When I upgraded to a half set from my Dave Daye practice set, I decided to keep the Daye bellows because they seemed more efficient than the bellows that came with the half set. I’ve since tried a number of other bellows and have found all of them to be less efficient than the Daye bellows.
The Daye bellows have straight sides, where all the other ones have had a more traditional, curved “teardrop” shape to the clappers.
Is there a reason this teardrop shape is preferred by the majority of makers? With the straight sides, when the bellows are fully opened, the gusset is pretty much fully stretched all the way around. With all the teardrop-shaped bellows I’ve tried, there’s always been a little bit of extra material, so that when closing the bellows, the first few degrees of motion go simply to filling this excess gusset material, rather than pushing air immediately through the bag.
At first, I thought it was just that particular set of bellows, but I’m beginning to suspect it’s just an impossibility to get as perfect a fit for the leather to the curved shape as you can get to the straight-sided clappers. Am I wrong about that?
I’ve got a friend and fellow CF’er preparing to work on a new set of bellows for me, and I’m inclined to have him pattern the clapper shape after the Daye bellows. Is there any reason, other than a more traditional look, to go with a common, teardrop-shaped clapper?
I suspect there is an advantage to the teardrop shape (besides aesthetics). But getting the gusset the right shape isn’t trivial. I also suspect the efficiency problems you’ve encountered have to do with factors other than clapper shape.
No doubt that having an efficient set of bellows is essential, but whether they are tear drop or straight edged shouldn’t really matter too much if your set of pipes are running in good order. i.e no leaks, balanced reeds that don’t take too much air, etc. Better to fix these problems than compensate them with larger capacity bellows.
In saying that, I do prefer using my Ian MacKenzie “coffin” bellows over another traditional shaped one I have…
Not efficient bellows designs are a bit of a plague in the bellows bagpipe world unfortunately. I don’t think it has much to do with the shape of the paddles. But I have to say, most bellows I’ve tried are either somewhat to very leaky, or have efficiency problems. Good leather definitely helps the leak problems. But it’s surprising, when trying to design a bellows, how many factors can make for inefficiency. I know your pain Tristan. I have experienced this “extra bit of material” that needs to be filled before the bellows actually starts doing it’s job. It’s very annoying to have to pump an inch or two (or more!) before your bag starts getting any air.
Bellows efficiency is largely dependent on eliminating “lost motion” during the pumping stroke. If your hinge allows the clappers to separate - even a small amount - at this moment, then you will lose efficiency. It does not matter whether the hinge is a leather strap or a thong, the result will be the same. If you have a metal hinge then this can obviate the problem, but there can be a trade off in the comfort of playing, and the ease of reaching the regulators.
The lost motion is due to the thin leather that doesn`t impulse the air to the bag until it inflates completely, so you get an unusefull motion through this process.
If the leather is hard enough it doesn´t inflate so the full closing motion is pushing air to the bag.
I think it´s shape is related to the body. The teardrop better fits into the hip. Comes to that that in the old days the bellows were fixed differently:
I only replaced the string by this adjustable belt but kept the spring hook.
BTW, I never saw any pics of padded bellows before the invention of the “concert-pitch-compressor” Does anybody know s. th. or have any pics? I think the old flat sets (when volume wasn´t an issue) must have taken very little pressure?
Does anybody know s. th. or have any pics? I think the old flat sets (when volume wasn´t an issue) must have taken very little pressure?