Dumb Question/Momentum and Broadheads
 

I am just reading over on GMMAT's analytical thread[8D], and I have a couple questions.

1. Where does momentum effect the penetration of a razor sharp broadhead?

2. How does speed effect the penetration of a razor sharp broadhead?

I realize the weight of the broadhead is usually around say, 1/3 or less of the total arrow weight. So, if you shoot an arrow with a broadhead of say, closer to 1/2 the total arrow weight, would this in fact give better penetration? (with the same identical bow setup) Is it not going to give you slower speed getting downrange and therefore less penetration? Remember, we are talking razor sharp broadheads here. So if I shoot a a.)400 gr(total arrow weight) vs b.)600 gr(total arrow weight), same razor sharp broadhead at say, 30 yds, except one bow is shooting this arrow a. at 320fps and b. at 250 fps, which one has more penetration and why?

LT

RE: Dumb Question/Momentum and Broadheads
 

The faster one, its common scense... Think about this into ballistic gel so we get the same target every time.

RE: Dumb Question/Momentum and Broadheads
 

The answer to 1 is on a heavy bone hit.

2 will be debated but the fact is friction decreases with speed but
resistance increases.;)

IMO,Heavy bone doesn't really care how sharp the head is.

RE: Dumb Question/Momentum and Broadheads
 

Momentum is a measure of penetration potential, so is KE.

RE: Dumb Question/Momentum and Broadheads
 

Definitely not true ..... the sharper the head, the more it will penetrate heavy bone .... think of an axe...

RE: Dumb Question/Momentum and Broadheads
 

Velocity squared X weight divided by 450395 will = kinetic energy.:eek:

That should add to the confusion.;)

RE: Dumb Question/Momentum and Broadheads
 

Actually, that makes sense to me .... maybe cuz I have been teaching it for years..... let' go fishin Jimbo :D

RE: Dumb Question/Momentum and Broadheads
 

Its raining here in North west PA's newest rain forest, the hell with deer season we're gonna be hunting monkeys and listening to parrets if it don't stop raining soon.[:-]
If it stops raining some time soon I might hit the lake at the end of the week, this low pressure front is killing us.

RE: Dumb Question/Momentum and Broadheads
 

LOL! ..... it's been the same here ..... I feel like I'm in Florida ...torrential downpours .. thunder, lightning, and then .... sunshine .... then back to the rain ... it's nuts ...

RE: Dumb Question/Momentum and Broadheads
 

KE: speedxspeedxweight/450240
momentum:speedxweight/225120

RE: Dumb Question/Momentum and Broadheads
 

5 years ago I tested this theory with my recurve against a compound with an over draw. My recurve shoots about 210 fps, his compound was 260 fps. My arrows weighed in at about 600 grains, his on the compound were 400 I think it was. Whatever they were they were much lighter arrows. Both arrows were tipped with a bear razor COC broadhead. For the test we used a 5 gallon pail full of sand. My recurve smoked this compound for penetration at 10 yards. I had 2 holes, the compound only had 1. Thats momentum!!

RE: Dumb Question/Momentum and Broadheads
 

I no, i think this is about 36 hours of straight rain/thunderstorms/5 mins of sunshine

RE: Dumb Question/Momentum and Broadheads
 

yep or another anology would be- try and drive a nail in backwards on a piece of wood.

RE: Dumb Question/Momentum and Broadheads
 

I am not saying use a dull head but the bone is not going to slice apart like flesh or skin.A chisel point will do the majority of the work on a hard bone hit.Bone will most often shatter with momentum ime.That sharp head won't be sharp very long when in contacts bone.

RE: Dumb Question/Momentum and Broadheads
 

that last anology is incorrect, your dealing with pressure/in^2. Not sharpness.

RE: Dumb Question/Momentum and Broadheads
 

Wrong, the sharper , the pointier the easier the penetration on bone, ply wood , skin, meat, whatever.
Its all pressure. With enough you can make something dull and flat penetrate steel. With a given velocity, or pressure or kinetic energy, whatever you want to call it, the pointier or sharper the easier the penetration.
I can cut through the ribs of a deer with a simple sharp knife, try it with a dull one.

RE: Dumb Question/Momentum and Broadheads
 

My bad, forgot that were dealing with pressure on BH too. Just much smaller differences in thinkness. Didnt relate that micro differences on Broadheads.

RE: Dumb Question/Momentum and Broadheads
 

Yes sharper will penetrate bone better, not so much because its going to slice the bone or even crack the bone. In order to get to the bone you must first go through skin, muscle, cartilage, all kinds of stuff. Thats where the razor sharpness of your broadhead comes into play for penetration on bone. If it can slice through all that stuff with reletive ease it will carry more momentum to break that bone and keep going. There are differant kinds of penetration, the slicing kind which you need to go through muscle and organs and then the breaking/crushing kind which is needed to go through bone. To penetrate bone you need a sharp point but most importantlyyou needjust pure force to break it and keep on going.

RE: Dumb Question/Momentum and Broadheads
 

Bingo ! this is why fixed blades will always penetrate bone better than a mechanical.
Been there done that ! I will never use mech. again. I killed a bunch with mech. But given enough time you will see what I am talking about, mech. lose chingos energy on the rearward deployment, now contact bone. Blah they are out of steam.

RE: Dumb Question/Momentum and Broadheads
 

Ever considered how much momentum would it take to get a passthrough on a broadside deer at 20 yards?

This is / is not a hypothetical question, since I have an estimate based on hunting results with my wife's equipment.

RE: Dumb Question/Momentum and Broadheads
 

Guys,I am not disputing any of the above,it is all correct but a razor sharp broadhead won't slice HARD bone like it will tissue(a rib it will slice to a certain degree),that was the point I was trying to make and as soon as a razor sharp broadhead hits bone,it is dull.That is all I was illuding to.

RE: Dumb Question/Momentum and Broadheads
 

Have to disagree with you on this to some extent. Last year I had 2 complete passthru's with 100gr Slick Trick Magnums and cut thru ribs on entrance and exit. They were "more dull" than new, but still sharp enough to cut me or deer. So I would have to say they may not handle "all" bone. I do have a better understanding of how momentum comes into play at this point though. I will probably start experimenting with a higher FOC arrow after this season. I see no point in messing with my setup right now. Too close to D-day.

LT

RE: Dumb Question/Momentum and Broadheads
 

Read what I have in parenthesis.I am talking heavy bone.;)

I quess I should have emphasized heavy and hard bone in all my posts.Sorry.[8D]