L2 Cert Build. MAC Black Fly 38mm

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wij

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After having my L1 for almost 2 years now I am embarking on the L2 cert! I learned a TON building and flying L1 motors and rockets, also have figured out dual deploy with great success. I Built the 3" Black fly in the summer of 2020 and have had many successful DD flights using L1 motors. I have swapped the plastic nosecone for the wildman fiberglass nosecone and also have added a MAC av bay along with a small payload tube section to give more room for recovery gear and move the cg up a bit. The Mac avbay along with the wildman NC and the extended payload section adds quite a bit of weight compared to how I had it set up for L1 motors. I'm expecting around 4-5k ft on the motors I would be using. Shout out to MAC performance for the quality products and awesome customer service. I have been very happy with everything I have purchased from them.

I will be posting my progress as I build the avbay and forward section of the rocket. Any tips or suggestions are great, Always looking to learn from knowledgeable minds. Av bay will contain 2 independent flight computers ( Baro & Accelerometer).

Starting with the NC, I want to use an eyebolt screwed into the metal tip. I saw people used a piece of pvc to hold the eyebolt in place to screw it in so thats what I will be doing. I will loctite the threads to make sure it wont move.. The shockcord for the main chute will be 1/2" kevlar. what is the best knot for tying kevlar to a quick-link? Also what is the best way to cut the canvas phenolic tubes... is a dremel better or is a miter saw fine?
 

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eggplant

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After having my L1 for almost 2 years now I am embarking on the L2 cert! I learned a TON building and flying L1 motors and rockets, also have figured out dual deploy with great success. I Built the 3" Black fly in the summer of 2020 and have had many successful DD flights using L1 motors. I have swapped the plastic nosecone for the wildman fiberglass nosecone and also have added a MAC av bay along with a small payload tube section to give more room for recovery gear and move the cg up a bit. The Mac avbay along with the wildman NC and the extended payload section adds quite a bit of weight compared to how I had it set up for L1 motors. I'm expecting around 4-5k ft on the motors I would be using. Shout out to MAC performance for the quality products and awesome customer service. I have been very happy with everything I have purchased from them.

I will be posting my progress as I build the avbay and forward section of the rocket. Any tips or suggestions are great, Always looking to learn from knowledgeable minds. Av bay will contain 2 independent flight computers ( Baro & Accelerometer).

Starting with the NC, I want to use an eyebolt screwed into the metal tip. I saw people used a piece of pvc to hold the eyebolt in place to screw it in so thats what I will be doing. I will loctite the threads to make sure it wont move.. The shockcord for the main chute will be 1/2" kevlar. what is the best knot for tying kevlar to a quick-link? Also what is the best way to cut the canvas phenolic tubes... is a dremel better or is a miter saw fine?
Sounds like a fun project! I got my L2 with parts from MAC.

In addition to loctite-ing the threads on the nosecone tip, I would recommend a swivel to be sure there is minimal torque on the threads during flight. You will have a hard time cutting a tube of that size particularly straight with a dremel, so I would use the miter saw.
 

wij

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Sounds like a fun project! I got my L2 with parts from MAC.

In addition to loctite-ing the threads on the nosecone tip, I would recommend a swivel to be sure there is minimal torque on the threads during flight. You will have a hard time cutting a tube of that size particularly straight with a dremel, so I would use the miter saw.
Swivel on the main chute attachment point or swivel on the eyebolt?
 

eggplant

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Swivel on the main chute attachment point or swivel on the eyebolt?
I put a swivel right by the eyebolt on my rockets with that style of nosecone.
 
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Handeman

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Sound fun and hope it all works as you want it to.

Have you considered investing in a new kit instead of parts for your existing one? Something with a 54mm MMT, DD so you can fly J, K and small L motors.

What you learned about HPR flying L1 motors, there's that much more to learn flying the range of L2 motors. I'm sure you've learned the difference between baby H and full I motors. Those are only 4 times the thrust. When you get to L2, its 8 times from small J to full L plus that large L is 32 times what the baby H is.
That all sounds interesting with the numbers, but like when you entered the L1 range, entering the L2 range will be a learning curve that can only really be appreciated by flying the motors. I think that is the fun of moving up. Just the difference between a baby J like the AT 350W to a full J like the AT 415W is the thrust of a full I motor. Along with the increased thrust is the higher altitudes. That means learning to fly your field all over again.

Good Luck and enjoy L2, it's almost like starting rocketry all over again! Fun!
 

wij

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Sound fun and hope it all works as you want it to.

Have you considered investing in a new kit instead of parts for your existing one? Something with a 54mm MMT, DD so you can fly J, K and small L motors.

