Talk:Sikorsky S-76/Archive 1

Archive 1

Infobox or WP:Aircraft's spec template?

The infobox, and the table that floats the pics on the right side of the page, makes the page long. Wondering how other editors feel about how that may affect the readability of the article? (Born2flie 08:32, 17 September 2006 (UTC))

Image added

Sikorsky S-76A of Helijet Airways on scheduled service at Victoria, BC in 1996

As per Wikipedia:WikiProject_Aircraft/page_content#Images I suggest that this new image be removed from the article for three reasons:

1. the technical image quality is very poor - washed out colours, poor focus, etc
2. The primary focus of the picture is of a woman posing in front of the aircraft and not the aircraft and
3. The complete aircraft cannot be seen in the photo.

This is really a "tourist photo" and not of the normal image or subject quality one would expect in an encyclopedia. If anyone objects to removing it please indicate your reasons. - Ahunt (talk) 15:22, 15 February 2009 (UTC)

Sure. Not like that's the only image in the article. -Fnlayson (talk) 15:55, 15 February 2009 (UTC)

Lacking any other objections I will remove it. - Ahunt (talk) 23:24, 16 February 2009 (UTC)

Use of "Spirit" name

The use of "Spirit" as the name of the S-76 was discontinued in 1980 as a result of a conflict with a trademark owned by another firm. I have sited the memo (of which I have a copy) by which employees were told of this discontinuation. Aeroweanie (talk) 02:55, 9 June 2011 (UTC)

I'm sure this is true. However, references need to be publicly available to be meet verifiability requirements, e.g. WP:SOURCES, WP:RELIABLE. There should be some media article covering this. Looking... -Fnlayson (talk) 05:34, 9 June 2011 (UTC)

English

The English in this article needs a lot of tidying up - it's obvious that it's not a native-speaker writing - which isn't a problem in itself, but the English in an English-Wikipedia article should be real, correct English. Maelli (talk) 11:13, 6 July 2011 (UTC)

I agree and have fixed it. Have a look and see if that is an improvement. - Ahunt (talk) 12:16, 6 July 2011 (UTC)

Definitely, and thanks for citing the specs. I meant to check my books when I got back home for that, but you got it. -Fnlayson (talk) 14:57, 7 July 2011 (UTC)

I figured while I was fixing the language that the uncited specs could be updated with cited specs and the new template as well. - Ahunt (talk) 16:42, 7 July 2011 (UTC)

Article is not as neutral as it should be

The "Design and Development" section of the article contains various praises about the S76 Spirit highlighting performance aspects of the then new design ("In 1982 this model set class records for range, climb, speed and ceiling), But in the real life, in hot and humid climates like the one in the Campeche Bay offshore platforms, the S76 performance left a lot to be desired, requiring PEMEX pilots to reduce the number of passengers boarding the helicopter by one or two, because the design was very marginal in the 100F-plus ambient temperatures in Ciudad del Carmen heliport. The article should mention that the repowering of the original design with French made Turbomeca gas turbines was not only a huge improvement over the underpowered original ones, but a needed one (one thing is to set some records during factory tests, another is to meet the design objectives in the real life on the field). Another aspect related to the article lack of neutrality, is the absence of a short description of the accidents of the type, which are minimized as "INCIDENTS" when those were crashes, thus deserving to be described under the title of "Accidents", and one of them is still being actively discussed in the legal action field, with possible implications against the manufacturer. Many other Wikipedia aircraft articles contain relevant information on the Accidents section in addition to the links. — Preceding unsigned comment added by 192.100.180.19 (talk) 21:38, 5 October 2011 (UTC)

The section title is fixed. As far as the performance deficiencies go, if you can supply reliable refs then this can be added. As per WP:V we need more than rumours and blog postings to amend the article. - Ahunt (talk) 21:48, 5 October 2011 (UTC)

High and hot conditions hurt aircraft performance in general. Maybe mentioned, but I see no need for a lot of detail here. -Fnlayson (talk) 21:53, 5 October 2011 (UTC)

The subject is not the unavoidable performance reduction at hot or high (or hot and high) places, but the plainly insufficient power of the original design: even the manufacturer choosed to replace all the original engines in the numerous unsold units (according to the article)... Now, any experienced helicopter mechanic that worked on those models around 1982 was aware that the original engines were barely reaching the necessary power in hot conditions even at sea level, one of them explained to me that the easiest way to check that the helicopter engines were close to their thermal limits was to carefullly observe the color of the exhaust gases, which showed a very visible sign of darkening while being subjected to the load at take-off, producing the same look that older aero gas turbines (like those visible trails of soot that the old Boeing 707 left during take-off) produce at high power demand because the engine controller commands additional fuel into the combustion chambers. I cannot provide you with written proof of that fact at this moment, but lets just compare the power specifications of the original engines (Allison): 641 hp (each) vs. 922 shp for the Turbomeca... That´s MORE than 40% more (if the Fuel consumption is an important consideration, a larger than necessary engine will be less economical, both in fuel usage AND initial cost, therefore the fact that even Sikorsky decided to re-engine the unsold S76's tell it all: the initial engine selection was wrong, that's it. My opinion is based on actual experience on this engine, because I worked with PEMEX (the national oil company) that HAD quite a few Spirits in 1982... and ended getting rid of all them (preferred to use mainly Bell-212's and Aerospatiale Pumas instead, those were plenty powerful and responded accordingly. The comment on pilots having to unload one or two passengers are due to myself having to disembark at least on three circumstances. The late captain Rafael Garibay, Chief pilot for PEMEX' aerial transport unit fliying to Campeche Bay platforms at that time explained to me that the TIT (Power turbine Inlet Temperatures were just too high for a repetitive condition (every Take-Off from Ciudad del Carmen around noontime during hot season). — Preceding unsigned comment added by 192.100.180.19 (talk) 22:32, 6 October 2011 (UTC)

