Reducing to 25/2500

[Andy95W]

For cross-country flights, I do what Hank and Dev do with similar results.

What does everyone do for a just fartin' around flight, say at 1500-2000 AGL for 30-40 minutes or so?  It seems kind of excessive to climb WOT and 2700 rpm if I'm not actually going any where.

[mike_elliott]

41 minutes ago, carusoam said:

For anyone that hasn't read the Bob Kromer articles specific to their model...

Bob is an engineer who worked at Mooney in a modern post Bill Wheat kind of way.  He covered real world flying techniques for the C around Y2K.  It is worth pulling them out to read them if you haven't seen them yet...

Best regards,

-a-

Bob Kromer will once again be presenting at the Mooney Summit IV this October. Last year, everyone so enjoyed his presentations, we just had to make sure he would come back . Thanks Bob, for all you have done through out the years for the Mooney Community.

 

[ArtVandelay]

 

 

10 minutes ago, N1395W said:

For cross-country flights, I do what Hank and Dev do with similar results.

What does everyone do for a just fartin' around flight, say at 1500-2000 AGL for 30-40 minutes or so?  It seems kind of excessive to climb WOT and 2700 rpm if I'm not actually going any where.

 

 

 

I always cruise at 2400, it feels to me the sweet spot, and always 50 LOP, I'm not that much in a hurry...150 TAS works for me.

[carusoam]

Hmmmmm,  Kromer opinions on 310hp IO550 OPs in a long body would be really interesting.... 

Best regards,

-a-

[steingar]

1 hour ago, N1395W said:

For cross-country flights, I do what Hank and Dev do with similar results.

What does everyone do for a just fartin' around flight, say at 1500-2000 AGL for 30-40 minutes or so?  It seems kind of excessive to climb WOT and 2700 rpm if I'm not actually going any where.

Reduce to 25 squared on positive rate, reduce to 23 over 21 for short range cruise.  Mostly what I've been doing over the winter.  Hard to do Wintertime VFR trips in the North.

[Shadrach]

4 hours ago, N1395W said:

For cross-country flights, I do what Hank and Dev do with similar results.

What does everyone do for a just fartin' around flight, say at 1500-2000 AGL for 30-40 minutes or so?  It seems kind of excessive to climb WOT and 2700 rpm if I'm not actually going any where.

For an injected engine, Climb WOTFR and lean for target EGT.  Low altitude Cruise WOTLOP unless I want to go slow for some reason.

For Carb'd engines, Climb WOTFR and lean for target EGT. Low Altitude Cruise 24" by 2400RPM lean until rough and enrichen to smooth.

No matter the power plant, there is no upside to climbing partial power (I'm starting to sound like a skipping record).

[Hank]

6 hours ago, N1395W said:

For cross-country flights, I do what Hank and Dev do with similar results.

What does everyone do for a just fartin' around flight, say at 1500-2000 AGL for 30-40 minutes or so?  It seems kind of excessive to climb WOT and 2700 rpm if I'm not actually going any where.

I always climb WOT/2700. It just takes a very short time to reach 3000 msl cruising a county or two for breakfast or lunch. In keeping with MAPA's principal number theory, RPM + MP <= 47 for my C, so I just relax and fly 23"/2300 and generally indicate around 145 mph. Just did this Friday afternoon with the neighbors, a quick climb from 326 to 2500 msl to give then a different view of the Lake. Dropped down to 1500 once looking for landmarks, then all levers forward to climb back up that thousand feet.

When I fly people on 20-minute fundraising tours, I throttle back to match the Cessnas I fly with, 2300 and whatever MP is required to putter along with them, 16", 17", whatever. We discuss speed beforehand, and I keep it down around the target. But still, a takeoff is a takeoff, all levers full forward! Whheeeeee!!!

Shadrach's suggestion of 24"/2400 may work for his F, but not for our birds. Although I think bonal flies his D/C there a lot. Like I said before, it's your engine . . .

[Shadrach]

Just now, Hank said:

I always climb WOT/2700. It just takes a very short time to reach 3000 msl cruising a county or two for breakfast or lunch. In keeping with MAPA's principal number theory, RPM + MP <= 47 for my C, so I just relax and fly 23"/2300 and generally indicate around 145 mph. Just did this Friday afternoon with the neighbors, a quick climb from 326 to 2500 msl to give then a different view of the Lake. Dropped down to 1500 once looking for landmarks, then all levers forward to climb back up that thousand feet.

