feed tube height

I have heard builders say that they cut their wood short for the feed tube to limit the risk of tipping pieces out and I have heard builders say that the feed tube cannot be too tall or a second chimney effect may be created but since longer wood would be desirable I wonder why I haven't seen a tall mesh or perforated wood guide for the feed tube. Double the length of wood should equal half the loads and double the time between loading. Am I missing something?

Safety.
A mesh or other open guide would be fine if you could guarantee that all of your wood would have perfectly smooth sides with no knots or jogs. Any roughness could potentially catch on the guides and hang up, letting the burn rise up the wood if the draft is not sufficient.

A guide with smooth straight vertical ribs inside might be safe enough to load with long sticks, if the sticks are reasonably straight themselves and decidedly larger than the gaps between ribs. You also wouldn't want a bunch of them to be able to jam in the guide. Feeding large end first would be a prudent practice.

why couldnt you have this feed tube, up about 2 inches from the stove? the gap would kill the chimney effect wouldnt it?

I can think of at least three designs that should eliminate chimney effect and guarantee as smooth a fuel delivery as any of the ones I have seen profiled.

Wyatt; Consider air flow , Anything you build from the bottom up will affect air flow into the feed tube limiting your burn temperature. But try it and let us know how well it works.

I cut my wood pretty short...about 12" or so (for the most part). I know a lot of folks have an interest in getting longer burn times out of a rocket stove, but it seems like you might be kind of fighting against the nature of the beast... There's more to it than just having longer pieces of wood (IMO, anyway)...it seems like as the wood burns I have to do a fair amount of "adjusting" it's position in the feed tube to get the airflow just right, in addition to adding more wood. Building a batch box instead of a J tube could be a more workable solution... But, you never know until you try I...build a prototype, and share your results, I'm sure a lot of people would be interested to see if it works.

I think a prototype for testing is the way to go and I hope to do just that after the thaw. I have four more months of frozen ground and snow before I can try for a local clay source and rock for the bench. I do have some firebrick retrieved from a scrap stove and will put the word out that I want any to be had from the local dump. The one thing that is rare to scrounge in my area is a steel barrel. All the old ones are rusted away or have been used for burn barrels so I will have to look farther afield and probably have to buy one.