Lots of early versions of aircraft have been under-powered and had this rectified later on with growth versions. The Bell UH-1A suffered this fate, for example. The subject can be included in the article, but, by policy, we can't use original research, we need verifiable references to put it in. - Ahunt (talk)

FlightGlobal's archives have every issue they've published, so we might be able to find something about the issue in their archives from the 1980s. I don't know waht other aviation periodicals have online archives from that period. - BilCat (talk) 23:23, 6 October 2011 (UTC)

Possibly, but only if someone actually wrote a criticism of it! - Ahunt (talk) 23:25, 6 October 2011 (UTC)

True, if no one wrote something, we'd never find it! ;) - BilCat (talk) 23:42, 6 October 2011 (UTC)

I found something here, but it doens't place any blame for the problem. - BilCat (talk) 00:02, 7 October 2011 (UTC)

Excellent find Bilcat! While the short article on FLIGHT-International Oct 3, 1981 is mentioning (or basing) the repowering to be focused on a need to meet a given specific requirement, the information on that note makes clear the manufacturer was selecting the replacement from several turbine makers. The importance of this information is that the figures for power outputs for the several contenders range from 900 to 1,300 shp, compared to the original engines at 650 shp... I remember i must have an aviation magazine somewhere in my house that has an advertisement from Turbomeca, boasting the performance increase in the S76 in an enthusiastic manner, mentioning the number of conversions being performed at the time. At least this is suggesting lack of power is not only an opinion. amclaussen, Mexico City.

Well I meant an actual criticism of the earlier models saying that they were deficient, as opposed to just the normal flow of press releases offering newer and higher powered models. - Ahunt (talk) 00:09, 7 October 2011 (UTC)

I realize that. Anyway, there is a difference between a model not meeting its design specifications, hence being "deficient", and the model being used in roles and conditions for which it was not specifically designed for. The IP's case appears to be more of the latter, and it seems Sikorsky recognized that more power would address those needs, and provided it. - BilCat (talk) 00:23, 7 October 2011 (UTC)

I agree. Having worked as a helicopter pilot and test pilot for many years, it seems to be a common problem that a manufacturer designs a helicopter to carry a load of x lbs to an altitude of y feet and then all the operators try to use to to carry a load of x+1000 lbs to an altitude of y+5000 feet and the aircraft gets a bad reputation. - Ahunt (talk) 00:52, 7 October 2011 (UTC)

Absolutely, Ahunt! It is a well known fact that high temperature, high altitude, high humidity, or any combination of the three decreases the performance of any turbine engine. Additionally, it has not been established that the re-engining of the aircraft was because a deficiency was identified, or because an industry requirement for more power was a result of the aircraft's popularity; in order to allow it to be used more effectively in an environment other than what the manufacturer originally designed the aircraft for. --Born2flie (talk) 18:39, 7 October 2011 (UTC)

Overloading it as a practice by the operator was definitely NOT the case observed in the fleet of PEMEX, the Sikorsky S76 airframe has 13 passenger seats, mexican workers travelling to platforms average less than the typical american passenger by quite a few pounds; even with less than full fuel, the S76 performance at sea level in Ciudad del Carmen (Temp between 95 and 104 F from 11:00 to 16:00, april to august) was so close to critical, that the crews had to routinely disembark one or two passengers. When cargo or some spare parts were needed to be sent to a platform, PEMEX always prefered to use the PUMA or the Bell 212, even when the Sikorskys S76 were delivered with the external cargo hook installed, that's it. Other helicopters in exactly the same service at the time were the Bell 212, Aerospatiale Puma SA 330J and SA350 Ecureuil, and the Bolkow 105; none of them presented the lack of power to the degree that the Sikorsky did. When the first Sikorskys were received in 1982 at Ciudad del Carmen base, everybody noted how quiet, comfortable, fast and even "good-looking" those were, and were the only ones that had the inflatable emergency floats installed inside and not attached to any external skids... But also became aware they were just too limited in performance. For PEMEX, the S76 was partly a dissapointment, and those were retired from their fleet soon. In order to explain myself better, let me express that my source of information was the late Captain Rafael Garibay, which was the chief pilot of "Transportes Aéreos of PEMEX", the air branch of the (then) proprietary fleet of PEMEX, in charge of training the PEMEX crews flying to platforms. In 1982 PEMEX self-owned fleet comprised more than 45 rotary wing aircraft based at Ciudad del Carmen in order to serve the many oil platforms in Campeche Bay, producing more than 3 million barrels of oil at that time. You can check the fact that presently, there is not a single S76 flying today in Campeche Bay, even when the helicopter transport to and from platforms is no longer in PEMEX hands, since PEMEX sold its previously magnificent aircraft fleet to the private industry several years ago, mainly for political pressures from latter governments. Reason to comment on this article was because I felt it was written in a somewhat favourable tone, and ended being not completely neutral, as it should be. — Preceding unsigned comment added by 192.100.180.19 (talk) 00:10, 8 October 2011 (UTC)

Well as I said before, if you have reliable sources about this that we can cite, it can be added, but anecdotes and stories don't make an encyclopedia. - Ahunt (talk) 02:01, 8 October 2011 (UTC)

Relationship with the S-70

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

Discussion closed per WP:Not a forum, nuff said~!

