DaveC

Danny45, yes I' m up there now. The last time I shot through my chrony I was at 70ft/lbs k/e with a 426 grain arrow going 272fps. That is with me pulling 65#.

The question I have is 65# the same energy as 65 ft/lbs?
I know I' ve learned this some where along the way and feel kind of silly asking, but I just don' t use this stuff on a daily, yearly basis- so therefore I have forgotten.
I remember from somewhere way back about the " perfect machine" would have 100% efficiency. You' d put in exactly what you got out with no loss.

Arthur P

What you really have to do is plot out the force draw curve for your bow to figure out how much energy the bow is storing. Then shoot through the chrony and weigh your arrows to find out how much energy is going into the arrow. Then you divide energy out by energy stored to get efficiency %.

Compounds store a lot more energy than their draw weight. Otherwise, I couldn' t get 62 pounds of energy out of my bow at 60 pounds draw weight.

And, like Bob said, efficiency will vary depending on arrow weight.

mlaubner

How is this done???

Arthur P

You get a piece of graph paper and set up a graph. Draw weight on the side, one square per pound. Draw length on the base. One square per inch. Start the draw length at your brace height.

Then, using scales and some way to measure, like an arrow marked in inches, start at brace height and check the draw weight at each inch of draw. It is VERY important (and practically impossible to do by hand) to maintain the pull cycle all the way through the letoff and through the valley.

When you get the points plotted and draw out the line on the graph, then you count the squares under the line and that gives you your stored energy, each square is one pound.

While you' ve got the bow on the scales, you can measure the whole thing through the letdown cycle and plot that line as well. That tells you how much friction you have in the system (static hysterisis) which is also an indicator of how efficient your bow is.

If you' ll look at Norb Mullaney' s bow reports in Bowhunting World Magazine, then you can see how to set up the graphs. I' ve got most of his terminology figured out, but I' m still stumped on what the dickens ' virtual mass' is.

mlaubner

It sounds like I need to buy a " Hooter Shooter" or some device like that. I really would like to have one but don' t have the money to invest just to determine my bow effeciency.
Well, maybe I can start my new home business by having folks bring their bow by the house and I can determine their bow effieciency.
I had no idea this would be so difficult. And on top of that your % number would change with every change in your equipment of set-up.
I could have regular customers for that hooter shooter!
Maybe that does justify the purchase. I think I' ll run this one by the wife!

Now where to find that " virtual mass" indicator.....

Len in Maryland

Mark:

Let' s see, you asked me via private message to respond to your question and then state that you want to

Quote:

start my new home business

. Hmmm, I' ve got Bass Pro Shop just 7 miles away, Dick' s and Sports Authority within 2 miles of my shop, several ' Marts' within a few miles, about 6 or 8 archery shops within 15 miles (some of which operate out of their houses), and you want me to help you compete with me??????[]

Might I suggest, since you' ve never been by my shop, to stop by to introduce yourself. There are several others here on this forum who have visited from several hundred to several thousand miles away. I' ll buy you a drink and we can discuss how I can best slice my wrists.

Really, I' d be glad to discuss this issue in depth. It would, however, take a VERY lengthy thread to explain how and why I compute efficiency MY way. I know Mr. Mullaney personally and know why he computes the way he does. I just have different theories and methods. My way incorporates the variances that have been discussed above.

Pinwheel 12

Len--

Sounds like they' re (the mega stores) closing in on you! Put the wagons in a big circle my friend! Shoot till you run out of ammo![&:]

AND---

Boycott those manufacturers who sell to the " marts" and other mega-box-stores. I' m doing it aggressively starting in 2004 myself no matter how irritating and costly, and I know many other true " Pro shops" that are also. Strength in numbers to defeat the " beast" that is trying it' s best to destroy our industry. [X(][:@]

Back to the subject----

Art explained it well as to the best way to initially find the figures you are searching for. Bow efficiency has many variables as stated by Len, and I like he and Norb and Emery Loiselle(whom I know personally also) have my own formula for determination while subjectively focusing on these variables. As Len stated, it can get very lengthy, and unfortunately it is now my busiest season and I don' t really have time and/or really the inclination to get that far into it either to be honest. Good shooting, Pinwheel 12

Anthony Hunter

Had an interesting conversation with my pro shop owner about this last year. He believes that wal-mart carring bows is a good thing. His reasoning is that if wal-mart can get you into your first bow, he will get you the rest of your bow shooting life. I guess its just a different view.

