Primitive Archer
Main Discussion Area => Bows => Flight Bows => Topic started by: Badger on January 01, 2015, 03:24:48 pm
-
Here is one I am working on. I had planned on just using it for a broadhead bow but may use it for flight as well. 62" long, 2" wide at the fades, 16" non working handle and fades, last 11" of limbs is static as well. Not quite finished and I may come in a tad light. The draw curve is smoother than I expected. Looking for 50#@28".
I shot it this mornig and am very pleased with the performance. Mass weight will finish at 20 oz, way below what I had predicted. Funny thing about these extra wide bows I have been making is that they comming in at lower mass weight than the narrower bows. Can only be true if it means less damaged wood. Started with 5 1/2" reflex presently has 4 3/4". I usually stay away from big curves because I am horrible at linning them up. This one lined up beautifully for a change.
I need to smooth out the curves a bit and do some finish work, little tiller touch up and get the draw out to 28". Feeling really good about it. Limb thickness is about .3.
Will post more pics as I go.
-
wow very nice,, please tell me what it shot through chrono,, :) :) :)
-
Braced photo, not perfect but I can't take off anymore weight so will likely just leave it.
Brad, my chrono isn't working but I shot it side by side next to my world record bow which shoots in the low 180's and judging by how hard it hits the target it is no comparison, I shot it next to a glass recurve which also shoots very close to 190 and it seems to outshoot that one by a good margin also. Only shooting it at about 43# not to full draw yet.
I got this in the wrong forum, can I move it to the flight forum?
-
very very nice,, will you wait to pull to full draw when you compete,,???
-
That thing looks awesome!
-
Wow....can't wait to see more.
DBar
-
Very nice bow.
-
It has about 12" of working limb on each side.
-
Badger, you probably already know this, but.... why dont you hit the left limb in the fade with heavy heat? It will harden the wood there and help bring the tiller around for you.
Ok you got me studying your profile here. Looks like you deflexed in the handle. How did you do that or was that natural? Also, I think your prace profile matches your unbraced just fine the more I look at it. Heat can still line it all up. I realize you are 20 times better than I am but dont know why you are going to leave it as it is or why heat isn't an option for you?
What weight arrows are you shooting and when is the next flight shoot? You made me wanna build one.
-
I do plan to heat treat more in the fade area. I made a rooky mistake and overestimated the poundage before bracing. I am pretty close but if it holds up ok where it is I will leave it.
-
What, you didn't want to push your reflex in 2015?? haha. Killer stuff.
-
Excellent way to start the year. With such a short working section on each limb, did this have to start as a perfect stave? And what MC do you keep it at?
-
Looks good Steve. How about a back profile?
-
There is a lot of turk in that one. If you'd just added a bit more angle to the last four inches it would be identical.
-
Very nice, Steve. Looks like it will shoot far!
-
Thanks Jawge, Pat, I have a nightmare trying to keep the string aligned with anymore curve at the tips. Not one of my stronger bow building points. Even as it is I am surprised at how flat the force draw is.
-
I just tried to build a bow like this. I failed. Super thin rings on the osage was so hard to chase that by time I got a ring chased the stave went from 2.5" wide to 1 1/8" wide. It was very wedge shaped. So im looking at 45# and reflexed tips again. Got 3 more staves though. Darn you badger, you're gonna make me burn through my staves chasing this design.
-
Thats some huge reflex 8) very cool. what draw length are you shooting for?
-
whats the force draw curve looking like :)
-
I plan to clean it up tomorrow and hopefully chart the draw curve. I may give it another heat treat. I am kind of worried it might drop more weight as I draw it out further. I want to find the sweet spot and stop, hopefully no less than 26". 28" ideally.
-
WOW! just WOW!
-
Interesting!
PatM - How about the handle?! ;)
-
Great bow, very well and clever done. You know, I'm in a very similiar design, but found it never that delicious to line such a design up. Even when the tips are very small. Finally dry heat has done the job.
I swear you'll never do another design.
Great flights in 2015, Michael
-
Wow! Cool bow, will be following along.