---

The s-76 was created a year after the s-70 prototype first flew, and the only change in the mechanical systems seems to have been the change from a military spec engine designed for an application where military performance, and a higher lift both because of armoring, and the designed role, to a civilian spec engine more suitable for a civilian medium utility helicopter similar to a civilian huey. "The technology basis for the S-76 was the Utility Tactical Transport Aircraft System (UTTAS) that had been awarded to Sikorsky in 1972. In particular, the rotor blade aerodynamic and structural features including blade airfoil, twist, swept tip and titanium spar were all embodied in the S-76. The UTTAS elastomeric main rotor head design as well as the cross beam bearingless tail rotor design was also applied to the S-76." And the s-76 design shared these features: "two turbine medium life helicopter, Among the features are: titanium and composite main rotor blades, a bearingless composite tail rotor, bifilar vibration absorbers, and a simplified main rotor transmission" with the s-70.

It uses the same rotor, rotor head, rotor bearings, transmission, tail rotor, and rotor arrangement with the s-70 along with numerous other similarities.

What argument is there that the s-76 is not the civilian version of the s-70?TeeTylerToe (talk) 22:30, 17 July 2012 (UTC)

The S-70 is the civil version of the UH-60. The S-76 certainly benefited from the technological advancements paid for by DARPA and the US government, but while the two aircraft share the same common dynamic component features, that is about where it ends. The S-76 has a different fuselage, with a different structure and internal layout. It uses different engines, a different transmission, different and retractable landing gear. While the dynamic components are based on the same concepts they are quite different. The S-76 has a main rotor that is 44'0" in diameter, while the S-70 has one 53'8". The tail rotors are completely different designs - the S-70 is on the right side and the S-76 on the left, with different mounting angles and different aerodynamics. With a gross weight of 22,000 lbs the S-70 is twice as heavy as the S-76 at 11,700 lbs. Basically the two designs share almost no common parts aside from basic AN hardware. All they share is a common technology stemming from government funded research that produced two very different aircraft. As per WP:ONUS and WP:EXCEPTIONAL a claim that the S-76 is a version of the S-70 would be an "exceptional claim [that] requires multiple high-quality sources". - Ahunt (talk) 23:51, 17 July 2012 (UTC)

"a different transmission" Not according to http://www.sikorskyarchives.com/S-76.php The landing gear on, for instance the s-70 firehawk are designed to be crashworthy, a feature that would be out of place on most civilian helicopters. The change in engines alone saved it 500 lbs, and the s-70 is a military helicopter designed to resist bullets and crashes. A civilian helicopter is designed to weigh as little as possible while lifting a much much smaller load. The s-76 has a smaller rotor because it is designed to lift less than a military helicopter designed to lift howitzers. Both have composite tail rotor blades of the same design, they're both have cross beam bearingless tail rotors. Saying they share no common parts is disingenuous. My Honda civic EX has 15" tires instead of the standard 14" tires. It's also the sedan, which makes it a different car from the civic EX coupe because it shares so few common parts and the cabin is in a different configuration.TeeTylerToe (talk) 09:17, 18 July 2012 (UTC)

Exactly. Book sources reproduced on these web pages [1], [2], describe the S-76 as receiving technology from the S-70, primarily the main rotor. This is just a company carrying forward knowledge to its new model. -Fnlayson (talk) 00:08, 18 July 2012 (UTC)

knowledge, the rotor, the rotor hub, the rotor bearing, the transmission, it seems like every detail about the tail. The only thing they changed about the mechanical design was to replace the overpowered military engines with more appropriate civilian engines.TeeTylerToe (talk) 09:17, 18 July 2012 (UTC)

"Saying they share no common parts is disingenuous" - no, actually it is accurate. Even the ref you quote shows that on the subject of the transmission. The ref says "In order to achieve the design goals, the S-76 employed technologies developed for the UH-60 BLACK HAWK helicopter. Among the features are: titanium and composite main rotor blades, a bearingless composite tail rotor, bifilar vibration absorbers, and a simplified main rotor transmission." It also says "The technology basis for the S-76 was the Utility Tactical Transport Aircraft System (UTTAS) that had been awarded to Sikorsky in 1972. In particular, the rotor blade aerodynamic and structural features including blade airfoil, twist, swept tip and titanium spar were all embodied in the S-76. The UTTAS elastomeric main rotor head design as well as the cross beam bearingless tail rotor design was also applied to the S-76." These quotes make it plain that the S-76 uses the same "technologies", "features" and "design", not the same individual parts. If the parts were the same (ie same P/N) then they would be bragging about their parts commonality which is a logistical advantage. The transmission for the S-70's combined engine output of 3780 shp is larger and heavier than the S-76's transmission which only has to absorb 1844 shp even in the S-76C++ model. Why would they use a much bigger and heavier transmission than is required on a much smaller and lighter helicopter? It would just reduce payload. The article you have cited makes it clear that the S-76 uses technology developed for the S-70 series, but not the individual parts from the S-70. It supports my contention that there are very few parts in common, that the S-76 and S-70 merely benefited from the same research and are not different versions of the same helicopter. - Ahunt (talk) 10:15, 18 July 2012 (UTC)

