Sloppy Links

[eagleskinner]

I remember the Bell 47 had a lot of play on the servo input link (sloppy link) and as a tech, I even remember rigging them. As "You have" flying ballast I even recall that there was a fair bit of play in the cyclic too.

But for the life of me, I can't remember the jack schematic diagram... Anyone got one to hand? I have been trying to explain it to some youngsters who work with and for me and they can't understand a.: why and b.: how. :8

Was this a typically Bell 47 Sioux thing, or did other Bells use this slotted input link too? Hueys, Jet Rangers...

Thanks

[[email protected]]

I think a sloppy link is an essential part of a hydraulic system so you have a means of moving the pilot valve which then directs fluid to the appropriate side of the piston which then moves until the pilot valve is back in the middle etc etc. Not exclusive to Bell definitely:)

[TRC]

As Crab says.

The 206 has sloppy links, 109 too (I think)

[Coriolis]

Ditto, as Crab says.

I don't recall working on a helo hydraulic flight control system without a sloppy link, and I've seen a few.

The sloppy bit comes in a variety of guises, but it's not going to work unless you can move the selector valve to open the fluid passage to the power ram, which then moves and in so doing recentres and closes the selector.

It's what my old Dad would call a closed-loop system :ok:

[bob2s]

And here was me thinking that you were asking about the sloppy link between the seat and the cyclic!

[eagleskinner]

Oh... that's the SSI isn't it? (Seat-Stick-Interface)

Anyway - I recall the Sioux link being a slot at the end of the servo jack - on the outside. On others it may have been an internal arrangement with the valves. It's so long since I did any mech work - and to tell the truth, I miss it. Building commercial buses is no fun - all politics and shaving the pennies and other lies.

As for the Jacks, isn't it something to do with preventing jack-stall or lock-up.

So... I do recall our Sioux's had a lot of movement on the cyclic due to the sloppy link. Was this or is this so for other helis? Any 205 / 206 / 212 / 412 types know? Has this reduced over the years of development.

My last heli flights with "you have" time were in Gazelle and Lynx during post maintenance flight tests. 1987 - summer. I can't recall much free stick movement on either Gazelle or Lynx. But then I haven't just forgotten more than most young techs have ever learnt - I have probably even forgotten more than I ever learnt... :hmm:

[paco]

"Oh... that's the SSI isn't it? (Seat-Stick-Interface)"

How about meat servo? :)

Phil