Tuesday, 6 May 2008

Smashed Potato


I'm quite pleased with this pic - whilst it has a naive, snap-shot quality about it, the clever bit is the way the peaceful domestic scene outside the back door at Diplo Hall belies the devastation and and destructive forces about to be un-leashed at 07.00 hrs, May Bank Holiday. This was not to be a "test" firing so we can't really plead ignorance, experience has taught us that a flat trajectory of 70 metres using a 2 ounce round is quite achievable, early indications are giving an MV of around 750 to 800 fps. Ballistics at this scale does involve a certain amount of trial and error, for instance the calibre of 1.5" was arrived at by seeing what stock pipe we had in the 'shop. A variety of fuels have been employed to date but we have settled on the very expensive Sheer Blonde from the John Frieda Collection - quite what this stuff does to your hair doesn't bare thinking about. The detonator (or ignition system) is a modified pezo type spark generator from an old gas boiler delivering a finely tuned spark via two self tapping screws inserted into opposite sides of the combustion chamber. Any how - must be off to order some new fence panels and weird extruded aluminium greenhouse parts for the neighbours and pen a few well chosen words by way of an application to get my status downgraded from "irresponsible" to "eccentric". MORE KINETIC ENERGY (again)

5 comments:

Jon Dudley said...

Spooky! are these devices being fabricated across the nation against some future insurgence? I think we should be told. Post Sunday lunch a few weeks ago was enlivened by the test firing of a similar device constructed by the teenage son of one of my fellow lunchers. Constructed of plastic plumbing products, a 'U' trap was unscrewed and formed the chamber into which the hairspray was introduced, but the nice touch was the trigger mechanism from a redundant Bosch electric drill which fired the contrivance in the same way as yours. The years slipped seamlessly away as the adults merrily shot pieces of Marris Piper into the treetops to the annoyance of the pigeons. Better fun than a catapault...can you still get the square elastic?

Diplomat said...

Ah - jd - I'm pleased the word is spreading. According to back of Senior Sevice pack calcs we're delivering about 1500 joules on impact at say 50 metres - from memory, my deer stalking requirements by law are around 2300 joules - obviously we've some way to go before we can be sure of defending ourselves against buffalo or wild boar but plans to increase the bore of the combustion chamber should get us up to about 1200 fps and loads more power.

Jon Dudley said...

The joule...physics lessons passed me by regrettably but I think I follow your gist especially the Senior Service bit. Before you place this device between your bold self and a wild boar I think we should take counsel from either a gardener or a chef - clearly a floury potato will prove inadequate against the tough skulls of these porcine monsters. A good firm King Edward should do the job or at least give the beast a good stinging if my memories of spud guns are at all accurate.

A F-A said...

Marvellous Diplo!! Shoot more boar!

People of a certain age from the motor trade may remember Champion Spark Plug presentations of detonation. It use a 3foot long glass tube of about 3inch bore, and the technique was to introduce a good squirt of fuel - we used 'Banda Copier' fluid - to the tube which was sealed at one end. Then, one rolled two rubber balls (the kids' super-bouncy type were favoured) up and down the tube to distribute the fuel, removed the balls and lit the gas. A clearly visible flame front would roll down the tube until the remaining mix was so compressed by that flame front that it would detonate - with a gratifying crack and a flame of three or four feet shooting out the open end.

Easy....unless, like me the first time I did it, you forget to remove the two rubber balls! I had an audience of a hundred or so lads from a motorcycle club, in a community centre somewhere, and the sight of them bobbing and weaving as the two balls ricocheted around the room will live with me for ever!!

Diplomat said...

UP-DATE - neighbourhood watch classification now "certifiable"