Received-SPF: pass
 receiver=logan.com; client-ip=75.180.132.123; envelope-from=eanderson@carolina.rr.com
Message-ID: <A3915B99DC0441B2B4C9953EB53ED960@EdPC>
From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Filterless Values of MAP FlyRotary] Re: Blower does work
Date: Sat, 18 Jun 2011 07:57:59 -0400
MIME-Version: 1.0
Content-Type: text/plain;
	format=flowed;
	charset="iso-8859-1";
	reply-type=response
Content-Transfer-Encoding: 7bit
Importance: Normal

Regarding the Filterless values - in looking at your photo, if all you do is 
remove the filter and leave the curved intake tube in place - then what you 
may be getting is a prop effect of the wind blast past the end of the tube - 
causing a possible lowering of pressure in the tube (siphoning out the air 
trying to go down the tube) - just a WAG.

Ed

--------------------------------------------------
From: "Ed Anderson" <eanderson@carolina.rr.com>
Sent: Saturday, June 18, 2011 7:54 AM
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: Blower does work

> Ah, yes, interesting about the filterless values.
>
> I don't think MAP vs rpm is going to tell you anything - unless you have 
> the engine loaded properly (with a Prop {:>)).  The reason is that at even 
> very low MAP pressure you can obtain very high rpm (without a load).
>
> Now MAP vs throttle opening might be more revealing.  Assuming ambient 
> pressure then your MAP pressure is basically going to depend on two 
> factors.
> 1.  How fast the volume of the intake manifold is being exchanged
> 2.  Throttle opening.
>
> If volume of intake manifold is only being replaced (sucked down) slowly 
> then the MAP will tend toward ambient pressure even through a small 
> throttle opening.  If the volume is being replaced rapidly (high rpm) then 
> a small throttle opening should result in lower manifold pressure because 
> its not being replaced as fast as its being sucked down.
>
>  If the volume is being sucked down rapidly (high rpm) and you have a 
> large throttle opening then that should result in greater manifold 
> pressure (WOT?)
> But, not certain how you are going to correlate these two relationships 
> with your blower.
>
> Keep going, we are all waiting with anticipation!!
>
> Ed
> --------------------------------------------------
> From: "Ernest Christley" <echristley@nc.rr.com>
> Sent: Friday, June 17, 2011 11:45 PM
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Re: Blower does work
>
>> On 06/17/2011 06:10 PM, Ed Anderson wrote:
>>> 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?
>>>
>>
>> I'll be working on getting more load this weekend, but in the meantime I
>> probably should call the previous post a false alarm.
>>
>> This even I went set out to run a test that would be more methodical
>> than the previous "grab whatever is in the logs" method.  I set the
>> engine up in three situations:  with the blower charging the intake,
>> with the air filter turned around to pull ambient air, and with no air
>> filter at all.  I attached a picture showing how I turned the filter
>> around. (It should also be apparent why my front rotor is getting
>> cheated as far as air supply goes.  The air just goes rushing past it.)
>>
>> For each configuration, I made a run, trying to hold the throttle at
>> every 500 RPM on the way up for 5 seconds (1500rpm, 2000rpm, 2500rpm,
>> etc), then did the same on the way back down. I made a datalog for when
>> the engine was warming up, with the blower active, with the filter turn
>> around, with no filter (filterless), and again with the blower in
>> action.  That graph is attached.  Basically, this shows the same MAP for
>> every RPM, except for the filterless run, which has the MAP jumping all
>> over the place.  I don't know what the deal was with the data I got last
>> night, but given the strict control and short time frame under which it
>> was taken, I trust this data much more.
>>
>> Upon further reflection, I think I'm may be looking at the wrong thing.
>> Given the constraints of such a light load, the RPM is going to follow
>> whatever the MAP is.  Is that a "No duh!" statement?  Looking at the
>> graphs, I think what would be more telling is RPM vs throttle opening,
>> or MAP vs throttle opening.  What say you all?
>>
>
>
>
>> --
>> Homepage:  http://www.flyrotary.com/
>> Archive and UnSub: 
>> http://mail.lancaironline.net:81/lists/flyrotary/List.html
>>
>
> --
> Homepage:  http://www.flyrotary.com/
> Archive and UnSub: 
> http://mail.lancaironline.net:81/lists/flyrotary/List.html
>