Counterweight made from fishing lead sinkers

by AG Pro | November 10, 2014 | (0) Posted in How To

Fishing lead sinkers as counterweights


C.O.G (Center of Gravity) location is one of the most crucial parameter provided by the model’s manufacturer. The proper C.O.G location enables easy and stable flight. However, some pilot prefer different C.O.G location; deviating from the factory setting in order to obtain unique flight characteristics. They can be nose heavy or tail heavy. In most cases, battery mount location is adjusted to obtain the desired C.O.G.

There are some cases where the desired C.O.G is failed to be achieved, for example when using a much larger and heavier battery or smaller and lighter battery. This might also occur when using FPV models without mounting any FPV gears (just for flying the model). Additional weights called counterweights are used to solve this issue. There are many ways to find additional weight to be used as a counterweight (coins, stones, etc). Solid lead sinkers for casting/fishing are another option.



They come in a variety of sizes and weights. You might directly use and load them to your model, or you might want to merge a couple of them into a single shape.

Firstly, the required weight is to be measured or you could try loading some of the lead sinkers to the model until the desired C.O.G location is achieved.



Secondly, construct the mold / die using wooden materials to a desired shape. Cover the internal part of the mold / die with thin aluminium sheet.




Finally, the lead sinkers are to be heated until they reach melting point and formed into liquid state. Immediately pour in the liquid lead to the mold / die.


Notes : Consult a professional for heating and melting process as the gas fumes from lead is extremely hazardous to human health.


After the liquid lead has turned back to solid state and cooled down, remove it from the mold / die. There is some weight loss due to evaporated lead during the heating process and it is recommended to add some additional numbers of weights to the desired counterweight before melting the lead sinkers.



D.L. ENGINEERING - The Sky is Home


hellcat on November 11, 2014
Hi Ive found old car wheel weights are spot on the weight is printed on them go from 5grams to 50 grams they are flat and easily fitted. you can get em by the bucket load at tire suppliers and at scrppies
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AG Pro on November 11, 2014
Hi hellcat. Thanks for the additional info. Thanks for sharing the option of counterweights What are they look like?
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udo789 on November 11, 2014
Check out the FT Spitfire - Build Video at 45:50. These are adhesive backed lead wheel weights, but you can also get the same item lead free at Amazon or any auto supply store.
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AG Pro on November 11, 2014
Thanks for sharing udo789. The lead free weight should be highly recommended. With this, we don't have to worry about the lead gas fumes anymore.
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Sirglider on November 13, 2014
For the mold I use aluminium fish frozen dish packaging. You can shape it easily the way you want.
My question: how do you heat the lead to melt it? That's the part of equipement I miss in my workshop...
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AG Pro on November 13, 2014
Any small size stainless steel cooking pan; with handle to ease pouring into the mold. A bunsen burner to heat up the pan. Be aware of the hazardous lead gas fumes and don't use the pan for cooking afterwards if you decided to use your cooking pan from the kitchen. It is recommended to use a separated pan dedicated for heating this lead material.

If you don't need to use a heavy counterweight, you should use the adhesive backed lead wheel weights as explained by udo789 above. It will save your time and energy and save from lead gas. The counterweight in the article is heavy ( 300 g - 400 g ) and is used to simulate the payload of FPV and autopilot gears.
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Counterweight made from fishing lead sinkers