S-67 Blackhawk
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S-67 Blackhawk
Gents (and Nick in particular)
The AH-56 thread reminded me of a 70's prototype that looked fantastic - the S-67 Black Hawk. I am talking about that "Hind" style attack/transport helicopter that had wings with weapon hard points and could also transport 10 or more troops and was tandem seating.
When in Rucker, the Sikorsky rep had a video of the S67 low flying and conducting weapons firing trials. Any one fly it? Or know what it was like? Nick, is there still one tucked away in a Sikorsky museum?
What caused it's demise: complexity? Too many roles in the one wrapping? The Airshow accident in the Middle East (or was it Farnborough)? Beaten fairly by the Apache and YAH 23 Cobra in the post Cheyanne competition? Too expensive? To much high speed wing V rotor issues?
Here is a link to the best photos I could find (scroll past the model).
http://www.anigrand.com/AA2022s-67.html
The AH-56 thread reminded me of a 70's prototype that looked fantastic - the S-67 Black Hawk. I am talking about that "Hind" style attack/transport helicopter that had wings with weapon hard points and could also transport 10 or more troops and was tandem seating.
When in Rucker, the Sikorsky rep had a video of the S67 low flying and conducting weapons firing trials. Any one fly it? Or know what it was like? Nick, is there still one tucked away in a Sikorsky museum?
What caused it's demise: complexity? Too many roles in the one wrapping? The Airshow accident in the Middle East (or was it Farnborough)? Beaten fairly by the Apache and YAH 23 Cobra in the post Cheyanne competition? Too expensive? To much high speed wing V rotor issues?
Here is a link to the best photos I could find (scroll past the model).
http://www.anigrand.com/AA2022s-67.html
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The S-67 was a fine aircraft, built with company funds back in the late 60's to show what was possible. It had the rotor system lifted from an H-3, and good for about 22000 lbs GW, and it weighed about 10,000 lbs, so it could carry literally 4 tons of ordnance and 3+ hours of gas. It had speed brakes (set the speed at the start of a dive, and it would automatically hold the max speed during the dive!) Smooth as glass and very very fast. Held the world's speed record at about 219 mph for many years.
It was not built to any customer's request, so it was an uphill battle to try and sell it, back in pre-Apache days.
As the newest addition to Sikorsky's pilot's office, I flew it for a few hours as it was prepped for the Farnborough Air Show in 1974. Loops, rolls and split S maneuvers were taught to me then by Kurt Cannon. Those photos with it in desert camo were taken then (August 1974).
It crashed at Farnborough that year, in Sept. It dished out in a roll at low level, and settled into the ground where it came apart and burned, killing both crew. The pilot was Kurt Cannon, a very fine test pilot. The co-pilot was also a friend, Stu Craig.
It was hand-built with no hard tooling, so the cost to reconstruct it was high. With no firm sales, there was no impetus to do anything, so it faded from sight.
The design for tail cone and transition section were resurrected later in the Rotor Systems Research Aircraft for NASA. Some sharp eyes might see the similarity from photos.
It was not built to any customer's request, so it was an uphill battle to try and sell it, back in pre-Apache days.
As the newest addition to Sikorsky's pilot's office, I flew it for a few hours as it was prepped for the Farnborough Air Show in 1974. Loops, rolls and split S maneuvers were taught to me then by Kurt Cannon. Those photos with it in desert camo were taken then (August 1974).
It crashed at Farnborough that year, in Sept. It dished out in a roll at low level, and settled into the ground where it came apart and burned, killing both crew. The pilot was Kurt Cannon, a very fine test pilot. The co-pilot was also a friend, Stu Craig.
It was hand-built with no hard tooling, so the cost to reconstruct it was high. With no firm sales, there was no impetus to do anything, so it faded from sight.
The design for tail cone and transition section were resurrected later in the Rotor Systems Research Aircraft for NASA. Some sharp eyes might see the similarity from photos.
Last edited by NickLappos; 19th Oct 2004 at 01:48.
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Senis Semper Fidelis
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Hey Nick,
How did the Rotor head work, every blade seems to be at a different point and not evenly spaced, did it balance itself out no matter what happened to the position of the blades?
Peter R-B
Vfr
How did the Rotor head work, every blade seems to be at a different point and not evenly spaced, did it balance itself out no matter what happened to the position of the blades?
Peter R-B
Vfr
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A different point of view
To: Vfrpilotpb
What you are seeing is the effect of leading and lagging.