Len in Maryland

PW: I don' t think anyone can ignore the mass merchants. Learning to deal with them and how to work with and around them might be a better strategy. I did a seminar on this subject last year at the ATA Trade Show. We recognize their strengths and weaknesses and, believe it or not, they recognize ours. They actually send us a decent amount of business. They do this because they realize that they look better in the customers' eyes by directing them to someone who can meet their needs rather than just turning them away.

It would be impossible to boycott the manufacturers who sell to them. If you think about it, you could ' cut off your nose to spite your face' . []

Mlaubner/Mark: Thanks for stopping by the store Saturday. It certainly was a pleasure to meet you and share some information/stories. Hope to do it again soon.

Pinwheel 12

Len-

The mass merchants have no " strengths" other than how to make money. They are locusts that feed off of our industry, but have no care in the world for it. Sending people to you is a tease for complacency. Anyone who thinks differently is either a mass merchant themselves or is getting greased by them IMHO.

What will happen to our industry over time if the mega merchants drive the mid sized and even smaller REPUTABLE Pro shops out of business with their " buy in bulk" BS? Certainly there are not many if any who can compete with the substantial price breaks mega stores receive. If this continues they will ahve no choice but to bow out... I feel such breaks at retail level are very detrimental to our industry---a retail outlet is a retail outlet, doesn' t matter if they sell one or a hundred items, they should receive the same pricing IMO. IF they want to step up and pay the associated fees/taxes/overhead/etc to become a full-fledged distributor who deals wholesale to other dealers, then fine, price breaks should be there, but I have a sore open wound about these " buying groups" , major chain stores, and " outfitters" , and all of that other nonsense that comes with them and them getting price breaks for buying in bulk. Geographically speaking and according to populace numbers determines alot as to how many items a certain dealership will sell in an area, and if they have been in the industry X amount of years they have more than paid their dues by hanging with it, (let alone the knowledge gained) and should receive the same pricing for their products as the new shiny Wal-Mart that has been next door or within a certain radius for 6 months, irregardless of who buys what or how much.

Further, what will happen when all of the true " Pro-shops" with dedicated technical people who have been in the industry many decades and actually KNOW what they are doing disappear? What, people will get their equipment tuned at Wally World, Dicks or Bass Pro by the resident " tech" college student who is working there for the summer? HAHAHAHA. No, the mega stores are nothing more than a thorn that needs to be removed.....quickly. Along with all of the " buying groups" too IMHO.... Big bunch of BS...." pay up and buy stock to receive best pricing and protection" ? Didn' t the Mafia do that? Wasn' t that illegal? Same thing here... Just another way to line certain companies' and orgs/maufacturers' pockets if you ask me, and I will not have anything to do with that. VERY sore subject here that I' ve watched develop for the past decade and the incentives just reel certain dealers in without giving thought to anything other than the savings...money isn' t everything, the sport itself is what matters most, along with it' s future. It certainly isn' t heading in a good direction if you ask me with this garbage happening.

I already have others who are joining this fight and who will boycott strongly against certain manufacturers who cater only to the mega stores, and soon more will join in also, make no mistake there. The eyes are being opened.. Manufacturers will either cater to true Pro shops who are the backbone of the industry, or they will be gone and that' s the bottom line, along with those who wish to help them destroy our industry. Bow manufacturers know this as well----you cannot go to Wally World or other major box stores/" outfitters" and buy a Hoyt, Mathews, Parker, Bowtech, Merlin, Kodiak, or Diamond, along with many others. You also cannot get Copper John, Kodiak, HTM and many other sights for example, and then we have the other accesories and clothing, broadheads, stands, etc. who do not. We WILL win over the long haul. Might take some time, yes, but it has to start somewhere. Good shooting, Pinwheel 12