New Owner Questions - ROP/LOP & MP/RPM Settings

[jetdriven]

Lets not be too hard on John Green.  After owning fifty airplanes of all sorts, I believe him when he says his TSIO-540 is really difficult to setup running LOP.  Many Bravo owners simoly cannot get them to do it smoothly.    However, the fuel savings are real if it will, and adding two inches of MP to compensate for the loss of power when going to the lean side is a demonstratable fact. you dont have to get 50 LOP to get it either.  We have mostly been using 15 LOP, and leaner if any cylinder over 380.

Our IO-360 Lycoming would  not run smooth LOP either. Cleaning the injectors and adding the fine wire Tempest plugs just as Norman did, was as different as night and day.  The flight back from the shop, I did WOTLOP at 1200' at one point burning 6.2 GPH and going 100 knots. This on 29 inches of manifold pressure. 150 degrees LOP, running like an electric motor.   The hottest cylinder was 280.  After a couple test flights, I convinced my partners as well. Ignore MP.  Set RPM for noise.  Set FF for power.

I took a friend with an S35 Bonanza out last week, he was running 17.5 GPH, ROP, 150 KIAS at 7500'.  Cowl flaps open and 400-425 CHTs.  After I got done, he was LOP, 12.5 GPH, same 150 KIAS, cowl flaps closed and 300-325 CHT.  From 9.5 NMPG to 14 NMPG.

However, there is something in the TSIO-540 Lycoming that is funny, and some won't go LOP and run smooth.  If it were me, I would investigate the injectors and the plugs before giving up.

[testwest]

Quote: jlunseth

 If you are turbocharged and fly in the flight levels, aren't pressurized mags a necessity? Not for an reason having to do with engine ops or engine timing, but to avoid "high altitude miss?" Air acts as an insulator to prevent tracking along the mag cap.  Too thin air and the tracking starts to happen, resulting in a very disconcerting failure to operate on the part of the engine.

[Parker_Woodruff]

Quote: jetdriven

Cleaning the injectors and adding the fine wire Tempest plugs just as Norman did, was as different as night and day. 

[jlunseth]

FWIW at the APS Seminar I attend a year and a half ago, the APS people were not big fans of fine wire plugs, they had discovered some issues with them. 

[jetdriven]

TAT issued a service bulletin saying that Champion fine wire plugs crack insualtors, leading to preignition and engine failure.  It happnes pretty fast on a TN engine.  They may not be big fans of Tempest fine wires, but no call to remove them.

[aviatoreb]

Quote: jetdriven

TAT issued a service bulletin saying that Champion fine wire plugs crack insualtors, leading to preignition and engine failure.  It happnes pretty fast on a TN engine.  They may not be big fans of Tempest fine wires, but no call to remove them.

[KSMooniac]

Well, I've succumbed to peer pressure and just ordered some Tempest Fine Wires to replace my old Autolite massives that have a few hundred hours on them.  Two of those already failed prematurely, too.  So much for resisting the urge to upgrade anything during this annual!

[KSMooniac]

At the APS class in 2007 that I attended, they didn't think the Champion fine wires were worth the expense either, and recommended old-fashioned massives at the time.  I believe they were the only ones on the market then, and Tempest came along later.  I've read enough anecdotal evidence to convince me to give them a try to squeeze a little more power and/or efficiency out of my engine.  I do remember the SB that went out to TN Cirrus and Bo operators about the Champions.  

[jetdriven]

Quote: aviatoreb

That's scary.

I am running tempest fine wires on the lowers and massive plugs on the uppers.  I wonder if that would stave off such a failire if the fine wires ever cracked?

[KSMooniac]

Quote: aviatoreb

That's scary.

I am running tempest fine wires on the lowers and massive plugs on the uppers.  I wonder if that would stave off such a failire if the fine wires ever cracked?

[jetdriven]

90 seconds from application of takeoff power.  Thats how long this Bonanza engine lasted, until the piston melted and shut down that hole.   A good engine monitor with an alarm woud have probably gone off on 400 CHT at 30 seconds, giving you enough time to jerk the power back to something like 16", which would end the preignition event and save the engine.  Something to think about. Engine monitors are for so much more than LOP.  

http://www.avweb.com/news/pelican/184108-1.html

[aviatoreb]

Quote: KSMooniac

That's scary.

I am running tempest fine wires on the lowers and massive plugs on the uppers.  I wonder if that would stave off such a failire if the fine wires ever cracked?

