Mailing List flyrotary@lancaironline.net Message #45359
From: <wrjjrs@aol.com>
Subject: Re: [FlyRotary] Re: Fuel economy -
Date: Thu, 05 Mar 2009 11:36:44 -0500
To: <flyrotary@lancaironline.net>
Ed,
Jim Clark's crash in one of the PowerSport powered RV-8s was not caused by an engine failure. His problem was a single battery electrical system which failed. Jim did break his arm in the crash but wasn't hurt otherwise. The plane was supposed to be rebuildable. I was very saddened by the Vans test BTW because they didn't let the rotarys fly an optimum flight plan but made them do exactly what the Lycs did. The post Everett Hatch Powersport EMS was also far from optimum. The Dave Lenard N4AVY flight in Dan Checcoways 100 mile race shows that the rotary is very comparable in cost and fuel consumption.
Bill Jepson


-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Thu, 5 Mar 2009 5:47 am
Subject: [FlyRotary] Re: Fuel economy -

Yes, Mike,  I read that article about the comparison as well.  This was clearly a case of two guys who had more money than knowledge of the rotary.  One eventually had an engine failure which damaged fortunately only the aircraft – never did hear the cause.  So I personally did not get any indication reading the results that either of the pilots really understood how to get the best out of their rotary.  But, yes, the powersport engine certainly looked nice – but at $30K it should {:>).
 
=0 A
One the other hand, I personally saw Tracy Crook win the Sun & Fun 100 air race on two occasions before they decided to stop the air races because of the embarrassment of his junk yard engine (yes, this was before his Renesis installation) beating lycomings that in some cases had $10,000 of additional prep. 
 
Here Tracy was in a rather dirty airframe (compared to some of the racers), with automotive muffler hanging in the slip stream and a fixed pitch wooden prop winning the air races.  Didn’t hear anything about it in any of the aviation publications did you?  – too embarrassing to all those Lycoming owners.   So they decided to cancel the air races to preclude further embarrassment – Yeah! I know they claimed it was due to insurance consideration, Yeah! Right! {:>)
 
 
 
Ed
 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Wednesday, March 04, 2009 10:50 PM
To: Rotary m otors 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,=2 0the 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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