Thermite dry ice rocket

Rocket fuel is scary because it blows up and catches on fire. Dry ice rockets are less scary in that respect. Dry ice is a nice way to handle a compressed gas because it is not runny or reactive. But a dry ice rocket is really not much better than a pressurized air / water rocket - the pressure built up on the ground is what the rocket gets to launch with. Just as a flying water rocket expels the water behind it, I suspect that a flying dry ice rocket expels unsublimated dry ice behind it. The problem is that the relative slowness of sublimation on the ground (which is good, because it is safe) is too slow to sustain flight in the air.

What is needed is some way to accelerate sublimation in the air and turn a large mass of dry ice into hot hot gas in flight. The hotter it is, the move volume it occupies, and the more propulsion you get. I propose thermite. Thermite is cheap and packs a lot of heat into a small area. It does not require oxygen to react and can be jiggered so it does not react explosively. A thermite reaction in a dry ice rocket will turn that dry ice into nice hot CO2 for propulsion. The thermite and dry ice should not be loaded willynilly in the rocket (but if you try, please post video). I think a central core of dry ice filling the rocket with the sides of the rocket lined with thermite would work best. Maybe the thermite could be seperated from the dryice core with a ceramic mesh, but this is getting a little Tom Sawyer.

If the thermite was doped with something to slow the reaction, it could start at the bottom of the rocket and proceed upwards, sublimating the adjacent dry ice as it went.

A problem is if the rocket explodes and showers bystanders with reacting thermite, which would hurt. The standard 2L soda bottle would be inadequate for this use because it would melt. I think an aluminum scuba tank might be used as the rocket body.