Mailing List flyrotary@lancaironline.net Message #45352
From: Patrick Panzera <Panzera@Experimental-Aviation.com>
Subject: RE: [FlyRotary] Re: Fuel economy -
Date: Wed, 4 Mar 2009 20:13:39 -0800
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>

Well…

 

Here’s the place to hold a performance event:

 

http://www.ContactMagazine.com/roundup.html

 

And I can guarantee that the results will be published in CONTACT! Magazine

and EAA’s Experimenter.  http://eaa.org/experimenter/

…after all, I’m sleeping with the wife of the editor of both publications.

 

Pat

 

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Wednesday, March 04, 2009 7:50 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Fuel economy -

 

There was an article in the May 2006 issue of Sport Aviation. Two RV-8s powered by Powersport Rotaries compared to two of Van's factory demo RV-8s. Time to climb and speeds were pretty comparable. The rotary powered airplanes were a little heavier. Fuel consumption for a 160 mile out and return flight the rotaries burned 12.9 and 11.5 gallons while the Lyc powered RVs burned 8.9 and 9.5 gallons. Cruise portion of the flight was rotaries 7.85 and 7.1, Lycs 5.05 and 5.45.

 

 My guess is that if the pilots could have aggressively leaned the numbers would be closer but the rotaries were equipped with Powersport's FADEC. No idea what it does with mixture.

 

 Anyway its articles like this that perpetuate the ideas about rotaries being gas hogs. Until we generate some numbers to contradict, this is going to be the perception. If you guys generate the numbers I'll volunteer to write the magazine article!

 

 I should also mention that the Powersport RVs looked WAYYYY cooler than the Lyc powered RVs!

 

Mike Wills

RV-4 N144MW

----- Original Message -----

From: Al Gietzen

Sent: Wednesday, March 04, 2009 7:27 AM

Subject: [FlyRotary] Fuel economy -

 

Mark wrote:

Most are just plain scared to run their engines lean of peak where they are able to get close to the "advertised" bsfc.

 

That seems to be the rule.  I chatted yesterday with a hangar neighbor with his beautiful Lancair Legacy with Continental 550.  Does he run lean of peak? “Eh-h, well, I tried it, but it sounded different, and I hear the valves don’t last as long; so I run it rich of peak.  It’s a few more dollars, but cheap insurance”

 

Alcohol and possible vapor lock are the only issues I know of, and with a properly designed EFI fuel system, vapor lock isn't an issue.  As long as they don't start blending alcohol in the fuel in my neck of the woods, I'll keep burning mogas and pocketing the difference. 

I did the ethanol test on my auto fuel yesterday. Within the accuracy of the test, the fuel had between 4 and 6% ethanol – consistent with what Mike said regarding CA fuels.  So I got out my light and little my mirror and stiff wire with a sharp end; and inspected my fiberglass/EZpoxy fuel tanks. No sign of any softening of the surfaces; no sign of anything happening. Nothing in the fuel filter. So far, so good.

So I’ll keep runnin’ with auto fuel – certainly when near my home base.  Saves close to $15 for every hour of flying – including the 6 – 8 cents/ga for the 2-cycle oil (SuperTech 2-stroke oil, $10.97/ga at Walmart, mix ¾ oz per ga.).

 

You stated, "But really the biggest motivation was to do something a little different."  As for that statement... I couldn't agree more, but how do you quantify something like that? 

I like to put it differently: "But really the biggest motivation was to do something a little better." 

Al G

 

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