Surprising Chrono Results to me.

[Gil Verwey]

Today I tested several bows I have through the chrono. I found that as the arrow weight increases the speeds of these bows become very close, while with lighter arrows there is a much larger difference in speed.

I tested a fast flight Dye recurve 55 @ 28 and a Hill Wesely longbow 55 @ 28. I tested others but the draw weights were different. I have a spread sheet that computes momentum, kinetic energy and realative performance. I tested the bows with a 400 gr, 580 gr and 730 gr arrow. This is what I found.

Dye  400 gr 217.5 FPS, KE 42, MOMENTUM .39
Hill  400 gr 202.3 FPS, KE 36, MOMENTUM .36      

Dye  580 gr 184.3 FPS, KE 44, MOMENTUM .47
Hill  580 gr 174.7 FPS, KE 39, MOMENTUM .45

Dye  730 gr 166.7 FPS, KE 45, MOMENTUM .54
Hill  730 gr 165.1 FPS, KE 44, MOMENTUM .54

It looks to me that bows that appear to be very fast with light arrows, loose their edge against other bows as the weight increases. Has anyone else found this to be true.

Gil

[Curtis Haden]

That's very interesting, Gil.  Thanks for posting!  I have to say I was a little surprised at the numbers on the Hill.  Pretty impressive!

[Kevin L.]

I don't have a chronograph, but I've seen that Hill-style longbows (American flatbows) perform a lot better with arrows from 10gr per pound on up. I just got a 7 Lakes in that absolutely loves some 800gr maple arrows I have.

[Gil Verwey]

I have found that a chrono is only good for comparing bows relatively to each other on the same day at the same time. Depending on light conditions the results can vary day to day. Not by much but they do. But relatively when you shoot bows against each other the results seem to come out the same.

I used to think I had some screamer bows but that was with a light arrow. I think there are a lot of advantages to a heavy arrow and those screamers don't seem to have much of an advantage as weight increases.

Just my opinion though.

I should have mentioned that both bows were using 8125 padded loop 12 strand strings.

Gil

[pdk25]

Interesting results.  Almost everyone that I have spoken to that has tested other recurves versus longbows has not had results nearly as impressive. My limited testing also hasn't produced such numbers, although most of the time testing was only done up to 12 grains per pound rather than over 13. I'm not familiar with the Dye recurve.  Does it have exceedingly thing limbs?  Were all of your arrows tuned well to your bows?  I had a recent post pertaining to this topic and no one had data like this.  I'm trying to understand what physics principle could explain this behavior.

[JRY309]

Very interesting results,it must be a narrow deeep core limbs handle the heavier arrows better.I know my Hill's like heavier arrows better,they just seem to shoot better with them.

[pdk25]

There was a recent post regarding performance of hill style bows.  Gil did some testing awhile back, so I am bumping it to the top for some others to see.

[hybridbow hunter]

An  HH bow shooting 175 fps at 10.5 gpp and 165 fps for 13.3 gpp !!. And a speed loss of only 10 fps for an increase arrow weight of 150 gr/ 2.8 gpp is simply impossible!!  Or maybe in Wonderworld.

in a crontroled trial (checked draw lenght, checked draw weight at DL and checked arrow weight) this will never happen, unless you shoot the Hill bow at 34" DL and recurve at 28"


You "HH bugged guys" are very funny when it comes to assess the performance of those bows...  

[M.Kerry Bird]

Something's off here. Were these bows shot by shooting machine or by hand? It's pretty easy to tweak chrono results when your shooting the bow by hand.
 
I think for a test like this to be really accurate it needs to be done indoors through tandem chronos with a shooting machine, so the human factor is eliminated.

[Bladepeek]

I would guess the numbers will be argued back and forth without ever reaching any agreement. I think what it does show is that some bows are far more efficient than others until the arrow mass gets heavy enough to absorb more of the wasted energy.

It would appear that the less efficient bow "likes" a heavy arrow because more of its wasted energy is recovered by the arrow. The efficient bow also "likes" a heavy arrow - it just doesn't have to have one to perform well.

Don't get me wrong. I am very fond of my "D" type longbow and it's a very accurate bow for me, but the RER Retro I used to own with the same draw weight shot rings around it. I usually shot around 10 - 11 GPP. If I upped the arrow weight, the difference would probably decrease, but the "D" bow would never completely catch up.

