Scratch Pad Stik (Launch Pad) Original Design / Scratch Built

Scratch - Pad Stik (Launch Pad) {Scratch}

Contributed by Larry Brand

Manufacturer: Scratch
(Contributed - by Larry Brand - 05/11/05) (Scratch) Pad Stik

Brief:
Some years ago, I saw an article mentioning a rocket launch pad made from a surf-fishing rod holder, which is a short length of PVC tube cut to a sharp bevel for sticking into beach sand to hold the fishing pole and freeing the fisherman's hands to hold more important things (like a cigarette and a beer) while waiting for a fish to bite. The idea was to affix a launch rod to the pole holder, creating a very simple launch pad infinitely variable as to angle and also able to operate from inclined or uneven surfaces. I never could find the article again, so as part of the NARTREK Advanced program I decided to make my own version. It is the most compact launch pad I have seen.

Construction:
It starts with a High Impact Sand Spike (Stock No. 195-S, Rahway, NJ 07065) from Jeros Tackle Co., Inc. that I bought from a local bait shop. I suppose thick plumbing grade PVC tubing might suffice also. Other parts used were a 3/16" Estes Maxi-Rod, 12" each of 1/4" ID and 3/16" ID heavy wall aluminum tubing, a 6" Craftsman aluminum oxide metal cut-off wheel ($1.99), a small Estes blast deflector, and some duct tape.

The lower end of the Maxi-Rod was telescoped halfway into the 3/16" ID tube and the lower end of this was telescoped halfway into the 1/4" ID tube. These parts were secured in place with duct tape. This entire assembly was then securely taped to the upper half of the "sand spike" opposite the bevel. To assure a snug fit, a gouge was first cut out with a grinder bit in the reinforcing lip of plastic overhanging the top of the sand spike (although I found not all brands of sand spike have this). For robust blast deflection, an old Estes blast deflector was placed atop the ceramic cut-off wheel and both were pressed together over the Maxi-Rod onto the duct tape junction with a spent "D" motor casing used as a standoff.

(Scratch) Pad Stik(Scratch) Pad Stik

For use, the spike is pounded into sand or soft soil with a rubber mallet and the upper section of the Maxi-Rod is screwed into place, It is only necessary to cover the beveled portion when driving Pad Stik into the ground. The Pad Stik can be canted slightly toward the wind direction when driving into place. No other adjustment is necessary. Pad Stik is designed for mid power rockets and large model rockets up to H power and weighing no more than 2 1/8 lb. I have load tested Pad Stik with various rockets and it is perfectly stable even with a 48" four pound AUW rocket, however, this is far beyond the load capacity of the Maxi-Rod component. For added safety with larger rockets and G and H motors, the tube portion of the Pad Stik should be weighted by filling with local sand to prevent a jammed launch lug from launching Pad Stik along with the rocket. Properly placed, it takes a good twist combined with a hard pull to free Pad Stik from the ground. It's better to be safe than sorry. I have never had a launch dislodge Pad Stik even slightly.

Flight:
I have tested Pad Stik with motors up to AT G80 and CTI G79SS. The largest rocket flown from it is my 2 1/4 lb (1070g) "BottleBat", a G or H powered tube fin design, which launched perfectly albeit with a bit of "twang" to the rod end. However, this is the absolute upper limit I would recommend, especially with the Maxi-Rod. Pad Stik is more at home with mid power designs like the LOC Onyx on an F23-4, a Launch Pad ASRAAM on twin D12s, or my kit bash design Eagleator (an extended Estes Eliminator) on an E30-7. If Pad Stik will be used mostly on G or H powered rockets, a 36"x1/4" steel rod should be substituted for the Maxi-Rod. For safety, I have placarded Pad Stik as follows:

WARNING:
Only for use by ages 18 and over or with adult supervision.
Ground angle not to exceed 10 degrees from vertical.
Rocket weight limit: 1Kg (2.2 lb), including motor weight.
Not for use with motors exceeding 320 N-sec ("H" power).
Use only non-metallic hammers for placement.
Beveled portion of base must be completely covered for proper use.

Summary:
PROs: The Pad Stik is a simple to build and inexpensive mid power pad perfect for soft or uneven surfaces that would make a conventional pad wobbly and can be infinitely adjusted for wind direction. It is compact and easy to transport, quick to set up, reposition, or take down. Pad Stik even remains fully usable for its original purpose (fishing rod) with the blast deflectors removed and upper Maxi-Rod section unscrewed!

CONs: The Pad Stik only works with soft soil, grass, desert, or sand. It is not usable with impenetrable solid surfaces like hard playa, rocky soil, or asphalt. Launch angle restricted to 10 degrees from vertical. Restricted to G-power with Maxi-Rod and to 1 Kg total rocket weight. It is probably unsafe to use any sand spike based design pad with I impulse or higher motors under any circumstances.

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