Very excited to be beginning my first rocket stove which I'm going to use to replace my BBQ in the back garden
One of the remaining decisions I have is the feed tube. I gather that an L-Shaped feed / burn tube allows for my more control which is preferable when cooking i.e. you can move the sticks in and out to regulated the heat. However, my preference would be a gravity fed system. So I'm considering the pros and cons of a J-shaped profile, or perhaps what you could call a V-shaped profile where the feed tube is at say a 45 degree angle.
So far I can't really see why you would use the angled feed. It takes up more space, and friction in the pipe may prevent the sticks sliding down as easily as a vertical tube in the case of the J profile. However, the sticks should be much closer to the vertical insulated chimney flue. Maybe there's a benefit there? Maybe less smoke back?
Any thoughts about the J and V profiles welcome thanks
In my experience, the combustion is getting worse when fuel is getting in the tunnel, same goes for an angled feed. In case of the latter there isn't actually a tunnel so no horizontal flame path either. Flames will go up the riser just like that, maybe very long flames but also a dirty burn. The horizontal flame in a j-tube is doing most of the mixing which is really the reason why it burns so clean.
Stick to what is known to work, don't re-invent the wheel.