When I fly people on 20-minute fundraising tours, I throttle back to match the Cessnas I fly with, 2300 and whatever MP is required to putter along with them, 16", 17", whatever. We discuss speed beforehand, and I keep it down around the target. But still, a takeoff is a takeoff, all levers full forward! Whheeeeee!!!

Shadrach's suggestion of 24"/2400 may work for his F, but not for our birds. Although I think bonal flies his D/C there a lot. Like I said before, it's your engine . . .

I never pull the throttle on my F unless I want to go down or slow down. I have flown lots of O360s at 24x2400 but admittedly don't have a lot of experience in C models and certainly not recently. What's different about the application in a C that makes it challenging?

[Hank]

5 minutes ago, Shadrach said:

I never pull the throttle on my F unless I want to go down or slow down. I have flown lots of O360s at 24x2400 but admittedly don't have a lot of experience in C models and certainly not recently. What's different about the application in a C that makes it challenging?

It's not challenging, it's just not what is recommended. 47 is a nice, comfortable 65%, I think 50 is 75%, so no harm. I'm not sure where / when / how the numbers were developed, but MAPA has stood behind them for a long time. Gentle to our engines is good, right?

Edited May 3, 2016 by Hank

[DXB]

7 hours ago, N1395W said:

For cross-country flights, I do what Hank and Dev do with similar results.

What does everyone do for a just fartin' around flight, say at 1500-2000 AGL for 30-40 minutes or so?  It seems kind of excessive to climb WOT and 2700 rpm if I'm not actually going any where.

For fartin around down low- e.g. sightseeing with passengers I find 20/20 with mixture pulled back to 7gph fuel flow seems to works great.  I have an advantage without any rpm restriction on the top prop, but I think I could go 19/19 and it would be just fine with a tad of nose up trim. It gives an IAS of around 120mph- amazing to me - same IAS as the Warrior I trained in running at 75pct cruise power, burning almost 10 gph.

[N33GG]

For a check ride, I recommend doing exactly what is advised in the POH, and don't try to demonstrate that you know better.

just my 2 cents.

[mooniac15u]

Getting your complex endorsement isn't a checkride, it's a learning opportunity. You've read the POH and you know what it says. You are also aware that others use a different technique. Why not just ask your CFI about this?  Asking the question shows you have a deeper understanding of engine management than just memorizing what's in the POH. 

[bonal]

Since I was referred to I suppose I will add a couple cents I climb at WOT 2700 MP varies depending on DA In cruise I pull power just enough to make the MP needle move and settle out at 2500 and am seldom below 6500 so MP is usually maxed around 22 using Hanks 47 seems a good place to set to. Tested the 25/25 method and found no real benefit it feels like driving a car up a hill in too high of a gear.

[MyNameIsNobody]

13 hours ago, Shadrach said:

For an injected engine, Climb WOTFR and lean for target EGT.  Low altitude Cruise WOTLOP unless I want to go slow for some reason.

For Carb'd engines, Climb WOTFR and lean for target EGT. Low Altitude Cruise 24" by 2400RPM lean until rough and enrichen to smooth.

No matter the power plant, there is no upside to climbing partial power (I'm starting to sound like a skipping record).

Yes, you are (broken record), but since you are playing "my song" feel free to groove the hell out of it.  When I fly I don't putter.  I bought the Mooney to fly cross country fast and efficient.  Whether climbing to 2000 of 10000 WOT gets you there more quickly with no penalty other than fuel flow.

It is safer (altitude is life), cooler (on the engine and the passengers as cooler air is higher) and faster.  This s a no-brainier, but "Max" for many (It's your engine etc comments) is just a hard concept for some to grasp.  This concept is a lot like LOP.  Some get it and some think bad dark thoughts.

WOT in climb is NOT "hard on the engine."  IT is BETTER for cooling.  Now leaning in climb...THAT has the potential to cause problems if not done properly.  

Enough Noobs and non-believers to make this resurface like a Crakken from the depths...

and to Mr. "Check ride"...I rode a tank and a generals rank when the Blitzkrieg reigned and the bodies stank.

