Chinook low flyby vid doing the rounds on Facebook......
I think it is an air-to-air shot of a Chinook flying straight and level, in formation with another aircraft. then the film is skewed port by 30(ish) deg and superimposed on the footage of another flypast with the aircraft flying just out of the frame at the top, leaving just enough room to put the Chinook imagery below that of the aircraft, apparently, closer to the ground.
4468, It would appear we are having a Apples and Orange's discussion when we each talk about our recollection of the Chinook.
I qualified my experience ending with the C Model having flown a lot of A models, some B models, and C-, full C models in the standard US Army Configurations.
Chinook 240 kindly provided a copy of the CH-47 Familiarization Manual that addresses the LCT system which I knew as the Speed Trim System.
DASH was not installed on any of the Models I flew.
That was part of the upgrade to the D Model.
The D Model Operators Manual I linked has a description of the AFCS Components in Section 2-5-7 (d) and (f) where the Differential Air Speed System (DASH) is discussed and mentions that it incorporates airspeed hold above 40kts and also provides positive stick gradient through the autopilot.
So....does this clarify things a bit for you.
You are talking D Model or later when you talk DASH and PSG services it provides.
That does not apply to earlier models of the US Standard Configuration A-C Models.
Here is the Army Operators Manual for the D Model.....perhaps not the latest edition but good enough for our purposes.
http://www.chinook-helicopter.com/Pu...520-240-10.pdf
If you move to page 51 of the Fam Manual provided by 240.....you can see a discussion and diagram of the LCT or Speed Trim System as I have described it in an earlier Post.
You can see the DCP Link in the diagram.
That is controlled by the Trim Wheel in the Cockpit which moves the cyclic fore and aft and its position is indicated by a display. marked in "Inches of Displacement".
The use of that Trim Wheel is for comfort purposes primarily and has limitations for on-ground use.....in the A-C Models it was a Two inch Aft of center Cyclic movement with the DCP adjusted to Zero.
The other half of the DCP actuator acts to facilitate a Positive Stick Gradient.
In my Operational Unit anytime that Actuator (either half of it) went U/S it was noted in the Maintenance Record of the Aircraft and labeled "In-Operative"....with no limitations on Flight applying.
In the D Model Operators Manual we see an Altitude Hold Capability which was not present on the A-C models.
I qualified my experience ending with the C Model having flown a lot of A models, some B models, and C-, full C models in the standard US Army Configurations.
Chinook 240 kindly provided a copy of the CH-47 Familiarization Manual that addresses the LCT system which I knew as the Speed Trim System.
DASH was not installed on any of the Models I flew.
That was part of the upgrade to the D Model.
The D Model Operators Manual I linked has a description of the AFCS Components in Section 2-5-7 (d) and (f) where the Differential Air Speed System (DASH) is discussed and mentions that it incorporates airspeed hold above 40kts and also provides positive stick gradient through the autopilot.
So....does this clarify things a bit for you.
You are talking D Model or later when you talk DASH and PSG services it provides.
That does not apply to earlier models of the US Standard Configuration A-C Models.
Here is the Army Operators Manual for the D Model.....perhaps not the latest edition but good enough for our purposes.
http://www.chinook-helicopter.com/Pu...520-240-10.pdf
If you move to page 51 of the Fam Manual provided by 240.....you can see a discussion and diagram of the LCT or Speed Trim System as I have described it in an earlier Post.
You can see the DCP Link in the diagram.
That is controlled by the Trim Wheel in the Cockpit which moves the cyclic fore and aft and its position is indicated by a display. marked in "Inches of Displacement".
The use of that Trim Wheel is for comfort purposes primarily and has limitations for on-ground use.....in the A-C Models it was a Two inch Aft of center Cyclic movement with the DCP adjusted to Zero.
The other half of the DCP actuator acts to facilitate a Positive Stick Gradient.
In my Operational Unit anytime that Actuator (either half of it) went U/S it was noted in the Maintenance Record of the Aircraft and labeled "In-Operative"....with no limitations on Flight applying.
