REFLECTOR: Fuel Consumption Performance

[Al Gietzen]

Terry;

 

Good numbers.  They are a bit lower than you previously reported, and right
in line with what I get with my rotary.

 

There was some discussion awhile back on another list about slowing down and
reducing the cost of flying.  I'm thinking- wait a minute; one of the
reasons I have an airplane is to go fast.  I can make a 500 nm leg on about
28.0 gals of fuel at 170 KTAS.  If I slow down to 150 I can save about 1
gal, and take over 20 minutes longer.  The cost of that gas (especially
mogas at $3.00) is completely negligible compared to the overall cost of
having an airplane.  I think I'll start flying at 190 :-).

 

Al

 

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Terry Miles
Sent: Thursday, August 27, 2009 10:00 AM
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Fuel Consumption Performance

 

Al,

Here is my cruz engine log to include this last IN to CO trip.  Westbound
was full power.  10,000 will get me mid 180 Kts TAS and 12,000 gets mid 190
kts TAS.  That runs about 11.5 at full throttle and leaning 50 LOP.  Thanks
to Scott I did it right and pulled the mixture out until they were all LOP
and enriched back on the first to peak so to get 50 LOP.  It was hardly any
real effective difference, but better to do it right.  (And I never got to
KLMO when I was asking about high dens alt ops.)   

 

As the log shows, on the way back at 11,000 I pulled back to try and hold
mid 170's for speed, and I pulled the prop rpm back some too, but it doesn't
sound good below 2100 for some reason.  Anyway I was able to get 9.5 for a
fuel flow.  Next good tailwind and  I'll try mid 150's for a speed.  

 

Also for what it worth for you other fellow newbies and flatlanders out
there, I had it in my head and in my muscle memory that cooler temps mean
more leaning since those are the mixture adjustments I have been making
hundreds of times now.  When I got out on the runway for takeoff run.I put
the throttle in full, then I leaned the mixture leaning for peak.when I got
to peak I instinctively leaned for the 100 cooler instead of enriching to
get the 100 cooler.  Of course I immediately saw this and  fixed it, but I
was surprized at myself.all while the engine is at full blast and my head is
on the departure matters and checklists.  Thought I'd toss that in.  What
not to do is often as good as knowing what TO do.

 

Terry

 

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Al Gietzen
Sent: Wednesday, August 05, 2009 11:34
To: 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Fuel Consumption Performance

 

Al,

Hey thanks for that.  Can I do anything to help fill in the matrix any
better?  I could get you some 165 TAS numbers on my next long trip.  It
seems like runs at similar altitudes and TAS would make for the easiest
comparisons.  But,  I could fly at whatever altitude or fuel flow, etc you
wanted to know about.  

Terry;

 

I think I've gone as far as going with that - I was just
tabulating/correlating the reported data for easier viewing.  I'd be more
interested in comparison data for alternative engines, although that then
needs to be compared with the certified engines.

 

I think each person should gather some data on their own plane, for their
own purposes; starting with verifying the accuracy of the airspeed and fuel
flow readings.  Then it might be fun to compare some data for the same
models at the same TAS at the same elevation.

 

So if all you folks flying would, whenever convenient, like to post some
data for your M&M and engine type at, say:

Leaned cruise

150 KTAS

9500 ft;

it would be interesting.

 

Best,

Al

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20090827/4767297a/attachment.htm>