ARLISS-K

A Single Can-Sat Experiment

For The ARLISS Rocket Project

 

I am building this rocket (on rather short notice) as a test variant of the standard ARILSS rocket.  ARLISS is a joint program of Stanford University and Aero-PAC.  (I’ll put a link here for the official ARLISS web page soon.)  The standard ARLISS rocket is an M1419 (3-grain 98mm) powered 6” diameter rocket.  It carries three can-sats to about 12,000’ then releases them.  A “can-sat” is a scientific educational research project.  The details of the project matter not to the rocketeer except that the can-sat is based on a standard 12-ounce soda can (thus the “can-sat” name).

 

The ARLISS-K testing this year came up with rather short notice when discussing the issues of coordination between the rocketeers and the satellite project teams.  Some times only one or two teams are ready when a rocket is ready to accept the payload.  It was decided to attempt to produce the same results with a rocket capable of flying only one can-sat.  An additional benefit of this plan is that the rocketeers will only need Level 2 certification to participate so it is hoped that more participants will be recruited.  So, I volunteered.

 

Let’s build a rocket! 

Requirements:

  • Carry a 12” long, 3.0”diameter can-sat carrier to greater then 10,000’
  • Separate from the booster deploying separate parachutes.
  • Wait 6 seconds then eject the can-sat carrier & nose cone
    • Nose cone recovers on separate parachute
    • Can-sat carrier remains tethered, and on reaching the end of it’s tether inertia causes the can-sat to eject from the carrier.
  • Use a K700 motor.
  • Incorporate a very stabile design (preferably using 4 fins), capable of safe flight carrying from 1 to 12 ounces of payload with minimal adjustments.

I ordered carbon-fiber parts from PML and an Aeropack elliptical tail cone.

 

I installed the 54mm motor tube, one centering ring at the forward edge of the fin slots, and tacked in two fins.

When the first two fins tack-job had firmly set, I jigged up again and tacked in the last two fins.  Note the motor tube hanging out enough for the tail cone / motor retainer.

Taping for the fin fillets.  Some times I just use a reference block instead of measuring device, 3/16” plywood in this case.

 

As soon as the epoxy is laid down the tape comes off, this lets the edges disappear instead of leaving tape ledges.

 

Once the fillet is firm, it’s time for the carbon cloth.

 

I found that my first time playing with carbon-fiber was pretty rewarding.  Perhaps because it was a simple easy tip-to-tip fin reinforcement.  These two pics [right] show my prep table.

 

 

 

Left, is a close up of the carbon-fiber material ready for wet-down.

 

Right, my epoxy tools at the ready.  The paper plate gets stuck to the table on the masking tape “T” before I use it for an epoxy roller tray.

 

 

The PML carbon-fiber nose cone is smaller then the OD of the .056” heavy-duty tubing.  So I had to grind a transition into the end of the tube.

 

This angle of the shows the bulk plate I had to install to provide a nose cone chute mounting point, but also you can kind of see just how thin the it is.

 

Because of the thin material, I installed this base-ring on the nose cone to aid in ejection reliability.

The PML carbon-fiber parts come with this really cool smooth glossy finish.  So I sanded it off!

 

After sanding, a section of airframe is bonded to the center of one coupler that becomes the electronics bay.

 

I installed a bulkhead and two 10-24 all-thread rods, and made an electronics mounting board.

 

The other coupler becomes… a coupler!  Surprise!  Ok it’s not a design breakthrough.  So sue me.  But I did cut an inch of the custom ordered 9” coupler to make the 8” coupler for the booster section, right.  I used the extra inch below as a stop-block for the can-sat carrier below.

The booster section needs a recovery attachment point so I made a typical bulkhead with PML style attachment.

 

Of course since I wanted serious durability, I enhanced the concept for extra strength.

Below is a [poor] diagram.

Looking forward through the bottom of the payload section the bottom of the carrier sets the location of it’s own stop-block while epoxy sets up.