Hi, thought i'd ask around here since there are a number of pros around :-)Today during a lesson on airframes, systems and powerplants we were going over hydraulic systems. For the life of me, I can't visualize how an engine driven pump (constant pressure/variable volume type) works. Does anyone know of any animations of such a pump. I'm currently looking at a 2D image, I just can't figure out how it worksThanks

Might be over my head on this one, but I know GE's main website has a lot of nice animations on how their engines work.Bretthttp://www.precisionmanuals.com/images/forum/800driver.jpg

ya, ill second that. GE has a really kool website. They even got an interactive thing where you put the engine together and stuff. very neat. just wish PW and RR did the same.adam

Hmm, sounds alot like a rotary piston pump to me. Use them alot in industry as well. Work great since they automatically feather when volume is not needed reducing the power requirements. Since I don't have access to the picture you are looking at, I'll give ya quick rundown of a rotary piston pump.The main rotating section of the pump looks like the magazine of a revolver. Each chamber of this is like a large needle syringe. The back of each syringe type section rides on a swash plate or pivoting unit. This unit (swash plate) is held to it's maximum angle of deflection by spring pressure. This spring pressure is countered by hydraulic force, as the system pressure increases, the plate starts to straighten out. So when system pressure is low, the swash plate angle is at it's greatest. This results in the "syringes" having maximum travel therefore pumping maximum volume. As the system pressure rises, the swash plate angle is reduced by the counteracting hydraulic force reducing the volume that the pistons, "syringes" travel therefore reducing their volume.Clear like mud, eh? If I had some pretty pictures, I'd post them but this is about as far I go in the forum. Take care.

Yeah thats the one, but still having problems trying to picture it working. Anyway thanks for the info, it does help :-) I'm sure i'll get there in the end lol