In one or more helicopter aerodynamics books the author offers the following and hopefully I get it right.
If you could stand above the helicopter and observe the rotor looking at the driven plane of rotation the blades will appear to be evenly spaced.
However if you could observe the rotor system centered on the driving axis (rotor mast) the blades will appear to be unevenly spaced. On a four blade fully articulated system the blades will be disposed like a peace sign.
In either case the system is in balance.
What you are seeing is the effect of leading and lagging.
In one or more helicopter aerodynamics books the author offers the following and hopefully I get it right.
If you could stand above the helicopter and observe the rotor looking at the driven plane of rotation the blades will appear to be evenly spaced.
However if you could observe the rotor system centered on the driving axis (rotor mast) the blades will appear to be unevenly spaced. On a four blade fully articulated system the blades will be disposed like a peace sign.
In either case the system is in balance.
Thread Starter
Thanks guys,
A truly magnificent aircraft, and now that you have confessd to flying it Nick, I am truly jealous. by the size of the pilots, It does look like a very large aircraft, how many troops could it take (if any)?
Lu, I can hardly wait for Nick's response to your post. It's almost worth waiting up for.....
Hint: count the number of blades.....
A truly magnificent aircraft, and now that you have confessd to flying it Nick, I am truly jealous. by the size of the pilots, It does look like a very large aircraft, how many troops could it take (if any)?
Lu, I can hardly wait for Nick's response to your post. It's almost worth waiting up for.....
Hint: count the number of blades.....
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Does something get lost in the translation when a message gets to OZ?
To: helmet fire.
I can only assume that Nick read the two textbooks I alluded to and that he would have to agree. The statements may not be word for word but they get the meaning across.
I did note the Blackhawk has more than four blades but I would find it difficult to describe the relative positions of the blades and compare these positions to some known quantity such as a peace sign.
Looking down on a four bladed helicopter in flight the advancing blade would be ahead of the lateral axis and the retreating blade would also be ahead of the lateral axis the other blades would be aligned with the longitudinal axis forming a peace sign.
I can only assume that Nick read the two textbooks I alluded to and that he would have to agree. The statements may not be word for word but they get the meaning across.
I did note the Blackhawk has more than four blades but I would find it difficult to describe the relative positions of the blades and compare these positions to some known quantity such as a peace sign.
Looking down on a four bladed helicopter in flight the advancing blade would be ahead of the lateral axis and the retreating blade would also be ahead of the lateral axis the other blades would be aligned with the longitudinal axis forming a peace sign.
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Oh Well! Here goes:
Lu is right.
The actual place each blade is at at any millisecond is surely not where it "should" be for perfect visual symmetry. The balance of forces and moments is what counts, and the mass balance of the blade (due to its mass and position in space) is only one part of that equation.
Thanks for posting those pictures, guys. Brings back memories! I am in the front seat of that picture with the desert camo and all the rockets and stuff under the wings. That was Sept of 1974 (30 years ago!!)
The pilot in the head-on shot that Heliport posted has Kurt Cannon in the back seat, he was the S-67 project pilot. A former US Army Warrant Officer, he took some grief from all the Marine RLO's who populated the office when I first arrived. A great guy, and a great stick. The guy in the front seat was Byron Graham, the dean of Sikorsky test pilots, and one of my mentors. He was a Corsair plot in WWII and a civil engineer. What he forgot about helicopters could have built the industry. He could fly the box the helo comes in, I think.
In the pics that tacks put up, note the speed brakes that pop out automatically in a dive. The mountains in the other pic in that set are in Iran, back when the Shah was in charge.
I must add that the S-67 was built in a few months, and was designed by the master Sikorsky designer of that period, Aristide "Al" Albert, who passed away about 3 years ago. Al also designed the S-76, the ABC, and had a big hand in the Black Hawk. Not a bad set of helicopters to have spawned!
Lu is right.
The actual place each blade is at at any millisecond is surely not where it "should" be for perfect visual symmetry. The balance of forces and moments is what counts, and the mass balance of the blade (due to its mass and position in space) is only one part of that equation.
Thanks for posting those pictures, guys. Brings back memories! I am in the front seat of that picture with the desert camo and all the rockets and stuff under the wings. That was Sept of 1974 (30 years ago!!)
