Sunday, December 18, 2005

Close only counts in horseshoes and hand grenades

Applied Ergonomics

Volume 37, Issue 2 , March 2006, Pages 113-118
Influence of hand grenade weight, shape and diameter on performance and subjective handling properties in relations to ergonomic design considerations

Cheng-Kang Yuana, Corresponding Author Contact Information, E-mail The Corresponding Author and Cheng-Lang Kuob, E-mail The Corresponding Author

aDepartment of Business Administration, Lunghwa University of Science & Technology, Taiwan, ROC
bDepartment of Industry Management, China Institute of Technology, Taiwan, ROC

Received 8 September 2004; accepted 20 June 2005. Available online 15 August 2005.


Three hand-grenade design factors, namely shape (ball, oval, can), diameter (55, 60, and 65 mm) and weight (300, 400, and 500 g), were assessed. The objective criteria were (1) throwing distance from the grenade stop point to throwing point, and (2) error distance from the grenade stop point to the target. The subjective criteria were (3) the overall rating of handling (to hold and control) properties and (4) the rating of perceived exertions of throwing strength. Twenty ROC Army soldiers threw a Mark II practice grenade to familiarize them with the throwing procedure, and then, while standing, threw 21 experimental, mockup grenades at a target indicated by a flagpole 40 m away from the throwing point. Grenade weight had the greatest effect on both subjective and objective criteria. The 300 g grenade had the greatest throwing distance (38.6±6.5 m) and had the greatest accuracy (6.9±3.9 m). Grenade shape was also a significant influence based on both the subjective and objective criteria; with the ball shape being the best. Grenade diameter, within the range tested, did not affect either the subjective or objective criteria.

BrooklynDodger comments: Science marches on. Not that we don't need science applied to everyday life and death situations. In this case, it's a death situation suited to military planning.

The Dodger was not surprised that the lightest grenade shaped like a ball had the greatest throwing distance and accuracy. For comparison, a baseball weighs about 145 grams (compared to the 300-500 for a grenade). The circumference of a baseball is 230 mm. [The Dodger had a lot of trouble with the math for was while, but the 60 mm diameter grenade would appear to be about 180 mm circumference; this suggests grenades are denser than baseballs.] The Dodger guesses that home to second base is about 40 meters. In the Dodger's personal experience, substantial air must be put under the baseball for a non athelete to reach second base.

It would appear the reviewers should have complained about reporting distance in the abstract in this fashion. The grenadiers are not throwing for distance, they are throwing for accuracy not to overshoot the target. Presumably they would have go a lot more distance if told to really air it out. A more interesting observation is that grenadiers when throwing for accuracy fall short on the average. On the average, they missed the target by about 25 feet.

At least in movies, the Dodger remembers the grenade throwing technique as a stiff armed underhand sling, rather than overhand with follow through.

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