Haha thanks, I embrace the nerd! Glad you enjoyed.

Less nerd out baby!!

Thank you for your support! Take care, Lucas

That is an interesting question, we actually could approach that question from a momentum perspective and relative velocity I'll look into it. I grew up on a cattle ranch, farm boys are some of the smartest people I know don't discount yourself.

Good observation there Rick.

@@Lucas_Palmer_bownerd_engineer Subscribed!!

Thanks!

Thanks , this is what I meant 💯. I was just too lazy to type that much out.

Step by step we'll get there. Thanks for watching.

Thanks for watching another coming soon. take care, Lucas

Thank you glad you enjoyed watching. Next video will be about animal drop difference between fast and slow arrows. I can definitely do an in depth tuning video in the future lots of videos in the pipeline.

Glad it was helpful!

Thanks for watching!

Awesome! Thank you!

what's your biggest concern with trajectory? Time in flight? The height of the arrow? Or the drop difference between distances for example range a bull a 40 he moves closer your already at draw now is it 30, 35 or somewhere in between?

@@Lucas_Palmer_bownerd_engineer drop distance

Have you shot heavy arrows? I have shot both Heavy 700grains and Light sub 400 advantages and cons to both, I live and hunt out west Idaho to be exact inside of 40 yards I'm not concerned about animal movement while at full draw with a heavy arrow anything past that I would require the exact yardage before feeling comfortable to release the arrow which might require a draw and let down or two. However, I have a 29.5in draw and shoot 70 sometimes more pounds my 700 grains arrow was still leaving the bow at around 250fps. Not exactly slow.

I do believe there is a balance and its completely different for each person and their setup.

​@leap_outdoors I also hunt out west. My primary concern on elk is not animal movement (deer or antelope it's huge) but it's range forgiveness. The number one goal should be to hit where you're aiming. Very often a bull comes into a setup I've pre-ranged and i have no time to range him again. My accuracy ranging is plus or minus say 5 yds. So my goal is to minimize the range error. I've shot both heavy/light and a 5 yd range error is my number 1 concern. Shoot both setups at 45 with your 50 yd pin and see what the difference is. Even at whitetail ranges say 30 yards at my setup a 5 yd range error between a 294 fps arrow and 246 fps is 1.5". An entire large cut broadhead high or low. Unacceptable in my book. My experience is that some people who make claims (not saying you) are shooting pretty terrible groups. Say a 8" group at 50. Then they put on a heavy arrow and they generally hit in the same area. Two overlapping bad groups. Then claim it doesn't matter. These compounding errors are what keeps me above 280 fps.

Number 1 is structural integrity. If the point bends, breaks or fails, flight doesn't matter. #2 is flight. You are 1000% correct on 650 grains. IT MOVES AROUND!! Not needed in a Plan A hit. Oh, but you put a bone in the way, it moves to number 3.

@@RanchFairy thanks for correcting me. I knew that those were the top 2, and that weight moved to # 3 with a hard impact (bone).

Thank you glad you enjoy the content. Take care, Lucas

@@Lucas_Palmer_bownerd_engineer can’t wait for the next uploads!! Really enjoy the math/physics associated with arrow flight. Have my degree in applied math and another in mech E. so this hits a little different lol

Excellent! If you notice something that seems wrong on incorrect or have question about assumptions please let me know. I am not perfect by any means and I am sure I'll make a mistake or maybe an invalid assumption, feedback is always appreciated.

Thank you! Great questions! lift is generated from drag or geometry. In this case lift would be the force of drag which causes rotation about the center of gravity. In my opinion It's better to use drag because when we say lift most assume it is upward lift however that's not always true lift can be directed downward as well. Thanks for watching.

@@Lucas_Palmer_bownerd_engineer exactly. I guess when you're making videos for the masses its best to stick to common terms. I appreciate your objectivity in the videos.

Thank you while I must admit I had/have some bias to what is best, I am trying to remain neutral.

