What are the small tabs on the trailing edge of the rotor for?
Joined: May 2002
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From: Downeast
They are the Rotary Wing equivalents of Mexican Pinatas that provide great sport for the Pilots to bang around with the long handled brushes when when washing the aircraft. It becomes a group sport when the Engineers get to figure out why the aircraft is out of track following the wash job!
Joined: Aug 2000
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From: A very long way North
They're an optional extra that you can add to make your helicopter sound right. This is so old boys can hear the sound, look wistfully to the skies and say "ah, the 105, I recognise that sound anywhere". Also available in "Chinook Thump", "Bell 47 for Filmmakers" and "Blade Tape in the Rain".
Joined: Jan 2012
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From: Germany
Sorry guys!
But i think the picture is showing the following:
Eurocopter highlights its innovation and bluecopter® technology at Heli-Expo 2010 - Eurocopter, an EADS company
Normal Flaps are not connected with cables!
This are piezo Electric elements designed for noise reduduction!
But i think the picture is showing the following:
Eurocopter highlights its innovation and bluecopter® technology at Heli-Expo 2010 - Eurocopter, an EADS company
Normal Flaps are not connected with cables!
This are piezo Electric elements designed for noise reduduction!
Joined: Aug 2000
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From: UK
Vortex: they are STATIC trim tabs, which allow engineers to 'tweak' them by bending them to allow the blade to fly in harmony with the other blades in the horizontal plane. In the ends of each blade there is a tip cap. Inside this tip cap can be found mini weights (shot or lead blocks) these are DYNAMIC trims. They assist in flying the wing in the vertical plane. New generation helos can adjust some of these settings whilst in flight 
Something to do with voodoo magic 
Something to do with voodoo magic
Joined: Jul 2000
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From: Wiltshire
I used to think that they acted like an elevator ie, if the tab was bent down, more lift would be generated and the blade would fly higher. Only when i started doing in-flight tracking with the gingerbeers that I found they have the opposite effect- bending a tab down causes the blade to twist slightly reducing pitch and causing it to fly lower.
Avoid imitations
Joined: Nov 2000
Aviation Qualifications: ATPL
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From: Wandering the FIR and cyberspace often at highly unsociable times
Kaman used servo tab control, didn't they?
Servo Flap Controlled Rotor
It's a bit like doing the washing up at home. Break a few bits of the best crockery, never get asked again. 
Servo Flap Controlled Rotor
Quote: Pilots to bang around with the long handled brushes when when washing the aircraft.
Now I know you're having a laugh! 3D
Last edited by ShyTorque; 4th December 2012 at 11:05. Reason: link added
Joined: Nov 2007
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From: 55 degrees north ish.
TC
Not quite. The trim tabs are to get all the blades flying in the correct plane (tracking), which is carried out along with PCR adjustments, the weight chambers are to adjust the weight of each blade (balancing).
Most blades have static trim tabs and static weight chambers (which are set up at the factory, and none adjustable) and dynamic trim tabs, dynamic weight pots/washers which the engineer can adjust.
A combination of adjusting all three on the ground, some measurements at flight idle/hover/ differing speeds and then some more adjustments should hopefully have your helicopter flying smoother, help preserve wearing of components and keep your vision clear....
Vortex: they are STATIC trim tabs, which allow engineers to 'tweak' them by bending them to allow the blade to fly in harmony with the other blades in the horizontal plane. In the ends of each blade there is a tip cap. Inside this tip cap can be found mini weights (shot or lead blocks) these are DYNAMIC trims. They assist in flying the wing in the vertical plane. New generation helos can adjust some of these settings whilst in flight 
Something to do with voodoo magic 
Something to do with voodoo magic
Most blades have static trim tabs and static weight chambers (which are set up at the factory, and none adjustable) and dynamic trim tabs, dynamic weight pots/washers which the engineer can adjust.
A combination of adjusting all three on the ground, some measurements at flight idle/hover/ differing speeds and then some more adjustments should hopefully have your helicopter flying smoother, help preserve wearing of components and keep your vision clear....
Last edited by RotaryWingB2; 4th December 2012 at 13:30.
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From: Texas
Fareastdriver:
USN, Kaman SH-2F Sea Sprite (for that matter, A-E and G as well) had that feature which allowed for exceptionally fine tunning of the rotor disk. You could, using two switches in the overhead panel, adjust the cones, (A/C and B/D) as well as asjusting the track (using A and B) motors. I don't think any other helicopter I've ever flown could be tracked to such a fine degree, in terms of how smooth the ride is. (A well tracked CH-53E, with seven blades, produces nearly as smooth of a ride).
I flew SH-2F's back in the 80's. There are plusses and minuses to that design feature.
One plus is that you can fly the bird with zero hydraulics.
USN, Kaman SH-2F Sea Sprite (for that matter, A-E and G as well) had that feature which allowed for exceptionally fine tunning of the rotor disk. You could, using two switches in the overhead panel, adjust the cones, (A/C and B/D) as well as asjusting the track (using A and B) motors. I don't think any other helicopter I've ever flown could be tracked to such a fine degree, in terms of how smooth the ride is. (A well tracked CH-53E, with seven blades, produces nearly as smooth of a ride).
I flew SH-2F's back in the 80's. There are plusses and minuses to that design feature.
One plus is that you can fly the bird with zero hydraulics.
Old age. 
Joined: Nov 2010
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From: Earth
Your picture is from Mide, an engineering company that worked with Sikorsky on their AATD program offering nitnol-based active trim tabs. Sikorsky's actual AATD blade ended up being a S-434 blade with an electric linear motor and bellcrank, as the nitnol has a litany of issues.
There are a few AHS whitepapers out there with studies by DARPA using piezoelectric actuators for active trailing edge flaps, albeit with some inherent flutter and response issues at frequencies necessary to be actually useful (for vibration and acoustic attenuation).
Very large bandwidth trailing edge flap motion and sizing could be used for primiary flight control a la Kaman. Piezos are inherently unsuitable for these applications, regardless of that press releases you read from Eurocopter Even the MD900 blade with the force multiplying X-frame apparatus for piezos could not demonstrate full spectrum response and deflection.
Boeing, Sikorsky, and Bell have also been working with active blade flaps for some time. Nothing has been developed into a production application at this point.
There are a few AHS whitepapers out there with studies by DARPA using piezoelectric actuators for active trailing edge flaps, albeit with some inherent flutter and response issues at frequencies necessary to be actually useful (for vibration and acoustic attenuation).
Very large bandwidth trailing edge flap motion and sizing could be used for primiary flight control a la Kaman. Piezos are inherently unsuitable for these applications, regardless of that press releases you read from Eurocopter
Even the MD900 blade with the force multiplying X-frame apparatus for piezos could not demonstrate full spectrum response and deflection.Boeing, Sikorsky, and Bell have also been working with active blade flaps for some time. Nothing has been developed into a production application at this point.
Joined: Jul 2010
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From: Shelton WA.
If you want the helicopter to be free of vertical bounce, and who doesn't, you must adjust the track using the tabs, mentioned in the original post, to get the blades to "fly" in the same path.
In ancient times flag tracking was used when each blade had a differant colored marker applied to the tip and ground tracking was completed when, after individual tab adjustment, all the colors were transferred on to the flag in the same vertical position.
In ancient times flag tracking was used when each blade had a differant colored marker applied to the tip and ground tracking was completed when, after individual tab adjustment, all the colors were transferred on to the flag in the same vertical position.