[jlunseth]

At or under 65% HP, the APS folks tell us we can run our engines anwhere we want, LOP, ROP, or right at peak, without harming the engine.  We also know that controlling power output on the lean side is entirely a function of fuel flow, not of MP.  In other words, once you get over on the lean side and provided your engine will run LOP, you can lean it out to slow it down for a joyride. Frankly, its alot nicer for me to fly around at 8-something GPH, than at 11 or 12 GPH for the same power output.  I don't do quite what Shad does (WOTLOPSOP) because my aircraft is a turbo.  We have a component of the mental math about what is going on with the engine that a Normally Aspirated engine doesn't, and that is, how hard do we want to run the turbo.  So for farting around flights I dial both MP and fuel flow way back, but in an NA aircraft, doing it just with fuel flow would work well, be nice to the engine, and save quite alot on fuel, provided your engine will run smoothly on that side.

[jetdriven]

Power is not completely controlled by fuel flow on the lean side of peak EGT. In the range of 10 to ~50F LOP, yes. Beyond that, power drops off faster than fuel flow.  LEvel off at WOT at 1000' then pull the mixture, the "BMP" to 10.0 GPH. let it staabilize and note the speed.  The EGT will, depending on OAT and barometric pressure, be abiout 100-150 LOP. Now, richen the micture to where the EGT is closer to your normal cruise range. ( Our plane, peaks at 1510, and cruise is set to ~1480.  yours will vary)

the FF will be around 12 GPH. now pull the throttle back to 10.0 GPH once more.  Now, go back and fine tune the mixture to cruise EGT, and the reset the throttle if needed to 10.0 GPH.     let it stabilize.

Now look at the speed.  On a cold day it can be 10-15 knots faster.  The engine is more efficient at EGT's richer than 50 LOP.  Its the same fuel flow, but the speed is free.

 

Regarding "sightseeing" power settings, I usually use 15-17" of MP and 2300 RPM, and just slightly rich of peak EGT.  With some serious deliberation you can get the fuel flow down to 4.0 GPH. Yes, 4.  But you are perilously close to min drag speed (~100 MPH) here, and any turns or downdrafts can push the plane to the other side of the drag curve which will require a major adjusting of power to recover it. Which wastes fuel.  slightly ROP and the 2300 RPM seem to hold on the the speed better than,say 2100 RPM.   110 MPH is a good target airspeed.

Edited May 4, 2016 by jetdriven

[markejackson02]

12 minutes ago, jetdriven said:

Power is not completely controlled by fuel flow on the lean side of peak EGT. In the range of 10 to ~50F LOP, yes. Beyond that, power drops off faster than fuel flow.  LEvel off at WOT at 1000' then pull the mixture, the "BMP" to 10.0 GPH. let it staabilize and note the speed.  The EGT will, depending on OAT and barometric pressure, be abiout 100-150 LOP. Now, richen the micture to where the EGT is closer to your normal cruise range. ( Our plane, peaks at 1510, and cruise is set to ~1480.  yours will vary)

the FF will be around 12 GPH. now pull the throttle back to 10.0 GPH once more.  Now, go back and fine tune the mixture to cruise EGT, and the reset the throttle if needed to 10.0 GPH.     let it stabilize.

Now look at the speed.  On a cold day it can be 10-15 knots faster.  The engine is more efficient at EGT's richer than 50 LOP.  Its the same fuel flow, but the speed is free.

 

Regarding "sightseeing" power settings, I usually use 15-17" of MP and 2300 RPM, and just slightly rich of peak EGT.  With some serious deliberation you can get the fuel flow down to 4.0 GPH. Yes, 4.  But you are perilously close to min drag speed (~100 MPH) here, and any turns or downdrafts can push the plane to the other side of the drag curve which will require a major adjusting of power to recover it. Which wastes fuel.  slightly ROP and the 2300 RPM seem to hold on the the speed better than,say 2100 RPM.   110 MPH is a good target airspeed.

Flying around WOT at 1000' around Houston will allow you to collect a lot of antenna tower guy wires..... :-)

 

[Immelman]

I don't reduce after takeoff in a normally aspirated Mooney.

 

Edited May 4, 2016 by Immelman

[jetdriven]

33 minutes ago, Hyett6420 said:

I was always taught 5 at 5, which basically means reduce to 2500 and 25 at 500 feet.  I have ALWAYS assumed it was due to the engine, ie if you look after the engine it will look after you, but it may have been noise.  At the end of the day, 25/25 gives me great climb performance for the weights I carry, two up full fuel and a few bags so I will carry on using it, once I get to 1500 I then cruise climb at 24/2600 and approx 100-115 knots.

Mines a J so not sure whether yours has the same engine, that's technical stuff and I might get my hands oily if I touch it!