​@@Lucas_Palmer_bownerd_engineerif you have bias, it doesn't show. Keep up the good work.

Very interesting thank you for sharing! Do you have a shoot through modern design riser or more traditional where the arrow must bend to shoot around the riser of the bow?

​@@Lucas_Palmer_bownerd_engineermy longbows and selfbows all have a small shelf cut in them but they are not perfect center shot if that makes sense. All draw to around 50 pounds.

@@bowdeer5074 Yes it does! for that type of equipment I think FOC or really front of arrow stiffness becomes even more important! Thanks for sharing!

Both are technically correct, you can’t have lift without drag, drag crates lift based on attack angle. I use the term drag because if I use lift some assume lift in the vertical direction, however “lift” can be in any direction. Lift is a portion of the force of drag causing rotation about the center of gravity. Thanks for your question glad you enjoyed the videos.

@@Lucas_Palmer_bownerd_engineer Keep rolling man!!! Spot on.

Interesting questions, I am dedicating at least 2 videos to broadheads 1 for flight the other for penetration hopefully I can answer some of these questions then. However a great video on broadheads can be found by born and raised outdoors, they shoot a bunch from a hooter shooter using the same arrow for each. They shoot a three shot group from each broadhead, some performed a tighter group than the field points. Check it out if you haven’t.

@@Lucas_Palmer_bownerd_engineer absolutely! Great video. John Stallone did similar as well. Fletch testing too

@@TheArrowBuilder John deserves some more attention for the testing he does!

Very well said create a well balanced system and it will perform great!

I have factored vane angle it was discussed more in video 2 on drag but only briefly, the CD values were determined based on this study pdf.sciencedirectassets.com/278653/1-s2.0-S1877705813X00116/1-s2.0-S1877705813010680/main.pdf?X-Amz-Security-Token=IQoJb3JpZ2luX2VjEBYaCXVzLWVhc3QtMSJHMEUCIQD14RR6TXu%2FpNLMKbZz5rNSDBIuFbfeM9Ji4QRLiVOEWwIgXBG%2BOqLYTIy5nl8nWt5SYOSexvv0zPtDZd4ec60TfwQqvAUIv%2F%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FARAFGgwwNTkwMDM1NDY4NjUiDIJvc2V4JdCC1AStISqQBbT82mrn%2F1Aw8%2BrcYLhtC60xw%2FZrLakUhlsXw4idVBvi0cXn2dKb17iatwQDHpkJza7P9Y0erEX0uwhJhZvsZjykLlwDIXCx4dbo%2FF6ZWIL%2FkGFRlU%2BxiCtZUsz6QtnDZmrn24eNtFWgXHJ646qD2DQTGFh13u2Y4dKRZPQw8S4V0fyuQcL2hsWmBbjAR0Njv2iyE0q5nMgkExUft%2FreyUsjnKGjxo5Y2ZDIBjtSskjVHeefK%2FLfWnlH8bOAfkcLLKZljw65cbQb3x0SAada4wcKiU%2F5xhiPys%2BBrGmMqL3cMU3t5EMOjpL6%2BcywhejfCE1%2BmFomRLY3ZcQQ%2BcFQqr5OxOZUAhvoaAUau7mViwKl0OP1nEaFI7UpDbBEenKIGUYzAiE%2BMraHtCSNuFF14EWergT%2B5usSFnEuXVGx3QgILfSq7%2BODuhbZbevpDoV39U9Wb0Bqb2DBYbUOmEWW0vN3nLBAALvo9syJUAhZsNHzZmkfK9ZRre%2FUHQHoca1WCbNHzhahTAOkaSqV7X4kIsMfASbrs03mJOUJnGJQ7CMtACHnKIDvG0bjZM2DLgrLK0n%2FWs%2FxmmI2P7l2LQvjlRB81lmITtA6g7OlilnXRuN4mTlpqaJ2sDQvnXpolpa74QqCVPMCLrw6EeQ2AqpQT2jq%2B178ciBtsW7edBn1veGPNPXrqiny5zMzI4ZUKiYufoKgWkxrqnNLD7oNdkkHayg3ijAf9CCdoxWQhQi51uaL4aELm3tXiKEQc1PqXeu0ZJ%2FRNviPmhBCfo52UV0ys0i3sjUqTorwSqJHcL6Xe4aPsNRGPByV00L7NoB4lXfRAKO%2BaAmgPr9%2FF%2BWG2yMoNjdkfG1tknEFCN5O0uMbmXuGMNeqn60GOrEB9%2Bw5fs65IosDjJjkFVsqppgAnvJJTNMYUTDO8mn7Q9Sf46JkmnEq94h6p3hryCEKqq6xGV9AfgfRKgkXYotx8WvFsM3Qg4mgYMKd1akVhwr1I5Gp9lNJgTJ0EDEuqMFTNbsNGjkpsRa3Wl1Bvm7CruGVrTtodL260AZnQxIyfdeNCbWdyMtfjmhnD%2BG3X6LqsAZiSddxZNhnYesGV5K0odxUv7ZdXwIfJ1RA6PrOvOrL&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Date=20240117T142103Z&X-Amz-SignedHeaders=host&X-Amz-Expires=299&X-Amz-Credential=ASIAQ3PHCVTYYPF66ANM%2F20240117%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Signature=bb6c1cee2d1754f0c7d8715c440b2ca748139d392ad8adeb5be8b183dc9910fb&hash=70224eb8a2db5fec1f6b5896a17e4f32b9ea4a152bccc052fc5dd5c517a09e57&host=68042c943591013ac2b2430a89b270f6af2c76d8dfd086a07176afe7c76c2c61&pii=S1877705813010680&tid=spdf-9e4c1aba-7b55-411f-9bc6-caed19455c48&sid=7ba7227c29582145d02994e073de6708f34dgxrqa&type=client&tsoh=d3d3LnNjaWVuY2VkaXJlY3QuY29t&ua=0f175e575609540b5600&rr=846f3e0f5fb1c87c&cc=us

