Additional heat dissapaters on conventional Rocket heaters

I have been reading about rocket stoves, heater and mass heater for days now.
I haven't built anything yet. I have ideas I want to try but
figured other people already tried them so I'll ask here.

Lets say I build a rocket heater and use a 30 gallon drum over the riser tube.
I understand that the drum will get hot and heat the room somewhat.
Has anybody added side fins on the drum to help dissipate heat?
How about putting a big thick plate on top of the drum that is bigger in diameter than the drum?
I remember seeing years ago these fins that wrapped around the flue pipe on an old time wood stove. The fins help add heat to the room.
I can picture a drum full of plates, fins etc to really draw the heat off the drum.

What has been tried?
Are there any pictures of the devices?
How did it work out?

This would be for regular heaters, not mass heaters...

Thanks
Danford1