Wargasm

I know that people have said that flow benches offer little help to the rotary port designer because of the fact that the rotor moving past the port adds a lot of variables that are hard to duplicate using just the end plate by itself...



So why hasn't someone taken an engine block and hooked up a bell housing to it and driven it with an electric motor and then monitored airflow somehow? I would think that if you only ran the engine for a short time you might be able to get away with little or no oil (use heavy grease) and no cooling system. This would be strictly a "bench engine" and not have full functions.



Maybe you could even just make a ONE rotor version somehow... I dunno doesn't seem that hard! I would think that in theory you could take it apart and put in different plates pretty quickly and then "dyno" it with an electric motor and measure the airflow....



Am I a wacko?



Brian

Travis R

Yes, wacko.



Trying to make pressure measurements on a "running" engine would be pretty difficult. I think if you wanted to incorporate the rotor dynamics into the flow bench it would be easier if you assembled the engine and made measurements at discrete rotor positions. That way when you make changes and put it back on the bench you know exactly what numbers correspond to what rotor positions, instead of just an average. Especially if the home flow bench is using a water manometer... they take a little bit to stabilize.

Good luck

j9fd3s

its so crazy it just might work! dont piston engine guys flowbench at different valve lifts? you could do the same with different rotor positions

mazdaspeed7

But valve lift to a piston engine is port area to a rotary.



I read something a while ago on while its not generally done on rotaries, but I cant remember anything particular, and moreso, I dont see why it wouldnt do anything. You will need to realize though, that the ports flow A LOT, and its going to need a pretty big setup to measure the flow.



I also think that its not very useful on a rotary because the ports themselves are so well designed. The general shape of the runner/bowl is nearly perfect in stock form, and with some minor porting and cleaning up of the casting, you have a fluid dynamics engineers wet dream.



Some porting styles work better than other, but thats already been proven without flowbenches. There are less variables in our ports. No kinks, no valves, no valve guides, etc.



edit: I dont see how the rotor moving past the port would affect the flow any more than the opening and closing of the valve in a piston engine. Generally, thats ignored. Whats measured is the peak flow at the ideal opening. Because air flows horizontally into the chamber in a rotary, the end plate would need to be rotated 90 degrees, so the flow will be vertical, from top to bottom.

cach22

take 2 (i just replied and my f*&k*$ #$%^$#^% computer crashed grrr)



this is a good topic you guys are on,



a few years ago i had a good think about how you could flow bench the rotary, as i think there is a lot of potential in doing so. You need to simulate the combustion chamber of the rotary. I think the easiest way is as follows, imagine a single rotor setup, ie a cast housing either side, a rotor housing and a modified rotor, no eccentric shaft, the rotor is modified by cutting a hole at the tip of the rotor, i have added some pics below of the rotor i started to modifiy. The way it works is the cast housings, rotor housing and rotor are assembled, then the hole in one of the cast housings where the eccentric shaft fits, is mounted onto the flow bench horisontally so the air is sucked through the eccnetric shafts hole, the eccentric shaft hole on the other cast housing is blocked off. Air is sucked through the cast hole mounted on the flow bench, which then sucks through the center of the rotor then through the hole in the rotor, which then simulates the combustion chamber and then the air is finally sucked through the inlet port/s. Flow measurments would have to be taken of the rotor to see how much its port flowed and added into the equation. It would be good to make it so that the rotor could be moved during flow bench testing to calc the best shape etc of the ports. If this couldn't be done it wouldn't be a major drama it just means that it would have to be dis assembled, then the rotor moved and then re assembled again. Other things that would be good is to fit the inlet manifold onto it as well and see how that effected flow. Also if you moved the rotor around, you could make it simlutate the exhaust flow aswell. Obviously instead of the flow bench sucking it would be switched to blow. The air would blow out of the hole in the rotor and then finally out of the exhaust port, also extractors etc could be fitted to see what effects they had. Guys i really think there could be a lot of information gained by rigging up something like this! thoughts????? it might not be the best setup but at least it is some form of measuring flow, and it really wouldn't be that expensive to make up. I haven't gone any further as i don't know anyone with a flow bench surely someone out there is keen to try it and has a flow bench or access to one! Anyway please feel free to give me your thoughts, and if the above makes no sence i will attempt to explain it again. I have added the links to the pics below.















cheers



Lance

Fluid Dynamics

Lol