There is a destinction to be made between building on some experience, components, and technology derived from previous projects, and a 're-badging' exercise. Westland Helicopters, for instance, manufactured the medium-lift ASW Westland Sea King under licience from Sikorsky - would it be arguable that the later AgustaWestland AW101 is in fact the same helicopter? After all, it is a medium-lift helicopter, likewise it is marinised and used for ASW and troop transport duties. Westland even developed specialist rotor blades for the Sea King - that were then carried over on the new AW101 Merlin. Certainly, the AW101 drew on that experience, those supply chains, and the know-how of the earlier Sea King construction work, but most would agree that it is an entirely destinct helicopter in its own right, and does not closely resemble the Sea King even with some 'borrowing' of ideas and developments. There will always be some features carried forward in the next generation of aircraft - especially when you've just had a big government development contract, you'd try and develop techniques and knowledge that you can pass back onto your civvie projects as a subtle freebie, it only makes financial sense to make use of the 'free' R&D to make something that's useable beyond that specfic project and to enhance the other projects in your portfolio (with in reason! There's shrewd business economics, then there's corruption if you're misdirecting money with no application to what it is supposed to be being spent on!). I do see the S-76 as a seperate helicopter that uses some of the Sea Hawk's tooling to its advantage, that's my opinion of it anyhow. Kyteto (talk) 00:20, 18 July 2012 (UTC)

By the argument you are advancing TTT, the Bell 47 is the same as the Bell 206 because it has the same rotor design, the Boeing 707, 727 and 737 are the same because they have the same fuselage design, and the Beechcraft Queen Air and Swearingen Merlin are the same because the Merlin was initially built using Queen Air wings. YSSYguy (talk) 10:51, 18 July 2012 (UTC)

Is that the same as the Lancaster being a four-engined Spitfire because they both use Merlins? MilborneOne (talk) 11:10, 18 July 2012 (UTC)

Are the only differences between the dynamic mechanical components of the bell 47 and the 206 the length of their rotors, and whether they use a military engine, or a lower rated civilian one?TeeTylerToe (talk) 13:42, 18 July 2012 (UTC)

Just wondering, have you actually seen an S-76 or an S-70 up close? YSSYguy (talk) 14:07, 18 July 2012 (UTC)

What would be wrong with the statement that the mechanical differences between the s-70 and s-76 are weaker engines, a transmission of the same design that's probably weaker, reduced rotor diameter, and the orientation of the tail rotor was changed, making them virtually identical.173.66.178.25 (talk) 18:22, 18 July 2012 (UTC)

What would be wrong with it is that, as shown above, it would be inaccurate. As we have discussed the two aircraft are completely different, built from different parts that were developed from a common research program. As explained at WP:EXCEPTIONAL you would need multiple, reliable references to back that up and so far the refs you have provided in fact contradict that.

It is clear that you have no refs to support your assertion and the clear consensus here is against what you are proposing. I really think you need to read Wikipedia:Drop the stick and back slowly away from the horse carcass at this point. - Ahunt (talk) 19:16, 18 July 2012 (UTC)

What other differences are there in the mechanical design?TeeTylerToe (talk) 00:06, 20 July 2012 (UTC)

As noted above you have to provide references that show these designs use the same parts. The ref you have provided, plus the others mentioned, show the opposite. You haven't proven your case, so unless you have a new reference, it is time to move along. - Ahunt (talk) 00:17, 20 July 2012 (UTC)

There is an interesting quote from Gerald Tobias, the then Sikorsky President in the march 1980 issue of Air International magazine: "it is not a derivative aircraft in any sence of the word, but rather a direct result in stuying the needs of the commercial marketplace and applying the mnost advanced technology at our disposal to the challenge of coming up with precisely the right aircraft for the times". This does not suggest that the two helicopters are "Virtually identical"Nigel Ish (talk) 19:35, 18 July 2012 (UTC)

• Alright guys, you know the drill... if it doesn't help to improve the ENCYCLOPEDIA, it is out of here. This thread is now closed. --Dave ^{♠♣♥♦™№1185©♪♫®} 01:07, 20 July 2012 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

Who copied who?

Our intro says the following:

The Sikorsky S-76 ...... "is powered by two turboshaft engines, which drive both the main and tail rotors, each with four blades. The S-76 landing gear is retractable."

This Sikorsky archive says the following.

The Sikorsky S-76 is...... "powered by two turboshaft engines, which drive both the main and tail rotors, each with four blades. The S-76 landing gear is retractable."

Moriori (talk) 03:21, 22 July 2012 (UTC)

The two pages have more than that in common. It's probably only possible to find out which is the copy by contacting the archives. YSSYguy (talk) 03:25, 22 July 2012 (UTC)

That is one problem with Wikipedia getting more mature these days, we have found what looks like copyright violations in WP articles only to discover that the official sources have copied us. Of course that is allowed, but the CC licence requires attribution, which sometimes gets missed. This can be reworded to deconflict it, which I will do. - Ahunt (talk) 10:15, 22 July 2012 (UTC)

Transmission

Because four sources weren't enough I added a direct quote supporting the statement. While the transmission still uses planetary gears, the final reduction gear that had, in previous sikorsky transmissions, been a planetary gear was replaced with a bull gear, reducing the number of planetary gears in the transmission, reducing the number of parts, reducing rates of failure, and lowering cost.TeeTylerToe (talk) 11:55, 24 July 2012 (UTC)

None of your sources cited support the text that you keep edit warring to include. This matter has been passed to an admin for review. - Ahunt (talk) 12:05, 24 July 2012 (UTC)

TeeTylerToe is welcome to try to persuade other editors that his desired edits are properly sourced. If he does that, he will have consensus and his edits will stay in the article. If he cannot convince anyone, he has two choices. drop the WP:STICK or be blocked for edit warring. --Guy Macon (talk) 12:55, 24 July 2012 (UTC)

