Stroboscopic Images:

The images below were taken by an Olympus C8080 Wide Zoom digital camera using an external flash unit that was triggered by a contact trigger placed behind the target object.

The flash unit has automatic exposure control, which can be used to produce very short duration flashes. A piece of reflective material was oriented to capture some of the light from the flash bulb and redirect it into this light sensor. Manufacture specifications stated the shortest flash duration possible with this flash (Promatic FDT4000) is 1/30,000 second. Given this information and by measuring the amount of blur in specific portions of an image, velocities can be determined. I calculated the speed of the projectile in the third photograph (after exiting the can) to be between 138-159 feet per second. If the initial projetile velocity was known, the energy trasfer of the projectile to the target could be calculated as well.

The flash triggering means was a momentary electrical switch placed behind the target object. When the projectile struck the target object, the object was moved backward, depressed the switch, and triggered off the flash. I suppose the delay time between impact and triggering to be determined by the weight of the target object.

The launching platform was the HVPL-01 and utilized pressures in the range of 100-140 psig. It was positioned approximatley seven feet (muzzel to target) from the target area to keep the air exiting the muzzel from moving the target object and triping the flash before the projectile impacted.

 

[A fishing sinker has just passed through this water balloon]

 

[Here is another water balloon impact. The plastic bag wadding is clearly seen exiting the balloon on the right.]

 

[I am still amazed by this photograph.]

 

[The apple was severed in half after the projectile passed through it (the crack is visible). The sinker is visible in the mist on the right.]

 

[A different apple that has already sustained many hits. Notice the juices squirting out of the crevice from the missing chunk]

 

[The sinker did not penetrate both sides of this can, but tore a small gash in the top where the liquid is exiting.]

[Small water balloon with plastic grocery bag wadding to the left.]

 

[The sinker nicked the side of the shaving cream can causing a 1" tear, which directed most of the cans contents onto the photographic equipment. The rest of the shaving cream was sprayed up to twenty feet away from the impact site.]

 

[Here the fishing sinker has ricochet off the can and was captured in the photograph. The impact dent is visible to the left of the "Net Weight" markings on the bottom of the can.]

 

<:Back: :Home: