Acclaim Type S Cruise Power Settings

[Joe Zuffoletto]

Greetings,

After flying a beautiful 1998 Encore for the past 11 years I decided it was time to trade up, so I'm now the proud owner of a 2008 Acclaim Type S. Wow, what a fire breather!

I'm looking for advice on cruise power settings, both best power and best economy, from more experienced Acclaim owners. Or should I just fly it by the numbers on the visor? LOP or ROP? The only advice I've received so far is to power back to 30.5", leave the prop full forward and let 'er rip, and dial in LOP or ROP as preferred. Not sure about that and I'd like to hear more opinions from real-world Acclaim drivers.

Thanks in advance,

Joe

[Parker_Woodruff]

Absolutely fly LOP. Congrats on the upgrade.

[Clarence]

Joe,

I would suggest the engine management course from Advanced Pilot.  A client of mine with serial number 110 took it and reports it is very worth while.

Clarence

 

 

 

 

[KSMooniac]

I have no Acclaim experience but will second the recommendation for the APS class Clarence mentioned.  I took it 4 years ago, and it was the best money/time I've spent as an owner.  They will give you the education you need to intelligently operate any aircraft engine so that it will give you a long, happy service life.  Once you take it, you'll pretty much never need to look at an OEM recommendation for power settings again.

[jlunseth]

That's a beautiful Acclaim.  You got the one with the "Bandit" paint scheme that has been on Controller for awhile it looks like.

I think I must be in a skeptical mood this morning, so take what I say with a grain of salt.

First, I have attended the APS.  It was very good, but notably short of advice on how to run a turbocharged engine LOP.  I am not saying there was no advice on that, just not nearly as much time as they spent on big bore normally aspirated engines.  Further, there was practically no time spent on small bore turbos.  Yours is not exactly a small bore turbo, mine is.  But the 231 engines like mine are notably finicky about running LOP, and so far I have not had alot of luck trying to run LOP, which leads me to my next point.  I am coming to the conclusion with my engine, that LOP is a great theory, but my engine won't do it, and trying to force it is probably not good for the engine.

There is not much information out there on the Acclaims, because they were not in production long before the factory shut down.  But the one piece that has concerned me (I have been looking at them and thinking about getting one) is the scuttlebutt that there have been quite a few Acclaims that have needed a TOH at between 200 and 400 hours SNEW.  The MSC I take my aircraft to (Willmar) has said it depends on what training the pilot has gotten about how to run the engine.  That is all I know.  I can tell you if I had the privilege of owning an Acclaim, I would want to find out what method of running them is causing the TOH's.  I think it is the "firebreathing dragon" method. 

[andysmith11]

Hi Joe,

As per other posts, not a lot of detailed info around on running ROP/LOP on the Acclaim Type S. I was trained to pull MP back to 30.5" as you mentioned, with the prop either at max RPM or pulled back closer to 2400 RPM (supposedly matches RPM efficieny with MP). Then run ROP or LOP as preferred. I've heard the rumor about TOH at 200-400 hours too, but I have run almost exclusively LOP other than engine break-in and have almost 400 hours on the engine with zero problems. Now, I am hitting the high end of the rumored window, so we'll see what happens. I burn ~16.5 gph LOP, max CHT is 330 degrees or less, and max TIT is just over 1600 degrees. I generally see about 195 TAS between 10,000-12,000 ft That ramps up nicely as I go higher. The one thing I've found is the fuel/speed benefit of ROP vs LOP in the Acclaim S doesn't make sense to me (potential maitenance costs from ROP aside - given the unknowns). I burn an additional 4-5 gph running ROP and only gain about 7 kts running ROP vs LOP, so for me, the extra costs of fuel for a 7 kt improvement in speed is just not worth it.

The couple of things I try to be very finicky about is pulling power back gradually on descent/approach. I look for 1" of MP reduction per minute. The Acclaim will force you start thiniking in terms of time and not distance quickly. The other engine management technique is a 5 minute cool down of the turbos with the engine at idle. One question I've had about this, and have never gotten an answer I felt was a solid answer is how the temperature of the internal rotating parts of the turbo behaves relatively to TIT. I find that in the last ~2 minutes of the cooldown window, the TIT levels off. I get the concept that the internal rotating parts of the turbo can be hotter than the TIT, but my question is how does the tempture of the internal rotating parts converge with the TIT? In other words, if the TIT levels off, are the internal parts of the turbo still cooling down. I've taken it on a bit of faith that the 5 minute cooldown window is the result of some analysis of these factors, but have yet to have an explanation I feel really confident with.

[andysmith11]

btw...congrats on a sweet new ride.

[Dan]

Andy,  The folks at APS will tell you that idling your engine for a 5 minute "cool down" is a complete waste of time.  What they've shown is that your engine is about as cool as it's going to get when the wheels touch the runway upon landing.  After that, it starts to heat up during the taxi back to the hangar.  It really starts to heat up when you stop in front of the hangar to allow it to "cool down" as there is very, very little air flow through the cowling at that point.

BTW, where are you based in Houston?

 

 

[Joe Zuffoletto]

Thanks to everyone for your feedback and comments. Has anyone taken the APS online course, or is it essential to go in person?

jlunseth, you're right... I picked up the BMW Acclaim that has been on Controller the past few weeks. I was initially skeptical about the "bandit" paint scheme but that all went away when I saw the plane in person. The colors, both the blue and gray, are truly unique and look great together. And the shade of blue is very rich and unlike any I have ever seen.

