Just thought it might be interesting to post a series of frame capture stills from the movie we made of Ernie's bowling ball heading for the stratosphere from Cut Bank, Montana. We don't really expect to gather any data for analysis from this one, but rather, we thought it would offer a unique glimpse into what muzzle blast and trailer jump is all about. Despite laboriously building two 4' X 8' timber cribs under trailer, directly under the Paixhans Monster Mortar, there still was quite a bit of trailer jump and resulting, mortar jump. It starts in frame # 22 and ends in # 37. A minor, secondary mortar jump starts in #39 and ends 4 or 5 frames later. Hard to believe the trailer jumped like that; 90% of the weight was on those stout timber cribs after I pounded the large, tapered wooden wedges in place between the trailer bottom and the top of each timber crib.
Using one and a half pounds of Fg powder, we launched Ernie's ball across the mowed field, over the grassland, above the plowed field, over more grassland and into the next section. We had about 49 people observing that shot, but not one saw that 16 pound bowling ball as it sizzled skyward at 60 degrees. Not even by studying the clip, filmed at 600 FPS, can you get a peek at that ball.
Just before the trailer tremors start, look at the area of the deck immediately to the left of the mortar. Dust jump! Concussive effects of the compressed air of the muzzle blast.
The movie is way too long to post, almost 6 minutes.
Tracy and Mike
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