Rare site...

[Roondog]

I live in Denver Colorado and you rarely see a Chinook flying overhead, we mostly have Blackhawks and Hueys in the area. Tonight I had the pleasure of seeing a Chinook fly over my house. I have no knowledge of how they work, but the question came to mind, how do you auto one? If the transmission to one of the M/R fail and the other keeps turning under power, if that's how it works, what are the EPs? Thanks, Jeff

[Witch]

Very interesting. I'm a little curoius about that myself.

 

My guess that if a shaft breaks, you'd notice a pitch change and probably throw the collective down and land asap.

 

I wonder if there's a chinook EP dot com out there?

 

Later

[Sparks]

I spent a week working on Chinnocks at an RAF base here in England. Very interesting...

 

There were 4 in from the Middle East and i was given the task of taking the gear shafts down to components and cleaning the sand out Then trying to put em back together. So i could tell you how the gear shaft works but not a clue how they auto...

 

 

Another experience for me was flying in one to a museum about a year ago. They are EXTREMLY loud...Earplugs required just for sitting in the back. And also very cold and breezy. Bloody good fun though

[Brianmech72]

Yes, I asked my instructor at ground school this morning and they do have a driveshaft between the two rotors. He wasn't sure how an auto would work in one either. What made me remember the question was a video he showed of a Chinook during a test that was tied down to the ground. The topic at the moment was ground resonance. It shook so bad even after he killed it that it ripped the rear rotor tower off the helicopter.

 

I spent a week working on Chinnocks at an RAF base here in England. Very interesting...

 

There were 4 in from the Middle East and i was given the task of taking the gear shafts down to components and cleaning the sand out Then trying to put em back together. So i could tell you how the gear shaft works but not a clue how they auto...

Another experience for me was flying in one to a museum about a year ago. They are EXTREMLY loud...Earplugs required just for sitting in the back. And also very cold and breezy. Bloody good fun though

[RHS1]

Yes, I asked my instructor at ground school this morning and they do have a driveshaft between the two rotors. He wasn't sure how an auto would work in one either. What made me remember the question was a video he showed of a Chinook during a test that was tied down to the ground. The topic at the moment was ground resonance. It shook so bad even after he killed it that it ripped the rear rotor tower off the helicopter.

My personal opinion would be that a chinook would auto the same way a ship with a coaxial rotor system would would auto . The twin engines would be most likely connectedto a common trans and if both fail power would be lost to both of the rotors at the same time. The fact that they spin in opposite directions to cancel torque out should not interfere with the auto. This is of course just speculation on my part not fact.

[Goldy]

ROONDOG- Change the name of your post to "Chinook question" .... There are several pilots on this forum that are flying Chinooks today, get their attention and you will get answers....

 

Good flying,

[copter doctor]

I used to work as a flight engineer on the Chinook. Doing autos was basically the same as a conventional helo, if you had a power failure, you lowered the thrust lever ( its not called a collective on the chinook) and did the auto. We never did touch downs and power recoveries were always done at a high altitude like 500 ft. As for the power train, the two engines power a combining gearbox that then uses synch shafts to transmit power to the fwd and aft gearboxes. The synch shafts are what keep the blades from eating each other so as long as you don't lose them you can auto or fly single engine. When I got out of the Army in 99 they were getting ready to put a guard or reserve Chinook unit in at Fort Carson in Colorado Springs, that may be where the one you saw was from.

[500pilot]

A friend of mine that I used to work with at Rucker used to be an MTP while in the army flying Chinooks up in Alaska. He told me a pretty interesting story about Chinooks and autos. He mentioned while performing single engine auto to recovery that the good engine failed. He tried to bring the idled engine back to full throttle but it failed to respond. Now he was committed to a full down in a 32million dollar machine. All he said was he just started a decel at around 200-250ft and just held it until he felt the back wheels touch. After that it was just use the thrust lever to cushion. The rotor system has TONS of inertia in it. The problem he said was after touchdown. As he lost rotor rpm he also began losing hydraulic pressure. This cause a lack of steering in the wheels as he rolled down the runway. (it wasnt to a complete stop) He basically was a passenger until it rolled of the runway to a stop in a small embankement. Luckily there was no damage is what he said, just some browm stains in his shorts.