Mailing List lml@lancaironline.net Message #56785
From: randy snarr <randylsnarr@yahoo.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: efficiency
Date: Thu, 25 Nov 2010 10:27:52 -0500
To: <lml@lancaironline.net>
If I recall it was between 2000 and 2100 rpm between 6-19 MAP.
Randy.,

"Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible"
-Simon Newcomb, 1902

--- On Tue, 11/23/10, Bill Hannahan <wfhannahan@yahoo.com> wrote:

From: Bill Hannahan <wfhannahan@yahoo.com>
Subject: [LML] Re: efficiency
To: lml@lancaironline.net
Date: Tuesday, November 23, 2010, 9:42 AM

Thanks Terrence,

Power settings after takeoff ranged from cruise climb at 1900 x 20 inches to 1750 x 18 inches in cruise to 1550 x 15 inches in descent.


What power settings did you use Randy? I noticed you were  quite a bit faster.


I leaned until the leanest cylinder began to misfire, then enriched slightly. At these low rpm’s the fuel has plenty of time to burn with the factory timing.

 

The fuel mixture distribution is poor at part throttle; a well calibrated injection system would probably give significant improvement under race conditions.

 

In normal cross country flying I go high with the throttle about a half inch off wide open which results in all four egt’s peaking at the same time, with no loss of MP. FI would probably not offer much improvement in that environment.

 

A higher compression ratio and EI would probably help significantly at high altitude. If I were doing it again I would go with 9.5:1 and red line MP at 25 inches, even on takeoff.


At my home base, Longmont CO , 5050 msl, I see 22 inches on takeoff and  use 1800-2500 feet of runway depending on weight and density altitude.

 

By the way, at these low rpm’s you need to check that you are not flying with the prop on the high pitch stop. It is a bit like trying to crank your power steering past full lock. The governor has a relief valve, 350-400 psi, but you do not want to be on that continuously. So pull the rpm back about 50 below your set point, then back to the set point. If it is on the stop the rpm will not pull down. If you accelerate in descent check it again.


Regards,
Bill Hannahan


--- On Mon, 11/22/10, Terrence O'Neill <troneill@charter.net> wrote:

From: Terrence O'Neill <troneill@charter.net>
Subject: [LML] Re: efficiency
To: lml@lancaironline.net
Date: Monday, November 22, 2010, 4:05 PM

Zowie!  What power settings did you use for that, Bill?
You had to have matching EGTs... how did you do that?

Terrence
L235/320 N211AL


On Nov 21, 2010, at 9:17 PM, Bill Hannahan wrote:

Please excuse a little bragging.

 

Steve Alderman and I flew my Lancair 360 to the Copperstate fly-in SW of Phoenix and competed in the Fuelventure efficiency competition.

 

The planes are weighed with fuel onboard. Payload [pilot passenger and baggage, up to 200 lb per seat] is weighed separately.

 

The planes fly around a 383 mile course. Timing is from liftoff to overflight of midfield on return from the course. The planes and payload are weighed on return to determine the mass of fuel burned.

 

The score is calculated using the latest CAFÉ formula;

 

Café score equals payload raised to the 0.7 power, times, miles per gallon, times, average speed in mph raised to the 1.7 power.

 

This formula puts a strong emphasis on speed, reflecting reality in the evaluation of cross country aircraft.

 

Steve is an experienced CAFÉ racer having obtained a remarkably high level of performance from his KR2 under an earlier CAFE formula. He even outperformed Lance Neibauer flying the first Lancair 235.

 

http://cafefoundation.org/v2/pdf_cafe_cafe400/86CAFE400.pdf

 

Steve let me know when I was a degree or two off course and kept track of our ground speed and true airspeed.

 

Our average speed around the course was 188.9 mph at 36.58 MPG, [5.16 GPH]

 

Our CAFÉ score was 1,223,333.2   second to Klaus Savier’s highly developed VariEze.

 

http://www.fuelventure.org/documents/2010_results.html

 

To my knowledge it is the highest CAFÉ score by a Lancair using the latest formula.

 

The engine is a stock Lycoming 360 A1A, with 8.5:1 compression ratio, two magnetos and a carburetor, swinging a Hartzell prop. Empty weight is 1,015 pounds.

 

Steve is building a Lancair 360 of his own, and plans to kick my a## next year.

 

It is good fun, a test of planning and flying skills, and a great way to meet a group of friendly, interesting, like minded people. I recommend that everybody give it a try.


Regards,
Bill Hannahan




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