(edit conflict)Three of the four refs have info about the design of the S-76 transmission and the other has info about the design of the S-70 (UH-60) transmission. Not only do the sources fail to state that the two types have the same transmission, two don't mention the S-70 at all and one notes that the S-76 transmission is different to "previous Sikorsky models" and as the S-70 is a previous Sikorsky model, that would suggest that it's not the same. Then the US Army training notes make no mention whatsoever of the S-76 and clearly show a planetary gear and sun gear arrangement as the final reduction in the UH-60 gearbox; again, not the same. So, full marks for digging up the extra refs, but they either directly or by inference contradict your opinion that the two types have the same gearbox. YSSYguy (talk) 13:10, 24 July 2012 (UTC)

The sikorskyarchives compares the technologies from the S-70 used in the S-76, including the simplified transmission using a bull gear final reduction gear rather than a planetary gear final reduction gear of sikorsky helicopters prior to the S-70. Yes, both the S-70 and S-76 use a planetary gear, but not as the final reduction gear. From the cryogenic PDF: "For example, Sikorsky helicopters of the S--76 series, e.g., S--76A, S--76B, S--76C, have a main transmission that includes three stages of reduction gearing: a first stage for each engine output consisting of helical gearing, an intermediate stage consisting of spiral bevel gearing, and a final reduction stage comprising a central bull gear that intermeshes with right and left hand bull pinions (to combine the inputs of the two engines that provide the motive power for the helicopter)" And from the UH-60 pdf: "The main module is a single-stage planetary, gear-type XMSN. The components of the main module are a main bevel gear and planetary gears. The upper bevel gear is driven by the two input modules which drives the planetary gears and tail rotor. This assembly is referred to as the main bevel gear." For both helicopters, the first reduction gear is a planetary gear. The second reduction gear is a bevel gear, and the final reduction gear is a bull head gear.TeeTylerToe (talk) 15:19, 24 July 2012 (UTC)

By quoting the ref you have proven that the text you added is factually wrong: "The S-76 shares Sikorsky's new simplified helicopter transmission developed for the S-70." As everyone else has said, while the two transmissions benefited from the same research, the transmissions are both different. Are you the only one who can't see that? - Ahunt (talk) 16:07, 24 July 2012 (UTC)

What is the factual error, what is your basis for that claim, and what references are you using to support that claim? Right now I'm saying that on both transmissions, the input shafts connect to the bull gear reduction which connects to a beveled gear which connects to the planetary gear that drives the rotor shaft, as described and depicted in the uh60 pdf and described in the cryogenics pdf confirming the sikorskyarchives statement that the final reduction gear of both transmissions uses a bull gear.TeeTylerToe (talk) 16:21, 24 July 2012 (UTC)

"What is the factual error, what is your basis for that claim, and what references are you using to support that claim?" The emphasis is placed on the editor adding the content, not the detractor, to prove his addition is factually correct. While yes, you have proved that the two transmissions share similarities in design features; that DOES NOT mean that they are the same. Earlier you were also adding the following into the article: "(probably lower torque)" - There should NOT be any 'probably' about it, either evidence is found that it IS of a lower torque, or the speculation should be left out - Guessing, 'probablies', aren't acceptable in an encyclopedia, you're guessing at some of the content you've been trying to add, and that is a BAD sign for quality-control. Kyteto (talk) 17:17, 24 July 2012 (UTC)

That is a very strange comment from the editor that penned the current revision that states that the transmission of the s-76 is a "simpler" version of the transmission of the s-70. A statement that is false, and unsupported. If you prefer the wording "of the same design as the transmission of the s-70" that's fine, or some wording to that effect that is fine. The transmission of the S-76 is a version of the transmission designed for the S-70.TeeTylerToe (talk) 17:22, 24 July 2012 (UTC)

One problem with this article is that the helicopter and its systems is not very well described, and the current discussion about the similarlty or otherwise is only picking around the edges. What we probably say is something like "...The S-76 rotor blade, main and tail rotor heads[] and transmission [] used design concepts from the UH-60."

and then starting a paragraph with a DETAILED description of the helicopter, which can include the transmittion, rotor blades etc as well as things like avionics, materials of construction and the cabin layout.Nigel Ish (talk) 17:42, 24 July 2012 (UTC)

All those details would be the same as the descriptions that belong in the uh-60 article, the sh-60 article, the pavehawk article, the jayhawk article, the s-70 article, the s-92 article, the sh-60j article, and the sh-148 article, except for the details about the fuselage configuration, and the deletion of some of the survivability and crashability features, and change in rotor diameter, and engine model.TeeTylerToe (talk) 17:48, 24 July 2012 (UTC)

Since you are now blocked for 31 hours for edit warring on this topic I would suggest you take the time to consider what you would like to do when you get unblocked. If you come back here to get on with your edit war your next block will be much longer. - Ahunt (talk) 19:25, 24 July 2012 (UTC)

The usual progression is a day or two, a week or two, a month or two, then either a year or indefinite. That being said, I have seen indefinite bans on the second offense in cases where it becomes clear that the edit warrior simply refuses to read and follow WP:3RR. An example of ignoring the rules would be arguing that "As I'm sure you looked at the edits, it was not a simple revert -> revert repeated over and over ... As the discussion evolved in the talk page I changed the article" when WP:3RR clearly says "An editor must not perform more than three reverts on a single page within a 24-hour period. Undoing other editors—whether in whole or in part, whether involving the same or different material each time -- counts as a revert." --Guy Macon (talk) 20:18, 24 July 2012 (UTC)

Just a note to indicate that TTT is now indef blocked for personal attacks on his talk page during his week-long block for edit warring. - Ahunt (talk) 10:38, 30 July 2012 (UTC)

