Friday, August 19, 2011

Tennis Ball Launcher - Cont'd

The Preliminary Tennis Ball Launcher Performance Results are In.

Note: this is an implementation of the Triitent Pneumatic Launcher.

Using the Launcher, an antenna will be strung in my trees before long. I am still waiting for the Bow Fishing Reel and Line to arrive.

Also, see previous posts; here and here.

The first few low pressure test shots in the Shop scared Tess (my Dog) to death, it sounds like a fog horn.  But later outside shots, where the sound did not reverberate, and where there was a ball to chase became great fun for her. Although Tess has not yet learned to look up, to see the ball fly, she usually waits for the first bounce, and then she is all over it!

Jury-Rigged Switch and Battery
The first few outside shots were at low pressure and with an un-weighted ball. It became clear after the first few shots that I need to hook-up the electric solenoid to a switch, instead of just using loose wires connected to a 9 Volt Battery. I jury-rigged a switch and battery with tape to the launcher.

Now it was time to try some high pressure shots.

The first high pressure shots were at 10, 20, 30, 40, 50 and then 60 pounds, with an un-weighted ball. Tess retrieved each with pleasure.

Fill Connection and Pressure Gauge
The Mountain Dew Bottle was used for it's Extra Buzz :-)
Read for Test Launch
Most web Tennis Ball Launcher users weight the ball by inserting 16 pennies (via a cut slit). Tess could not figure out what I was doing to her ball, and then she found it strange, it rattled when carried or rolled. We played catch with the weighted ball for a few minutes, and now thinks it is normal. I also threaded a cable tie through two holes (across the penny slit) for tying a streamer and later a fishing line.

So now, for the first weighted shot; A Tennis Ball, containing 16 pennies, a 3 foot red marking tape streamer, and at 60 pounds of pressure.

When shot almost straight up, the weighted ball when above the top of a tree in the drive next to the Shop.

Now, how high was that?

I am not very good at estimating height (and, I do not have a sextant or barometer to drop :-).

But, I do have a Cell Phone, with an APP, . . . a Level with voice output. Moving away from the tree and sighting along the edge of the phone to the top of the tree, until the level spoke the words for 45 degrees, I can now measure the distance to the tree and add 6 feet for my eye level. The tree was 40 large paces away, plus 6 feet, implies the tree is 40 x 3 + 6 = about 126 feet.

My first full pressure, weighted ball, shot went up about 126 feet !!!!!

An attached fishing line may reduce the performance (the bow fish reel still on order).

For several more shots (and until it got dark) Tess was have as much fun as I, shooting this thing.

There were several things noticed that may need refinement:

  • A lot of air comes out after the ball has left the chamber, which implies that the valve may be restricting the flow, maybe a double value is necessary? Or, maybe the current 26 inch barrel needs to be longer?
  • The trigger switch worked well, but it seems un-safe. I initially considered a inline safety toggle switch and I may still install one.

But, What Fun !!

More later.


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