Blade Dampers

[EtheAv8r]

OK so we all have Blade Dampers on the blade grip/spindle assembly of our rotor heads, and they come in different hardnesses. Why?

What is the purpose/function of these dampers.

What is the result / how is it experienced when flying if the dampers are too soft?

Ditto too hard?

How do you know when they need replacing?

[trvo]

Have a read of this, the last link has some info on damping: understanding your heli

Trev

[scallybert]

On a G5 with a new set of the green damper rubbers (the ones everyone says are too soft, and are no longer supplied); if you apply a couple (pitch or roll) to the grips to try and make the dampers deform - the frame flexes before the dampers noticably deform.

This made me wonder how much those dampers actually deform in use, and to what degree the heli behaves like they're rigid. (That aside, the blades will flex ('flap')).

Having said that, those green dampers seem to have softened up, as I was shocked to discover the (unbent) feathering shaft isn't perpendicular to the flybar. (!!) I haven't done anything about this as this particular G5 is still the one that seems nicest to fly - which is kind of worrying...

[darryl]

Have a read of this, the last link has some info on damping: understanding your heli

Trev

soem of that blew my mind in about 3 seconds... pretty heavy stuff

[trvo]

soem of that blew my mind in about 3 seconds... pretty heavy stuff

Colin knows stuff

Trev

[EtheAv8r]

OK I have staggered through Understanding your Helicopter, and it has not really answered my questions. It does say "The stiffness of the damper rubbers, etc. determines how closely the body follows the main rotor attitude" but what does that mean in practice?

The reasons for asking the original questions, apart from general interest and expanding my understanding is that I have uprated my Innovator MD530 by moving from the standard Foam blades to the Wood blades of the Innovator EXP, and upped the headspeed appropriately. I am now seeing the helicopter 'nodding' in forward flight and this can be amplified or triggered by applying forward or backward cyclic (elevator). So I wondered if this is because I have the soft damper meant for Foam blades and whether upping to the harder dampers is the solution.

[trvo]

The nodding can be a few things, insufficient headspeed for the blade / damper combo or slop etc... I think you are seeing point nr 2.

- Harder dampers will cause the nodding at low headspeed.
- Dampers that are very soft (with stiffer blades) will cause a nodding on cyclic input.
- Slop in the control system could cause a nodding on heads with stiff blades / hard dampers.

Characteristics of damping
- Harder dampers = crisper cyclics, less stability
- Softer dampers = smoother cyclics, more stability

That's a VERY limited and rough overview and may not always be true in certain circumstances...

Trev

[EtheAv8r]

OK - I will pop in a set of the EXP dampers and see what results. Err when I get help or finger a little less sensitive!