In the D Model Operators Manual we see an Altitude Hold Capability which was not present on the A-C models.
Thanks to SAS for a PM- could not recall the name of what was, in the CH-47A I flew from 1963-65 called the Differential Collective Pitch system, whose function was similar to the Pittch Bias Actuator in the S-76. The early UH-60’s had them as well, until the Army decided to take them out because: 1) they were a maintenance headache, and )2 the pilots couldn’t tell whether it was on or off anyway ( something we had told them a long time before that ).
The speed trim really wasn’t put in to provide a level fuselage attitude-that was only partly true-the other part was that it was there to reduce the main rotor shaft bending loads at speed and thereby allow for a higher shaft component replacement time. You might recall some difficulties the USMC had with pilots using the CH-46 speed trim manually to control attitude during approach to an LZ in Vietnam. Think they had at least one shaft failure as a result.
( Background: after flight school I had wangled an assignment to the Test Board at Ft Rucker. The prototype 47A’s they had ( 3 of them ) had been landing at various spots around Ft Rucker, and maybe it was the landing on the golf course* that got me, a 2nd LT into getting a Chinook checkout, and by two of the Boeing Test Pilots to boot, as they were there to assist the program. One could ask them questions and get very straight and detailed answers. It was ironic that after a short tour there and a visit to SE Asia, I wound up at Sikorsky, and while the CH-53A could fly rings around the CH-47A I’d get into some “interesting” conversations over the years with SA folks who failed to pay attention to the gradual and effective improvement programs the Army and Boeing effected into the Chinook product line.
*there were two explosive failures of the nose gearbox, traced to a gear resonance and which caused nose gear box failure and parts etc being ingested into that side’s engine with very noisy further results. Another ship had what was referred to as floating SAS links, resulting in a ship rolling on its side. Lastly, there was an aft shaft bearing failure, in which the crew was able to get it on the ground on the north part of Cairns AAF, but th blades hit the tunnel and the engine controls were cut, so they were shut down via a fire truck directing their turret into the inlets, one at a time. I happened to be landing at the north helipad and folks were running across the path to my tie down in front of me, so I turned the D model around and watched all of this one. No injuries. Anyway, the field grade types started finding other things to do. Except one: we had a civilian Joe Givens who was an O-6 in a USMC fighter sad at NAS New Orleans and he still flew them. Turned out later that this Joe Givens was in the same F4U-4 squadron in the S. Pacific with Byron Graham, my future boss as Ch Exp pilot at Sikorsky. Sorry, had to keep the record straight re field grades.
The speed trim really wasn’t put in to provide a level fuselage attitude-that was only partly true-the other part was that it was there to reduce the main rotor shaft bending loads at speed and thereby allow for a higher shaft component replacement time. You might recall some difficulties the USMC had with pilots using the CH-46 speed trim manually to control attitude during approach to an LZ in Vietnam. Think they had at least one shaft failure as a result.
( Background: after flight school I had wangled an assignment to the Test Board at Ft Rucker. The prototype 47A’s they had ( 3 of them ) had been landing at various spots around Ft Rucker, and maybe it was the landing on the golf course* that got me, a 2nd LT into getting a Chinook checkout, and by two of the Boeing Test Pilots to boot, as they were there to assist the program. One could ask them questions and get very straight and detailed answers. It was ironic that after a short tour there and a visit to SE Asia, I wound up at Sikorsky, and while the CH-53A could fly rings around the CH-47A I’d get into some “interesting” conversations over the years with SA folks who failed to pay attention to the gradual and effective improvement programs the Army and Boeing effected into the Chinook product line.
