Running lean of peak and fuel economy

[Jay Maynard]

(This has nothing directly to do with Bonanzas anymore, so it gets a new
thread...)

On 2008-03-20, Dan > wrote:
> The JPI is the greatest thing since -- GPS!
> Running LOP with GAMinjectors, I can get a lightly-loaded A36 to fly
> 130 KIAS on 10 gph.

I decided I'd rather know than guess, so I added a fuel flow sensor to the
Zodiac's Dynon D10 EMS. It's already got CHT and EGT sensors and nice pretty
bar graphs for each cylinder, so between the three, I should have all the
information I need to run the O-200 at its most economical.

The aircraft I trained in a long time ago didn't have such fancy
instrumentation. One leaned the engine in cruise by the tried-and-true
method of leaning till it ran a little rough, then back rich until it ran
smooth again. This worked, but wasn't exactly precise.

I'm sure this is a subject of some controversy. Where would I find guidance
on the best approach to managing this wealth of information? I know that I'm
not going to make a difference comparable to getting a Bonanza to run at 13
vs. 16 GPH, but going from 6 to 5 would be worthwhile.
--
Jay Maynard, K5ZC http://www.conmicro.com
http://jmaynard.livejournal.com http://www.tronguy.net
Fairmont, MN (FRM) (Yes, that's me!)
AMD Zodiac CH601XLi N55ZC (ordered 17 March, delivery 2 June)

[Dan[_10_]]

On Mar 20, 6:55 pm, Jay Maynard >
wrote:
> (This has nothing directly to do with Bonanzas anymore, so it gets a new
> thread...)
>
> On 2008-03-20, Dan > wrote:
>
> > The JPI is the greatest thing since -- GPS!
> > Running LOP with GAMinjectors, I can get a lightly-loaded A36 to fly
> > 130 KIAS on 10 gph.
>
> I decided I'd rather know than guess, so I added a fuel flow sensor to the
> Zodiac's Dynon D10 EMS. It's already got CHT and EGT sensors and nice pretty
> bar graphs for each cylinder, so between the three, I should have all the
> information I need to run the O-200 at its most economical.
>
> The aircraft I trained in a long time ago didn't have such fancy
> instrumentation. One leaned the engine in cruise by the tried-and-true
> method of leaning till it ran a little rough, then back rich until it ran
> smooth again. This worked, but wasn't exactly precise.
>
> I'm sure this is a subject of some controversy. Where would I find guidance
> on the best approach to managing this wealth of information? I know that I'm
> not going to make a difference comparable to getting a Bonanza to run at 13
> vs. 16 GPH, but going from 6 to 5 would be worthwhile.
> --
> Jay Maynard, K5ZC http://www.conmicro.comhttp://jmaynard.livejournal.com http://www.tronguy.net
> Fairmont, MN (FRM) (Yes, that's me!)
> AMD Zodiac CH601XLi N55ZC (ordered 17 March, delivery 2 June)

The JPI manual -- while presented in a convoluted, rambling way -- is
very helpful.

JPI mentions GAMInjectors as required for the Lean of Peak method.

The argument is that lean of peak the temperatures are cooler than
peak and burns less fuel. Thus you prevent heat damage (which you
might see at peak or even slightly ROP) and save $ on 100LL.

Not a bad deal....


Dan Mc

[Matt W. Barrow]

"Dan" > wrote in message
...
> On Mar 20, 6:55 pm, Jay Maynard >
>> I'm sure this is a subject of some controversy. Where would I find
>> guidance
>> on the best approach to managing this wealth of information? I know that
>> I'm
>> not going to make a difference comparable to getting a Bonanza to run at
>> 13
>> vs. 16 GPH, but going from 6 to 5 would be worthwhile.

>
> The JPI manual -- while presented in a convoluted, rambling way -- is
> very helpful.
>
> JPI mentions GAMInjectors as required for the Lean of Peak method.
>
> The argument is that lean of peak the temperatures are cooler than
> peak and burns less fuel. Thus you prevent heat damage (which you
> might see at peak or even slightly ROP) and save $ on 100LL.

As well, intern chamber pressure is lower/better point peaks.

Here's a couple sources:

http://www.buy-ei.com/UBG-16_LOP.htm

http://www.buy-ei.com/Manuals/EI%20Ultimate%20Bar%20Graph%20(UBG-16)%20OI.pdf
(Explained rather well in the Op Manual)

http://www.avweb.com/news/pelican/182544-1.html (Engine series)

http://www.avweb.com/news/pelican/182084-1.html (Mixture)

[Frank Stutzman[_2_]]

Dan > wrote:
> On Mar 20, 6:55 pm, Jay Maynard >
> wrote:

>>
>> On 2008-03-20, Dan > wrote:
>> The aircraft I trained in a long time ago didn't have such fancy
>> instrumentation. One leaned the engine in cruise by the tried-and-true
>> method of leaning till it ran a little rough, then back rich until it ran
>> smooth again. This worked, but wasn't exactly precise.

Actualy, Jay, that method is stil pretty good. The engine monitor helps
you be more accurate, but thats about all. My favorite graybeard pilot
just slowly yanks the mixture until he sees about a 5 knot drop in
airspeed. I think he was doing that before there were even CHT or EGT
gauges.

> The JPI manual -- while presented in a convoluted, rambling way -- is
> very helpful.

I beg to differ. Its downright wrong in several ways according to
some folks (sorry, I can't be more specfic, I don't remember the details).
The links in Matts post (especially the pelican perch ones) will be
much more useful reading.

> JPI mentions GAMInjectors as required for the Lean of Peak method.

Which is just one way the JPI manual is flat wrong. The big radial engines
in airline use were run LOP as SOP. That was way before fuel injection.
I can run my carbed E-225 LOP (although only about 20 degrees before it
gets too rough) as can lots of other carbed engines. It may take some
induction tuning or playing with carb heat to make it happen though.

> The argument is that lean of peak the temperatures are cooler than
> peak and burns less fuel. Thus you prevent heat damage (which you
> might see at peak or even slightly ROP) and save $ on 100LL.

--
Frank Stutzman
Bonanza N494B "Hula Girl"
Boise, ID

[Matt W. Barrow]

"Frank Stutzman" > wrote in message
...
> Dan > wrote:

>
>> JPI mentions GAMInjectors as required for the Lean of Peak method.
>
> Which is just one way the JPI manual is flat wrong. The big radial
> engines
> in airline use were run LOP as SOP. That was way before fuel injection.
> I can run my carbed E-225 LOP (although only about 20 degrees before it
> gets too rough) as can lots of other carbed engines. It may take some
> induction tuning or playing with carb heat to make it happen though.

True!, and Deakin emphasizes that point, but the context is that the radial
engines, due to their design, had more even fuel flow/distribution, even
with carburetors.

Currently, the Jacobs 755 radial has a single updraft carburetor and thus
has fuel distribution on par with a HO layout. They recently got approval to
replace the single carburetor with a FI unit and they report it's "turbine
smooth".

Now, Newps says he runs significantly LOP without GAMI's, but his is, I
believe, an anomaly. OTOH, my old TNIO-550 ran smooth right up to fuel
cutoff with GAMI's, and like a La-z-boy vibrator without them! :~)