[johnggreen]

And in closing.  "Big smile".

This has truly been an educational thread.  That being said, I won't be making any further effort to run the Bravo LOP.  I simply have no motivation.  My engine doesn't like it and performs beautifully the way I manage it ROP.

Byron, to be exact, I have owned 32 airplanes and flown a lot more.  Remember, I've been doing this since I was eleven years old.  The point of saying that is that in all those airplanes and all those engines, turboed, superchared, radials, etc. I can without hesitation say that my Bravo's engine is the smoothest, best running engine I have ever owned and that includes, several other O-540's and IO-540's.

Wires?  Plugs? If this engine had Western Auto Wizard lawn mower plugs and #8 romex house wiring for spark plug wires, I wouldn't change it.  IT WORKS.

That being said, I am truly a proponent of LOP where it works.  In fact, I lean the O-200 in my J-3 LOP almost all the time because if I don't it will start screwing up valves within hours because of the high lead content of aviation fuel.  (Low octane is complete bull shit, it ain't so).

Again, though thanks for the input.  In fact, I'm probably going to go back and read all your posts.  Truly good info.

Jgreen

 

[TLSDriver]

Quote: johnggreen

Richard,

I've been really busy lately and not spending much time on Mooneyspace.  I did not read all these posts quickly so I may repeat some things that have been said.  Still, here are a few brief comments.

1.  The Bravo POH is very complete with endurance, speed, and other charts, and I find it to be very accurate.  It will show that you get extra speed with altitude but very little additional range.

2.  I have taken the AP course and have this to say on LOP.  First, the only issue with where you run your engine from a durability standpoint is temperatures.  I have very good baffling, which is the key I think.  I simply don't have any problems with CHT's which raretly go over 330 at any setting.

3.  I have GAMI's and still LOP is a waste of time on my engine.  The lower fuel burns are matched with lower speeds.  Flying my engine LOP is a pain in the ass.  

4.  I use three settings for cruise  2400/30" and 2200/30", 2200/28".  I lean to 1650TIT or peak, which may come first at the lower settings.  At 2200'28" @ 15,000 I get 185 knots at 14-14.5 gallons depending on temp.  My CHT's will barely break 300 at that setting.  So, how do I improve on that?

5.  If I'm low and battling a head wind, I use the 2400/30 and still lean to 1650.

Again, in my dumb ass opinion, LOP or ROP makes little difference if you have acceptable temps.  

Jgreen

[Chessieretriever]

In my experience Gami was very good at working with us to get our engine to run LOP "at the power levels we were targeting" and supplied 4 sets of injectors for it. If you have a good engine monitor, confirmed a good ignition system (mags, wires, spark plugs) and have set timing properly (as advanced as you are allowed) you should be able to see which cylinder is misfiring when you are in the LOP state with your engine monitor and then work on that cylinder injector. It may still be hard to get to LOP but still may be possible (I know some that were succesful). We tuned our injectors for LOP operation as this is where we cruise. If you have an engine that operates great ROP and has the performance indicated by JGreen I would just go with it and don't waste time trying to go LOP. Looking at your fuel flow and engine power settings for the TAS quoted it appears that your airplane may be speriencing some avoidable drag.

On the air speeds you quote, maybe you are experiencing similar problems as we did when we puchased our airplane; it was slow due to the gear hanging down, the rigging being out and the ailerons being tuned to their lower spec setting. We gained over 15kts TAS by correcting these details and our fuel flow went down to boot once we were done with our engine work.

Good luck with your Bravo.

Chessie

N9154W

[donkaye]

I'm exhausted after reading all the posts in this thread.  I think I've had experience with most of what has been disussed.  I have had my Bravo since August of 1992, so I'm coming up on 20 years.  I'm on my second engine having taken the first one to 2295 hours.  During that time I have put on nearly 3200 hours on my airplane and flew another 700 with students in the Bravo.  You all are making it too complicated.

From my exoerience:

1.  On long cross countrys I'll fly between 15 and 18,000 feet as a good compromise between true airspeed and not having to wear an O2 mask.  At those altitude my true airspeed is about 205 knot at 75% power.  Of course this assumes no weather issues.  The Bravo allows for this by having it 25,000 foot ceiling, an altitude I rarely use.  Also, if you need to go up there for weather purposes you probably shouldn't be there anyway.

