View previous topic :: View next topic |
Author |
Message |
EightySecond

Joined: 19 Sep 2013 Posts: 17
|
Posted: Oct 11 2013 Post subject: |
|
|
Thanks a lot MongoNC, that's great. My tank is a 41" diameter by 104" I believe.
Also, does the 30.83(.5)" Half moon FB to CC opening translate to the measurement from the top center of the 1/2 moon to the bottom center of the arc below?
I think the 1/2 moon calcs have to be the most confusing part in my head so far. I should have paid more attention in math class apparently.
MongoNC wrote: | 82nd,
I just did a quick run of numbers on your setup and came up with a horizontal center line on your tank as around 50 inches based on a ground clearance of 12" and the info in your link.
12" + 36" - 30.83(.5) - 1 + 37(.5) = 50.085
12" Ground clearance
36" Height of FB
30.83(.5)" Half moon FB to CC opening
1" Grease bridge
37"(.5) Horizontal center line on 37 diameter 500 gal tank
None of this calculates the thickness of metal each component is made from and assumes your 500g tank is ASME sized. |
|
|
Back to top |
|
 |
k.a.m. BBQ Mega Star

Joined: 12 Dec 2007 Posts: 26020 Location: Southeast Texas.
|
Posted: Oct 11 2013 Post subject: |
|
|
Another measurement to calculate is grate height from the ground. You may have to modify your firebox dimensions to achieve a workable cooking height.
I will try to work up something tonight.
What is your desired grate height?
What is the distance from the ground to the trailer deck? _________________ Always remember slow and steady wins the race.
Hybrid Cooker |
|
Back to top |
|
 |
EightySecond

Joined: 19 Sep 2013 Posts: 17
|
Posted: Oct 11 2013 Post subject: |
|
|
I sure would appreciate that kam. My deck measured at 20.5" and the ideal height of my lowest cooking grate would be as low as 40" and as high as 48", I am 6'5" and could get away with the high end if I had to. Turns out my length is actually 103" on the tank.
Here is the label plate.
SoEzzy, I think I resized it correctly, I will fix it if not.
k.a.m. wrote: | Another measurement to calculate is grate height from the ground. You may have to modify your firebox dimensions to achieve a workable cooking height.
I will try to work up something tonight.
What is your desired grate height?
What is the distance from the ground to the trailer deck? |
|
|
Back to top |
|
 |
Wreckless BBQ Super Pro

Joined: 15 May 2009 Posts: 2292 Location: New Braunfels, TX
|
Posted: Oct 11 2013 Post subject: |
|
|
I had a similar problem with a 30" build on a trailer rig. I ended up with a min of 11" fb ground clearance and 37" grate height. I achieved it by not going with a true / full radius on my inlet. I took the top inlet cut almost to the edge of the cooker and gradually added mat'l along the radius to maintain somewhat of a grease retaining wall down into my grease bridge and still had a proper fb inlet opening and a decent distance from my plate to first cooking grate. The calculation was made using A-B tangent points and opening height using the below link. Hope this help getting it all to mesh.
http://www.1728.org/circsect.htm |
|
Back to top |
|
 |
EightySecond

Joined: 19 Sep 2013 Posts: 17
|
Posted: Oct 12 2013 Post subject: |
|
|
Thanks for sharing that, I will take a look.
Wreckless wrote: | I had a similar problem with a 30" build on a trailer rig. I ended up with a min of 11" fb ground clearance and 37" grate height. I achieved it by not going with a true / full radius on my inlet. I took the top inlet cut almost to the edge of the cooker and gradually added mat'l along the radius to maintain somewhat of a grease retaining wall down into my grease bridge and still had a proper fb inlet opening and a decent distance from my plate to first cooking grate. The calculation was made using A-B tangent points and opening height using the below link. Hope this help getting it all to mesh.
http://www.1728.org/circsect.htm |
|
|
Back to top |
|
 |
k.a.m. BBQ Mega Star

Joined: 12 Dec 2007 Posts: 26020 Location: Southeast Texas.
|
Posted: Oct 12 2013 Post subject: |
|
|
EightySecond, based on a 41" tank and a 48" grate height along with a 20" deck height I came up with this.
1/3 volume of a 41" x 103" tank is 45305.75 Cu.in.
A firebox 32.5" high x 39" wide x 36" long will give you 45630.00 Cu. in. slightly larger than you need.
Your firebox to cooking chamber opening should be about 365.4 Sq. in. A half moon of 30.5" wide x 15.25" tall will be 365.31 Sq. in. No bridge will be required because of the cooking chamber size. Center line on your tank is around 20.5" if your firebox to cooking chamber opening is at the top of the firebox and you drop the firebox 4" down from grate height you still have about a 1.25 bridge.You can get more bridge by manipulating the opening as Mike mentioned
Now with a 20" deck height you should see about 11.5" firebox clearance.
Bare in mind your trailer will sink from the weight causing a closer distance, measurements I just gave are on paper not real life scenario.
You can also decrease the distance between the R/F plate from 4" to as close as 1" for more clearance.
I hope this helps.  _________________ Always remember slow and steady wins the race.
Hybrid Cooker |
|
Back to top |
|
 |
EightySecond

Joined: 19 Sep 2013 Posts: 17
|
Posted: Oct 14 2013 Post subject: |
|
|
That's great kam, I sure do appreciate that! I feel good about making some cuts now.
k.a.m. wrote: | EightySecond, based on a 41" tank and a 48" grate height along with a 20" deck height I came up with this.
1/3 volume of a 41" x 103" tank is 45305.75 Cu.in.
A firebox 32.5" high x 39" wide x 36" long will give you 45630.00 Cu. in. slightly larger than you need.
Your firebox to cooking chamber opening should be about 365.4 Sq. in. A half moon of 30.5" wide x 15.25" tall will be 365.31 Sq. in. No bridge will be required because of the cooking chamber size. Center line on your tank is around 20.5" if your firebox to cooking chamber opening is at the top of the firebox and you drop the firebox 4" down from grate height you still have about a 1.25 bridge.You can get more bridge by manipulating the opening as Mike mentioned
Now with a 20" deck height you should see about 11.5" firebox clearance.
Bare in mind your trailer will sink from the weight causing a closer distance, measurements I just gave are on paper not real life scenario.
You can also decrease the distance between the R/F plate from 4" to as close as 1" for more clearance.
I hope this helps.  |
|
|
Back to top |
|
 |
|