-
It is selfbow ? Very intresting idea, looks similar like crab bows
-
Good news or bad news first? Bow far exceeded my expectations but will have to be rebuilt as I grossly misjudged the high fdc and the bow came in lighter than I expected. I should have listened to my own mass formula!.
The good news, exeptional FDC bow stores 119.8% of draw weight. About 96% is more typical. Draw weight is only 38.8 # at 28". Stores 46.5# energy. I still plan to shoot the bow in the 50# class and will give it to a youth to shoot in the 35# class.
I need to verify this last one as my chrono is not working right but I did get 2 readings with a 385 grain arrow (10 grains per pound) one was 201 and one was 202. I hope this checks out. My former best with a self bow is 184 fps.
When I rebuild the bow as a 50# I will need to find a stave with a very low crown as I plan to go 2 1/4 wide in the working area and I want it as flat as possible. I never have been the best at execution. With only 12" working limb its really hard to avoid taking set.
-
Steve, did you just break the 200fps mark with a 10 gpp arrow?
-
201 at 10gpp would be amazing indeed. Hope it checks out. Are you shooting through the chrony outside?
-
It would work out to be about 75% efficiency at 202 fps which is not unreasonable, about what I would expect. I think it is a good reading but I don't want to claim it as fact yet. I took the reading outside in morning light.
-
I have a chronograph you can borrow if you want to double check? Where you at?
-
It would work out to be about 75% efficiency at 202 fps which is not unreasonable, about what I would expect. I think it is a good reading but I don't want to claim it as fact yet. I took the reading outside in morning light.
Thats awesome. Only reason i asked is because i have had mixed results using a chrony indoors
-
I thought about similar model years ago and even make shape wit steam but never tiller, I call this bow "hat bow". If this bow connect very good energy storage and good energy transfer it could be holly Graal in traditional archery. Respect.
-
Id love a profile view Badger if/when you get a chance. Also whats string type and strand count are you using?
-
Sleek, the string I am using would not be legal or flight shooting because for my everyday primitive strings I add a few strands of fast flight just for convenience sake so they don't break as linen often does. The weight of the string however would be the same as an official string and performance likely would not change. The string just lasts longer.
-
Why couldnt you just decrown a stave Badger instead of having to find a low crowned one?
-
I don't like decrowned osage and thats about the only wood I would use for this design.
-
Wow Steve! I believe you have a great year ahead!
Alan
-
Awesome design indeed!mr badger you lend a. Great bit of. No how. On pa! Thx's rob!
-
That some nice work Steve. Just looks like it's got to be fast. :)
Pappy
-
Have you confirmed your fps?
-
Sweet....that's right up my alley. Those types aren't easy for anyone to make,you or me,or anyone else. There always a booger to line up,and I'd make more if they weren't such a pain sometimes. Looks like its time to narrow your outers and put some string bridges on to keep the string on and lose some mass in your outers? I know thats a smooth drawing rig there.
-
Falcon, I am going to build a slightly heavier version and concentrate on that. I am going to set this one aside for flite shooting. I have destroyed more good flight bows testing them than I like to think about. It is kind of a jinx. Whether or not it actually did hit 200 is not so important because I feel like the math and the physics behind it easily allow for a 200 fps shot. This means I can build another one a little bit better and more refined.
Besides that if I did hit it where would I go from there? It would be like jumping off a cliff. I have been chasing it for so many years I feel like it would be the end of something if I finally caught it. The thought of raising the bar to 210 is amost terrifying my stubborness and inability to let go of something borders on being self destructive! LOL. I am just going to settle for I think I may have hit it.
-
Blackhawk, interesting comments almost worthy of a chapter initself. Because of a minor change in design I will go into a lot of the problems with long highly reflexed curves just goes away. Anybody could easily build it. No need to narrow the tips either. A simple design variation makes the bow a lot more tolerant of outer tip mass.
I am going to start a seperate thread on outer tip mass you may want to jump into.
-
V impressive, I still have to break the 200fps with any bow or arrow weight (I think! As I never chrono'd the 100# Elm warbow with a flight arrow, as I was scared of shooting the chrono :o)
Del
-
V impressive, I still have to break the 200fps with any bow or arrow weight (I think! As I never chrono'd the 100# Elm warbow with a flight arrow, as I was scared of shooting the chrono :o)
Del
I think Steve has done that
-
Mark, I would really like to see you try a couple of the componets in one of your bows some time. I feel like I took your design to a large extent and added a couple of tecnique componets. I have a feeling it would come out much better if you did it.
