Mac Performance 4" Scorpion - Modified

[ether]

Next on my build queue is the 4" Scorpion from Mac Performance. 1st time using canvas phenolic airframe. This is not strictly a kit build, modifying it similar to how I built my L3 certification rocket with a single airframe break with dual deploy. Mike at Mac Performance been great to work with, modifying the airframe length and putting a package together of only the pieces needed.

Went with the 6:1 wildman nosecone and got an ABS tailcone printed for the build. Will be using an internal bulkhead/coupler with a threaded rod for motor retention. Electronics sled will slide from the top and the recovery gear will reside in bottom space of the nose cone (drouge+shock cord) and top part of the airframe (main in deployment bag). Will put in a ham GPS tracker in the nose cone - one reason to use the 6:1 nose cone is to get internal length for the antenna.

Using the rocket as a test-bed for using the ham gps tracker, may use this nose cone with my L3 rocket when using 98MM motors in it.

The fun part of the rocket are the payloads in the electronics bay. Will be using two high definition 360 cameras, to hopefully create a 360 degree video that one can pan while watching it. The other fun part is building it as a night capable rocket with a four 10watt LED strobes in the electronic bay, flashing out curved windows built into the airframe.

Designing it around the long burn CTI L395 motor, should be a fun rocket to launch when things get back to normal.

 

[Theory]

good call there! i am a HUGE fan of the 4" Wildman 6-1 NC

IMHO the best looking NC on the market.

 

[spigalau]

Looks good, how long are your tubes ?

We found working with Mikes canvas was really easy. And after burying ours in the ground, how strong the material is. !

 

[ether]

Just one tube, 43.3 inches long. This is a single break design

I'm in awe of how light it is, 15.8 grams per inch in weight, lower than a CF tube. Might not be the same strength laterally as a CF tube, but vertically seems very robust and the cost is 1/3 of CF

 

[crossfire]

Are you doing HED? JLCR?

 

[ether]

Not the typical method. Bottom 1/3 of nose cone will be left open for the drouge and shock cord. The main will remain in the main airframe (parachute area is 6 inches from the top of the airframe) in a deployment bag. Using a tender decender to hold the drouge attached to the main airframe till lower altitude. Then the tender decender will activate and let the drouge pull the deployment bag/ top of main chute.

 

[ether]

check this write-up, doing basically the same method. I don't do the motor charge backup, use a CPVC charge tube to direct the charge at the airframe/nosecone break area from centrifugal tube at the bottom of the CPVC pipe and use a sheath for the tender descender instead of the G10 plate

https://www.rocketryforum.com/threa...dd-with-a-deployment-bag.138223/#post-1655468
reason i like this method is (1) the drouge will actively pull the deployment bag and the pull out the main chute (2) main chute stays in the airframe until released avoiding tangles/deployment interference (in theory). Will be trying it out on Saturday with the L3 shakedown flight.

 

[ether]

got the AV bay lasercut plywood pieces in, starting to assemble portions of it

its upside down in the pictures, dry fitting at this point

still need to get the batteries and the protons to double check fit and fully assemble the AV package

Debating how to handle the side hatch that allows loading of the cameras, will either cut a portion of spare bodytube, 3d print or create a fiberglass, tempted to do a 3d print to ease construction/sanding.

since I finished the AMW parrot builds, this is now my next project to get done, will take a couple of months as I gather some remain bits (windows for the LED lights, batteries and protons)

in the meantime will start getting familiar with the cameras and creating test 360 videos, it comes with a wireless controller to control both at the same time.