I do something much simpler…
MODEL WITH THE GEARS UP!!
But, if you REALLY want to model gears-down, I’d use the same lead shot everyone else has been suggesting.
Just a thought for the glass nosed stuff.(B-29 B-24etc.) Put the weights behind the engines, since that is generally forward of the center of gravity of the aircraft and generally is empty space on a model,however it will require more weight as it is closer to the cg.
Believe it or not I have found candle wax is not bad as a weight, it can be driped in a small area and works well as a fixative for lead shot or BB’s. It ill not hurt the plastic and fills an area very well. Its also cheap[:D]
If you want nasty, dirty lead try local tire shops. They usually throw away the lead wheel weights they pull off , and most places will give you all they you want. Downfall is that they are usually dirty and nasty and have a steel piece in the middle that clips to the wheel. If you aren’t real picky it’s a cheap place to get them.
I use the lead beads sold in diver stores for use in “soft lead belts” mixed with glue. its cheeper than BB ammo, and easy to get a hold of.
// Claes
Window sealing putty from the hardware store. Cheap, extremely malleable, no effect on plastic, dense. Just stuff everywher you can’t see. Fits in the tightest spaces imaginable. If you put too much in, it stays soft so you can clean it off withthe edge of a knife or your fingers.
I use 50 caliber lead balls, the kind used for muzzleloaders. You can flatten them with a hammer and then you can cut them into the size you want. If those little chunks are still too big you can flatten them as well. You can get these balls at walmart, they are made by Hornady in a small red box and can be had in .32, .45, .50, .54, and .58 calibers. Theyre usually pretty cheap too, cheaper than sinkers per pound!
I use nuts from the local hardware store as they come in a variety of sizes, and are generally pretty heavy.
And being hezagonal they usually sit easily in fusalages and behind engine cowlings. I usually hold them in with a few spots of super glue.
Karl
I’ve use lead shot mixed with 2-part epoxy; this is good for filling odd shaped spaces. I’ve also used spent bullets, which fit very well in the nose cones of modern aircraft. As a shooter with my own place in the country to shoot, I’ve literally got thousands laying around(or just under the ground) at my “range”. Simply epoxy the bullet into the nose. Good luck, Gary.