The pilot in the head-on shot that Heliport posted has Kurt Cannon in the back seat, he was the S-67 project pilot. A former US Army Warrant Officer, he took some grief from all the Marine RLO's who populated the office when I first arrived. A great guy, and a great stick. The guy in the front seat was Byron Graham, the dean of Sikorsky test pilots, and one of my mentors. He was a Corsair plot in WWII and a civil engineer. What he forgot about helicopters could have built the industry. He could fly the box the helo comes in, I think.
In the pics that tacks put up, note the speed brakes that pop out automatically in a dive. The mountains in the other pic in that set are in Iran, back when the Shah was in charge.
I must add that the S-67 was built in a few months, and was designed by the master Sikorsky designer of that period, Aristide "Al" Albert, who passed away about 3 years ago. Al also designed the S-76, the ABC, and had a big hand in the Black Hawk. Not a bad set of helicopters to have spawned!
Last edited by NickLappos; 20th Oct 2004 at 05:57.
Thread Starter
Ok, ok...I agree, Lu was right about the blade leading and lagging. But the question was about the blades being so unevenly spaced. The answer is in part lead lag, but I believe the photo that most drew vfrpilotpb was the black and white head on in which the culprit is much more camera shutter effect than lead lag (though lead lag is most certainly involved). And Lu's balance bit is sketchy. Lead and lag does not always keep the system perfectly in balance, and is the source of vibrations.
But none of this should detract from such a beautiful aircraft.
Could it take troops? Were there any interested parties looking to buy? The Shah eventually took Cobra (J or Ts werent they?)
But none of this should detract from such a beautiful aircraft.
Could it take troops? Were there any interested parties looking to buy? The Shah eventually took Cobra (J or Ts werent they?)
Nick, in one of the references mentioned, it states that the Blackhawk had a ducted tail fitted; was that `ducted` as a pusher, or ducted as a `fenestron`..? Secondly, was there any roll assistance via differential airbrake/spoiler ? Syc.
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The Cobras' are dead.
To: helmet fire
Almost every AH-1J in Iran was left to die at the Isfahan training facility due to the lack of qualified pilots. They were done in by solar radiation and ingestion of sand.
Almost every AH-1J in Iran was left to die at the Isfahan training facility due to the lack of qualified pilots. They were done in by solar radiation and ingestion of sand.
Hey guys,
I have a video thats 2.05MB but I need someone to host it.
Anybody interested?
bb in ca
[email protected]
I have a video thats 2.05MB but I need someone to host it.
Anybody interested?
bb in ca
[email protected]
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sycamore,
Here is a picture of the fan-in-fin Blackhawk (the distinction between the older experimental Blackhawk and the newer production model was to use two words for the production Black Hawk, vice the "One word Blackhawk" back in the old days around the Sikorsky pilots office.
The drag brakes had no differential control effect, they were depoyed symmetrically. The Blackhawk needed no roll assistance, the roll rate was well over 100 degrees per second!
Here is a picture of the fan-in-fin Blackhawk (the distinction between the older experimental Blackhawk and the newer production model was to use two words for the production Black Hawk, vice the "One word Blackhawk" back in the old days around the Sikorsky pilots office.
The drag brakes had no differential control effect, they were depoyed symmetrically. The Blackhawk needed no roll assistance, the roll rate was well over 100 degrees per second!
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Nick,
Never knew you guys actually flew the fan-in-fin in the S-67. Thanks for teaching me something today! Was there any crossover into the fantail S-76 (Comanche demo), or was that a clean sheet project? Also, over in the Cheyenne thread you state that the AH-56's unswept wing incurred a 10% hover penalty. What was the figure for the Blackhawk?
Lu,
'Course, not all of the Iranian Cobras rotted away. Seem to recall they claimed a 10:1 air-air record during the war with Iraq, claiming several dozen Hinds and Gazelles using TOW/M197, plus a handful of fast jets.
I/C
Never knew you guys actually flew the fan-in-fin in the S-67. Thanks for teaching me something today! Was there any crossover into the fantail S-76 (Comanche demo), or was that a clean sheet project? Also, over in the Cheyenne thread you state that the AH-56's unswept wing incurred a 10% hover penalty. What was the figure for the Blackhawk?
Lu,
'Course, not all of the Iranian Cobras rotted away. Seem to recall they claimed a 10:1 air-air record during the war with Iraq, claiming several dozen Hinds and Gazelles using TOW/M197, plus a handful of fast jets.
