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Post by josephcrawley on Mar 12, 2015 9:58:58 GMT -8
I was looking through the original post for the S portal and thought this info would be a nice addition to the reference section Firebox and riser dimensions are based on peterburg batch box dimensions. Primary air is Calculated as 12.5% of riser area. Secondary air is 12% of riser area. The tube area(the size of the vertical metal tubes that supply secondary air) for the channel is secondary air/2 * (1.5 - 2 needs more research?) The slots for secondary air should start 20mm above box floor and be as close to the riser opening as possible. The channel opening is width = Base * .5 and Height = Base * 2.2. Hope this helps someone. Let me know if I have made errors or misstated things and I will edit this post. JOseph |
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Post by pinhead on Mar 12, 2015 11:22:03 GMT -8
I haven't added S-Portal dimensions to the spread sheet because, as far as I know, the ratios haven't yet been finalized.
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Post by jliebler on Apr 1, 2015 7:02:50 GMT -8
I was looking through the original post for the S portal and thought this info would be a nice addition to the reference section Firebox and riser dimensions are based on peterburg batch box dimensions. Primary air is Calculated as 12.5% of riser area. Secondary air is 12% of riser area. The tube area(the size of the vertical metal tubes that supply secondary air) for the channel is secondary air/2 * (1.5 - 2 needs more research?) The slots for secondary air should start 20mm above box floor and be as close to the riser opening as possible. The channel opening is width = Base * .5 and Height = Base * 2.2. Hope this helps someone. Let me know if I have made errors or misstated things and I will edit this post. JOseph NO! donkey32.proboards.com/thread/1040/secondary-air-modification-batch-rocketWhere the original "disclosure" was made says CLEARLY that primary air is 12 % of riser CSA and secondary is 10%! |
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Post by josephcrawley on Apr 2, 2015 8:39:02 GMT -8
"The steel floor duct doesn't run uphill or downhill, just level. At the moment, it looks like the primary air and secundary air using an S-portal is working best within a 50/50 ratio. Total air inlet is still around 25% of the riser cross section area. The primary inlet is simple, just a square hole at the front bottom of the firebox and 12.5% of the riser csa. " donkey32.proboards.com/thread/1040/secondary-air-modification-batch-rocket?page=5This is a quote for peterberg later in the original S portal thread. In researching this I can no longer find were I got the 12% figure for secondary air instead of 12.5% |
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Post by jliebler on Apr 2, 2015 20:22:26 GMT -8
I think it is fair to say that optimization of the primary & secondary air supply for the "S Portal" and "Walker channel" is incomplete. Much more testing could/should be done. My plan (for a Walker channel), in the interim, is to go with a slightly bigger secondary, 12%, and smaller primary, 9%, (I can increase primary by opening the door air wash).
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