Ernest, 
A quick check of my calculations suggest that 170 MPH should be good up to our RPM requirements. So if your wrong we are both wrong. My figures are based on a 44 mm PP and the inlet speed in well below that, however I note the smaller diameter speeds get up to over 200 mph at 7,500 rpm. I can't remember how your configured. 
George ( down under) 
 
> Ed Anderson wrote: 
>> 
>> The way a turbo/super charger works, of course, is not by increasing the >> air volume flow through the engine but by increasing the air density. The >> 100,000 rpm impeller accelerates the air velocity inside the compressor >> vanes and then using the old Diffuser principal, slows this air down at >> the compressor exit and converts the increased dynamic energy of the >> accelerated air stream into a static pressure increase reflecting the >> increased air density produced. 
>> 
>> 
> And the turbo charger is a centrifugal pump. 8*) One of a comparatively > small diameter, but high speed. I'm looking at a much larger diameter, > but a much slower speed. Diameter and speed are what determines the > maximum static pressure. How well the pump can hold that pressure is > determined by its flow rate, which is in turn determined by the volume of > the pump. I calculated that the air would flow at 170mph, with the intake > and exits being 3" diameter. Not exact numbers, but the speed point is > higher than my projected cruise speed, and the intake diameter is smaller > than the runner I'll actually have. I have a relatively large volume > between the flywheel and PSRU plate, being about 4" thick. All that > scribbling is at home someplace, and I'd be hard pressed to find it. > Basically, I'm counting on that thickness to overwhelm the engines needs > and keep the pressure near the max static. 
> 
> I do admit that I'm remiss in not applying the technical rigor to carry > out the equations to the 4th digit. You and Al are good at that, Ed, but > I am content to run some rough numbers. I figure the practical won't > match the theoretical anyway. So if it looks good at first pass, build it > and then take a measurement. 
> I think this would be a good move if I can get 5 to 10 extra horses out of > it. On the other side of the equation, I'm looking at what are the > drawbacks (other than the design/build workload, which is supposed to be > the fun part anyway). Failure modes, other than shedding blades, should > be benign or non-existent, as I'm not providing for any control hardware. > If the flywheel stops turning, the intake can suck air around the > blades...but that is a moot point, because if the flywheel stops the > engine is about done sucking air for a while anyhow. A leak in the intake > means that I don't get as much boost as I hoped. In that case I'm just > another normally aspirated rotary. The worst case scenario would be the > highly unlikely event that I get TO MUCH boost. That will prove out easily > enough during testing, and would only require some sort of restriction to > rectify. 
> 
> There may be up to twenty Hp waiting there, and it'll only cost about 3 to > 5lbs of aluminum. If it works, I'll have one of the coolest, most unique > engines at the fly-in, with one of the highest Hp/weight ratios around. > If it doesn't work, I get to wear the "I tried something that didn't work" > badge that makes one a true Flyrotarian. ;*) 
> 
> 
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