Bacon Lee : I think we are going to have to scratch our heads awhile before we come up with the right question to ask. Be patient with us.
Now about covering The top of your feed tube- Yes, at the end of your burn when you can look in there and only see a small amount of embers
That is the time to cap off the Feed Tubes Top.
The other day I saw someone who was using a short piece of wide board as a temporary cover substitute - please do not do that !
We also partially cover the Feed Tubes Top when we are burning less than a full load of fuel in our rocket, without some restriction of excess air
it will have a cooling effect on the fire potentially reducing clean combustion . As always your ear will tell you if you are 'running' your rocket
correctly.
I am very concerned about your dads habit of covering the Feed Tubes Top while mid burn !*
The last few days I saw my dad running into the house watching TV during the burn and he covered the feed tube completely when he left.
Because he is leaving a Fueled and
Red Hot Combustion chamber** behind -the person that next uncovers the Feed Tube can be in for a nasty surprise!
Because the Red Hot Combustion Chamber is still converting your solid wood fuel into unburned and highly flammable wood gases -with no oxygen
to ignite them or any flow of air to carry them away they can -and have- built up into an explosive cloud of gases needing only oxygen to Flash to Flame
This is will occur just as ones face is close to the Feed tube as its cover is removed. Any time a Rockets Feed Tube is covered
Tightly the rockets
fire should be allowed to go out and Not be lit again until the rocket is cold !
This condition often seen by Fire fighters is called a 'Flashover' and is scary !
It is likely that if this practice is continued someone is going to have to explain why grandpa has no eyebrows, lashes or hair on his head ! Also this is
a bad practice for any 3rd party to see and think it is O.K. to use .
I hope this is timely and useful, for the good of the Craft! Big AL
* this also will cause your rockets burn to be Temporarily very inefficient, and possibly sending wood gases down stream to collect on the interior walls
of your Horizontal piping. This coating will reduce the efficient transfer of heat
energy from the hot exhaust gases to the Thermal Mass and even deposit
enough creosote there to potentially cause a chimney fire-
It would be very interesting to stop covering a Red Hot rockets Feed Tube Top and see if this condition goes away after a day or two ! A.L.
** While initially hard to see in a well lit greenhouse, the firebricks in the Burn Tunnel should start to show a red glow after about 15 minutes into your
burn, this can be clearly seen in the twilight of early morning or late evening ! This is what I mean by Red Hot Combustion Chamber . a.l.