I/C
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Ian,
The vertical drag estimate is a rough one, based on the fact that the wing is a flat surface presented to the rotor downwash, thus creating some vertical load. For a normal helicopter, the fuselage usually creates about 4 to 5% download. For a tilt rotor, where the wing is large, and the downwash velocity is high, it is up to 12 to 15%. The H-56 had a wing sized somewhere smaller than a tilt rotor but much more than a simple fuselage, so I guessed 10%. That means the wing costs about 1000 lbs of payload relative to a helicopter.
The fan in fin Blackhawk flew in 1974, and the Fantail S-76 flew in 1991. We did study the old data to help lay the S-76 out, and it came in handy, especially the duct shaping, which is critical to the efficiency of the fan.
The vertical drag estimate is a rough one, based on the fact that the wing is a flat surface presented to the rotor downwash, thus creating some vertical load. For a normal helicopter, the fuselage usually creates about 4 to 5% download. For a tilt rotor, where the wing is large, and the downwash velocity is high, it is up to 12 to 15%. The H-56 had a wing sized somewhere smaller than a tilt rotor but much more than a simple fuselage, so I guessed 10%. That means the wing costs about 1000 lbs of payload relative to a helicopter.
The fan in fin Blackhawk flew in 1974, and the Fantail S-76 flew in 1991. We did study the old data to help lay the S-76 out, and it came in handy, especially the duct shaping, which is critical to the efficiency of the fan.
Hey guys,
Here is the link to the video.
Sikorsky S-67 Video
Everyone can thank John Eacott for hosting this. It's much appreciated.
Best Regards,
bb in ca
Here is the link to the video.
Sikorsky S-67 Video
Everyone can thank John Eacott for hosting this. It's much appreciated.
Best Regards,
bb in ca
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I can only assume that the quoted figures are a bit suspect.
To: Ian Corrigible
Based on my first hand experience I would assume if the figures are correct there were non-Iranian pilots at the controls. The Iranian pilots were trained to US Army standards. A US Army pilot would receive his wings after about 180 hours of training and then he would either be sent to an operational unit for further experience in the mission or possibly streamed into a training program on a specific aircraft.
The Iranian pilots most of which lacked high school graduation were subject to about two hundred hours of training. They would then receive two hundred hours of supervised solo and then be sent to an operational unit where they would receive another two hundred hours of instruction by a US Army pilot. Even at that point they lacked the skills of a freshly graduated US Army pilot.
It was for this reason that all of the AH-1Js were parked at the Isfahan airfield. I also based on conversations with Iranian fighter pilots feel that the Iranian helicopter pilots lacked the will to join in close combat. An Iranian Air Force F4 pilot lived in my apartment complex and he told me that in the war in Oman they would drop their bombs and fire their guns at 10,000 feet and return to Iran.
Iran also sent helicopters to Oman and in doing so they changed the tail numbers and did not log the operational time on them. When they returned to Iran the tail numbers were changed back and most were returned to the overhaul depot with bullet holes in them. All with no explanation to Bell Helicopter who was running the overhaul depot. When the Iranians saw the Bell personnel inspecting the bullet holes the Iranians cut the bullet holes out with a hole saw and in the process damaging the primary structure.
It was this mentality that led me to make my original statement about the AH-1Js rotting away in Isfahan.
'Course, not all of the Iranian Cobras rotted away. Seem to recall they claimed a 10:1 air-air record during the war with Iraq, claiming several dozen Hinds and Gazelles using TOW/M197, plus a handful of fast jets.
The Iranian pilots most of which lacked high school graduation were subject to about two hundred hours of training. They would then receive two hundred hours of supervised solo and then be sent to an operational unit where they would receive another two hundred hours of instruction by a US Army pilot. Even at that point they lacked the skills of a freshly graduated US Army pilot.
It was for this reason that all of the AH-1Js were parked at the Isfahan airfield. I also based on conversations with Iranian fighter pilots feel that the Iranian helicopter pilots lacked the will to join in close combat. An Iranian Air Force F4 pilot lived in my apartment complex and he told me that in the war in Oman they would drop their bombs and fire their guns at 10,000 feet and return to Iran.
Iran also sent helicopters to Oman and in doing so they changed the tail numbers and did not log the operational time on them. When they returned to Iran the tail numbers were changed back and most were returned to the overhaul depot with bullet holes in them. All with no explanation to Bell Helicopter who was running the overhaul depot. When the Iranians saw the Bell personnel inspecting the bullet holes the Iranians cut the bullet holes out with a hole saw and in the process damaging the primary structure.
It was this mentality that led me to make my original statement about the AH-1Js rotting away in Isfahan.