Hybrid, that is an insult.  He is merely telling us what his numbers were and you are calling him a liar. I have done lots of testing myself and I have tested my favorite Hill style bows, (the ones I keep) that have, on six different chronographs, that consistently came up with grain per pound numbers even higher than his.  I have tested a number of them that had numbers lower than his as well,(the ones I sell or give away), some Hill bows are quicker than average and some are slower. Which is exactly why I check them out every chance I get. The bows that shoot the fastest are sometimes also the smoothest to shoot and that is the bow I want. I have however, tested super heavy Hill bows that  did not like very stiff arrows. What I found with those is that the difference in cast from a light to a heavy arrow was closer, the cast with grains per pound was less and those same Hill bows were very accurate and forgiving.  I was told the reason longbows do not lose as much speed with heavier arrows is because the ratio of the arrow weight to limb weight. The light tipped recurve target bows that I have had showed a much greater slow down with heavier arrows. On the other hand I have never seen a longbow pass the faster bow as the arrow got heavy, as this comparison shows as well. They get closer, but the order stays the same.
Maybe that point can happen, but that arrow would be too heavy to be practical.

[joe skipp]

I would be real happy with the 184 fps with the 580 grain arrow. That will give great penetration and more quieter coming off the bow. Adding the Dye takes Dacron string only, impressive.

We are lead to believe that a shooting machine will always get a faster arrow speed than a longbow shot by hand, not true. As Pope and Young discovered a longbow also shoots more accurately when held by hand than when held by a mechanical brace.

[el greco]

I find those numbers hard to believe.By no means I am saying those are not the numbers that poped up in the screen.But there is a proper way to shoot an arrow through the chrony.For example if you move the tip of the arrow right there in front of the chrony and release it will always show 10-15 fps faster.I had two different models and both said in the instructions you are suppose to shoot at LEAST an arrrows length from the beginning of the first sensor.Did you do it that way?

[pdk25]

I would be surprised if he didn't stay the same distance from the chrono with each bow.  That is the interesting thing, the diminished advantage of the recurve with heavier arrows, not the absolute numbers. I didn't do the test, but the mechanical equivalent of impedance matching may play a role.

[SlowBowinMO]

The point here is the actual comparison.

Gil's test actually lines up with a recent Firefly test we did.  We tested a Firefly hybrid longbow against a recurve.  The recurve beat the Firefly with light 400-ish arrows.  But with increasingly heavy arrows the Firefly eventually ended up  passing  the recurve.

So I find Gil's results very believable.  Common thought for years has been the faster bow will always be faster, but I think we are starting to find that may not always be the case.

Thanks for testing and posting Gil!  

[Beau J]

Yeah...It would make sense that the faster dry fire speed of the recurve would have the advantage on lighter arrows, and the longer length and maybe more massive longbow limbs could transfer more energy into the heavier arrow????    Beau

[jackdaw]

I like to see tests like this performed by members on here, but I also wondered about those velocities...??? We have 2 chrono's at out bow club and we frequently test various members bow velocities just for the fun of it..! My 51# Holcomb 59' Kodiak repro launches a 405 grain carbon at 188 fps at 3 feet from the chrono screen...which is o 2 fps faster than a friend of mines 52# 2012 Black widow recurve.....its one of the fastest recurves in the club in the 50-53# range......that's why the Dye 55#er at 217 fps really caught my eye...!!! Now I'm not calling anybody anything here, but if that's an accurate velocity, then its downright incredible...!!! Possible chrono error...???? who knows...??? I've seen some 202-203 fps stuff at 9GPP...!!! However, the gap closing at the heavy arrow weights is interesting.....just my 2 cents worth....john

[gringol]

I agree, Jack.  Lots of incredible numbers posted on the internet.  Those numbers may have actually popped on the screen, but that doesn't mean they're right.

A while back I tested a bow, got 165fps with a 10gpp arrow.  A few weeks later someone posted 198 fps with the same bow, same gpp, and same dl.  Now, I'm.now byron Ferguson,.but my release is no way causing a loss of 30+ fps.  

I also find it interesting that the HH guys say HH style bows are better because they're more stable and then post numbers like 195 fps.  Absolutely unbelievable.  

In conclusion, ignore the absolute numbers people post online.  The relative numbers in this test are interesting though.

[jackdaw]

Glad you agree Gringol. Im not trying to offend anyone on here, just perplexed by the high velocities pisted here...???? I have a nice Longriver Elk  bow of Gus DelAgaffo which is 53# and a RD design...just cant match velocity with my recurves in the 47#-51# range....usually  6-8fps slower at the same gpp.....Hill or no Hill....just sayin'...curious???