They make bronze elbows!
How does it impeed flow? Gee, how did that go because I barely remember science class?!... objects on motion tend to stay at a constant speed and direction until acted on by an outside force?... eh, close enough! 😉
The water is flowing in one direction and it reaches from a directional standpoint, the end of the line and has to then get physically acted upon by the elbow to change its direction of flow.
Relax! this is not as big a deal as it might seem. Here's the short ansd easy and accurate as long as you don't get carried away answer... it's not enough in as much as four elbows to cause any trouble for a good pump.
Now here's the more nausiating and complicated and part I half understand and can half explain...
Now, you go elbow over elbow over elbow and sooner or later it will add up. My Mechanical Engineer Father is spinning over in his grave because I'm not laying all the calc. out for you!... yes, for each bend in the tubing and how fast it bends and how far it bends and then there's something called the venturi affect and the doppler effect and a few other minor things... man, Luckyboy, how complicated are you going to make this simple answer of yours anyways?!
Ok, for every elbow, there's a tad more resistance and the good news is that like the exhaust on a car, if you then do a tuned pairing or a bend back the other way at just the right or even nearly the right moment, you recover most of that resistance!... he's probably thinking... Whatever!
Ok, ever notice on car exhaust, they put a bend in the exaust pipe to get around something and then you'll se a bend or two that seem to be there for no reason? That's called tuning the pipe! It brings in all that venturi rot and whatnot.
Relax, get a couple of brass or bronze elbows or very high quality plastic elbows and enjoy the results!
