Message-ID: <367D22F3.924721DE@tstonramp.com>
Date: Sun, 20 Dec 1998 08:17:02 -0800
From: Hal Woodruff <woodruff@tstonramp.com>
To: lancair.list@olsusa.com
Subject: control surface balancing
References: <19981220053424.AAA24141@truman.olsusa.com>
Mime-Version: 1.0

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>>

I, too, used the lead shot slurry method of balancing the control

surfaces.  Like you guys, I added a little to compensate for the paint.

When I was installing the surfaces I found that I needed to add a

considerable amount of lead to compensate for the weight of the primer

and paint.  Don't underestimate the weight of the paint.  Like you

suggest, it is a lot easier to drill out the extra lead than to add more

in later.


I fixed the problem by digging out all of the slurried lead and then

melting in new lead.  I suspended the control horms in an ice bath and

then very carefully poured molten lead into the control horn.  This was

accomplished without marring the painted surface.


One thing I learned in the exercise is that  solid lead is considerably

more dense than the lead slurry mixture - on the order of 40%.  I was

astounded by this.  You can check it yourself by pouring lead shot into

a mixing cup.  Mark the level of the shot with a marking pen.  Weigh the

cup.  Now pour water into the cup up to the level of the shot.  Weigh

the cup again and take the difference - this is the weight of the water

in the spaces between the lead shots.


Now pour out the lead/water and refill the cup with water to the line

earlier marked and weigh the cup.  Again, weigh the cup empty and take

the difference.


You can now compare the weight of the "solid" water to the weight of the

water "in the spaces" to see how much more dense the solid lead would

be.  Check it - you'll be amazed.


Using solid lead, rather than the slurry, will get you more increase in

counterweight density than going from solid lead to depleted uranium and

you won't glow in the dark.


Hal   360HW