2. If you value your $65,000 for a reman engine, then you won't run it LOP.  Been there tried to do it.  Even if you can get it to run LOP, after a year expect at least $3,000-$7,000 in exhaust system repairs.  That will kill any benefit of running LOP.  No good explanations have been put forward as to why the exhaust system gets damaged, but it does in a number of Bravos including mine.

3. Lean by TIT.  This is a turbocharged engine and all the exhausts combine to generate the TIT, so use that to lean.  TIT should never exceed 1650 for engine longevity (forget the 1750 maximum.  Go  there and you won't have an engine for long).  I lean to between 1600 an 1625.  You will find that this is greater than 100° ROP.  NEVER lean to 50° ROP unles you are operating at power settings below 60%.

4. The APS should be a requirement for a signoff.  Outstanding course.  I've taken both the in person and online courses.  Both are good, but take the in person if able.  You have the 3 most knowledgeable people on modern engine management teaching it and who know how much longer they will be available due to health issues.  If you're a CFI they give a $100 discount.  Ask for it.

5.  Airspeed management is critical for Mooney operations.  5 knots too fast is too fast.  Always know your landing weight.  Approach speeds can go down to 65 knots with one person and 1 hours of fuel on board.  For every 300 pounds you're under gross deduct 5 knots from the nominal speed.

6.  Don't "overthink" Bravo operations.  Flying this plane is like flying a Cessna 150 compared to the CJ (I have the Single Pilot type rating for that airplane).

Bottom line:  Givien a choice between any single engine airplane, the Bravo would be and is my airplane of choice.

Enjoy yours!

 

 

 

[TLSDriver]

Quote: donkaye

 

I'm exhausted after reading all the posts in this thread.  I think I've had experience with most of what has been disussed.  I have had my Bravo since August of 1992, so I'm coming up on 20 years.  I'm on my second engine having taken the first one to 2295 hours.  During that time I have put on nearly 3200 hours on my airplane and flew another 700 with students in the Bravo.  You all are making it too complicated.

From my exoerience:

1.  On long cross countrys I'll fly between 15 and 18,000 feet as a good compromise between true airspeed and not having to wear an O2 mask.  At those altitude my true airspeed is about 205 knot at 75% power.  Of course this assumes no weather issues.  The Bravo allows for this by having it 25,000 foot ceiling, an altitude I rarely use.  Also, if you need to go up there for weather purposes you probably shouldn't be there anyway.

2. If you value your $65,000 for a reman engine, then you won't run it LOP.  Been there tried to do it.  Even if you can get it to run LOP, after a year expect at least $3,000-$7,000 in exhaust system repairs.  That will kill any benefit of running LOP.  No good explanations have been put forward as to why the exhaust system gets damaged, but it does in a number of Bravos including mine.

3. Lean by TIT.  This is a turbocharged engine and all the exhausts combine to generate the TIT, so use that to lean.  TIT should never exceed 1650 for engine longevity (forget the 1750 maximum.  Go  there and you won't have an engine for long).  I lean to between 1600 an 1625.  You will find that this is greater than 100° ROP.  NEVER lean to 50° ROP unles you are operating at power settings below 60%.

4. The APS should be a requirement for a signoff.  Outstanding course.  I've taken both the in person and online courses.  Both are good, but take the in person if able.  You have the 3 most knowledgeable people on modern engine management teaching it and who know how much longer they will be available due to health issues.  If you're a CFI they gove a $100 discount.  Ask for it.

5.  Airspeed management is critical for Mooney operations.  5 knots too fast is too fast.  Always know your landing weight.  Approach sppeds can go down to 65 knots with one person and 1 hours of fuel on board.  For every 300 pounds you're under gross deduct 5 knots from the nominal speed.

6.  Don't "overthink" Bravo operations.  Flying this plane is like flying a Cessna 150 compared to the CJ (I have the Single Pilot thpe rating for that airplane).

Bottom line:  Givien a choice between any single engine airplane, the Bravo would be and is my airplane of choice.

Enjoy yours!

 

Donkaye,

I have had my Bravo for a year now and still struggling with engine managment.  I seem to burn more than the other users (22 gph) and go slower (190 kts at 15,000ft.) 

Can you comment more on items 1,3 and 5?

1) I am not getting those TAS numbers at that altitude.  What is the mp/rpm combo you are using?  What kind of full burn?

