ATC: Mooney is already 20 knots faster than you

[201er]

I was flying the Hudson Skyline route in NYC this evening on a bravo clearance. I think it was an arrow that joined in close behind me and reported me in sight. The arrow offered to slow down to improve separation but the controller replied, "no need, the Mooney is already doing 20knots faster than you."

[jetdriven]

on the exact same engine no less.

[scottfromiowa]

Heh, heh.  N.I.C.E.

[jetdriven]

Thats where you tell him you have it pulled back to 23 square.

[201er]

Quote: jetdriven

on the exact same engine no less.

[Parker_Woodruff]

I would have added throttle. Just doing that will bring you farther LOP. Confirm you're sufficiently LOP by fuel flow

[jetdriven]

Try opening the MP up to 27-28" to give it enough air to be LOP or to have enough excess air to cool. (2" more MP than a ROP book power setting)  Then set FF to 10.0 GPH. I jusrt did this 2 days ago. I tried something new.  Situation was 1200', 58 degrees F OAT,  27" MP, LOP, 9.7 GPH, 2500 RPM.  CHT creeping up to 375.  I opened the throttle up to 29", of course FF went up some too. I leaned it back to the same 9.7 GPH.  everything is the same but now more MP.  The CHT came down 10 degrees.

[201er]

I'm having a hard time breaking with "oversquare." It was a cool night and I was quite low. Seeing the throttle in all the way and prop at 2400RPM would give me a quiver. Power chart recommends 26.2"/2400RPM for 75% so I used that as my intial configuration. Obviously when higher up I just stay full throttle.

Can you elaborate your workflow starting with full climb power level off at 2,000ft and 5C OAT? In what order are you moving things and what are you basing your settings on? I've just been following the classic work flow of throttle, prop, mixture. But when you have surplus CHT buffer to play with when cowl flaps are already closed, makes you wonder how to make it work for you?

[Shadrach]

Quote: 201er

I'm having a hard time breaking with "oversquare." It was a cool night and I was quite low. Seeing the throttle in all the way and prop at 2400RPM would give me a quiver. Power chart recommends 26.2"/2400RPM for 75% so I used that as my intial configuration. Obviously when higher up I just stay full throttle.

Can you elaborate your workflow starting with full climb power level off at 2,000ft and 5C OAT? In what order are you moving things and what are you basing your settings on? I've just been following the classic work flow of throttle, prop, mixture. But when you have surplus CHT buffer to play with when cowl flaps are already closed, makes you wonder how to make it work for you?

[jetdriven]

thats how you do it.  Sometimes I limit MP to 28" if the engine is nearing 90-100 LOP and it begins to run rough. Richening it gives more HP, which is what you dont need while slowing down near the pattern to land.  It feels like cheating though.

[Jerry 5TJ]

ATC lore says Mooneys generally leave two primary radar returns on their display.  One, for the aircraft.  The other, for the pilot, about 5 miles in trail.  At least the airplane is fast.

[jetdriven]

Climb: full throttle, prop 2700 RPM, mixture at target (currently 1250) cowl flaps in trail.

Level off at 2000', cowl flaps closed first or 200' early, let the speed build to 145-150 KIAS.  Throttle stays full,  prop to 2500, big mixture pull to 9.5 GPH (fast), then bump it up to 9.7 or 10.0 GPH. Whatever you want from 7.5-10.0.   Let it stabilize. Monitor CHT. 

If you want to loiter, set MP to 23" , prop to 2200 and you can lean into the 5.0 to 5.5 GPH range.

If you are still running 330 CHT with a 10.0 FF, thats 75% power, and I havent done much exploring in that area yet.  I do treat >75% power with a little more respect and try to limit CHT to 330-340 or so.

Quote: 201er

Can you elaborate your workflow starting with full climb power level off at 2,000ft and 5C OAT? In what order are you moving things and what are you basing your settings on? I've just been following the classic work flow of throttle, prop, mixture. But when you have surplus CHT buffer to play with when cowl flaps are already closed, makes you wonder how to make it work for you?

[201er]

Thanks. Very inciteful and what I'm looking for. So if CHTs are ok, you don't care where you are in respect to peak as long as CHTs are acceptable?

But here's a question. How can you rely so much on fuel flow instrument? I've been working on calibrating my ei fp5l. It's becoming pretty accurate between fill ups but still can be +/-2 gallons out of 100. It's good enough for remaining fuel readouts but not sure that's close enough for setting mixture. One of the things that's throwing it off I think is throwing away fuel. I had water in one tank so I was sumping and dumping until the cap was fixed. Also clearing the gascalator before flights must give away a little. Point is these misc losses of fuel, though small, add up and impact the fuel flow read out. The fuel flow is based on pump to pump usage rather than the fuel flow at that precise moment. Seems like this equates to +/- 0.2gph. Is this close enough to base leaning on? Seems like it can make actual horsepower off by +/-5%.

