Rocketry Planet

My first attempt at dual deployment came in the form of Public Missiles' Sudden Rush kit featuring the new Quantum Tube airframe. I had previously purchased an Adept ALTS2 altimeter in hopes of starting a dual deployment vehicle from scratch but after much head scratching, I decided to use a pre-engineered kit such as the Sudden Rush to learn the basics.

PML's Close Proximity Recovery (CPR) 2000 parts with altimeter

Unfortunately, the Close Proximity Recovery (CPR) 2000 system included in the Sudden Rush kit only works with the Transolve P5, P6 or the Adept ALTS-25 altimeter in most cases, including mine.

The hole patterns are the same but the components on my altimeter interfered with the fit.

The CPR 2000 altimeter bay is a masterpiece of miniaturization.

If you need a 9 volt battery with your altimeter, you won’t be using it here.

Applying epoxy to the motor mount

Everything resides in a 4" long 38mm BT section. The system requires 2 Robby's Rockets Loadable Ejection Systems (LES) units. The CPR system should have a method of arming the ejection charges after insertion of the CPR unit into the rocket – but it doesn't say so in the directions.

As usual, I find myself working late and press on with the kit's construction. There should be more documentation on the CPR 2000 both in the advertising and in the actual construction. Unless you have seen it, it is difficult to imagine how it works.

This is my second kit using the PML Kwik-Switch 2000 motor mounting system. If you want the ability to quickly change from 29mm to 38mm to 54mm motors without adapters, this is for you.

The instructions are straight forward but I still wonder why the motor tube needs to extend ½ " beyond the tailcone. The directions call for internal epoxy fillets to each fin. Even with a long thin stick this is difficult to do without epoxying up the motor tube.

Syrofoam template is use to align the fins accurately

I covered the body tube with a plastic bag to keep the mess workable. Even so, when it came to dry fitting the tailcone on, it only got to within ¼" of the main body tube before becoming permanently lodged.

Note the blue painter’s masking tape. This tape works well with epoxy and can be easily removed even after the epoxy sets.

For fin alignment, I used a styrofoam template cut out during the construction of another vehicle. This is not my idea, but I like it and thought you may want to try it as well.

Sudden Rush sitting in primer

The rest of the kit went together easily as described in the directions.

The Quantum Tube finish is smooth and cool to the touch. The first time you screw the drogue recovery airframe into the main recovery airframe, you will fall in love with the CPR 2000 system.

There is not much room in the drogue recovery airframe so pack your chute and wadding carefully.

My Transolve P5 altimeter arrived shortly after writing this piece. Connecting it to the LES units and to the external switch Transolve provided takes a steady hand and a lot of patience. There isn't enough room in the CPR-2000 for much wiring.

To retrofit the on/off switch into the Sudden Rush, I had to cut a slot forward of the connection ring, run a connector (provided) into the CPR-2000 bay via a slot that had to be dug into the CPR connection ring.

In order not to tear out this connection, I "pinned" the CPR-2000 into the forward connection ring with 2 finishing nails so it would not turn when screwing the aft end of the rocket tight.

This kit taught me a lot about dual deployment. I understand Transolve is out with their new P6 altimeter that has connections on it for the two LES units and the kill switch. This will make the CPR-2000 even easier to use.

This is my second PML kit but not my last. They seem to be well engineered and arrive very quickly after ordering. All in all, I learned enough to scratch build a dual deployment rocket to use the ALT-2 altimeter purchased earlier – but that is another story.