Auto Log Feeder for RMH in Aquaponics Hoophouse

I received the Rocket stove videos last night and look forward to viewing them this weekend. I have a rocket mass heater in my aquaponics hoophouse and it burns great but i need to figure out how to auto-feed logs to it so it will burn through the night. I used sand as my thermal mass and it doesn't work so well. I am using an electric heater now to warm the water and a 3 hour burn keeps the hoophouse 10 degrees warmer than the outside temperature throughout the night.
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My system consists of a 275 gal. IBC tote for the fish tank, gravity draining to 9-half 55 gallon plastic drums (ebb-flow). I have a U-siphon to drain the drums to a 12"x3'x20' raft bed. I have a pump at the other end of the bed flowing back into the IBC tote. I plan to take out the 9 half barrels and build another raft bed instead. The plastic liner for this bed will be in contact with the 8" exhaust of the rocket stove. This should heat the water throughout the winter.
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https://plus.google.com/photos/109588703017864308792/albums/5695281208279446401

Do you have any ideas for auto loading logs? I tried a 70 degree vertical chute, but it started on fire. The smoke was drawn into the rocket stove but this proved to be too dangerous.

Best regards,
Tom Helmers

Replace the sand with fireclay bricks. See the chart on thermal storage at the Dragon Heaters blog.

I intend on using the water as the thermal mass. I have R6 insulation lining the beds.

What I am most interested in is a way of auto feeding logs into the burn chamber.

There have been feed rings and tubes listed somewhere, not sure if they worked.

You can't make the feed tube itself tall or it will chimney, as you found out.

The ring idea should work well for burning lumber scraps, but any sticks/twigs with forks or shoots will hook and jam.

A tube that is at least a foot up off the burn chamber should not chimney. Maybe add a tight lid on top to completely prevent it.