Yes I would assume the flexing of the shaft at launch would be greater unless hard hit or if the broadhead does not hit square to target. The difference is (in my opinion) at launch the arrow is free to flex while still moving forward since the string is applying the impulse it still delivers energy to the arrow at the same rate, however at the target the arrow is applying the impulse. What we will discuss in the next video is if the shaft starts to buckle the impulse/force the arrow is capable to direct in the direction of penetration, this will greatly reduced penetration until the reaction force between arrow and target lowers to below the buckling point at which point the cg and broadhead will be aligned again and all energy will be capable of being directed into penetration.

Also to add some clarity, it would not be appropriate to compare power stroke distance to penetration distance as an indicator of impulse at impact, because the impact resistant force is based so heavily on the density of the target/animal and the broadhead sharpness, design, etc. All of these variables are changing for example it is possible to have a vary high impact force initially at target for example when deploying mechanical that then drops of rapidly your penetration distance maximum maybe greater than the power stroke distance but that only indicates that the average force over the time (change in momentum i.e. impulse) or distance (energy change) was less than the average force applied over the power stroke.

I agree that usually it is greater. However, we need to take into consideration which broadhead is being used and what you hit in an animal. On a hard bone impact, the impulse force will be greater than the peak force of 70# say on your power stroke. Impulse force is time based, so going from V280 to V50 it will be a very large spike. You can look at KE/Work as the average over that short distance and the impulse being the peak. When you look at mechanical broadheads they dissipate a ton of KE in a short amount of time. A very large impulse force. A mechanical broadhead, in my opinion, will require a stiffer shaft. I typically recommend going up one spine shaft. With a mechanical you can also get away with a stiffer shaft as you have less planing and will yield better flight. I'm not a mechanical advocate to be clear, but it's a good setup for some people and their target species.

