Flashcards in Timber (Chapter 8) Deck (30)
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16. Where should you prime a ring charge?
Two opposing places
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11. How big should charges be on external method?
Rectangular
1-2” Thick and twice as wide as they are high
On circular timber, charge should cover at least ½ the circumference
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12. In order to achieve maximum charge to target contact, you must do what?
Remove the bark or notch tree to match dimensions of charge
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14. What is the formula used for ring charge?
Used for external formula P=D^2/40
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7. How many holes are used for an internal charge?
Trees up to 18” diameter = 1 hole
Larger than 18” diameter = 2 hole
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8. Name and describe the two types of hole placement
a) Dimensional
Holes are side by side and should face direction of fall
b) Circular
Holes are at right angles and the direction of fall is in between holes
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2. What types of explosives are used for internal?
Dynamite, plastic and sheet explosives
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5. What are some considerations when cutting timber?
Wind and Lean
Most critical factors for determining direction of fall
Always attack the least dimension
For unknown types make a test shot to determine optimal size of the charge
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18. What is an abatis?
Fallen trees partially attached to their stumps, used as an obstacle
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6. What is the formula for internal charges?
P (lbs of TNT) = D^2 (Diameter) /250
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4. What types of explosives are used for ring?
Plastic and sheet explosives
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15. How big should ring charge be?
The explosive band should be as wide as possible
At least ½” thick for trees up to AND INCLUDING 15”
1” thick for medium and large trees up to 30”
Add 15% to circumference when constructing the charge
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13. How do you influence the direction of fall while using external method?
Add 1 lb kicker charge, optimally 2/3 up tree opposite of the main charge. Fire simultaneously with main charge.
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19. What are the considerations for an abatis?
Ensure obstacle is at least 75 meters in depth
Fall trees 45 degrees towards ENY
Detonate one side of road, allow delay then other side of road IOT avoid deflecting
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9. What is the measurement of holes that are drilled into timber for internal charges?
2” diameter, and 2/3 deep in timber
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17. What is the formula used for Abatis?
P=D^2/50
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1. What types of explosives used for Timber?
Internal
(Dynamite, plastic and sheet)
External
(Circular: Plastic and sheet; Dimensional: TNT, plastic, and sheet)
Ring
(Plastic and Sheet)
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10. What is the formula used for external?
P=D^2/40
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3. What types of explosives are used for external?
Circular, plastic and sheet explosives
Dimensional: TNT, plastic, and sheet explosives
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How should you attack timber with a charge?
Attack the least dimension
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What are the most critical facts for determining direction of fall?
Wind and Lean
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What should you do after placing explosive in hole for internal charges?
Cap bore holes with mud or clay using a non sparking tool
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What should you do to the circumference when constructing a ring charge?
Add 15%
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Two types of ring charges
Dimensional
Circular
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Where should abatis charges be place?
5' above ground level
(Use kicker charges when necessary)
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How long should an abatis be?
At least 75 meters in depth
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How big should abatis trees be?
At least 2 ft in diameter
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How far apart should abatis tree be?
3-5 meters apart
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Which direction should the felled trees of an abatis be facing?
45 degrees toward enemy approach
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