Public Missiles

Public Missiles Tethys

Public Missiles - Tethys

Contributed by Scott Weihe

Construction Rating:
Flight Rating:
Overall Rating:

Diameter:	3.90 inches
Manufacturer:	Public Missiles
Style:	Sport

Public Missiles, Ltd. Tethys Brief:
This is a big beautiful stock PML kit with 3 fins, parachute recovery, and would be perfect for level 1 attempts.

Construction:
The kit came with a 36" x 4" PML Quantum body tube, G10 fins, plywood centering rings, PML's 54/38/29 Kwik-Switch motor mounts, a tough plastic nose cone, PML's piston ejection system, 12 feet tubular nylon shock cord, a 48 inch chute, 2 brass lugs, and some very good instructions.

My Tethys came with very good instructions and assembly went smooth. I have built other PML kits all with similar results. I used a good 5 minute epoxy which worked perfectly for the entire build. No special tools or gotchas of any kind. That plus the fact PML kits are so sturdy is why I chose this kit for Level 1 rocket.

Finishing:
Finishing was a breeze. The Quantum tube, G10 fins and the nose cone all require very little prep before paint (as long as your epoxy work is clean). The kit came with some nice looking decals, but since I have a tendency to repaint my rockets every few launches, I left them out and settled on a red and blue paint scheme.

Construction Rating: 5 out of 5

Public Missiles, Ltd. Tethys

Flight:
I used a Aerotech H123 with a 7 second delay for my level 1 attempt. PML kits come with a piston ejection system which eliminates the need for any wadding or chute protection--one of my favorite things about PML kits. I used a simple double clamp motor retention system from Giant Leap. 5, 4, 3, 2, 1, and lift off. The flight was perfect with just a touch of weathercocking into the 5-10mph breeze.

Recovery:
The piston ejection worked perfectly right at apogee. The 48 inch chute brought the rocket down at a perfect speed to within 50 feet of the launch pad with not a scratch on it.

Flight Rating: 5 out of 5

Summary:
The Tethys is a great level 1 rocket. It was easy to build and finish, it's extremely sturdy with the Quantum tube and G10 fins, and it flies great! I am seriously considering using this kit for my Level 2 certification attempt.

Overall Rating: 5 out of 5

Other Reviews

Public Missiles Tethys By Greg Gardner
Mostly stock rocket for my Level One certification. This is my first rocket higher than an Estes kit. First Flight on this rocket was my L1 attempt as built weight was too heavy for a "G" test flight. The kit includes: 1 36" x 4" PML Quantum body tube Piston ejection system 3 G-10 .093" fins 2 1/4" plywood centering rings 54mm Kwik-Switch motor mount with 38mm & 29mm ...
Public Missiles Tethys By Kevin Drayson
Photo Courtesy of PML The Tethys is a basic 3FNC kit, capable of flying on G motors or bigger. The Tethys came with a single length of airframe tubing (phenolic, per my request), 3 pre-cut G10 fins (the thickest fiberglass fins I've used to date), a 4:1 ogive plastic nose cone, a thick nylon strap, a length of tubular nylon, piston kit, a 48" parachute, two brass launch lugs, and the 54mm ...

Flights

Comments:

D.J. (November 1, 2000)

I built and flew the PML Tethys for a level 2 certification. I really liked the kit and would recommend it to anyone seeking a rocket for level 1 or 2 certification. I built it stock except for an eyebolt in the back of the nose cone and replaced the elastic shock cord with 12 feet of 1 inch tubular nylon. My level 2 cert was flown on a J350 with a 14 second delay. It didn't waste anytime getting off the pad for an out of sight flight. I like the PML phenolic airframe, except for the groove which took a fair amount of time to fill. I also Would recommend glassing the airframe for added strength and I think it would take less time than filling the groove and sanding it smooth. I give this kit a thumbs up. I found this review to be accurate.

A.D.W. of PML (January 1, 2001)

The reviewer mentions that they ordered the Tethys with phenolic. All Tethys kits come in our Quantum Tube unless specified otherwise (as he did). Also, the kit must have been ordered quite some time ago, as we have been packaging tubular nylon in all our kits since about 5/00.

(January 3, 2001)

Kevin has come back and said: "Just thought I should add a quick clarification about my review... the extra length of shock-cord I added was from an older PML kit, which was no longer in service. The Tethys itself did come with tubular nylon instead of elastic.

G.S. (April 1, 2001)

If you build this kit again and decide to go with the phenolic, might I suggest instead of using 'glass cloth, try maybe a 5 oz/sq.yd. Kevlar cloth and a high grade epoxy (AeroPoxy works great for me)? I've found Kevlar to be extremely tough and durable. Don't sand the laminate though, use a high-build primer to fill the weave. Sanding into a laminate destroys the structure you just created.

D.B.M. (August 17, 2005)

My Tethys has the Quantum tubing. A fast and simple build, gotta love those G-10 fins and plastic tbing for easy and quick finishing! I upgraded my chute to 54" for flying on out desert playas, but in retrospect I wish I had kept the stock 48" chute as I've had to take some long walks using J's. My Tethys, with a two-part, three color automotive finish, came out at 52 ounces without motor casing (but with 54mm QS adapter installed). I had to add 8 ounces of nose weight to balance out at 1 caliber using the 38mm J285's and J350's. I'd suggest going to 1.5 calibers as I've had some wiggle off the pad. Suggest anyone building these use an eyebolt in the nose cone rather than the stock shock cord mounting. I've bought now some 3.9" main and coupler tubing and will be building a payload bay to add some length (and move the CG forward). Overall, a great kit and rocket!

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