This is my first build thread, so go easy on me 
I've flown a few minimum diameter rockets in the past, and I typically prefer to build them with four fins. However, one issue I've ran into with four-finned rockets is with regards to launch equipment. Every time I fly one, I have to use fly-away rail guides since the clubs I fly at only have launch towers for three-finned rockets. I love the idea of the rail guides, but they seem to break after hitting the ground on every flight, and buying new guides for every flight is not sustainable.
I decided on a few requirements to design my tower around:
(I'm aware that Chris Attebery's towers fulfill all the requirements stated below, but I thought it would be more fun to do it myself)
Top-down view of the tower.
Detail view of the top of the tower.
Detail view of the bottom of the tower.
The tower consists of two 3/8 thick 6061-T6 plates, with four groups of holes spaced 90° apart around the circumference. The holes are countersunk to allow the 1/4-20 bolts to fit flush against the plate. Each of the four vertical rails have a short, perpendicular section of rail at each end, held on by an angle bracket. These legs allow the rails to be fixed to the plates, and the tower to be adjusted.
With the design finished, I contacted a local fabrication shop, and got the plates cut on a waterjet. The cuts are remarkably clean, though you can definitely tell where the stream of water started to disperse before coming through the bottom of the plate. I suspect they were cutting with pure water, without additional abrasives
As expected, the stock wasn't exactly 3/8, but certainly close enough for my purposes. Notice the imperfections on the edges from the stream of water starting to disperse.
My father is a machinist, so he helped me do the countersinks on a vertical milling machine at his work place.
The bolts fit perfectly!
That's all for now, but I'll have more updates and photos in the coming days!
David
I've flown a few minimum diameter rockets in the past, and I typically prefer to build them with four fins. However, one issue I've ran into with four-finned rockets is with regards to launch equipment. Every time I fly one, I have to use fly-away rail guides since the clubs I fly at only have launch towers for three-finned rockets. I love the idea of the rail guides, but they seem to break after hitting the ground on every flight, and buying new guides for every flight is not sustainable.
I decided on a few requirements to design my tower around:
(I'm aware that Chris Attebery's towers fulfill all the requirements stated below, but I thought it would be more fun to do it myself)
- Have the ability to be fabricated and assembled without welding equipment.
- Rails need to be interchangeable to allow for rockets that may need more rail length.
- Tower has to be adjustable to accept rockets from 38-75mm in diameter.
Top-down view of the tower.
Detail view of the top of the tower.
Detail view of the bottom of the tower.
The tower consists of two 3/8 thick 6061-T6 plates, with four groups of holes spaced 90° apart around the circumference. The holes are countersunk to allow the 1/4-20 bolts to fit flush against the plate. Each of the four vertical rails have a short, perpendicular section of rail at each end, held on by an angle bracket. These legs allow the rails to be fixed to the plates, and the tower to be adjusted.
With the design finished, I contacted a local fabrication shop, and got the plates cut on a waterjet. The cuts are remarkably clean, though you can definitely tell where the stream of water started to disperse before coming through the bottom of the plate. I suspect they were cutting with pure water, without additional abrasives
As expected, the stock wasn't exactly 3/8, but certainly close enough for my purposes. Notice the imperfections on the edges from the stream of water starting to disperse.
My father is a machinist, so he helped me do the countersinks on a vertical milling machine at his work place.
The bolts fit perfectly!
That's all for now, but I'll have more updates and photos in the coming days!
David