Yes the equation I used are two differential equations one which factors tissue cutting the other as you stated is “drag” more precisely it’s the force required to move the mass of tissue by the arrow which does increase with the square of velocity. The poncelet equation is an estimated solution to those two different equations. It does increase with the square of velocity. Video 4 illustrates as you said impact force of a slower arrow is less. Thanks for watching!

@@Lucas_Palmer_bownerd_engineer Oh, so it's already factored in. I see. Only such a small difference? I expected more. I thought I got it roughly figured out, but obviously not, because the observed difference seems to be higher than what we see here. Thanks for your explanation. Good luck in figuring it all out. I'll be watching this channel!

@@bakters a big thing is these are all estimates. Your absolutely right in that physically shooting animals is the best tell. My biggest question is every weight of arrows seems to work depending on who you talk to. My question is why are they not working this goes for both light and heavy arrows thanks for you comment.

@@Lucas_Palmer_bownerd_engineer " *these are all estimates* " At least they scale with the square of velocity, so they can't be off by a factor of two, or so. There's got to be more to it. " *every weight of arrows seems to work depending on who you talk to* " Nobody did the study anywhere close to Ashby. That study is definitely consistent with what we see on hunting videos. Lots and lots of weak penetration out there. On the other hand, Ranchfairy's friend shot out a leg off a pig recently. The arrow severed the humeral joint. This big ball was in pieces. I butcher pigs at times. That thing is tough! It's possible that your guess about the so called "target paradox", or arrow bending and wobble as it hits the target, is the real answer. Light setups don't need much spine in order to fly well, they go faster and have less FOC, so it's possible that they bend at impact much worse than slow, stiff and high FOC arrows. FOC at launch works in reverse to what it does at impact, not? I'd try to put a piece of plywood on some sort of a consistent target and shoot at it *at an angle* . Perfect 90 deg impacts hardly ever happen in reality. There's got to be a way of replicating what we see in a convenient way. Sorry for being so verbose, but it irks me we don't simply *know* such stuff yet. Good luck, sir.

That’s perfect! Lmao glad you enjoyed the video.

I'm sure he knows. He's just doing his thing the way he knows how

Absolutely lots of great stuff from RF. I am more seeking to answer or maybe give guidance that if you absolutely do not want a heavy arrow what is everything else you need to do to still obtain adequate penetration. I have also read all of the Ashley reports each about 5 times. They recognize a lot of correlation or cause and effect but puts no effort to answer the why. Why does FOC help, Why 650 grains, Why great arrow flight (although that the easiest to understand why), I asked myself Why so many times reading those and RF that I figured id investigate and see where it leads. I have not intentions of proving anyone right or wrong simply to educate. Take care, Lucas

​@@Lucas_Palmer_bownerd_engineerkeep in mind that Dr. Ashby was shooting a recurve. I believe that the high foc and heavy arrow was masking the imperfect arrow flight that is inherent in a recurve.

That was my thought as well I’ve already ran some numbers I think the maximum axial force limit is a big deal. We could make an assumption that the rate of slowing down while passing through an animal is linear. From that we could estimate the time and determine how far the animal could potentially move before Cg enters body. But it would be a pretty rough estimate. One thing that is deceptive is a 27in arrow with 15%foc vs a 29in arrow with 15% foc are not equivalent the front column of the longer arrow will be longer and this takes more time. So like all things the true answer is it depends.

Thanks for the comment I’ll try to answer all these questions in coming videos.

@@Lucas_Palmer_bownerd_engineer initial straightness of the compressed member is also big factor. And while it’s tempting to reduce the compression between CM and the point, the arrow behind CM does change the support condition in relation to buckling length. At that point the calculation becomes bit too complicated for me. Definitely if the shaft is still vibrating on impact the result can be unpredictable. But assumptions need to be made and each variable looked one by one. For average bowhunter watching these it would probably be good to keep a frame of reference so average person can comprehend the importance of each factor so they don’t spend time on 1% and overlook a matter with 30% importance, as sometimes seems to happen.