And now he cannot edit his own talk page because of continued PAs. Hopefully that will be the end of that, and we can just archive this whole section. - BilCat (talk) 20:27, 30 July 2012 (UTC)

I think so. - Ahunt (talk) 20:45, 30 July 2012 (UTC)

Sources

I've looked at the Flight International article here. It states, "The S-76 rotor and drive system draws heavily on Black Hawk technology." Isn't that what our text says, in different words? Next, it says, "The same form of one-piece main rotor hub carries the blades in elastomeric sockets allowing flap, drag and pitch - change movement without roller bearings." Thus, the rotor hub isn't identical, but of the "same form", probably meaning it's a little smaller in scale, but that's an assumption on my part which I'd never include in our text. Later, it says, "The twist of the S-76 main rotor blades is, by Black Hawk standards, a modest 10°", which suggests the blades aren;t the same either. It does say "S-76 also has the Black Hawk crossbeam tail rotor, in which opposing pairs of hollow blades are sleeved onto plastic beams clamped at right angles between the titanium plates of the rigid hub." Thus the tail rotor, at least on the early prototypes, does seem to be the same. - BilCat (talk) 20:58, 27 July 2012 (UTC)

I think that ref just supports all the other cited refs which say that the two aircraft have components that both stem from the same research, but are not identical part numbers. The description of the tail rotor that you have quoted seems to again indicate that they used the same general design principles, but since the tail rotors are mounted on different sides of the tail boom and at different angles, that they only share similar design concepts. Also, since the Blackhawk has twice the gross weight and twice the engine output torque of the S-76, the tail rotor would have to provide twice the anti-torque force so it must be larger diameter, turn faster, or use other techniques to produce the force needed to do its bigger job. Comparing photos shows that the S-70 tail rotor seems to have a larger hub and longer tail rotor blades, but is constructed along similar design principles. - Ahunt (talk) 21:14, 27 July 2012 (UTC)

Thanks. Since you're an actual helicopter pilot, your interpretation is probably correct. :) - BilCat (talk) 21:19, 27 July 2012 (UTC)

Well I am not sure that anyone's background gives anyone any authority, it is the written, reliable refs that count. But the years I spent as a helicopter test pilot do give me some appreciation for how the machines go together and how they work. One thing I do know is that the designers will do anything to save a couple of pounds and putting transmissions, tail rotors, main rotor blades, drive shafts and other components from a much larger helicopter onto a smaller one just doesn't commonly happen as it eats up your payload and kills sales, particularly in civil helicopters, where payload is more critical (the military just buy more helicopters to carry more). The refs all show pretty clearly that the S-76 uses parts that were designed upon the same principles as those used on the S-70, but smaller and lighter, which makes sense on a much smaller and lighter helicopter. - Ahunt (talk) 21:29, 27 July 2012 (UTC)

The March 1980 Air International reference, which does not make any comparisons between the S-76 and S-70, but describes the S-76 gearbox as "a simple, three stage reduction unit with 30 per cent fewer parts than planetary types previously used", states on p 114 that the S-76A's transmission is rated at a total of 1300 shp from both engines. p. 721 of Jane's All The World's Aircraft 2003–2004 states that the UH-60A (2× 1622 shp T-700-GE-700 engines) has a transmission rating of 2828 shp, increasing to 3400 shp with later more powerful engines. Read into that what you will.Nigel Ish (talk) 21:39, 27 July 2012 (UTC)

S-76

S-70

I think I found proof that the tailrotors are not identical, short of having the actual parts manuals available (Sikorsky doesn't make them publicly available - I checked). If you check the two photos at the right you can see the two tail rotors clearly. When viewed facing the hub the S-70's clearly rotates counter-clockwise, while the S-76's rotates clockwise. This means that the gearing and drive is all built the other way around and clearly can't use the same parts. The blades are also a different shape. - Ahunt (talk) 21:42, 27 July 2012 (UTC)

...which is exactly what I said days ago on the dispute resolution page, but apparently that was "overstating" the differences, so I assume that idea won't gain any traction, but hey, I could be wrong.

Now for the MGB. In addition to the horsepower limits and the implications of those limits mentioned above, quoting from the UH-60 training notes presented by TTT as support for the claims of "they're the same": The mast is directly connected to the planetary gear of the XMSN (copy-and-pasted from page D-5) and on pages D-6 and D-7 of the training notes there are pictures showing a sun-gear-and-planetary-gear arrangement as the final reduction. The picture on page D-6 also states the main rotor RPM is 258. For the S-76, quoting from the paper Isotropic Superfinishing of S--76C+ Main Transmission Gears presented by TTT as support for the claims of "they're the same": Sikorsky helicopters of the S--76 series, e.g., S--76A, S--76B, S--76C, have a main transmission that includes...a final reduction stage comprising a central bull gear that intermeshes with right and left hand bull pinions (to combine the inputs of the two engines) (copy-and-pasted from page 1). The S-76 Type Certificate doesn't explicitly state a figure for main rotor RPM, but does say that 91% Nr is 266RPM and 115% Nr is 336RPM, from which it can be calculated that the main rotor RPM is 292.

