Dr. Ed Ashby's Published
Arrow & Broadhead Penetration Research
Dr. Ed Ashby and an Asiatic Buffalo taken with a prototype Ashby broadhead
Ashby Audio
Ashby Reports
12 Arrow Penetration Enhancing Factors (Start here with audio above)
Clotting Cascade (read with audio above)
Momentum, Kinetic Energy, & Arrow Penetration (And What They Mean for the Bowhunter)
Ashby's Arrow Lethality Results In Graph Form (From Original Natal Study)
Papua New Guinea Bows and Arrows (A Study of Primitive Arrow FOC)
Arrow Lethality
Ashby On Arrow Lethality Part 1: The Need for Knowledge
An Introduction to the Natal Study and the need for arrow lethality studies.
Ashby On Arrow Lethality Part 2: Broadheads - The Natal Study
Initial testing of broadheads, shaft materials, shaft diameter and arrow mass.
Ashby On Arrow Lethality Part 3: Turning "Hits" into "Kills"
Thoughts on arrow selection and design after the first decade of testing.
Ashby On Arrow Lethality Part 4: The Physics of Arrow Penetration
First decade insights into arrow penetration and postulates based on testing to that point.
Ashby On Arrow Lethality Part 5: Predicting Arrow Penetration on Real Animals
A partially successful attempt to develop a formula to predict tissue penetration.
2008 Update
FOC terminology, the Heavy Bone Threshold, testing the arrow’s FOC effect on the Heavy Bone Threshold.
Comparing of the 40# longbow’s EFOC arrows with commonly used arrows from heavier draw weight bows.
Arrow force and the Heavy Bone Threshold, why higher FOC increases penetration, how arrow efficiency compounds the penetration gain.
Testing a ‘slightly above Heavy Bone Threshold’ Ultra-EFOC arrow and comparisons against other arrow setups tested.
More (amazing) comparisons of the Ultra-EFOC arrow’s performance against other arrow setups.
Ashby 2008 Update Part 6
How much increasing FOC affects penetration, FOC and arrow mass.Ultra-EFOC and arrow shaft integrity, more broadhead testing, broadhead ‘ratio’ vs. Mechanical Advantage; a word of caution.
2007 Update
What is FOC? How is it measured What does it do?
Misinterpretation and misuse of Study data, intentional or otherwise.
Common bowhunting misconceptions, arrow shafting comparisons and internal shaft footings.
Internal footing test, how other penetration-enhancing factors affect Extreme FOC, Extreme FOC’s implications, Extreme FOC testing with the 82# and 70# longbows, and how they compare.
Penetration Enhancing the 54# longbow, another look at a single-bevel broadhead vs double-bevel broadhead of matching profile, on matching shafts, the importance of high broadhead Mechanical Advantage(MA), note on understanding the Heavy Bone Threshold, Single-bevel effect on high MA broadheads, testing the 54# longbow with EFOC arrows.
Extreme FOC’s demonstrsted advantage, a comparative analysis of the EFOC arrows from each bow tested, broaghead MA’s effect on EFOC arrows, Kinetic Energy’s comparison with EFOC arrow penetration, comparative efficiency for Extreme FOC arrows.
More broadhead testing and more broadhead design features to consider
The broadhead’s Angle of Attack, more broadhead test results.
The Penetration Enhancing Factors, considerations and comments.
2005 Update
“Penetration” and “penetrated” defined, testing of different broadhead tip designs on bone penetration, single-bevel vs double-bevel penetration with matched arrow/broadheads, effect of not matching direction of rotation of single-bevel broadhead and fletching.
A first look at Weight Forward of Center (FOC) and its effect on penetration.
Testing more broadheads
Recommendations for a buffalo arrow setup based on the first two decades of testing.
Summary overview, trends, tendencies, FAQ’s and comments.
Early Heavy Bone Threshold data.
2004 Update
A detailed look at the effect of edge finish on penetration of different broadhead types.
Arrow Shafting effect on penetration, Kinetic Energy and Momentum in predicting arrow penetration, shot placement on Buffalo, skip-angle for broadheads and how to tell when an Asian Buffalo is getting ready to charge.
1987 Update
PDF of the first US publication of the Natal Study data.