Mailing List flyrotary@lancaironline.net Message #54788
From: Tracy <rwstracy@gmail.com>
Subject: Re: [FlyRotary] Re: Intakes old and new
Date: Sat, 30 Apr 2011 11:37:48 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Everybody has their own technique for cruising.  I typically aim to get the highest reading on the EM2/3 MPG readout along with a reasonable airspeed.  On my RV4 this is usually around 17 - 18" Hg. MP and 130 - 135 IAS / 170 - 175 TAS at 15,500.   This is way less than WOT.   Pumping losses are a factor in efficiency but IMO it is way over rated.   There is no question that aero losses at higher speeds more than make up for the pumping loss improvement.  If pumping losses were that big, cars would get terrible fuel mileage at 55 mph. 

Tracy

On Sat, Apr 30, 2011 at 10:52 AM, Bill Bradburry <bbradburry@bellsouth.net> wrote:

Ed,

 

I have heard you mention that you seldom fly at max speed.  How do you do this?  Do you fly at WOT but high enough to lower the output and lean for economy, thus reducing the speed?  Do you reduce throttle??

 

I have been given to understand that the throttle should be at WOT all the time to reduce “pumping losses”.  Engine power would then be affected by other means, leaning, altitude, prop speed if you can adjust it???

 

What is your method?  For that matter, what method do others use?

 

Bill B

 


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Saturday, April 30, 2011 9:49 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Intakes old and new

 

Here is the induction system set up I first flew with Phtos MVC-007F JPG).  4 injectors into a TWM dual throat Webber Throttle body (2" dia throats) into a two into four manifold.  The engine started easily and operated fine - with the exception it was low on power.  Top speed was 185 MPH TAS. 

 

The apparently problem was that while this set up did well for the rotary racing crowd when theirengines hit 9000 rpm - it sucked (but not very well) at the lower rpms like 5000.  So I swap it out for my current design using an 65mm dia mustang throttle body and smaller diameter runners and immedately picked up 10 MPH top airspeed and 400 ft/min improvement in Rate of climb.

 

It was the beginning of my understanding that what works well for one environment and set of operating conditions may provide lousy results under different circumstances.  The other two photos show the intake that produced the best results for my installation and which has now been on the aircraft for over 6 years, top speed achieved with this intake was 196 MPH TAS with the old 2.17:1 and 68x72 prop.  Same intake with the 2:85:1 and 74x88 prop topped out at 200 MPH TAS.

 

Ed

Edward L. Anderson
Anderson Electronic Enterprises LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com


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