3) Specifically, You say lean by TIT. What is your lean procedure?   Are you going to peak TIT or peak +/-some value of just going to a TIT of between 1600-1625.  What are the CHT's at those numbers?  ( I have been told not to exceed 380.) 

 

5) I think a lightbulb just went off in my head.  Floating has been a big issue for me and I just realized I am flying the same approach speeds at gross as coming in with just me and a few gallons.  You say for every 300 pounds under gross lower your speed by 5kts.  What are you using as 'nominal' value/starting value?

Thanks in advance.

David

 

 

 

 

 

[carqwik]

David -

First, are you sure your fuel flows are 22 gph?  Is that what the Shadin is telling you?  Have you physically verified that the plane burns gas at that rate?  It could be that you're burning less but the K factor needs to be adjusted in the Shadin.

Second, Don's plane must be exceptionally fast.  My Bravo at 16,000 feet at 78% power does about 193 knots (based on last Thursday's flight), and goes about 198 knots at FL200 at the same power settings (30", 2400 at 18.5 gph, TIT at 1610).  Back in the late 1980's, I flew about six different 252s that were available for rent at various Socal flight schools.  Some were faster than others at identical power settings...likely the same situation in the Bravos. 

Third, lean by TIT only.  TIT probes start failing at around 400 hours (probe time)...I've been through three probes already and they all show the same symptoms when failing...a lowering TIT.  Engine management in the Bravo is simple...but all the numbers should be in relative alignment for a given power setting (e.g., TIT, CHTs, fuel flows).  Your fuel flow appears out of whack but it could simply be an erroneous reading.

My lean procedure is to find peak TIT and add back 100 degrees of fuel.  Do not exceed 1650 for more than a minute when finding peak.  At 78% power, I am usually around 1600 on the TIT after leaning. 

If you float, you're too fast...BTDT.  At the right airspeed over the fence for a given weight, the Bravo will just land in the flare with no float and no bounce.  But it does seem weird that a Bravo which was doing 120 on downwind, 100 on base, and 85 for some of the early final can land at 70 kts or less over the fence at lighter weights.  Trim is your friend and the Bravo needs a lot of it.  And if it's just you and 20 gallons...that's pretty light for a Bravo.

Ken

[TLSDriver]

Quote: carqwik

David -

First, are you sure your fuel flows are 22 gph?  Is that what the Shadin is telling you?  Have you physically verified that the plane burns gas at that rate?  It could be that you're burning less but the K factor needs to be adjusted in the Shadin.

Second, Don's plane must be exceptionally fast.  My Bravo at 16,000 feet at 78% power does about 193 knots (based on last Thursday's flight), and goes about 198 knots at FL200 at the same power settings (30", 2400 at 18.5 gph, TIT at 1610).  Back in the late 1980's, I flew about six different 252s that were available for rent at various Socal flight schools.  Some were faster than others at identical power settings...likely the same situation in the Bravos. 

Third, lean by TIT only.  TIT probes start failing at around 400 hours (probe time)...I've been through three probes already and they all show the same symptoms when failing...a lowering TIT.  Engine management in the Bravo is simple...but all the numbers should be in relative alignment for a given power setting (e.g., TIT, CHTs, fuel flows).  Your fuel flow appears out of whack but it could simply be an erroneous reading.

My lean procedure is to find peak TIT and add back 100 degrees of fuel.  Do not exceed 1650 for more than a minute when finding peak.  At 78% power, I am usually around 1600 on the TIT after leaning. 

If you float, you're too fast...BTDT.  At the right airspeed over the fence for a given weight, the Bravo will just land in the flare with no float and no bounce.  But it does seem weird that a Bravo which was doing 120 on downwind, 100 on base, and 85 for some of the early final can land at 70 kts or less over the fence at lighter weights.  Trim is your friend and the Bravo needs a lot of it.  And if it's just you and 20 gallons...that's pretty light for a Bravo.

Ken

 

I never considered the shadin could be off.  I am going to take off with full tanks.  Once level I will switch tanks and start the watch.  Flip back when I am headed back down hill.  

I will try that lean procedure on the next flight.

Typical landing weight is 370lbs of people, 40 pounds of baggs and 40 gallons of gas.  What would you say the speed should be over the fence?

[donkaye]

 

 

[donkaye]

I forgot to say that base leg should be flown at 80 Knots, but that is easily gotten to because full flaps and the maintenance of the 3° slope will add enough drag to comfortably slow the plane down.