[jetdriven]

I would keep it at least 10-20 LOP at 75% power. More at a higher setting. I treat 10.0 GPH as a LOP fuel flow limit.  

  A sure sign of detonation is rapidly rising CHT, and a severe detonation event the CHT can climb 3 degrees a second. By the time you notice, its over.   I wouldnt want to tempt fate with my knowledge level in that area yet. I havent been there.

Your FF is accurate to 2%. Thats all ours is accurate to.  A  0.2 GPH variance is 3 HP, I wouldnt worry too much.  You can change the K-factor on some units to really super dial in the FF.

[co2bruce]

My wife and I were recently in Asheville, NC and decided to go to Kitty Hawk for the day. I called in the morning for a weather update. When the briefer asked me how long in route, I told him 2 hours. He immediately said you can't make it in 2 hours. I love my Eagle. (2hours 6 min. actual flight time)

If you haven't been to First Flight Airport it is worth a trip. Very interesting museum, and a real challenging landing.  

[KSMooniac]

Quote: 201er

Thanks. Very inciteful and what I'm looking for. So if CHTs are ok, you don't care where you are in respect to peak as long as CHTs are acceptable?

But here's a question. How can you rely so much on fuel flow instrument? I've been working on calibrating my ei fp5l. It's becoming pretty accurate between fill ups but still can be +/-2 gallons out of 100. It's good enough for remaining fuel readouts but not sure that's close enough for setting mixture. One of the things that's throwing it off I think is throwing away fuel. I had water in one tank so I was sumping and dumping until the cap was fixed. Also clearing the gascalator before flights must give away a little. Point is these misc losses of fuel, though small, add up and impact the fuel flow read out. The fuel flow is based on pump to pump usage rather than the fuel flow at that precise moment. Seems like this equates to +/- 0.2gph. Is this close enough to base leaning on? Seems like it can make actual horsepower off by +/-5%.

[mooneygirl]

Mitch and I were headed to Livermore, CA KLVK a couple months ago. There was a Bonanza inbound as well.  We had to slow for him three times.  The Bonanza was audibly irritated.  Oh well, gotta love that Mooney SPEED

[Shadrach]

Quote: KSMooniac

You should be able to dial in your FF instrument to get nearly exact readings, so keep working towards that.  2 gallons out of 100 is fairly significant IMO, and I doubt you sumped anywhere near that much, even with water in the tank unless you had a ton.

[Becca]

Quote: mooneygirl

Mitch and I were headed to Livermore, CA KLVK a couple months ago. There was a Bonanza inbound as well.  We had to slow for him three times.  The Bonanza was audibly irritated.  Oh well, gotta love that Mooney SPEED

[Ron McBride]

I was over Oklahoma City a couple of weeks ago. Approach told me that I had a Seneca at 10 oclock 3 miles and a parallel track. A few minutes later, reported the Seneca at 8 oclock, still parallel track, no longer a conflict. This felt fantastic as I was in my stock F.

Ron

[201er]

Quote: KSMooniac

CHT is only one part of the concern when setting mixture.  What is equally important, but impossible to measure with our standard instrumentation is the peak pressure inside the cylinders (ICP).  CHT is influenced greatly by OAT, so as it gets cooler outside it is possible to have a high ICP but still have CHT below 380 dF.  At 75% power you should indeed still maintain 10-20 dF LOP, even if your CHTs are cool.  Keeping that LOP setting will ensure that you aren't pounding away inside the cylinders.

[jetdriven]

I had some sort of a mooney pass me in a Cessna 402 once.  I was flying it at "top of the green" power setting burning 33 GPH.   Somewhere around 175-180 knots.  

[jetdriven]

Excellent point both.  Busch doesn't address this much but Deakin does. You can exceed a safe ICP at a low altitude on a cold day yet still have a 330 CHT.   Deakin explained this on one of his pelicans perch articles.  I limit fuel flow to 10.0 gph while LOP to avoid running more than 75% power in cruise.  

Quote: Shadrach

You should be able to dial in your FF instrument to get nearly exact readings, so keep working towards that.  2 gallons out of 100 is fairly significant IMO, and I doubt you sumped anywhere near that much, even with water in the tank unless you had a ton.

[KSMooniac]

Quote: 201er

This is a very good point!

So bare minimum LOP for 75% is 10-20LOP? For 65% and below peak is ok if CHTs are good?