Acclaim Type S Cruise Power Settings

[orangemtl]

I've been stepping up a little at  time with my Acclaim, in terms of distance, and altitude (based upon MY capacity, not the aircraft). Upon reaching cruise, I've run it at 25-26", and 2500 RPM. While the engine is fine to run LOP as we know, I've reasoned that fuel is cheaper than an engine, and I've run a bit rich of peak with more attention to cylinder temps: call me ignorant, but cool seems better than hot.  Any mortal errors in my logic?  Yes, hurtling along >200knots is great, but on a 3 hour flight, the additional 5-7 knots is not going to save me that much. Am I better off with a higher manifold pressure, and yet <30inches?

[Awful_Charlie]

Not an Acclaim driver (unfortunately!) but a Bravo one, so naturally numbers are likely to be wrong, and I don't read the same POH, so take this all as you like.

I wouldn't use more MP than you need to get the fuel burn you want at LOP.  Eg, if you can burn 15GPH at 24" LOP, then why run 30" to burn 15GPH?  At 30" the turbo is working harder, the outlet temperature will be higher, and even with an efficient intercoller, the induction temperature is going to be higher, which will make the CHTs hotter.  Yes, you are going to flush more 'clean air' out of the exhaust, so I suppose it is possible the the EGT's and TITs *might* be lower, but the turbo itself is going to get more of the exhaust to do the compressing (wastegate more towards closed) so will be running hotter.

In theory (wonderful stuff!) when LOP the power is set by the FF, so would be interested if you see any performance difference when LOP at the same FF with different MPs

Ben

[danb35]

Quote: orangemtl

While the engine is fine to run LOP as we know, I've reasoned that fuel is cheaper than an engine, and I've run a bit rich of peak with more attention to cylinder temps: call me ignorant, but cool seems better than hot.

[jetdriven]

Thats an old wives tale, don't believe it.

At 4-5 GPH more ROP thats 20-25$ an hour more just in fuel, and so that's 40,000$ - $50,000 EXTRA in fuel in a 2,000 hour TBO cycle.

so, "free engine and prop" when operated LOP.

Quote: orangemtl

I've been stepping up a little at  time with my Acclaim, in terms of distance, and altitude (based upon MY capacity, not the aircraft). Upon reaching cruise, I've run it at 25-26", and 2500 RPM. While the engine is fine to run LOP as we know, I've reasoned that fuel is cheaper than an engine, and I've run a bit rich of peak with more attention to cylinder temps: call me ignorant, but cool seems better than hot.  Any mortal errors in my logic?

[orangemtl]

Makes sense. Lean of Peak it is. Thanks!

[daveydog]

Joe ... brother Dave here.  After a long talk with TCM, they feel pretty strongly that the issues with the cylinder longevity is directly related to the breather tube that terminates into the tailpipe.  The tube builds carbon and restricts the breather tube and therefore the pressure inside the cylinder builds (measured with an airspeed indicator which is rigged to where the oil filler cap is).  The indicator reads water head pressure converted through the use of the airspeed indicator attached to the oil cap during a good run-up.  The test is called a blow-by test and anything over 90mph is a problem and indicates too much pressure inside the cylinders.  With this restricted breather tube due to carbon build-up, poor line routing and perhaps even an undersized oil/air separator. the result is increased oil consumption and wear on the rings.  This is principally the cause for reduced life cylinders.  As a result, and SB has recently been issued to clean the breather tube at each oil change (50 hours) to ensure this tube is not restricted. I felt TCM was very knowledgeable on the subject and feel confident this is a correct assessment based on feedback from my service center. So Acclaim drivers ... sounds like a good idea to check that breather tube and make sure it stays clean.  I hope this helps!

 

[Daniel]

Dave,

Interesting information.  Have you seen (could you upload or reference) the SB?

