Rudder Counterweight

How to keep the Cessna 170 flying and airworthy.

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N2520V
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Joined: Tue Oct 03, 2006 4:36 pm

Rudder Counterweight

Post by N2520V »

Any one out there have any experience re-attaching a rudder counter weight?
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GAHorn
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Post by GAHorn »

There are two common ways to attach elevator and rudder balance weights. Originally the factory used "cherry max" type self-locking rivets (CR163C-4-2 and CR163C-4-8's), also known as NAS445 types. These are the same type rivets that hold the leading edge onto the rudder, and if well done can double-duty to hold the weight.
But most repairs to rudders/elevators weights simply used a couple of #8 X 7/8" PK sheet metal screws.
Either fastener goes through the end-rib or tip-rib and into the weight. (The head of the fastener lives in the airspace between the counterweight "horn" and the stabilizer. Be careful no interference exists to control movement.)

As a matter of interest, many pilots overlook the necessity to inspect the security of those weights on each preflight. Make it a regular habit, not only to avoid a loose weight, but also to avoid a protruding fastener from interfereing with control surface movement when the fastener backs out and interferes with the stabilizers. (It'll lock up the rudder and/or elevators.) 8O
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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Squirrly 170B
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Re: Rudder Counterweight

Post by Squirrly 170B »

Are there any updates or pictures of this procedure? I just finished installing lower rudder skins and a new bellcrank. I am now 10 OZ underweigh at 27 inches and will have to open the horn to install the weight. I think this might loosen the factory installed 4 lb weight. Any ideas would be grateful.
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DaveF
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Re: Rudder Counterweight

Post by DaveF »

Here’s what the balance weight looks like from the inside of the rudder horn. Just FYI, since most people have never seen it.
Image_2023-11-15 14_31_34_194.jpeg
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cessnut
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Re: Rudder Counterweight

Post by cessnut »

I could be wrong, but I don't remember ever having to add that much weight to a rudder that wasn't heavily modified. Is this rudder stripped or painted? Are you certain the math is correct?
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DaveF
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Re: Rudder Counterweight

Post by DaveF »

Cessnut, how many have you balanced and what do you normally find?
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cessnut
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Re: Rudder Counterweight

Post by cessnut »

I have not balanced many 170 rudders, although I will be doing 2 soon. However, I have balanced many Cessna rudders ranging from 150s through 208s. Like I said, I could very well be wrong. 10 oz. at the balance weight would be approximately 8 in. lbs. That would mean it is +35. Seems like a lot.
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