eengelgau
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Gene's L3 Project
I'm in the process of doing my L3 project and I thought it would be fun to use the forum to document my build. I think this is a fun venue to share my build ideas with others, as well as provide the necessary documentation to my L3 advisor James Marino (thanks James for doing this!).
A good deal of the beginning of this thread is going to focus on composit fabrication of things like centering ring and fins. My goal is to keep the aft end of the rocket light to minimize weight. With my past experience using carbon and glass reinforcements, and my ever handy vacuum baging experience I should be able to cut 30 to 50% weight of may components.
I'll start by posting my project introduction:
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1) Introduction
For my L3 project the goal was to have a fun, reliable rocket that is a solid design, relatively conventional construction, easy to load-up and fly. Pervious experience includes a range of L2 projects including a 2 stage K to K projected called the Foley a Deux. Over the last year I have had very good luck working with altimeter controlled – dual deploy rockets. Much of the experience is on my EVE rocket. It’s a cool 2.6” / 54MM rocket that just goes and goes. It’s been really fun to fly and very reliable. I have quite a few good flights on my Talon 4 (five I think) and my 5.5” Jay Hawk. My goal for my L3 project is a similarly reliable vehicle.
Most of the components for this build were originally from Jeff Race’s Polecat Patriot rocket. He bought it for his L3 but never finished it. Also included in the purchase was an extra nose cone and coupler. He had a 75MM Aeropac retainer as well. I thought for some time if I wanted to just build it as is, but fundamentally not really liking the Patriot, I decided to change it. A few things I don’t like about it are that it has a big 7.5” airframe, but only a 75mm motor. After my L3 then what? Also the fins are actually pretty small, leading to stability concerns or the need for lead in the nose. Also construction of fins and rings are all from 3/8” ply and that causes the tail to be quite heavy. And what do I do with an extra nose cone?
So I decided to modify the rocket to 98MM (L3 attempt will be a 75mm though) and use the extra nose cone as a boat tail – I like Boat tails, makes the rocket more efficient. Adding the boat tail also lengthens the rocket some. To lighten up the tail I’m using honeycomb composite fins. There are four centering rings. Primary load bearing rings will be ½” birch-ply with carbon reinforcement. The other centering rings will be carbon lay-up over honeycomb to save weight while having great strength. Similarly I will attempt to save weight on the av-bay using carbon-composite end caps with birch inlays.
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Next up - how to make carbon / honeycomb composits rings and parts
I'm in the process of doing my L3 project and I thought it would be fun to use the forum to document my build. I think this is a fun venue to share my build ideas with others, as well as provide the necessary documentation to my L3 advisor James Marino (thanks James for doing this!).
A good deal of the beginning of this thread is going to focus on composit fabrication of things like centering ring and fins. My goal is to keep the aft end of the rocket light to minimize weight. With my past experience using carbon and glass reinforcements, and my ever handy vacuum baging experience I should be able to cut 30 to 50% weight of may components.
I'll start by posting my project introduction:
----------
1) Introduction
For my L3 project the goal was to have a fun, reliable rocket that is a solid design, relatively conventional construction, easy to load-up and fly. Pervious experience includes a range of L2 projects including a 2 stage K to K projected called the Foley a Deux. Over the last year I have had very good luck working with altimeter controlled – dual deploy rockets. Much of the experience is on my EVE rocket. It’s a cool 2.6” / 54MM rocket that just goes and goes. It’s been really fun to fly and very reliable. I have quite a few good flights on my Talon 4 (five I think) and my 5.5” Jay Hawk. My goal for my L3 project is a similarly reliable vehicle.
Most of the components for this build were originally from Jeff Race’s Polecat Patriot rocket. He bought it for his L3 but never finished it. Also included in the purchase was an extra nose cone and coupler. He had a 75MM Aeropac retainer as well. I thought for some time if I wanted to just build it as is, but fundamentally not really liking the Patriot, I decided to change it. A few things I don’t like about it are that it has a big 7.5” airframe, but only a 75mm motor. After my L3 then what? Also the fins are actually pretty small, leading to stability concerns or the need for lead in the nose. Also construction of fins and rings are all from 3/8” ply and that causes the tail to be quite heavy. And what do I do with an extra nose cone?
So I decided to modify the rocket to 98MM (L3 attempt will be a 75mm though) and use the extra nose cone as a boat tail – I like Boat tails, makes the rocket more efficient. Adding the boat tail also lengthens the rocket some. To lighten up the tail I’m using honeycomb composite fins. There are four centering rings. Primary load bearing rings will be ½” birch-ply with carbon reinforcement. The other centering rings will be carbon lay-up over honeycomb to save weight while having great strength. Similarly I will attempt to save weight on the av-bay using carbon-composite end caps with birch inlays.
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Next up - how to make carbon / honeycomb composits rings and parts