Sikorsky S-58 and Westland Wessex

[Weaver]

One thing I've always found interesting is that while the Wessex was turbine powered, the H-34 was piston powered. An S-58T in US service would be a good whiff.

Air-craft models do an S-58T conversion:
https://www.air-craftmodels.com/product-page/aca72118-sikorsky-s-58et-klm-helikopters-resin-conversion-set-1-72nd

They also do an auxiliary fuel tank for the Wessex, and skis for the S-58, although the latter work out a bit pricey as they only come with the full Operation Highjump conversion. Still, only one of the two S-58 airframes in that conversion had the skis, so you could always nick them for a Wessex and build an S-58 with the other one.

One of the S-58s in that set also had something I've never seen before: a V-shaped lower main wheel strut that pivots off the fuselage at two points like a car's wishbone suspension, instead of the normal S-58/Wessex setup, which is a single tube that works more like a trailing arm.

The "V" landing gear was the later
production type for the S-58/H-34
and has also been retrofitted to
earlier models. From looking at
photos it appears that it's only the
Wessex series that didn't make the change.

Cheers Jon - very interesting! 

Now that I'm looking for it, I can see that Air-Graphics' S-58T conversion has the V-gear as well. So that's another subtle what-if you could do to the Wessex: have the RAF upgrade the undercarriage in similar fashion to the Americans. The Antarctic S-58 with the V-gear is from 1970, so the timeframe lines up.

Looking at the auxiliary fuel tank, it uses an F-84G drop tank, which makes sense for the US but less so for the UK. Still, the bracketry's the main thing (you do NOT want to scratchbuild that rat's nest of struts and pipes!) and you can always use a different tank. My first though was that the big Hunter tank would work, but havin glined the bits up, it's too long. The teardrop-shaped F-84 tank is already hard up against the main undercarriage and the tubular Hunter tank (both 230 gal) is longer and thinner. However the little 100 gallon Hunter tank should fit nicely. A bonus from a modelling POV is that a plastic tank nicked from a kit will be lighter and put less strain on the delicate strut work. That argument hold true for the F-84 tank too, actually: it's not like cheap Heller F-84Gs are hard to find, and you can always build them with bombs on the pylons...

[Weaver]

Came across an interesting bit of
trivia related by a Vietnam vet USMC H-34D pilot, evidently the H-34 was still flyable if the tail rotor malfunctioned or was lost. The S-58 has so much side area that when allowed turn to about 45° off the direction of flight it would stabliize and you could keep flying and land safely.

It was also able to land in surprisingly small spaces. The pilots would come in hot, descend in a corkscrew using full power but letting the machine rotate around its centre a few times. Once close to the ground they'd straighten out and let the tail drop so the tailwheel would touch first, the wheel acting as a "feeler", then drop onto the main gear. The wider track V-type landing gear, larger wheels/tires and stronger oleo absorbing the shock.

You can do a lot by modifying the main rotor flow around the tail boom. The most extreme example is, of course, Hughes NOTAR systems which blow air from a slot in one side of the boom to effectively turn it into a "blown wing", "flying" sideways in the downwash. There's a less extreme mod for Hueys called Fast Fin. It consists of two long strakes on the left side of the tail boom that disrupt the airflow around it, cause differential pressure, and thus reduce the load on the tail rotor. A lighter loaded tail rotor absorbs less power, so there's more for the main rotor, so the helicopter flies faster. It also has greater control margins, because there isn't so much permanent "rudder" trim on the tail rotor.

[jcf]

One thing I've always found interesting is that while the Wessex was turbine powered, the H-34 was piston powered. An S-58T in US service would be a good whiff.

Air-craft models do an S-58T conversion:
https://www.air-craftmodels.com/product-page/aca72118-sikorsky-s-58et-klm-helikopters-resin-conversion-set-1-72nd

They also do an auxiliary fuel tank for the Wessex, and skis for the S-58, although the latter work out a bit pricey as they only come with the full Operation Highjump conversion. Still, only one of the two S-58 airframes in that conversion had the skis, so you could always nick them for a Wessex and build an S-58 with the other one.

One of the S-58s in that set also had something I've never seen before: a V-shaped lower main wheel strut that pivots off the fuselage at two points like a car's wishbone suspension, instead of the normal S-58/Wessex setup, which is a single tube that works more like a trailing arm.

The "V" landing gear was the later
production type for the S-58/H-34
and has also been retrofitted to
earlier models. From looking at
photos it appears that it's only the
Wessex series that didn't make the change.

Cheers Jon - very interesting! 

Now that I'm looking for it, I can see that Air-Graphics' S-58T conversion has the V-gear as well. So that's another subtle what-if you could do to the Wessex: have the RAF upgrade the undercarriage in similar fashion to the Americans. The Antarctic S-58 with the V-gear is from 1970, so the timeframe lines up.

