Ballast

Q: My model aircraft is tail heavy, what do I use for ballast to keep the nose down, and where should I put it?

A: There are many things that you can use, and many places in the model that the ballast can be placed. Lets look at where to put the ballast first.

• The radar nose radome is a good place to start. It is in general the point most forward from the wheels, so the lever arm is longer and less weight is needed.
• Engine nacelles. These are forward of the wheels on many aircraft. The major drawback is that since they are in general not as far forward, more weight is needed, and if too much is used, the landing gear could bend or even collapse.
• You can place weight in the ejection seat. And for many 1/72 aircraft, there are actually white metal seats that are weighty. This can help.
• Remove weight from the rear of the model. Sometimes, in some older kits, there is structural overkill in the rear section of the aircraft. Some of the inner supports can be removed if they are deemed unnecessary.

Next, what materials work well as ballast? There are many materials that can be used, each with advantages and disadvantages.

• BB's, for BB guns make good ballast. They are small and fill space pretty well. They can be held in place in the nose, nacelles, or around the cockpit tub with epoxy or gap filling superglue.
• Lead fishing weights work very well. They come in different sizes, and being lead, their density is high, so not much is needed to add a lot of mass.
• You can literally put your money into your models. Pennies can be used to supply weight.
• Modeling clay can be used. It fits into difficult places, and can be used to hold BB's and lead in place. However, there can be a problem. Some commercial modeling clay begins to separate after a number of years, and the oil component can migrate out and damage the finish.
• Glazing putty can be used like modeling clay, with the advantage that it is denser.
• Flux-free solder works very well. It is dense, and can be easily coiled and made to fit into areas. Superglue can be used to fix it into place.
• Lead foil from wine bottles is very good also. It can be crushed and made to fill unusual shapes.
• If you are really in need of a lot of mass, you can mold a weight that fills the entire area. Use aluminium foil or wax to fill the area to get the shape. Remove this shape and make a temporary heat resistant mold. Nothing fancy, maybe clay or sand. Then melt solder into the cavity. Once hardened remove it from the mold and you have a custom weight that fills most of the available space. As in the other weights, superglue, epoxy, or even white glue can be used to hold the weight in place.