Dan

[daveydog]

Hi Dan... please see below or click on this link.  Dave.  

http://www.mooney.com/images/pdfs/sb-pdf/m20_312.pdf

 

MOONEY AIRPLANE COMPANY, INC. SERVICE BULLETIN

165 Al Mooney Road

Kerrville, Texas 78028

MOONEY AIRPLANE COMPANY, INC. 165 Al Mooney Road, Kerrville, Texas 78028 tel: 830-896-6000 www.mooney.com

Page 1 of 5

THIS BULLETIN IS FAA APPROVED FOR ENGINEERING DESIGN

SERVICE BULLETIN M20-312

Date: June 27, 2011

SUBJECT: Mooney M20TN - Crankcase Breather Tube Inspection and Cleaning

MODELS/ SN Mooney M20TN Acclaim and Type-S Aircraft w/TSIO550G( ) installed.

AFFECTED:

TIME OF WITHIN NEXT 15 FLIGHT HOURS - Re-inspect at intervals not to exceed 100 hours

time in service.

COMPLIANCE:

INTRODUCTION: Continental Motors Inc. has found instances of oil coking and deposit build up at the crankcase

breather outlet tube inside of the left hand exhaust tailpipe, which could result in the engine

exhibiting higher than normal crankcase pressures and or increased oil consumption.

This Service Bulletin is to provide instructions for inspecting and cleaning of the crankcase

breather tube outlet and/or replacement of the crankcase breather rubber hoses. The attached

compliance card needs to be filled out and returned to Mooney Airplane Company

upon completion of this Service Bulletin M20--312.

INSTRUCTIONS: Read entire procedures before beginning work.

BREATHER TUBE AND HOSE INSPECTION:

1.1. Turn master switch - OFF.

1.2. Remove top and bottom cowling per instructions provided in Chapter 71-10-00 of

applicable MAC aircraft Service & Maintenance Manual.

1.3. Using a bright light source, inspect crankcase breather tube tailpipe fitting on the left side

engine exhaust tailpipe. Viewing from tailpipe outlet look into the tailpipe and inspect for

oil coking and build up of deposits at crankcase breather tube tailpipe fitting on inner wall

of tailpipe (see Figure SB M20-312-1) .

1.4. The outlet opening is approximately 5/8 in. (.625) when clear. Inspect all rubber

crankcase breather tubes for damage or cracking (see Figures SB M20-312-2 & 3)

a.) If outlet is clear and rubber hoses are in good condition, proceed to step 1.9.

- Re-inspect at intervals not to exceed 100 hours time in service.

b.) If outlet has build up of deposits and/or rubber hoses are found damaged, proceed

to Breather Tube Cleaning.

BREATHER TUBE CLEANING:

1.5. Loosen clamp and slide hose from crankcase breather tube tailpipe fitting on left hand

exhaust tailpipe (see Figure SB M20-312-2).

1.6. Using a hard wire brush and/or a scraping tool sized to fit inside the tailpipe fitting, insert

tool into tailpipe fitting and break away any deposit build up from interior of tube.

CAUTION:

Care must be taken to prevent damage to the interior of tube and tube to tailpipe weld connection.

Remove only deposits from oil coking. DO NOT use any graphite impregnated tool on

exhaust pieces.

MOONEY AIRPLANE COMPANY, INC. 165 Al Mooney Road, Kerrville, Texas 78028 tel: 830-896-6000 www.mooney.com

Page 2 of 5

1.7. After removing build up, use wire bristle brush to clean any fine particles that remain and

flush with Stoddard solvent.

1.8. Reinstall hose(s) onto breather tube outlet tube(s) and tighten clamp(s)

(see Figures SB M20-312-3)

NOTE:

Replace any rubber breather hose if it is damaged or cracked using P/N 628555--45 (trim to fit).

Per the engine maintenance manual, inspect the entire length of the breather system for blockage

(FOD) and remove as required.

1.9. Re-install top and bottom cowling per instructions provided in Chapter 71-10-00 of

applicable MAC aircraft Service & Maintenance Manual.

1.10. Complete log book entry.

NOTE:

Fill out compliance card and send by MAIL or FAX to Mooney Airplane Company as indicated on

the attached Compliance Card (see to Figure M20-312-4)

1.11. Return aircraft to service.

1.12. Procedure complete

WARRANTY: Mooney Airplane Company, Inc. will warrant labor 1 hour when corrective action is done in

accordance with procedures of this Service Bulletin for aircraft currently covered under the

Mooney Airplane Company, Inc. factory warranty program.

