From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: alt.engr.explosives
Subject: Re: Det Cord R.O.B.
Date: 22 Jun 1996 19:44:48 GMT

In article <4qgnj9$4r0@nnrp1.news.primenet.com>, Thomas K
<rabbit@primenet.com> says:

>Just curious, what is the rate of burn for Det Cord, we used to cut small 
>trees down in LeJeune with it...-Tom

They must have been pretty small trees or you used a lot of det cord:)

The det velocity is around 21,000 ft/sec for the 50 grain PETN variety
and probably around the same for the military and oil well cord using
RDX.

A few wraps of det cord around a 1-ft diameter tree will blow a ring
of bark off.  Trees are tough targets for explosives unless placed
in a hole bored in the trunk.  When one does have to blow down a tree
from the outside, it is best to use two opposing and slightly offset
charges to produce a shearing action.  Some very large trees require 
up to 40 pounds of HE.

We used to fell trees with lightly gelled Astrolite G poured or 
injected from a squeeze bottle into the slit produced by forcing the 
tip of a chainsaw into the trunk. A pound or less will take out a 2-ft
diameter tree. This was a method developed for helicopter LZ clearance 
during the Viet Nam war.

Jerry (Ico)