General What is this for?

Smoggie

Well-Known Member
It;s the radius arm/ follower arm . It's there to drive the swash round. DFC heads dont need them as they have rigid pitch links, but conventional heads have to have them to turn the swash.. Read this: DFC Rotor Heads Demystified
 

Dennis H

Member
This is a very hard question to answer.

The part is designed to eliminate the washout height setting or angle phase of the cyclic. I believe it's referred to as the "integrated washout type FBL head".

It attaches on the shaft directly below the rotor head, then to the top of the cyclic which has arms to control pitch. It keeps the cyclic and blades in alignment and controls steadiness.

I understand some Heli's have it, and some don't.

I know the purpose of the part, but don't know if I am explaining it correctly. I know if your Heli had this part new, then you must keep it, or you will definetly have a disaster on your hands.

It works somewhat like your automotive suspension works keeping the wheels in a controlled position. Bad example, but the best way I know to explain it.

I have these parts on two of my Heli's, one being a 1/4 Scale. I know to watch them for any signs of wear. it's best to change them vs. the outcome if you don't. If there is any looseness or slop in the arm, replace it. There cheap, but definetly needed.

I welcome any comments, as I would like to understand the part more.

I hope this helps a little, Dennis.
 

Smoggie

Well-Known Member
Dennis, the purpose of the arms is really quite simple. All the arm(s) do is drive the inner part of the swash round so that the inner part of the swash rotates along with the head. The outer part of the swash of course is fixed in position to the fuselage, usually using an anti rotation guide and pin. Flybar heads have these arms and also flybarless heads except for DFC type designs (which use rigid pitch links to drive the swash around).

The link in my last post explains it quite well.
 

Dennis H

Member
Dennis, the purpose of the arms is really quite simple. All the arm(s) do is drive the inner part of the swash round so that the inner part of the swash rotates along with the head. The outer part of the swash of course is fixed in position to the fuselage, usually using an anti rotation guide and pin. Flybar heads have these arms and also flybarless heads except for DFC type designs (which use rigid pitch links to drive the swash around).

The link in my last post explains it quite well.

I should have taken the time and read it. Now I will.

Thanks, Dennis
 

Tony

Staff member
Yup, that is the part that I call the Swash Driver. It spins the swash to keep the collective control in alignment so that forward is forward, reverse is reverse and so on. It's a superior design IMO over the DFC.
 
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