Pocket rocket, long fuel, no smokeback?

I'm actively working on on a 8" batch box for my greenhouse,  but I can't help thinking of other designs.
The barrel stove known as a pocket rocket had a poor reputation in the RMH world.
Being made of un-insulated metal and lacking mass , what do they have to recommend them?

Supposedly they can burn long fuel without smokeback.
That intrigues me.
My first core was a ridiculously ambitious/complicated J tube with a water cooled feed tube.
It kinda worked,  but the point was to allow the safe use of long fuels.
If we could change the materials involved and add mass but still burn long fuel without  smokeback,  I think it would be a great addition to the RMH family.

Well William;
Pocket rockets,  being rocket stoves... would of course not be off much use in a rocket mass heater world!
Its adding the barrel over the riser that changes everything.

Well,  they're barrels....
Seriously though,  would be inclined to channel the exhaust into a bell with some mass , rather than a barrel

It's the lack of mass that makes them not a RMH.
It's the lack of an insulated riser that presumably affects their clean burning/efficency.

We could put a riser after the combustion chamber.
Heck we could build a batch box rocket with a feed tube inserted, but that isn't the point.
The option to gravity feed fuel could be very useful.

I'll just have to build a new one and mess with it, no way around it!
Shucks,  excuse to play with fire...

Uncle Mud's Cottage Rocket is a much improved design over the pocket rocket. It does have the ability to add a small amount of mass right in the stove itself or if you have the room, to add more mass beside it. Here are a few links to his design:

Rocket-Mass-Heater-Shippable-Core

podcast-Uncle-Mud-part

For using long fuel, I have built a rocket-fired cob oven and two rocket-fired maple syrup evaporators, all with L-tube cores. They take logs up to 30" long. Although this loses the self-feeding feature of the J-tube, the longer length makes up for it in the larger amount of wood that can be loaded at one time. I generally feed a log or two every 15-30 minutes depending on log size. With smaller branches (say 2" or less), you would have to feed more often, and there would be a greater chance of coal buildup at the back. Larger logs tend to hold their shape longer and burn to ash, while smaller wood collapses quickly into a heap of coals that cannot all get air to burn. (A grate or air channel under the fire to allow air supply to the bottom back would probably alleviate this issue.) My evaporators (both with 8" diameter x 10' chimneys) typically burn as hard and hot as possible for up to 10 hours at a time, and with skillful loading can keep fairly clean of coal buildup and always burn out to only a small pile of mineral ash.