Just for the heck of it I am going to list some of the problems I have had with highly reflexed bows and how I dealt with it here and with what results. The funny part is it all seemed to go back to one issue that solved a lot of problems.
1. Problem with tips too far behind the back, instability, limbs would tend to rock back and forth at brace. Shorter bending area solved that problem. Solid as a rock.
2. Problem, instability, limbs twisting especially at brace with too much limb contact. Again short working area solved that problem. Seems very solid at brace with only very slight tendency to want to twist.
3 Problem, loss of efficiency due to heavy tips and vibration and distorsion throughout the limb. The heavier tips were needed for stability to keep the string from comming off. Again the shorter working limb proved less sensitive to outer limb mass simply because it has no room to vibrate or distort improving efficiency.
4. Problem, takes set increasing histerias. Here I was lucky to get a low crowned osage stave which allowed me to go very flat and wide. Not always possible. God blesss osage. I think the design is really made to order for glass bows or at the very least backed laminated bows where you can keep them flat and wide.
5. force draw curve. Not sure if the curve I used is close to optimum or not, long sweeping 12" radius designed for a lot of string contact at brace. The results seemd good but others may very well be better.
6. Heat treating, Makes a lot of things formerly not possible possible.
I don't think this would be practical for most white woods as they would need to be about 3" wide I imagine. Might be real well suited to ipe with a hickory back. Anyway thanks for all the kind words but in all honesty I cannot claim I hit the 200 mark with a bad chrono. I wouldn't accept less than a verified test to claim that and wouldn't expect you to either.
-
I can see how this bow gave you fits Steve. It's a bit like this bow that I made years ago, only yours is a bit more extreme.
(http://img.photobucket.com/albums/v355/Marc-St-Louis/HHB%20Composite%20Bows/Duoflex/CombinationPicture.jpg)
That bow gave me fits as well and it didn't take long before the HHB belly started to develop chrysals. I just don't know if I want to tackle another and if I was I would most certainly use a more elastic wood even than HHB. Yew would be great with this design
-
.... Yew would be great with this design
Del's ears prick up and he scampers off to check his Yew stash :laugh:
-
I wish I had a yew stash. :-\ :-\
-
I've got a couple of deflexed yew staves that want to look like that :D :D Don't think if I'm up to it though :( :( Steve, have you tried Ocean Spray for that design?
-
DC, ocean spray would do great in that design. The only problem would be that you will have a hard timew finding one with no crown that yu can keep wide. If you go a bit less reflex maybe 3" max and allow a bit more working limb it should make a killer bow. More like Marks bow above.
I wouldn't even attempt that style if I couldn't have a flat bending portion in the limb.
-
Elm could do it crowned, but I havent been able to get it to bend that well for reflex.
-
You think so Sleek? I haven't run into a wood yet That I feel could do it crowned. Elm is a good candidate for large diameter trees which have very low crowns but I think it would need to be 3" wide minimum. Several factors at work you may not fully understand.
-
Hehe, "I reserve the right to be wrong " should be my tag line. But yes, in all respect to you Badger, I think it can. I have done some retarded stuff with elm that held when it shouldnt have. Though you are probably right about forces I dont fully understand. For fun of it, im going elm hunting this weekend to golive it a try. Elm holds an advantage with interlocking grain.
-
If holding together is your goal you should do it easily with elm.
-
Sleek, I think it is about priorities. When you get a super pice of wood with a low crown and good species, clean etc it opens up a lot of design options you won't have with a lesser stave. My first priority when making a bows is not overstraing the wood, working within its elastic limits. If that means I build a straight bow then thats what I do. If it means more working limb then thats what I do. It is always my first priority. As far as I am concerned a bow can be ruined long before it breaks.
-
Why would you want a low crown? Personally I would think that a higher crown would be the way to go, not too high mind you. I've always found that a higher crown tales stress off the belly
What was wrong with your chrono Steve?
-
@marc... Because with such short working limbs you need wide limbs,and if the crown is too high you cant get the width you need.
