a triple-T58 installation for hot-and-high.

That makes a lot of sense and I would think it's viability in 'hot and high-altitude operations' would have made the design much more successful on the world market.


Regards
Pioneer

 

[francescoranchi]

Any documentation/ technical data or drawing of the rotor prop s61?

 

[Kiltonge]

Agusta AS-61N-1 Silver: 1982, S-61N shortened by "about 4ft", fuel increased to 766 gallons, seating for 24 in offshore config . First flight 25 July 1984. Originally planned to replace T58s with CT7s but Alfa Romeo did not complete the work required to modify the CT7. Two built, cns 6401 and 6402; the latter became M39-02 with Royal Malaysian Air Force.

Helipro S-61 'Shortsky': 1995, S-61L/N shortened by 1.27m ahead of intakes. Sponsons removed, payload increased by 450kg. Six converted for VH Logging and Canadian Helicopters. First flight February 1996 as N301Y.

Helipro S-61 Offshore Short: 1999, S-61N shortened as per the Shortsky but sponsons retained. One conversion completed by Rotor-Dyne Systems of British Columbia. First flight 12 February 1999.

Carson S-61T Triton: 2008, SH-3D ( 12 ) and S-61N ( 7 ) re-lifed by Sikorsky and modified with modular wiring looms, Cobham avionics & glass cockpit and composite rotor blades.

 

[francescoranchi]

Any technical documentail. Or drawing of the s66 rotorprop

 

[TsrJoe]

Agusta AS.61 N1, manufacturers display model, IHM. Weston-super-Mare

 

[TsrJoe]

Westland/Sikorsky WS.61N Wiltshire, manufacturers display model, IHM. Weston-super-Mare, 2017

 

[TsrJoe]

Westland/Sikorsky WS.61N Wiltshire .. ref. Westland Sea King, Lee Howard, Haynes Publishing, 2014