*there were two explosive failures of the nose gearbox, traced to a gear resonance and which caused nose gear box failure and parts etc being ingested into that side’s engine with very noisy further results. Another ship had what was referred to as floating SAS links, resulting in a ship rolling on its side. Lastly, there was an aft shaft bearing failure, in which the crew was able to get it on the ground on the north part of Cairns AAF, but th blades hit the tunnel and the engine controls were cut, so they were shut down via a fire truck directing their turret into the inlets, one at a time. I happened to be landing at the north helipad and folks were running across the path to my tie down in front of me, so I turned the D model around and watched all of this one. No injuries. Anyway, the field grade types started finding other things to do. Except one: we had a civilian Joe Givens who was an O-6 in a USMC fighter sad at NAS New Orleans and he still flew them. Turned out later that this Joe Givens was in the same F4U-4 squadron in the S. Pacific with Byron Graham, my future boss as Ch Exp pilot at Sikorsky. Sorry, had to keep the record straight re field grades.
Anyone care to calculate the aircraft speed, based on known dimensions of objects in the frame?
If you were to plan a ultra low level flyby, what speed would you choose? (clearly the troops were given enough warning to climb the containers)
Can we use the rotor rpm to crosscheck the above (probably not but worth asking)
Numerous cameras in use but only one video published thus far?
The plastic cone positioned camera right is unmoved?
No markings or insignia discernible?
On the other hand...
The reflection of blades in the puddle is convincing.
At the end of the clip, the image slightly brightens when the operator sticks his finger into frame. The aircraft brightens to the same degree. (requiring an exceptional commitment to detail, if it were a fake)
Mjb
If you were to plan a ultra low level flyby, what speed would you choose? (clearly the troops were given enough warning to climb the containers)
Can we use the rotor rpm to crosscheck the above (probably not but worth asking)
Numerous cameras in use but only one video published thus far?
The plastic cone positioned camera right is unmoved?
No markings or insignia discernible?
On the other hand...
The reflection of blades in the puddle is convincing.
At the end of the clip, the image slightly brightens when the operator sticks his finger into frame. The aircraft brightens to the same degree. (requiring an exceptional commitment to detail, if it were a fake)
Mjb
Last edited by mickjoebill; 5th May 2022 at 13:15.
If you were to plan a ultra low level flyby, what speed would you choose?
Of course I know naught of such childish, dangerous, unprofessional antics as seen in the Video....why that would inject some fun into helicopter flying and that just isn't the done thing anymore.
I might be wrong, but don't the engines sound rather normal when the aircraft passes the camera despite the video being slowed way way down?
I would expect them to have a much lower sound.
I would expect them to have a much lower sound.
"Mildly" Eccentric Stardriver
SASless;
Seems so. As a friend has said, back in the day we were "Professional Hooligans"
.why that would inject some fun into helicopter flying and that just isn't the done thing anymore.
"Mildly" Eccentric Stardriver
Maybe a sense of humour failure. The critical word was "professional". Professional enough to keep the right side of dangerous. It was the amateur hooligans who got into trouble.
You suppose some folks got "old" for good reasons besides blind staggering Luck?
There are parallels with the F16 female OC thread. I had been told "Rules are for the guidance of the wise" and, while I can understand why such a comment would be made, these days particularly, rules are for everyone, with no exceptions.
This thread has headed down the proverbial rabbit hole me thinks.
It started off discussing whether a video was real or fake....and never decided that despite lots of effort....some good....some we could have done without.
Now we have seen a shift to bashing unseen.....unrecorded....purely imaginary similar exploits of airmanship.
The ultimate comment could be translated into an old adage that took quite a bit of bashing itself after a bit of unpleasantness......"Befehl Its Befell!".
Time to move on I would suggest.
It started off discussing whether a video was real or fake....and never decided that despite lots of effort....some good....some we could have done without.
Now we have seen a shift to bashing unseen.....unrecorded....purely imaginary similar exploits of airmanship.
The ultimate comment could be translated into an old adage that took quite a bit of bashing itself after a bit of unpleasantness......"Befehl Its Befell!".
Time to move on I would suggest.
But isn't that part of the living history that is PPRuNe? Over the years some of the most enjoyable reading has veered significantly from the thread starters words, gone down numerous rabbit holes and sometimes recovered and sometimes not. There's never a dull moment [well, sometimes] and on the whole it's all a good stirring of the pot of memories.
But that is so unfair to those of us with failing memories!
