Chook Answer For Grumpy Cobra

[FlyCookie]

In another thread Grumpy wrote....

++ Interestingly, (if the following article is to be believed and thats a big "if") our new CH-47F's may come fitted with auto blade fold as standard http://www.ingeniumtech.com/services/design/details/?id=4

"Newer Boeing CH-47 Chinook helicopters are equipped with automatic blade folding to allow the aircraft to be quickly and easily stored. Older Chinook helicopters employ a manual process to fold blades."

Very handy for ship board ops - even if they cannot fit in the hangar (as is), big advantage over our Euro Taipans if true!++

Here's some thoughts re the above link by someone very much in the know......

++ I don't know of any fielded powered blade fold system for the Chinook. The current 'system' uses a manual disconnection of the dampers, with blades swung round on to specially fitted cradles. It's an absolute mare of a task and one to be undertaken in nil wind and no deck motion. UK QEC ops are planning to use the Chinook unfolded.

I'd like to see the details behind the proposal outlined at the link. Personally, I'd expect there to be many more problems in turning a concept into a design, but I never discount ingenuity - the team may have come up with a clever, new way of power folding the head. However, I'd rate it as 'possible' rather than probable.

One of the biggest challenges is handling the pitch change rod loads generated when the folding blades swing away from their normal position. The Chinook has a unique arrangement of pitch change servos, and I'd need to reacquaint myself with that before offering any more opinion. These are monster blades, and the loads would be significant. You also need to develop some extremely reliable locking systems to ensure that the blades are secure before engagement. Plus some reliable signalling and fault detection systems. And get all that 'stuff' up to and back down from the rotor heads - both of them.

The other challenge is delivering a system that could operate in a reasonable set of weather conditions, not near calm. There's also the need to be able to motor the heads around to a datum position to start the fold cycle. That will mean some hefty hydraulic or electric motors, and the current Chinook utility hydraulic system is certainly not up to that - the DC electrics aren't great, either.

Not sayin' it can't be done - but I wonder which nation would pay for the development and certification - not the US, that's for sure. ++

That quote from here - http://tinyurl.com/oekm9zq

BTW the LHD hangars can accommodate the Chook: rotors removed, hubs depressed and loaded on tot he aft lift at an angle. Lift weight is OK. Deckhead clearance downstairs is a bit limited, though.

In short, never expect them to be anything but occasional ground-based visitors to the LHDs. At most, the ships can be used as ferries.

Ye, I know that this post is a bit of wordy, I hope some of it helps. ;)

This post has been edited by FlyCookie on Nov 29 2015, 07:26 AM

[Grumpy Cobra]

Well that is a great insight, by "Engines" into the current chook blade system so auto folding on CH-47F is a myth, even manual looks to be quite a job!!!! Much appreciated Fly Cookie!

Now if the RAN follows the stated RN intended practise of storing chooks unfolded, deck space might become an issue on the LHD - then again as you say they will rarely embark so maybe not! What a right royal ensemble we have - all the helicopters we plan to deploy on LHD don't have auto blade folding and the one we do have with auto folding (Romeo) they will not deploy on Canberra/Adelaide!

:lol:

[Grumpy Cobra]

As a post script - I had a look at photos of embarked chooks, mostly HMS Ocean and not one image of folded blades - amazing how one does not see things in plain sight until someone points it out!!!!! So thank you to Engines!

Found this image from the recent Trident Junk Exercise (same games that Marine Ospreys deployed on SPS Juan Carlos) which also puts things into perspective RE MV-22/CH-47 size aboard HMS Ocean!

(IMG:https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-xpa1/t31.0-8/s960x960/11224734_748642521908168_3312497663810930311_o.jpg)