So, TTT's claims of sameness between the drivetrains are directly contradicted by the sources s/he used, as well as other available sources. It is clear that the best that can be said is that aspects of the S-70 drivetrain design were used to design the S-76 drivetrain. Now as the S-76 is not a member of the S-70 family, it is entirely appropriate to discuss the drivetrain in detail in this article, and again in the S-70 article, even if the drivetrains of the two types are absolutely identical in all respects - which is clearly not the case. YSSYguy (talk) 06:58, 28 July 2012 (UTC)

Actually it makes perfect sense that the rotor 100% normal operating RPMs would be different, since the rotor diameters are different. Rotors using the same airfoil need to operate at the same main rotor tip speed. The smaller diameter one on the S-76 has to turn faster to produce a similar tip speed as the S-70 and therefore an equivalent lift distribution. You find the same effect on other aircraft with similar design rotor systems that are different sizes, like the OH-58A (255 RPM) vs the UH-1H and N (324 RPM). The different normal operating RPMs again would indicate that the internal drivetrain gearing would be different to accept the higher speed on the lighter weight components. - Ahunt (talk) 10:55, 28 July 2012 (UTC)

TTT has given made some specific comments here and here. I'd be interested in y'alls assesment in light of the above sources. Thanks. - BilCat (talk) 11:09, 28 July 2012 (UTC)

• (edit conflict)Got a question to ask everyone here... what are the chances that TTT is an employee (current or former doesn't matter) of Sikorsky? And even if he is/was, wouldn't what he kept reiterating here constitute as his own original research without official statement/press release? Suffice to say, he has started to attack the community after failing to gain consensus for his original researches, thence Act V of his wiki-tragedy is not far away now. Let us all move on and return to our contribution, we don't need to feed on his sin. Out. --Dave ^{♠♣♥♦™№1185©♪♫®} 12:45, 28 July 2012 (UTC)

User:BilCat: It is kind of hard to follow what he is proposing as his position keeps changing. He started out wanting to merge the S-70 and S-76 articles because he insisted that they were variants of the same aircraft, then he insisted that they were different aircraft that used identical drive train components and now he seems to be saying that they use components of similar design, but different scale commiserate with the size of the aircraft. His latest position seems to be much closer to everyone else's reading of the sources, but his position is such a "moving target" it is hard to tell. The insults, personal attacks and ravings about cabals don't help the clarity, either. Since he is blocked for a week I suggest we just get on and continue to improve the article. - Ahunt (talk) 13:27, 28 July 2012 (UTC)

He is still going back to his line of "the S-76 is a civil S-70", inspite of the sourced evidence against it. He's tried to compare the S-70/S-76 to the Ford F-350/F250, but to me, the S-76 is more like the Ford Expedition SUV than an F-250. -Sigh. - BilCat (talk) 15:44, 28 July 2012 (UTC)

Yeah I see that over on his talk page now. Too erratic, so I am not sure where he sits on this at any given time. Clearly the refs show that "the S-76 is a civil S-70" is incorrect. - Ahunt (talk) 15:47, 28 July 2012 (UTC)

Wording

The current wording states, "The S-76 used design concepts, in areas such as the rotor blades, rotor heads and transmission, that were developed for the UH-60." The concunclusion of the above discussion of sources seems to be that the S-76 rotor and drive system uses the same basic design as those of the S-70, though adapted for the S-76's size and weight, ie not the same exact parts. Is there a way to tighten the current wording to say that, but more succintly? - BilCat (talk) 12:24, 28 July 2012 (UTC)

The current wording seems pretty concise and according to the refs to me, but I am open to something clearer, if other editors think it can be improved. - Ahunt (talk) 13:29, 28 July 2012 (UTC)

Well, at the risk of opening a can of worms again, the main transmission of the S-76 is not to the same design as the S-70's. According to the two sources linked to in the subsection above, it employs a bull gear and two pinion gears in the final reduction stage while the S-70 has a sun gear and set of (apparently five) planetary gears as its final reduction stage. Both sources appear to be RS to me. YSSYguy (talk) 14:08, 28 July 2012 (UTC)

I think its probably best to stick to referring to concepts or technologies. Being more specific will require sources giving more detailed comparison. Of course, wording could always be improved.Nigel Ish (talk) 14:14, 28 July 2012 (UTC)

User:YSSYguy: I do apologize - you are quite right, the two refs you carefully cited above show that the two transmission designs are in fact not only not the same parts, they are not even based on the same design concepts. The S-70 clearly has a planetary gear system, while the S-76 uses a bull gear. Clearly the current wording does not conform to those refs. Perhaps it would be best to use something like "The S-76 used design concepts, in areas such as the rotor blades and rotor heads that were developed for the UH-60, while other components, like the transmission, are of a completely different design than the S-70 series." - Ahunt (talk) 14:18, 28 July 2012 (UTC)

(ec)A question - the article currently refers to "Sikorsky's government-financed design work on the S-70 helicopter..." - is this correct, or is it government-funded design work that was first used in the S-70? (i.e. was the work funded specifically for the UTTAS program or a more general package of government-funded R&D work?)Nigel Ish (talk) 14:24, 28 July 2012 (UTC)

It was for UTTAS. - Ahunt (talk) 14:31, 28 July 2012 (UTC)

I'm not sure if any of the "government financed" stuff is relevant, especially as the Sikorsky archive is probably not a reliable source. Also, it's prbably better not to mention the transmission at all; the rest of that looks fine to me, though I'd still like a more precise phrase than "design concept", which seems to vague to me. - BilCat (talk) 15:19, 28 July 2012 (UTC)

Not an expert on Helicopters but is the transmission and stuff really important in so much detail. Do we describe it in this much detail in other helicopter articles. MilborneOne (talk) 15:23, 28 July 2012 (UTC)

I don't think it's really that important. However, TTT believes that the transmissions of the S-70 and S-76 are essentially the same, so he kept putting that info back in, and that not including it is "weasel wording", hence the dispute here. - BilCat (talk) 15:30, 28 July 2012 (UTC)