Call me crazy but I think a piece of good clean black locust would do well for what your wanting as well. Its about as stiff and bend resistant as osage, but its lower density leading to light outer stiff levers. It doesnt take much locust to make your levers stiff(just as small as osage actually). Plus its a very snappy fast returning wood. IMO those combinations make for a fast dry fire speed. And a good piece is def strong enough in compression and elasticity to maintain healthy wood. But that's just my experiences with it.
The only other wood I'd try besides osage,yew,or locust is hickory. I hate to say it,but a good DRY piece of hickory can deliver the goods in this design as well. Just keep it no higher than 6%mc before and after its made,and design and tiller it right. Plus if your taking it to the salt flats it would really do well there as ya already know.
I'd put elm and hophornbeam at a distant 4th. They just vary to much from piece to piece in properties to gamble on. Although I have had one elm and one hhb make it and throw an arrow pretty dang far.
But I understand why one wood only want to use osage or yew in these designs as in my experiences have shown them to be more proven,and a higher consistency of success of making a bow. I've tried designs similar to this in a LOT of different woods. Other woods "can" work,and when they do they turn out awesome, but theyre just not as consistently durable to such stresses.
-
Mark, one thing I have never really got into or fully understould is the trapping effect, which is similar to have some crown. Intuitively I feel more confident with as flat as I can get a back. Some exceptions to this are when making long bows with long bending limbs. I have no idea why it just seems to work. The bow in question here does have a slight crown it measures .300 at the crown in thickness and about .260 at the edges. I consider this pretty flat for a 2" wide bow. Easy to find in hickory and elm but no so much in a lot of other species.
As for the chrono, the process I use involves me first shooting a glass bow that I know the speed of when shot from a machine. I use this to calibrate myself and my shooting tecnique and release. I don't have my shooting machine set up at present. Not real scientific but close enough for my purposes. My brand new chrono I put an arrow through testing out that 100# short osage bow so I dug through the box trying to get one of my old ones working. After about 8 or 10 shots without first checking myself I got two readings. I can't say if they are accurate or not with any kind of certainty or reliability. I can easily push a shot beyond its actual speed. So for that reason I am not making any claims on hitting a milestone.
What I will claim on this design which is a large part based on Mark St Louis designs and can be replicated is that putting together a series of little tecniques we have come to understand over the years will allow for a minimum of tradeoffs and compromises that all of us have come to understand so well. My workmanship leaves a lot to be desired and I don't apologise for it because I concentrate my efforts in other areas of bowyering. We all have different skill sets.
If we made a short list of things we do to gain energy and a list of things that cost energy we would find all of our designs are interpetations that attempt to maximise the good and minimise the bad by using tradeoffs. As we discover new sometimes small nuances about wood we are able to reduce the severity of a tradeoff to better favor a design element. The material we have chosen to work with has its own set of limitations that no matter how hard we try if we violate those limits we pay a price.
-
Steve,
I am really impressed that you figured out a way to bring this design principal to the self bow world. It is especially challenging for a long draw length bow of moderate draw weight. It seems such a design would be the exclusive domain of horn-wood-sinew composites or modern composites. The Drake flight bows were like this with small bending areas right out of the fades, huge static recurves, and very fat force-draw curves.
I'd be curious to know how it shoots a flight-weight arrow? I bet it is as smooth as can be.
Alan
-
Allen, what length bow do you think would be optimum for flight arrows. This was intended as a broadhead bow. The slow takeoff on the limb makes me think it may have help with clean arrow flight on light flite arrows.
-
Steve,
Okay, I'll give it a shot and see what you think.
If the Broadhead bow in this post can be drawn to 28", then I'd make the flight bow for the minimum 23" long arrow, which may be a equivalent of a 24-25" draw depending on the depth of the handle.
I'll assume the flight bow has a 24" draw for the maximum draw with a 23" flight arrow.
I'd make the flight bow identical in thickness and width, to the broadhead bow, except scale all the length dimensions (overall length, handle length, etc.) by the ratio of the draw lengths. Flight bow length = (24"/28") * 62" = approx. 53-3/16".