Has anyone asked Don Maxwell what he recomends and why?

Andrew

there is no time limit at 2700 RPM and 200 HP in a Mooney. Reducing power has been shown, in a scientific manner, to not only reduce climb rate, but lower climb angle, increase time to climb, run hotter, and use more fuel per trip.  You dont pull back the throttle in a 172R on climb out to "save the engine", and it is already running nearly 6 inches "over square"....

The only benefit seems to be in the pilot's mind that he is somehow easier on the engine, and that he is reducing his noise footprint.  I dont see how flying at a lower angle during climbout lowers noise.   If you're noise conscious, climb at VX to 1000', then carry on.  Besides, these arent noisy airplanes to begin with.

Edited May 4, 2016 by jetdriven

[Shadrach]

6 minutes ago, jetdriven said:

there is no time limit at 2700 RPM and 200 HP in a Mooney. Reducing power has been shown, in a scientific manner, to not only reduce climb rate, but lower climb angle, increase time to climb, run hotter, and use more fuel per trip.  You dont pull back the throttle in a 172R on climb out to "save the engine", and it is already running nearly 6 inches "over square"....

The only benefit seems to be in the pilot's mind that he is somehow easier on the engine, and that he is reducing his noise footprint.  I dont see how flying at a lower angle during climbout lowers noise.   If you're noise conscious, climb at VX to 1000', then carry on.  Besides, these arent noisy airplanes to begin with.

^^^^^^^This 

How is restricting airflow to an engine in climb helping to save it?  It's like taping a runner's mouth shut and making them run hills breathing through their nose only.  

At a given MP, reducing RPM increases internal cylinder pressure and there for increases CHT. Climbing at lower power means:

More time spent climbing

More time spent at a relatively high power setting

More time spent with a lower volume of air through the cowling

The notion that partial power climbs save anything is an OWT that the OT's at my drome have been following since they learned to fly in the 40's, 50's, 60's, etc... 

The fuel burn will be about a wash, but at least your engine will run hotter and it will take longer to get to altitude.

[carusoam]

Follow on question....

OWT or not....?

(Power failures occur often at the first change of power on the climb out)

I have heard this.  It may make sense.  It may have come from a knowledgable Mooney guy.

If it is true,

1) I wouldn't want to climb out at Vx to 500' agl and then start making power adjustments.  Too low and slow for whatever happens next.

2) I would prefer to climb out Vy to 1000' agl before making adjustments.

3) I'd rather climb WOT/ Max RPM with an eye on EGT/CHTs.

note: my O360 stuck valve experience came before reaching 1,000' on departure.  Partial power was enough to complete the traffic pattern to return to the next closest runway.

Bring on the logic!  

Thanks for the insight,

-a-

 

[Hank]

I climb WOT/2700 at Vx until comfortably over the trees, then "change" to Vy using only yoke and trim..

 

Edited May 4, 2016 by Hank

[carusoam]

Processing that idea, Hank...

That may be a change of load/stress on the engine too, as the govenor adjusts prop pitch to maintain rpm...

Lots of variables...,

-a-

[Andy95W]

1 hour ago, Shadrach said:

 

How is restricting airflow to an engine in climb helping to save it?  It's like taping a runner's mouth shut and making them run hills breathing through their nose only.  

At a given MP, reducing RPM increases internal cylinder pressure and there for increases CHT. Climbing at lower power means:

More time spent climbing

More time spent at a relatively high power setting

More time spent with a lower volume of air through the cowling

The notion that partial power climbs save anything is an OWT that the OT's at my drome have been following since they learned to fly in the 40's, 50's, 60's, etc... 

The fuel burn will be about a wash, but at least your engine will run hotter and it will take longer to get to altitude.

Not trying to be argumentative, Ross, but I think the rationale is more about internal cylinder pressure in "saving" the engine, not about restricting air flow.

Less horsepower produced = less internal pressure = ?

For me, if I'm actually going somewhere, I fly exactly the same as Hank (and others). WOT, max rpm, mixture at target EGT, rpm backed off a little as I climb for slightly less noise.

For just sightseeing or fun, WOT/2700 to about 1000', throttle back to something quieter after that and gently coast up to about 1500 AGL, then about 18" and 2300-2400 rpm (wherever the engine feels smooth and happy) leaned out as far as I can and still keep the engine smooth, and always keeping CHTs below 380.

[ArtVandelay]

You don't have to do both, i reduce RPM, but throttle remains WO on climbs.