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HAWK21M
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B747 Rudder Balance.

Mon Dec 27, 2004 3:24 am


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What is the procedure for Rudder Balancing on the B747 on line.Can it be done by Calculation Method.
regds
MEL
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EMBQA
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RE: B747 Rudder Balance.

Mon Dec 27, 2004 4:40 am

The rudder on the 747 is hydraulically actuated and not required to be balanced. Dampers in the system reduce any flutter, which is the main reason for balancing. This holds true with most any hydraulically controlled flight surface.
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miamiair
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RE: B747 Rudder Balance.

Mon Dec 27, 2004 8:42 pm

Ref: B747-100/-200/-300 SRM 51-80-03 "Upper Rudder Rebalancing."

The rudder can be rebalanced by the calculation method without removing the unit from the aircraft. But if balance weight need to be added/removed, removal is required.
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HAWK21M
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RE: B747 Rudder Balance.

Mon Dec 27, 2004 11:06 pm

Consider the Above Example.After the rudder is balanced & refitted to the Vertical fin The logo will need to be painted on the Fin area to match the Painted rudder [Done earlier].
Will this balancing be done by adding/removal of balance weights.
regds
MEL
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747NUT
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RE: B747 Rudder Balance.

Tue Dec 28, 2004 10:08 pm

Any flight surface has an upper and lower balance limit. When they are balanced off the aircraft as per a jig method, the idea is to balance it as close to the lower limit and then fitted.
This will allow you a bit of room to add weight to the surface i.e. painting or repairs, without adding balance weights, during the calculation method.

The rudder on the 747 is hydraulically actuated and not required to be balanced. Dampers in the system reduce any flutter, which is the main reason for balancing. This holds true with most any hydraulically controlled flight surface.
As far as I am aware every flight surface is balanced as per the SRM, and the dampers in the system are mainly used to prevent the surface knocking around in the wind when the hydraulics aren't pressurized

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miamiair
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RE: B747 Rudder Balance.

Tue Dec 28, 2004 10:49 pm

The only balanced flight surfaces on the 747-100/-200/-300 are the outboard aileron (SRM 51-80-01), the outboard elevator (SRM 51-80-02) and the upper rudder (SRM 51-80-03).
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HAWK21M
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RE: B747 Rudder Balance.

Tue Dec 28, 2004 11:40 pm

The only balanced flight surfaces on the 747-100/-200/-300 are the outboard aileron (SRM 51-80-01), the outboard elevator (SRM 51-80-02) and the upper rudder (SRM 51-80-03).
Are you saying the Rudder is not Balanced.
regds
MEL
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miamiair
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RE: B747 Rudder Balance.

Wed Dec 29, 2004 12:17 am

That's what the SRM is describing.
.
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CCA
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RE: B747 Rudder Balance.

Wed Dec 29, 2004 1:02 pm

As Miamiair said only the upper rudder is balanced on the "classic" the -400 has 3 separate PCUs on the upper rudder while the classic has a single tandem PCU which is why it requires balancing and the -400 doesn't.

Rgds CCA
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miamiair
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RE: B747 Rudder Balance.

Wed Dec 29, 2004 11:29 pm

On the 747-400, only the outboard aileron and outboard elevator get balanced.

Reference: Boeing Document D634U103, 51-60-01 & 51-60-02.
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