@@smau990 very true. Trying to do these videos with more common math has been difficult enough without explaining complex integration and such. I think it would be a safe argument that in the simplified case of only looking at the front of the shaft would be a maximum force that could be encountered by the shaft when the reality is the force is much lower than that due to the factors you pointed out.

@@smau990 thanks for the comment!

Yes it does very much so, I am dedicating a video completely on that topic everything from blade angle, sharpness and number of blades to illustrate how each design criteria affects penetration. For this test I tried to note the values given were based on a small 4 blade more specifically like a slick trick equal 4 blade or a tooth of the arrow type design. It was also assumed the broadhead was sharp but not razor sharp.something you find find straight out of a package of a quality head.

@@Lucas_Palmer_bownerd_engineer you should reach out to Troy Fowler, aka "Ranch Fairy", for some of this testing. He's been working on a lot of this stuff for a while. He's recently paired up with an actual "rocket scientist" and some of their testing is eye opening. Maybe the 3 of you could work together on some things?

Glad you like the videos! If you have any questions feel free to ask.

Yeah great question and you are correct all of these number only apply to these particular arrows and setups, In a later video I'll compute the difference for lower KE setups and difference broadheads as well. The resistive force from the poncelet equation is based on Yield strength of target and Density of the target. Of course animals are not consistent on either however, I was able to find averages for density I found bone at 115 lb/ft^3, Tissue at 62 and Hide at 58 these are from beef/bovine estimates found in the medical industry. I assumed 1 rib bone was hit and computed an average. The Yield strength is a little tougher for averages they are tissue 800psi, bone 18900 psi and hide at 2000 psi. Because the spread is so large I computed a weighted average here by assigning an effect % based on the amount each material. These are factored into the equation which estimates total penetration depth. The broadhead geometry is also estimated into that equation. That's kinda my question I would have no issue shooting a lighter setup if I knew it wouldn't fail. However, I know my wife can't do that at 25in draw and 50lb draw weight she needs that heavy arrow to do the job.

@@Lucas_Palmer_bownerd_engineergreat job, I like how you came up with that estimate.

Area of the broadhead increases. The time average area of the nose in the equation increases.

I see your point however that’s true only if the arrow hits square. If two identical arrows one poorly tuned hits the target sideways, the second hitting the target square. The second arrow which hits square will penetrate better. Now if we are comparing two arrows which both hit the target square then target resistive forces dominate.

@@Lucas_Palmer_bownerd_engineer Ah yes, the target can apply more force to the arrow depending on which part of the arrow hits the target.

@@Lucas_Palmer_bownerd_engineer but it's not the number one fact that determines penetration.

@@aaronward3882 fair enough, what would be your ranking?

@@Lucas_Palmer_bownerd_engineer I don't have a ranking system. In my neck of the woods, I hunt whitetails and turkey. I set up my arrow to have enough force to pass through a whitetail, which is a very dynamic target. . My current hunting arrow is the best all around arrow I have used since I started bow hunting in 1995. Arrow build: Shaft: Victoty RIP TKO Broadhead: Sevr 1.5 ti Insert: Easton hit 75 grain Collar: Iron Will titanium collar Fletch: 4 aae max 23 Nock: nu fletch lighted nock Total weight: 475 grain FOC: 14% Arrow speed: 268 ft per second I have shot 8 whitetails (broadside, quartering toward, and away) with this arrow using a PSE and Prime bows set a 60 lb. Draw weight. All have died with in 60 yards. This tells me that the maximum amount of force the target (vitals of a whitetail) can apply to my arrow is less than force than my arrow is producing. When hunting Turkey I use the same arrow but change the broadhead to a grim reaper 3 blade because Turkey can apply less force to the arrow compared to a whitetail. I guess you could say my number 1 would be understand the force it takes to penetrate the target. 2 would be understand how much force your arrow has when it impacts the target. 3 would be delivering the arrow to the target in the most efficient way.

No cat maybe you herd my kids 🤷‍♂️