REFERENCE 1. MAC Maintenance Manual (applicable A/C)

DATA: 2. Continental Motors M-18 Maintenance and Overhaul Manual

PARTS LIST: Refer to Continental Motors - Customer Service at 800.326.0089 for part procurement.

Parts Kit P/N:

Item P/N Description Qty

1. 628555--45 HOSE (.75 I.D. X 30”) Trim to Fit 1

MOONEY AIRPLANE COMPANY, INC. 165 Al Mooney Road, Kerrville, Texas 78028 tel: 830-896-6000 www.mooney.com

Page 3 of 5

HOSE ASSY

HAS BEEN

REMOVED

NOTE:

INSPECT

FOR OIL COKING

AND BUILD UP

OF DEPOSITS

5/8 in. (.625")

WHEN CLEAR

Figure SB M20-312-1 - CRANKCASE BREATHER TUBE INSPECTION

HOSE

CLAMP(S)

Figure SB M20-312-2 - CRANKCASE BREATHER TUBE, HOSE AND CLAMPS

MOONEY AIRPLANE COMPANY, INC. 165 Al Mooney Road, Kerrville, Texas 78028 tel: 830-896-6000 www.mooney.com

Page 4 of 5

REPLACE ALL

DAMAGED OR

CRACKED HOSES

IF REQUIRED

ANY BLOCKAGE

REMOVE

AND/OR COKING

LH SIDE VIEW

628555-45

HOSE P/N

TRIM TO FIT

(2) PLACES

Figure SB M20-312-3 - CRANKCASE BREATHER HOSE INSPECTION

MOONEY AIRPLANE COMPANY, INC. 165 Al Mooney Road, Kerrville, Texas 78028 tel: 830-896-6000 www.mooney.com

Page 5 of 5

MOONEY AIRPLANE COMPANY

KERRVILLE, TEXAS 78028 -- 1-800-331-3880

SERVICE (BULLETIN) (INSTRUCTION) NO.________________HAS BEEN COMPLIED

WITH ON AIRCRAFT MODEL _______________ SERIAL NUMBER ________________

Tach. Time:

Owner:

N-Number (Reg. No.)

Date of

Compliance:

Complied

By:

Form 07-0001

Inspection Report:

MOONEY AIRPLANE COMPANY

ATT’N: TECHNICAL SUPPORT

165 Al Mooney Road, North

Kerrville, Texas 78028

PLACE

STAMP

HERE

SEND TO:

Mooney Airplane Company

165 Al Mooney Road North

Kerrville, TX 78028

OR FAX: (830) 257-4635

Figure SB M20-312-4 -- Compliance Card

[Joe Zuffoletto]

Thanks, brother Dave! Arapahoe Aero is on top of it and performed the required inspection during my last oil change. Hey, that's a nice new plane you got there!

[daveydog]

Joe and others... here some new information. Any advise:

I am considering removing my oil/air separator due to crank case pressure buildup in my Acclaim.  I posted the breather tube issue and SB issued by Mooney for the same issue but my mechanic feels it might be prudent to remove it all together.  Sure it may need a little more belly cleaning and oil, but at the risk it causes to the cylinders, I'd rather do that.  Any thoughts.  He also stated some other and better separators such as air wolf.  Any thoughts?  Thanks!  

[N67HR]

Any word on an approved fix? 

[daveydog]

any acclaim drivers out there who did the midwest STC for the 310hp upgrade?  

 

[Randyb]

I have 1200 hours on my acclaim. So far I topped 1 cylinder only because the mechanic was misguided and held my plane hostage. At 1200 hours I’m using 1qt oil per 3 to 4 hours down from 1 qt every 8 to 10 hours.  the engine is 11 years old and is flown 100 hours per year. Compression is from 62 to 72. I usually fly at 14500 with 28” and 2400 rpm. I keep TIT at 1600  and CHT below 400 and burn 14.1 gallons in cruise LOP at 180 kts. Going ROP burns about 18 gallons and adds 10 KTS

 ROP gives me 10 extra KTS for 4 gallons or almost $20 per hour more  LOP saves about $1800 per year in fuel and lord knows how much in engine repairs  

 

[carusoam]

Nice informative first post, Randy!