If it ends up a 23" arrow can be draw the equivalent of a 25" draw length, then the overall length would scale down to (25"/28")*62" = approx 57-3/8" long.
The nice advantage of the shorter flight bow is that the lateral stibility will go up significantly. If you think about it, this is one of the key reasons great flight bows end up being so short.
Alan
-
Lots and lots of valuable information here guys. Thanks
-
Hi Badger,
there seemed some discussion on whether or not you should have a crowned back or not to maximize performance on your bow.
I'm inclined to think a crowned back is favourable because it shifts the neutral plane towards the belly, thereby allowing set at a later stage of bending than with a flat back. I'll start a new thread with the detailed explanation I'm giving to it, since this is going a bit astray from your initial post.
Joachim
-
I have never found a crowned back that I could get as much bend out of as a flat back. I have never really studied trapping and things like that but just from personnal experience I prefer no crown.
-
here's a link to my thinking on crowned backs http://www.primitivearcher.com/smf/index.php/topic,50344.0.html
-
Think of it this way, the belly is much more elastic in compression thatn a back is in tension. Backs don't stretch much. You really don't want to attempt to put the nuetral plane in the center of the bow. If the back starts to stretch it is ready to blow.
-
Wood may be more elastic in compression but it is much stronger in tension than it is in compression especially tension strong wood like Elm or Hickory. Finding the right balance is key. I have found that a flat back on Elm does not work well even when the belly is heavily heat-treated. The bow will take more set than one with a crown. Too much crown and there's a risk of pulling a splinter but it will keep more reflex up until it pulls that splinter. Same thing with HHB. It's all about balance
-
Mark, I have also found that high crowns will tend to hold reflex better. And one more time I am not absolutely certain about this but I suspect that the high crown will pull the stave back into shape masking some set. Flat backs will show set readily but when you start measuring the effects of set in draw weight the higher crowned bow will have slightly higher losses in weight for lower losses in set. This would be a good thing to actually test and take notes on. I will sometimes draw a conclusion on something I think I see happening when something else is actually having the larger effect.
I am open to learn here.
-
I dropped Dan Perry a line, hopefuly he will weigh in. I believe he was around at the very begaining of primitive flight shooting.
-
I can't say I believe that a high crown can pull a bow back into shape. It's more likely that a flat back would do that since there would be more wood on the back working to do so. No I think that a high crown takes some stress off the belly by making the back work harder thereby allowing the belly wood to take less set. I'm convinced that a balance between tension forces and compression forces will give optimum performance. Elm for instance is much stronger in tension than it is in compression and that's why it does so well when heat-treated. The increased compression strength it gets when heat-treated makes the bow work harder in tension giving the wood a better balance.
-
^ What he said. I would add to that but id only be parroting the TBB without any original thoughts, though I do agree.
-
Steve
You wrote that the bow did not reach the intended 50#. Do you think it would be a wise idea to heat treat the working section of the bow into a little bit of reflex, only 1/4", to reduce the set and increase the draw weight? Of course it would not reach the 50# but give you some fps more. Or would then the bow be to unstable for save stringing and shooting?
I was also wondering if you heat treated the recurves to a high degree to increase stiffness.
Matthias
-
The bow underwent extensive heat treating several times durring the building and tillering process. I cut the bow down to 57" NN to gain weight but after retillering wound right back up at 35# but with a better tiller. Performance is still very good but it lost quite a bit of stored energy at the shorter length.
-
I was fortunate that the gentleman who supplied me the first stave sent me the sister stve which was almost identical so in effect I was able to get a rematch.
I went a little less aggressive on this one. Slightly shorter riser, a little more working limb and less reflex. I charted the draw curve when the bow was fresh and immediately after charted it agin so I could see the difference due to set. The bow came in at 51.8#@27" so hopefully will settle in at 50# after sanding and break in. Very happy with it so far, a little handshock but tips have not been reduced yet. Will try and test when finished.
