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I also used tungsten from TIG welding rods. Some of them are fairly pure, they layed in nicely with expoy/flox. Careful with the rods though, some of them have small amounts of radioactive material, you might just get someone's interest the next time you land at an airport ;-)
Doug
>>> PAUL HERSHORIN <paulhershorin@bellsouth.net> 04/27/09 4:52 PM >>>
Tungsten--this is correct.
Paul
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From: terrence o'neill <troneill@charter.net>
To: lml@lancaironline.net
Sent: Sunday, April 26, 2009 9:23:01 AM
Subject: [LML] Re: Balancing MkII Elevators
Paul,
Do you mean tungsten powder?
I used that with epoxy to rebalance my elevators after adding trim tabs on both sides. I made little half-teardrops under each forward segment of the elevator.
I don't recall how I found them, but the two bags of sample powder are from Teledyne Wah Chang (google it). This was about four years ago, so I don't know if they still offer the tungsten powder. If I recall, it is a little more dense than uranium. Mixed nicely with epoxy and cast.
Terrence
L235/320 N211AL
----- Original Message -----
From: PAUL HERSHORIN
To: lml@lancaironline.net
Sent: Friday, April 24, 2009 22:11
Subject: [LML] Re: Balancing MkII Elevators
I used tunson in powder form--heaver then lead--mixes with resin very well--scrap recycle places have it.
Paul Hershorin
360--471LA
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From: "Sky2high@aol.com" <Sky2high@aol.com>
To: lml@lancaironline.net
Sent: Thursday, April 23, 2009 8:40:51 PM
Subject: [LML] Re: Balancing MkII Elevators
Rob, et al,
Yep and a certain aileron that contains a trim tab and actuator require even more balance weight.
Grayhawk
In a message dated 4/22/2009 8:27:23 A.M. Central Daylight Time, rwolf99@aol.com writes:
I, too, was surprised at how much lead I needed to balance my 360 ailerons. In fact, I have those lead half-rounds going nearly full-span (two of them, flat surface toflat surface). But let's stop to think about it. We need as much "moment" (mass x distance) in front of the hinge line as behind it. In practice, we have more weight (balance weight) forward of the hinge line than we do behind it (the control surface itself) since the CG of the control surface is generally much further behind the hinge line than the balance weights are forward of it. This is certainly the case with the ailerons, but less so for the rudder and elevators, since they have those forward overhangs for aerodynamic balance.
For preliminary design purposes, my airplane design group assumes that the balance weights weigh 1.5 times the weight of the control surface alone.
Bottom line -- your balance weights need to be at least as heavy as the control surface, and up to 50% more.
Yup, it's a lot.
- Rob Wolf
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