The gear change was fairly early, here's a photo of UH-34D 148788 taken in 1964, the helicopter was built
in 1961.

[PR19_Kit]

It was also able to land in surprisingly small spaces.

So could a Wessex, little more than its own rotor diameter in fact.

When I was on my last Naval Aviation course as a cadet at Culdrose, I was with 700H NAS who were the trials unit for the Wessex HAS1. On one of the flights I made with them the Capt. did an autorotation descent down to RNAS station Predannack on the Lizard, but he omitted to tell me that he was going to do it! 

Talk about frightening!   

Obviously it worked or I wouldn't be writing this, and it came down vertically, no flaring or anything, and the last few feet felt as if it landed on a big cushion. 

[Mossie]

I pretty sure I witnessed this as a teenager on my paper round. A yellow RAF rescue Wessex came very low, turned tight and touched down in a small paddock in the village, very close to some houses. I assumed it was an emergency.  It stayed for several minutes with rotors turning and then took off and disappeared again. Why it landed in there and not in one of the nearby fields, I have no idea.

[Weaver]

Of course when it comes to armament, there's always the DIY approach:

[Weaver]

A very simple Wessex/S-58 whiff, which might slip unnoticed past many a JMN, is to cut a second door into the port side.

The only trouble with that is that the Wessex has it's seats on the outside of the cabin facing inwards, nine to port, five to starboard behind the door and one in front of the door. Add another door and you lose three seats. Not easy to see how you'd claw them back either. You can't put seats facing forwards or backwards against the front or rear bulkheads because there are maintenance access doors in them. If you put two rows of nine seats in down the middle, back to back, then you lose the ability for every passenger to exit through either door.

[Weaver]

Here's a colour close-up of the armament platform. It could carry AS.11s in either position, and AS.12s on the outboard stations:

[PR19_Kit]

Of course when it comes to armament, there's always the DIY approach:

I wonder just how many Queen's Regulations they're infringing there. Must be almost in double figures. 

[Weaver]

At last! Post #64 on this thread: https://www.secretprojects.co.uk/threads/british-armed-helicopters.8808/page-2 has official diagrams of the Wessex armament system, as clear as you could wish for.


(More images in the thread)

Interestingly, the 2" rocket pod seen on these mountings was split horizontally into two parts, each with seven rockets. Scouts/Wasps carried the seven-round version but Wessexes carried the 14-round one.

[jcf]

It was also able to land in surprisingly small spaces.

So could a Wessex, little more than its own rotor diameter in fact.

When I was on my last Naval Aviation course as a cadet at Culdrose, I was with 700H NAS who were the trials unit for the Wessex HAS1. On one of the flights I made with them the Capt. did an autorotation descent down to RNAS station Predannack on the Lizard, but he omitted to tell me that he was going to do it! 

Talk about frightening!   

Obviously it worked or I wouldn't be writing this, and it came down vertically, no flaring or anything, and the last few feet felt as if it landed on a big cushion. 

The retired Marine pilot wrote that when he was originally assigned to the UH-34 he was
dissapointed to be flying the "rattle bucket" but later when the machines in his squadron
were replaced by the CH-46, he wished they'd kept them because he preferred it to the
Phrog, and the Huey that he also flew.
If a turbine version of the S-38/H-34 had been produced for the US military the Marines
would probably have loved it, based on that Marine pilot's comments he would have for
sure*, and would have kept using it through the '80s, if not later. It would have been a
perfect fit between the Huey and CH-46, especially continuing in the SAR role.

*Well, comments and the fact that he personally owned one that he flew regularly.

[Weaver]

If a turbine version of the S-38/H-34 had been produced for the US military the Marines
would probably have loved it, based on that Marine pilot's comments he would have for
sure*, and would have kept using it through the '80s, if not later. It would have been a
perfect fit between the Huey and CH-46, especially continuing in the SAR role.

The UK retired its last SAR Wessex HC.2 in 2003...

[jcf]

The French used armed H-34A gunships in Algeria, various MGs and 20mm cannon firing
out the sides of the helicopter. They also experimented with rockets.

In the early '60s the USMC used UH-34D armed with the TK-1 (Temporary Kit), two M60
MG and a rocket pod on each side. This was before the "official start" of the war in 1964.
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[Old Wombat]

Of course when it comes to armament, there's always the DIY approach:

I wonder just how many Queen's Regulations they're infringing there. Must be almost in double figures. 

It's RAN FAA, Kit - No-one expected us to follow the rules!     

[jcf]

Going back to the T58 engined HSS-1F, it was built as an engine testbed for the
S-61 program.
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It's an interesting contrast to the PT6 Twin-pack of the S-58T and the Coupled-Gnome of the Wessex, which is, for all intents and purposes, basically a T58 twin-pack.
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