What you learned about HPR flying L1 motors, there's that much more to learn flying the range of L2 motors. I'm sure you've learned the difference between baby H and full I motors. Those are only 4 times the thrust. When you get to L2, its 8 times from small J to full L plus that large L is 32 times what the baby H is.
That all sounds interesting with the numbers, but like when you entered the L1 range, entering the L2 range will be a learning curve that can only really be appreciated by flying the motors. I think that is the fun of moving up. Just the difference between a baby J like the AT 350W to a full J like the AT 415W is the thrust of a full I motor. Along with the increased thrust is the higher altitudes. That means learning to fly your field all over again.

Good Luck and enjoy L2, it's almost like starting rocketry all over again! Fun!
This is awesome to think about & exactly why i'm excited to step up to L2. I have given good consideration to going with a bigger kit for L2 but I decided this route because it has worked very well and I have good confidence in the setup. I have flown this rocket on I motors and dual deploy with a 100% success rate, swapping a few parts and moving up to a J350 or similar motor should allow me to achieve a successful flight while also feeling very confident in the setup itself. Having a whole new rocket with a new dd system brings in more variables to that cert flight. However I do have my eye on some 54mm kits that I want to get going.. but I want to get my L2 before I drop the money for a nice 54mm kit !
 

wij

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Got some good progress in the last few days. Nosecone has been sanded and clear coated. I got some loops sewn into my kevlar leads. Av bay is mostly together, Just need to fine tune how the wires sit.

Im using the eggtimer quark & pico AA1. I would normally just use the Quark but I want to get the accelerometer data fro the AA1. So ill be using the AA1 as primary drogue charge, Quark as the backup drogue charge and then main charge. Each flight computer is powered by a 2s lipo. Next up is getting the recovery harness all setup, my chute and tubular nylon should be here on Thursday.

Need to sand the switchband and the payload tube section, then final coat of paint. Also need to drill holes for shear pins on NC. Its coming together really nice, im targeting around 65oz all complete.
 

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wij

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Do you need shear-plates with the shear-pins on canvas phenolic tubes or can you put them straight in like fiberglass tubes?

On my dd setups with cardboard tubes I used brass shear-plates with great results. I'm curious how people have done it with canvas phenolic.
 

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Handeman

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However I do have my eye on some 54mm kits that I want to get going.. but I want to get my L2 before I drop the money for a nice 54mm kit !
Another advantage of getting L2 before you even get that L2 rocket is, you can start working shifts at RSO and LCO at the launches.
 

wij

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If using a barometric based flight computer ( Eggtimer Quark), along with an accelerometer based flight computer (pico AA1) for redundant drogue/apogee deployment, which one would be preferred as the primary and which the backup?
I was thinking of Accelerometer based for primary and Baro for delayed backup.
 

FlyBy01

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Got some good progress in the last few days. Nosecone has been sanded and clear coated. I got some loops sewn into my kevlar leads. Av bay is mostly together, Just need to fine tune how the wires sit.

Im using the eggtimer quark & pico AA1. I would normally just use the Quark but I want to get the accelerometer data fro the AA1. So ill be using the AA1 as primary drogue charge, Quark as the backup drogue charge and then main charge. Each flight computer is powered by a 2s lipo. Next up is getting the recovery harness all setup, my chute and tubular nylon should be here on Thursday.

Need to sand the switchband and the payload tube section, then final coat of paint. Also need to drill holes for shear pins on NC. Its coming together really nice, im targeting around 65oz all complete.
Your rocket is very well thought out; best of luck and I'm studying for my L2 as well. Thank you for the photos!
 
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wij

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Your rocket is very well thought out; best of luck and I'm studying for my L2 as well. Thank you for the photos!
Thanks! I figured why not take some time and really think it out. I was inspired by some of the neatly built rockets i've seen at the club I fly with.
 

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Do you need shear-plates with the shear-pins on canvas phenolic tubes or can you put them straight in like fiberglass tubes?
We use 3 x 2-56 shear pins on our 3" Scorpion XL payload tube - just drilled & tapped straight in to the canvas phenolic - have had no issues with them.
 

wij

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We use 3 x 2-56 shear pins on our 3" Scorpion XL payload tube - just drilled & tapped straight in to the canvas phenolic - have had no issues with them.
Good to know! I will be trying that on canvas phenolic in the future!
 

wij

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Heres what I did for shear pins... carved out some spaces for brass plates to sit flush and secured them in! Should have super clean shears with this. I have used this method on all my cardboard rockets with great results.
 

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