JT9D T/Rs
 

Are they Pneumatically operated ?
Thanks for replys in advance.

The short answer is....Yes!

Are they?

If you ask me there is not enough info. The airframe/engine combination determines the T/R configuration. It's like asking if 767's have pneumatic T/r's. The answer is yes AND no, it depends on the engine.

If the JT9D is fitted to a 767 then the answer to the question is NO they're hydraulic (JT9D is a 767 engine option). I suspect that they are pneumatic on the 747. (I don't have any 747 experience)

The RB211 on the 757 is hydraulic but on the 767 pneumatic.

Provide all the info and you will possibly get the right answer.

Cheers

Mono
Good point there, I'd put the 767 out of my mind and thinking purely classic 747:rolleyes:

With regard to the JT9D on the classic's.........
Going back many years............
Cold stream part was operated by airdriven motor and hot stream by mechanical drive from the gearbox (if I remember correctly - certainly remember always having to replace the hot stream drive cables !!)

The RB211 on a 75 is a -535 and on 76 it is a -524, in other words 2 completely different engines made by Rolls Royce.

jt9d trs
 

most definately mechanicaly actuated of a pneumatic motor :cool: