R22 Tail Rotor blades pitch angle variation
 

Hi,

I'm a french engineering student working on my final project dealing with the tail rotors of different aircrafts.

I would like to have the opinion of professionals (or people who knows the topic) about the mechanism of the pitch angle variation of the tail rotor blades on the Robinson R22 (from the pilot's spreader to the blade).

Does someone know the exact mechanism of this part of the aircraft ? Is is made with an addition of rods or anything else?

Thank you for your reply

Hi Anto

The TR control system of the 22 is entirely push-pull rods, from the pedals all the way to the spider.

Inputs by the pilot are transmitted via a bell crank at the rear of the tail boom to the non-rotating portion of the TR pitch controller, which is attached to the rotating part in a similar manner to that of a swashplate for the MRH.

The rotating part has two pitch horns and pitch change links attached to the TRB, collectively changing their pitch to provide directional control about the normal axis.

Hopefully this will help, from http://www.robinsonheli.com/manuals/

Maintenance manual;
P. 9.26C
http://www.robinsonheli.com/manuals/r22_mm/r22_mm_9.pdf

Illustrated parts catalogue;
P. 67.40
http://www.robinsonheli.com/manuals/...r22_ipc_67.pdf

:ok:

It's like the TR of a real helicopter, only smaller and not so well made;):ok:

Below the belt crab, but oh so true!

And you know I have the scars to prove it - mental and professional, if not physical:ok:;)

Frank knows more about tail rotors than most out there - that's why he put one on the top as well. :rolleyes:

Some real helicopters had cable operated tail rotors.

Don't brand me as a dyed-in-the-wool Robbie lover just yet, but at least there's generally enough pedal when you need it in most conditions!

RVDT
Now that is cruel :}

The fact that the Illustrated Parts Catalogue ships with a packet of crayons is the clue ....:}

....and yet it works so well.

Perhaps Anto, you should spend more time studying the TR of a Jetranger or a Gazelle? I'm no Robbie die hard, but nor a knocker, they serve their purpose in life. As a study Anto, it'll be good to look at the advances made to the R44 TR and then perhaps the R66 to see any improvements and why? Or just ask here for help on your thesis. :bored:

Cheers, FP.

Thanks for all your answers, it helps me a lot :)

I have checked the IPC and the AMM to better understand the whole tail rotor pitch control and now its okay i get it.

In a brochure of Robinson company, they explain that there is no maintenance to perform on rods... Is it true? Even no preflight checks?

Because I'm still wondering whether state of spherical bearings in rod ends will be still good after many Flight Hours (wear...). What are your opinions on that point?

Sorry if my English is not so good but I'm really interested in that topic :)

Yes, definitely preflight checks required on all the usual tail rotor elements - bolts and PAL nuts (the thin metal lock nuts they use all over the airframe), dings / nicks / corrosion / erosion on the blades, free movement of the pitch change mechanism, gearbox oil / security and lock wiring etc.

The spherical bearings in the pitch change links get worn and loose - there should be movement around the rod's long axis, but not much if any in any other directions when you hold the connecting bellcrank still. After a while they get too sloppy and can be first reversed and then replaced.

What are the materials used to manufacture these rods ?

Regarding weight of the whole pitch control command, how heavy is it ?