8" 12.4# 7.8#
9" 17.4 12.2
10" 20.2 15.2
11" 23.2 18.0
12" 25.6 20.6
13" 27.8 22.8
14" 29.2 24.4
15" 31.0 26.2
16" 33.0 28.0
17" 34.4 30.2
18" 36.4 32.6
19" 38.0 34.0
20" 39.6 35.8
21" 41.0 38.0
22" 42.5 40.2
23" 44.8 41.2
24" 46.2 43.8
25" 47.6 46.0
26" 49.8 48.2
27" 50.2
28" 51.8
The reading on th right is freshly drawn bow, excersised at each point, the left is the second reading. You can see where the breakdown first starts to take place at 17". This is where the spread between the two sides starts to narrow. Just based on the stored energy and typical efficiency the bow should hit about 190 fps which is faster than any self bow I have ever built. I believe Mark St louis has crossed that bridge allready.
-
Chrono results not good.
Had perfect light for chrono today and was getting consistent readings. Bow started off great 192fps, 190 fps 187 fps 176 fps 168 fps 166 fps and leveled off. Bow dropped 6# nd 1 1/2" reflex shooting in. It dropped that same amount while tillering. Because the weight dropped the grains per pound went up so at 10 grains per pound it leveled off at about 172. I think the design is just a little too aggressive for wood. Perfect tillerig would have probably worked. I had a total loss of reflex of about 4" from where I had started. I always figure about 1 1/2" and I am good, at 4 I know I am toast.
-
Steve, thats proof of concept. Perhaps a bit wider inside would help?
-
I feel like the design is viable enough, I went pretty wide with the osage as it was 2/1/4".
Battle is not over yet. I reheated the bow back into it's orginal reflexed form and am retillering using the no set method best I can.
Here is the new force draw. I took it as far as I could until the bow started to drop weight. The number on the right is the number I got on rechecking my weight once I got to 14". It started dropping weight so early there may be nothing I can do or not much. I will see.
8" 14.4#
9" 19.2#
10" 22.4# 20.8# ( 1.6# loss from compression damage)
11" 25#
12" 26.4#
13" 28.2#
14" 29.4#
-
Longer bow in order to go furter back with less damage?
-
Steve,
did you ever get to take a picture of either of these bows at full draw?
Dave
-
I still have one and plan to bring it to the flight shoot. Its only 35# but performs great. I will try and take a pic tomorrow.
-
When is the flight shoot this year Badger? If it isn't the 29th of August I'm coming!
-
Septemeber 4th, what state are you comming from?
-
I live just south of salt lake
-
Yes. still at the Salt Flats, most of us get there on thursday to practice a bit before the shoot. Do you know where to enter the shoot? You will see a porta potty set up pn that long road going in and that is where we set up.
-
Awesome. I'm coming this year. If I decide to enter do yo sign up on site?
-
Yep sign up on site. registration runs about 100.00 if you are currently not a member of usa archery.
-
Ok Steve I finily got here. :) now I am dizzy between you and Mark. I don't know why I just prefer them longer when it comes to osage. I also don't understand mass not being used but storing energy. Meaning non working outer limbs. But prove is always in the pudding so to speak. So I am paying attention. I wish I had the time to come shoot with you guys this year.maybe next year. Arvin
-
Do the unlimited draw weight bows go through a weigh in process? It seems like it would be advantageous to shoot a bow that only gets stressed to full draw for one shot. rather than breaking it down before you even get on the line.
-
They don't weigh the unlimited bows. I have a bow right now I plan to shoot at 60# and I expect it will drop the weight about 2# or so when I do that. I plan to come back and shoot it in the 50# class after the unlimited class with a slightly shorter arrow. Right now it weights 50# with a 23" arrow about 1/2" from the back of the bow, I need to loose about 2# so it will read 50# with a 23" arrow falling off the back of the shelf.
-
Regarding set and flat back versus crowned.
The easy way to KNOW what is happening is to cut a sacrificial bow down the center. eg between the back and belly.
I have done this on quite a few bows now that I wasn't totally happy with and guess what almost every time the back springs back to it's original profile and the belly goes into more set. This tells me that most every wood is held in a 'less set' position by it's (normally!) understrained back.
-
I agree with you Mike, I have sometimes put too much reflex into bows and even though they held the reflex the tension at brace did not reflect the amount of reflex nor did the performance. The back of the bow can mask a lot of set.
-
I never put much stock in the Perry reflex theory that wood was less strained because of inner limb energy storage.