My rocket heater is based very heavily on plans by T2H with modification to the secondary air intake shown by PPotty1. The stove is made from 4 inch box section mild steel and is 13 inches long by 16 inches high. The vortex generator and riser tube are 2.75 inch stainless steel and the exhaust is 3 inch tube. Pictures show the various parts and a video will follow showing the stove in action. Measured temperature at the top of the riser/heat exchanger is 800f with the a fire box temp of 700f. The secondary air intake feeds to a 1/2 inch inlet which enters the vortex generator about two thirds the way up. Comments whether negative or positive will be welcomed.
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 2:06 am
url=https://servimg.com/view/19206296/8][/url]
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 2:08 am
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 2:09 am
url=https://servimg.com/view/19206296/10][/url]
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 2:10 am
url=https://servimg.com/view/19206296/11][/url]
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 2:11 am
I have now added another secondary air feed through an internal half inch tube running through the firebox to the vortex generator. First impressions are that the vortex is more turbulent although no increase in temperature seems to have occurred which has surprised me. Also the stove is now more controllable as the airflow into the fire seems to have been reduced resulting in a gentler burn. Not the result that I was expecting!
Any comments or suggestions appreciated.
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 2:17 am
Picture follows of vortex after additional secondary air intake added.
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 2:18 am
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 2:19 am
url=https://servimg.com/view/19206296/13][/url]
caotropheus Subscribers
Posts : 333 Join date : 2013-10-07
Subject: Re: First build Sat May 23, 2015 1:25 pm
If you see no increase in stove temperature, why add a second secondary air? I suggest you make air control for the primary air intake (if you need it) and keep the original secondary air design.
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 23, 2015 6:56 pm
I was comparing the external secondary air supply via the sloping angle feed as per ppotty versus the internal supply as favoured by T2H. Looks like in my case the external feed wins! I have a door on the heater with primary air control.
gadily Moderator
Posts : 1477 Join date : 2013-12-08
Subject: Re: First build Sun May 24, 2015 5:18 am
you could also try to heat up your primary air as it does make a difference to the temps of the stove
best way to do it is use a piece of tin to the primary air entrance and just clip it over with another piece of metal then test from there
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sun May 24, 2015 9:24 pm
4th pic down shows what I think is the hotest vortex based on the colour of the flame. Do you agree? This was with the external sloping secondary feed.
gadily Moderator
Posts : 1477 Join date : 2013-12-08
Subject: Re: First build Sun May 24, 2015 10:32 pm
to be honest id say it was with less yellow within the burn means better mixing of flame and air
heres mine while testing it and i was 2 metre away from tube as tube is metre and it was so hot couldnt stay there long but i can take a lot of heat than most people
id actually say the third one not the forth one
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Mon May 25, 2015 2:07 am
My understanding is that an orange flame is cooler than yellow so that would indicate to me that your burn is too cool, or am I missing something?
gadily Moderator
Posts : 1477 Join date : 2013-12-08
Subject: Re: First build Mon May 25, 2015 3:44 am
ever remember your school and the bunsen burner the yellow the flame the less oxygen is around
as its the same with burning wood
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Mon May 25, 2015 6:26 am
good point
gadily Moderator
Posts : 1477 Join date : 2013-12-08
Subject: Re: First build Mon May 25, 2015 11:22 am
i will rephraze the comment the more yellow the flame the more unspent fuel is lost that could have been burnt
now take a look on here by rom1nb did some tests trying to get to the blue flame from wood burning
just click on his name and look through all the vids with the pellet tests
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Mon May 25, 2015 7:37 pm
Great set of vids and very informative. I'm surprised he welded up all the secondary holes as the blue flame was with the 1/8 holes and looked best to me but I guess the final temp was the deciding factor.
CVI04
Posts : 49 Join date : 2015-04-06
Subject: Re: First build Tue May 26, 2015 5:33 am
gadfly, For some reason I can't see your video from yesterday. I can see the video you shared from Rom1nb.
gadily Moderator
Posts : 1477 Join date : 2013-12-08
Subject: Re: First build Tue May 26, 2015 8:09 am
thanks for that info but it works on mine and i havent set it to private so anyone should be able to see it
can someone else check to see if the link is working correctly
gadily Moderator
Posts : 1477 Join date : 2013-12-08
Subject: Re: First build Sat May 30, 2015 7:16 am
just found this hope it explains better
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Sat May 30, 2015 5:41 pm
Perfect! Best explanation yet and many thanks for finding this. Now I know what I am looking to achieve with my secondary air injection.
T2H Admin
Posts : 913 Join date : 2013-10-07
Subject: Re: First build Sun Jun 14, 2015 2:40 pm
You obtain greater btu's once the stove is up to operating temps, you then turn down the main air intake to almost nothing, almost smothering the fire, then open the secondary air.
This is when you get the major btu gains if done right. It takes some tinkering with the air controls to get just the right sweet spot.
Too much and no change too little and the fire cools.
g0aix
Posts : 34 Join date : 2015-03-15
Subject: Re: First build Tue Jul 21, 2015 8:17 pm
Despite making numerous changes to the primary and secondary air controls nothing improved the performance. I found adjustment critical and often resulted in secondary combustion being incomplete due to lack of air, usually accompanied by a minor flue gas explosion!
Changed the design to a vertical feed with air supply control and suddenly the stove is working - smokeless from the start and higher temperatures on the heat exchanger with the easy refuelling compared to the batch method resulting in much longer run time.
Only negative point seems the need to watch the stove in case of a blowback ejecting smoke and sparks up the feed tube air intake but so far this has not happened.