Contentious ROP

[stevecampbell]

Quote: jetdriven

I may be going about it backwards but you can install new GAMI's and do the test afterward and they will tweak to the test results. New GAMI's can't be worse than 25 year old, probably dirty, stock injectors I am thinking.

[aviatoreb]

Quote: danb35

Max economy, in this context, has nothing to do with the airframe; it's the conditions under which the engine produces the greatest amount of power for a given fuel burn (or, put differently, burns the least amount of fuel for a given power output).  You're looking at BSFC, brake specific fuel consumption, typically measured in lb/hr/HP, and lower numbers are better.  On Lycoming's and TCM's charts, minimum BSFC of around 0.40 is found ~ 20-50 LOP.

[Shadrach]

Well I've been away for a while. Good to see that not much has changed around here!  Carry on...

[M016576]

Quote: danb35

This is widely believed, but not completely accurate.  In point of fact, there is a range of mixture settings in which the fuel will all burn, from roughly 14.7 lb air per lb of fuel to 12:1 or so.  You can get combustion over a wider range than that, but there will be excess air when leaner than 14.7:1, and unburned fuel when richer than ~12:1.  Peak EGT is at 14.7:1.  Max power, however, is closer to 12:1, and at about 80-100 ROP.

Max economy, in this context, has nothing to do with the airframe; it's the conditions under which the engine produces the greatest amount of power for a given fuel burn (or, put differently, burns the least amount of fuel for a given power output).  You're looking at BSFC, brake specific fuel consumption, typically measured in lb/hr/HP, and lower numbers are better.  On Lycoming's and TCM's charts, minimum BSFC of around 0.40 is found ~ 20-50 LOP.

Now, if you're looking for economy as measured in terms of miles per gallon, that is airframe-dependent, but that's beyond the scope of this discussion.

[jetdriven]

Quote: stevecampbell

I'll show ya, Russ. I am down at KLVJ, Pearland. That said, our 201 wouldnt run LOP and had a horrible GAMI spread.  I put in some fine wire plugs and soaked the injectors in acetone, and later, MEK.  (Just use Hoppes #9 gun cleaner, its the best) Putting the cleaned injectors and fresh fine wire plugs triggered a religious experience. Zero GAMI spread.  Ignore MP. Ignore RPM. Just pull the red knob of death to "speed desired".  Monitor CHT.  done.

[danb35]

Quote: aviatoreb

Thanks Dan - where can I find those Lycoming and TCM charts?

[jetdriven]

Quote: N4352H

I am going to patent a mixture knob......to throttle, aileron, rudder, stabilizer, EDM 830 innerconnect. Just turn the red knob and watch the plane fly.

In four-banger Lyc's, there's nothing wrong with 50 ROP. A long service history proves this.

[Hank]

Quote: jetdriven

I'm going to invent a new power control for "old school" pilots. I am going to remove the throttle, prop, and mixture controls.   In their place I am going to have 5 buttons:

Start / Idle

Landing

23 square

24 square

25 square

Since these are the only approved power settings in the Lycoming manuals and the Mooney POH.   That should be simpler than all that fiddling with the 3 levers.   

[DaV8or]

Quote: jetdriven

I'm going to invent a new power control for "old school" pilots. I am going to remove the throttle, prop, and mixture controls.   In their place I am going to have 5 buttons:

Start / Idle

Landing

23 square

24 square

25 square

Since these are the only approved power settings in the Lycoming manuals and the Mooney POH.   That should be simpler than all that fiddling with the 3 levers.   

[PTK]

Byron, I'd like to ask you a question re target EGT climb. It's going to be a while before we get a standard atmosphere it seems! Until we do, is it ok you think to utilize ~1300 as target EGT? I'm at roughly sl (55 msl). I tried climbing this way the other day and I'm real excited about the efficiency! This along with LOP makes my Mooney an amazingly efficient  machine. I did the trip the other day at 17 nmpg and 150 plus TAS! I love it! Thanks Byron.

 

[jetdriven]

It all depends on where your probes are mounted. Ours are 2 1/2" from the flange. .  Ours peaks around 1510 EGT at 4,000' cruise and the target EGT is 1285.   If you have a B6 engine with 20 degrees of timing, your target will be 75 degrees higher.  Above 5000' you can lean to target +50-75.  Just shoot for a trailed cowl flaps CHT of 330.

[PTK]

OK thanks. I'll check these details and fine tune it but I think for now I'll aim for a ballpark 1350 target climb EGT. Until a standard day comes around anyway.

I'm also going to swap out the Champions to Tempest at annual in a couple months.  I just can't decide between massives or fine wires. Besides cost are there differences you think in NA application? I have a gami spread of .2-.4 with the Champions. I may just have a service done to the injectors and reevaluate.