# Large HPR Rail Base Build

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#### DRAGON64

##### Well-Known Member
TRF Supporter
Based on the brilliant ProRail Base (now referred to as Rail Launch Pad Base) built by John Coker

Many years ago, Inspired by John Coker's launch pad design, I built my own variant Rail Base for HPR use. My variant is designed around 2" square tube material, and handles anything that can launch using buttons for the standard 1010 8020 rail (F thru J impulse). My variant was completely assembled using stainless nuts and bolts, as I did not have access (or funding) to weld capabilities. The pad has served me well:

Now I have a need to build another pad, this time in support of much larger projects that will handle L, M & N impulse, utilizing the 1515 8020 rail, and supporting rockets weighing 45 to 100 pounds. This variant is a complete upscale of my original build, and will be based on 3" square Aluminum tube.

For the original pad I built, I sourced the raw material from OnlineMetals.com. The cost of raw material from Online Metals for this new build was a bit staggering, at $400+ I did a little consumer research shopping and stumbled across Mid West Steel & Aluminum; even with$51 shipping included, the cost for raw material was a comfortable \$235!

My wife said that the UPS guy was not happy dragging this box off the truck, but stated he was glad it was off the truck...

To my surprise, based the condition of the box, no parts material was lost in transit...

Once unboxed, the parts looked a little like overkill, especially considering the material alone weighs 61lbs without the rail, or any connecting nuts, bolt and washers... You can smell the cutting oil on this material... luv it!

Before I get to full design and assembly, deburring the material is first and foremost the most important first task...

poor UPS guy

#### tfish

##### Well-Known Member
looks good!

yes...Cokers design is pretty cool..I have 8 "Coker style" pads in the shop waiting for their 1515 rails.

On some of the pads I put 1010 rails on one side of the Boom and 1515 rails on the other side. Then you just have to flip the Boom to the size you need.

Tony

#### DRAGON64

##### Well-Known Member
TRF Supporter
Dual purposing the boom with both 101 & 1515 rails is a great idea! Question; are/did you Tig welding or bolt your pads together? I am considering getting a quote to get some of the key plates welded to save on stainless steel hardware weight.

#### tfish

##### Well-Known Member

They are both bolted and welded. I use a MIG with a spool gun.
Yep stainless hardware can add up fast. I use galvanized hardware on some price sensitive projects.

Tony

#### DRAGON64

##### Well-Known Member
TRF Supporter
Nice work on those pads, far more modified than what my mission plan is, hats off man!

#### DRAGON64

##### Well-Known Member
TRF Supporter
I have modeled the pad in SolidWorks, currently without hardware installed. Hardware installation in SolidWorks will highlight minor shifts in leg hole mounts, otherwise the pad is close to going into production.

Shown here with a single 6' piece of 1515 rail. I have two 6' lengths that I will link for the total working length of 12'

#### DRAGON64

##### Well-Known Member
TRF Supporter
This pad, like my original pad, will allow for 5° of adjustment from vertical, away from the flight line.

#### DRAGON64

##### Well-Known Member
TRF Supporter
A quick minor update; it looks like I will have a path to getting this pad welded together instead of using a nut and bolt assembly process. Now working on a drawing package to send to the welder so that I can get a quote... cost should come in under the cost of stainless steel hardware.