Best regards,

-a-

[Jeff_S]

On 9/18/2018 at 2:56 PM, Randyb said:

I have 1200 hours on my acclaim. So far I topped 1 cylinder only because the mechanic was misguided and held my plane hostage. At 1200 hours I’m using 1qt oil per 3 to 4 hours down from 1 qt every 8 to 10 hours.  the engine is 11 years old and is flown 100 hours per year. Compression is from 62 to 72. I usually fly at 14500 with 28” and 2400 rpm. I keep TIT at 1600  and CHT below 400 and burn 14.1 gallons in cruise LOP at 180 kts. Going ROP burns about 18 gallons and adds 10 KTS

 ROP gives me 10 extra KTS for 4 gallons or almost $20 per hour more  LOP saves about $1800 per year in fuel and lord knows how much in engine repairs  

 

Interesting numbers, although at 14.5K feet my Ovation will get 175 knots on 12.5 GPH so the performance is pretty close. Is 28/2400 really below the 65% hp recommended for LOP ops?  It seems like if I’m pulling that in my NA engine I’m at a bigger HP.  Admittedly, I have to be pretty low to see 28”!

[N231BN]

Interesting numbers, although at 14.5K feet my Ovation will get 175 knots on 12.5 GPH so the performance is pretty close. Is 28/2400 really below the 65% hp recommended for LOP ops?  It seems like if I’m pulling that in my NA engine I’m at a bigger HP.  Admittedly, I have to be pretty low to see 28”!

The acclaim has a low compression engine due to being turbocharged so the numbers won't match your ovation.

[Jeff_S]

Ah, yes...I wasn't factoring in the lower compression cylinders. Thanks!

[N231BN]

Also, if you run deep LOP you can do so at higher power settings and stay out of the red box.

[2659AU]

Interesting Discussion.

We have a 2009 Acclaim. Recently we have started seeing a white buildup in one of the turbos - significant enough that it is starting to interfere with the turbo impeller. Not really sure, but it may coincide with more operation at lower power settings (e.g. 27" 2400 50 LOP) and cooler TIT - as low as 1570 degrees.

Has anyone else experienced this? Can anyone suggest what is going on? Or suggest a solution?

[jackn]

Sounds like lead. If you’re LOP & getting this regardless of power setting, sound like a bad exhaust valve. Compression test & borescope. 

 

[carusoam]

Welcome aboard 9AU.

Got a pic of what you are seeing?

Do you have any JPI data / graphs you can share?

Since you have the turbo off... looking up the exhaust manifold can indicate which cylinder is the offending one...

If it is a valve issue...

JPI data is pretty good at finding/showing these things...

Dental cameras are pretty good at seeing valves from spark plug holes... bad valves have or leave strong visual evidence...

PP thoughts only, not a mechanic...

Best regards,

-a-

[Bentonck]

Great thread, and enjoyed the post Randy as I am stuck at 14500 feet for a while until I finish instrument training and get my license validated here.  (14500 is max VFR altitude in Brazil!) .. 

Does anyone have that SB in a saved pdf?  The link that is posted is busted and I would like to take that to my shop here...

[carusoam]

Benton,  @Bentonck

which SB number are you looking for?

This one?  https://cdn2.hubspot.net/hubfs/4147179/technical_documents/service_bulletins/M20_312.pdf
 

You should be able to access the archaic website that is still available...

I post the link, that should be a list of all the SBs for a Mooney M20TN...  https://www.mooney.com/service

Click around to see what you can find...

The site has never worked in a standard fashion... but the data has always been there...  

Best regards,

-a-

[Bentonck]

That's the one Carusoam, my plane is still in the shop and I'm going to shoot this over and have them look while it's still there.  They are buttoning it up tomorrow and if my wife let's me out I'm going to pick it up and bring it back this week....  

Thanks for the help!

[Bentonck]

Another question for other Acclaim owners, following the Mooney link above I found SB-319 which is much more extensive than the SB-312...now instead of a cleaning and inspection they wanted a revised breather installation...has everyone complied with this?  Obviously this would be out of pocket in my case, I asked the mechanic to take a look at it and see if it had been complied with and get back to me but my guess is that it has not.  

Anyone have any experience with this?   This is the SB I'm referring to....

 

M20_319.pdf

 

Has this been carried out on most of the fleet in the States?