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Hi Ernest,
I think Tracy's question might have it roots in the following.
First, the manifold pressure really did not change much with rpm. Typically you would see an engine under load go from lets say 12" Hg at idle to 29.8" Hg at WOT which in your units would be from approx 40KPA to 100 KPA at WOT. Without the blower, it looks like most of the orange was below 60 KPA although I think I see a bit up around 65 KPA. So that would indicate approx 13" Hg at idle to around 19.0 "HG at your highest - hardly what you would expect to see if the engine was loaded and turning those rpm.
So that indicates your blower is feeding a small throttle opening and an engine that is not processing too many CFM of through put. The blower appears to be producing approx 15 KPA above the orange or an increase of approx 4.5 " Hg. However, the question is with less restriction (WOT) would that pressure profile increase due to higher rpms or drop due to less restriction?
Put a Load on that thing and lets see!!!!!!!!
Ed
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From: "Ernest Christley" <echristley@nc.rr.com>
Sent: Friday, June 17, 2011 4:30 PM
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Blower does work
Tracy wrote:
Where is the pressure being measured?
Very strange if this is a graph of your actual Manifold Pressure. Is it? I can't think of any scenario where the manifold pressure would remain almost constant from 1000 to 5500 rpm unless the prop presented almost no load to the engine. Even assuming that, I can't see why the MAP should be higher with the blower on.
The video that I linked to last night...notice how the airplane didn't move?...very little load. Best it could do was blow over the fan I had setup for the cooiling intake. My big goal for the weekend is to get more pitch into this prop so that I have something resembling a load.
Why wouldn't you expect the map to go up when you have a blower pressurizing it?
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