Adjustable Penobscot Møllegabet 52#-75#@28"

[Rowan Bows]

do you think the tiller shifting is an advantage or maybe a disadvantage? I mean both limbs are still equal after connection but the bow has less bend in the inner limbs. this problem (if it is a problem) would be so with every double bow except you make an akward main tiller. there must have been a logical reason for the natives to make those.

[simk]

Hello  I don't think you can say the tiller shifting is an advantage or a disadvantage.... its just the consequence of attaching the second bow.
There's little documentation about these bows and various explanations why this design has been choosed. Maybe this double-bow- concept wasn't very successful in bow evolution because there in fact are not many advantages. You will find several threads to read about this concept on this site or paleo planet as well...altough I didn't find a fdc of one. The fdc will tell you a lot about function and theoretical performace. 
I personally am very critical about the general concept and do not see any advantages. I think it's performance is worse than from a "normal" bow of the same drawweight. Just think about under what bad string angle the secondary bow has to work and the consequences. this theoretically could be seen in the fdc chart (i'm still interested in). Practically you could test it by shooting your bow though the chrono and shoot the same arrow with a "normal" bow of similar drawweight....but still many other factors to affect the results 
cheers

[Rowan Bows]

true story but I just could not resist the temptation to build it 

[bassman211]

I have made the so called Mic Mac double bow with a sliding nocks, and the loops attach at  the riser on the shorter back limb. Much easier to adjust poundage that way, but no improvement in performance. My brother has a pro shop with a large, very expensive, and accurate chrony. That is were I did my testing. Take that bow to a shoot, and shoot it, and archers will gather around like flies on a sugar cube out of curiosity. It's  very design is a sales point, but no advantage in performance, and more time consuming to make. Still nice to build, shoot, and have fun with.

[Rowan Bows]

Nice, do you have a link or a foto? Id really like to see this solution. Mine needs 10 seconds to attach the cables on highes level, think thats quiet comfortable but Im always open for improvement.

[M2A]

Cool build! Enjoyed the read on this thread. Bow looks great.
Mike

[Rowan Bows]

Hey guys happy new year!
I have some speed scalings for you    the problem could have been my release.
I shot a 474,6 grain arrow with and without the backing. Let me point out that I really dont know if that is fast or not - ok but I think that arrow was quiet heavy.
the first shots went out stupid and mr. chrony has let me know maybe a 100 times that he has an error. but after a little release practise I could get the bow ~5m/s faster. I practised more and more and shot the bow without backing 49#on my draw with a 474,6gn arrow - 49,25m/s or 161,5fps
The backing attached gave me 68# on MY draw - same arrow 53.80m/s or 176,5fps
So... I dont know if thats good or not but I am a man of science  I gave you those numbers although I know now posting numbers is really dangerous here.
I had very much fun with this bow and I mean no matter if its worth it or not I couldnt resist to build it. cheers!

[BowEd]

Happy New year back at ya.Glad you worked things out with your chronograph and it's still usable.
Most bow makers,not all,who never concern themselves with testing their bows and then do usually are disappointed.Which leads them to ignoring it altogether in their bow making process.Many times it's just a matter of release.That type shooting can actually hurt accuracy though with many.Hitting what your looking at counts.
Nothing really dangerous about testing process if all done legitemate.
Most designs of bows are pretty efficient if fine tuned while tillering from 1 bow to the next.
Your numbers fell in right where I figured after seeing your initial testing.Interesting your added bow almost adds 20#'s to the draw weight.Starting out with a highly efficient main bow should transfer like numbers with the added second bow and draw weight IMO,but it would be interesting to see.
In time I will show a test of a different bow I'm making again on video good or bad.Deer season and accumulating snow of over a foot with high winds here will keep me busy for a while.I need to keep a 3/4 mile long lane open plus my yard and I live in the sticks.Plus my non heated tractor shed/bow making shed will be pretty cold to work in.Below 0 F. weather coming here for  while.The dead of winter is upon us here.

[Rowan Bows]

Chrony session: https://www.youtube.com/watch?v=RK8QcY_vU88

[BowEd]

Looks like the test was legitimately done.
Your release looks fine to me.I have a different looking type chrongraph though.
It has hoods for shadow casting I think and I shoot through the V about 3' in front of chronograph.

When diagnosing bows it's important draw length is the same and starting out at least with a standard.Using a 10 grain arrow on all bows.50#' with a 500 grain arrow.60#'s with a 600 grain arrow.It levels out all the bows on the same playing.
If number is odd like 53#'s it gets a 530 grain arrow.
It can get a little more confusing using an over draw then too.Then you see how much the added inch gives you.
An old timer said to me once when I showed him my findings.Makes sense he says... if you want the bow to go faster pull it farther back....ha ha,but in reality which I failed to get across to him was that the sustained freshness of limbs gained with good tillering is
 really where it's at.

[superdav95]

Great looking bow.  Love the concept!