We could go with something simple like "The S-76 incorporated research in areas such as the rotor blades and rotor heads, that were developed for the UH-60." That is supported by the refs and I think is relatively clear. Please critique! - Ahunt (talk) 15:34, 28 July 2012 (UTC)

Perhaps "design technology" or something would be better than "research". Or a paraphrase of the Flight International sentence, "The S-76 rotor and drive system draws heavily on Black Hawk technology." <Shrug> - BilCat (talk) 15:41, 28 July 2012 (UTC)

I like the term "design technology", as it is more precise. That would give something like: "The S-76 incorporates UH-60 design technology in areas such as the rotor blades and rotor heads." - Ahunt (talk) 15:44, 28 July 2012 (UTC)

Works for me. - BilCat (talk) 16:00, 28 July 2012 (UTC)

Let's see if anyone else has any thoughts on this and, if not, we can go with that wording. - Ahunt (talk) 16:46, 28 July 2012 (UTC)

Dont have a problem with your words. MilborneOne (talk) 16:56, 28 July 2012 (UTC)

I prefer "The S-76 incorporates S-70 design technology in its rotor blades and rotor heads"; that seems to be the limit of commonality so IMO there is no need to say "such as", and I think "UH-60" is too specific, barring evidence that the other variants have different rotors (which I think would be highly unlikely). YSSYguy (talk) 05:46, 29 July 2012 (UTC)

I like your wording - good precision! - Ahunt (talk) 11:30, 29 July 2012 (UTC)

Rotor comparisons

I'm being especially rigorous in light of all that's happened, so I've set out to establish how similar or otherwise the S-76 rotors are to the S-70. I found a paper Full Scale Higher Harmonic Control Research to Reduce Hub Loads and Noise; on the second page it infers the S-76 main rotor blade has a chord of 15.6", or 1.3 feet. Then I found another paper, Full-Scale S-76 Rotor Performance and Loads at Low Speeds in the NASA Ames 80- by 120-Foot Wind Tunnel ; on the ninth page (numbered Page 6) there is a table that discusses the S-76 rotor blade and states it has a chord of 15.6". On the sikorskyarchives website I found this page, which says the UH-60A has a main rotor chord of 1.73'. So, while I do not dispute that the S-70 main rotor drew on the S-70 rotor for its design, the S-76 rotor blade is clearly not a shorter version of the S-70 rotor blade. YSSYguy (talk) 13:43, 29 July 2012 (UTC)

Good finds! That all makes sense too, as rotors can't generally be cut cut down in length to make a new blade, they have to be scaled in all dimensions to make them work right. Once again they may be similar technology, but not the same parts. - Ahunt (talk) 18:19, 29 July 2012 (UTC)

I spent years working on the design of new aircraft, and I have never seen a design be re-used when a new design would be lighter, which would clearly be the case if the new rotor is smaller. Here on Wikipedia we don't need to show that tey are different. The person who wants the article to say that they are the same needs to provide a citation to a reliable source that says that, without any WP:SYNTHESIS required. --Guy Macon (talk) 20:14, 29 July 2012 (UTC)

Oh I agree, there is no need to say they are different, but the refs presented here show that they are, for future use. Lots of aircraft are different from the S-76, the S-70 just happens to be one of them.- Ahunt (talk) 20:17, 29 July 2012 (UTC)

Assessment comment

The comment(s) below were originally left at Talk:Sikorsky S-76/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Very little besides the infobox and some information about who operates this aircraft. (Born2flie 06:03, 29 September 2006 (UTC))

Last edited at 06:03, 29 September 2006 (UTC). Substituted at 06:10, 30 April 2016 (UTC)

Kobe Bryant Accident In Header

I'm adding this in the header because it the the most globally notable thing about the helicopter. — Preceding unsigned comment added by Wshallwshall (talk • contribs) 01:53, 27 January 2020 (UTC)

• It most certainly isn't. It's barely mentioned in the article. There have been numerous other accidents and deaths. Compare to AgustaWestland AW169 - you don't see the death of Vichai Srivaddhanaprabha mentioned in the lead. Expand the discussion in the accidents section instead - but then, what's the rush, it's an encyclopeadia not a newspaper. Nfitz (talk) 01:57, 27 January 2020 (UTC)

Hi Wshallwshall, the accident is absolutely not the most globally notable thing about this helicopter. See WP:RECENTISM. // sikander { talk } 🦖 02:07, 27 January 2020 (UTC)

I agree that this one crash is a far from "the most globally notable thing about the helicopter". It bears mentioning in the accidents section, but otherwise the accident is a minor footnote in the long history of this design. - Ahunt (talk) 14:20, 27 January 2020 (UTC)

Dimensions

Jeepers! I can’t keep doing this to every article! PLEASE stop using km/h or other metric system units! This is America! Please! MPH, feet, etc.!98.162.136.248 (talk) 14:56, 27 January 2020 (UTC)

What are you talking about? The article is in primary nautical units, which is the aviation standard in North America, with statute and metric units secondary. You can note that Wikipedia is a global publication, we aim to provide units that everyone can understand. We have guidance on this at WP:UNIT. - Ahunt (talk) 15:26, 27 January 2020 (UTC)

Operational History

Operational history The S-76 was the first helicopter to circumnavigate the world in an east-to-west direction, piloted by Australian adventurer Dick Smith, in 1975.[22]

The date is in error, Dick Smith performed the circumnavigation in 1995. (see wikipedia article on Dick Smith)103.3.237.12 (talk) 04:17, 29 January 2020 (UTC)TVanderkop

Apologies to all for my typo/slip. sirlanz 04:39, 29 January 2020 (UTC)