[Seth]

Hello Joe-

I was up in Benson, Minesota recently (KBBB) for some training in my new to me Mooney Missile, and there in the hanger next door was another Mooney Acclaim Type S.  Bruce Jaeger gave me the training and knows about engine management.  He put me through some ground school and at one point showed me the picture of an Mooney Acclaim engine and exaust system bright orange from being run too hot - he stressed that this was one of the reasons for the burned up cylanders and Top Overhauls within a few hundred hours many Accliam's face.  His website is www.jaegeraviation.com, give him a call, fly out there (Wilmar), and get some proper training.  He's an expert Mooney Instructor.  PM me for his driect contact infromation if the website is not sufficient. 

Take care,

-Seth

[jlunseth]

I would suggest the Willmar people also, either Bruce, who now does training for the most part, or Brian Negen who now runs Willmar Air Service, 320-285-4844 .  Brian does not do training but I am sure he would take a few minutes to talk to you about power settings.

I have not taken the online course, but what the in-person course provides that I think is invaluable in persuading people where they should be running their engines, is the ability to watch an engine run on their test bed and see the graphic results as various parameters are changed, particularly mixture.  To call it a "test stand" is a little bit of an understatement and it is truly sophisticated.  Much more impressive to see that happen than reading material.  The other thing the in-person course permits, is the ability to ask questions, and to hear other people ask questions, about what is happening with your engine and how you should be running it.

Its a fun course.  I flew down from Minnesota.  It started first thing in the a.m. and we went pretty much non-stop until Sunday noon.  Covered alot of material and alot of questions about engine management were answered. 

[Joe Zuffoletto]

Seth,

That's great information! Willmar Air Service told me Bruce retired when I called a couple months ago. I'm glad to hear he's become a full-time Mooney instructor. He did the pre-buy on my 1998 Encore and is indeed a very sharp Mooney guy. I'll definitely contact him. Many thanks.

[aviatoreb]

Quote: jlunseth

That's a beautiful Acclaim.  You got the one with the "Bandit" paint scheme that has been on Controller for awhile it looks like.

I think I must be in a skeptical mood this morning, so take what I say with a grain of salt.

First, I have attended the APS.  It was very good, but notably short of advice on how to run a turbocharged engine LOP.  I am not saying there was no advice on that, just not nearly as much time as they spent on big bore normally aspirated engines.  Further, there was practically no time spent on small bore turbos.  Yours is not exactly a small bore turbo, mine is.  But the 231 engines like mine are notably finicky about running LOP, and so far I have not had alot of luck trying to run LOP, which leads me to my next point.  I am coming to the conclusion with my engine, that LOP is a great theory, but my engine won't do it, and trying to force it is probably not good for the engine.

There is not much information out there on the Acclaims, because they were not in production long before the factory shut down.  But the one piece that has concerned me (I have been looking at them and thinking about getting one) is the scuttlebutt that there have been quite a few Acclaims that have needed a TOH at between 200 and 400 hours SNEW.  The MSC I take my aircraft to (Willmar) has said it depends on what training the pilot has gotten about how to run the engine.  That is all I know.  I can tell you if I had the privilege of owning an Acclaim, I would want to find out what method of running them is causing the TOH's.  I think it is the "firebreathing dragon" method. 

[KSMooniac]

I think that means just running it at max power without any regard to CHT or ICP in order to get the 242 KTAS claim at altitude... if owners are routinely running very high power at 25-50 ROP to get those speeds, then cylinders will not be long for this world!

[GeorgePerry]

What were your impressions of Mark and Delta Aviation?  Good transaction?  Flexible on sales price?

[Joe Zuffoletto]

George: As it turns out, the seller and I live across town from each other here in Denver. I flew my Encore to his airport to meet for a showing and we hammered out a deal to trade airplanes on the spot... turns out he was in the market for an Encore! We're both happy with the deal and our brokers were barely involved (mine was Jimmie Garrison, All American Aircraft). The stars were truly aligned.

[Daniel]

 

Joe,

I've owned an Acclaim S for about 18 month, and I've been flying turbocharged for thirty years. Here's what I have gleaned:

First, in the Cessna 340 with Continentals we always flew ROP. Didn't help; the airplane was always a maintenance hog. (But I loved it anyway.) In the originalMalibus with Continental, we started flying LOP, and we never had a problem with that airplane. That was with only a TIT gauge. No individual cylinder EGT or CHT gauges. In the Acclaim, I have flown ROP and LOP, and I agree with a previous writer who observed that the difference in fuel consumption could not be justified by speed difference. As far as what the engine likes, I notice that in the summer at 12,000 feet the cylinder heads will get up in that 380-90 range at 29" and 2500 RPM (and that is at 100 ROP--I think 50ROP is crazy), but you will take 20-30 degrees right off the CHT when you go lean of peak. Also, the cylinders seem very well balanced in my airplane, which is to say that when I go 50 LOP on the TIT gauge, each cylinder is at least 30+ cooler on the individual EGTs. So I know that I am LOP on every cylinder. That was always one of the big bugaboos years ago, that when LOP one or more cylinders would be at or near peak. Try this in your airplane and see.

Bottom line on the LOP question is that the book calls for it, Contiental calls for it, all CHTs and EGTs show engine cooler, and my most recent annual (last week) was a clean engine with good compressions. (Note: one cylinder replaced a year ago under warranty for bad compression.) Engine now has about 525 hours.

The prior owner always flew the airplane at 26" and 2500 RPM LOP. The flight instructor at Willmar who did my checkout was a big believer in that too, though others in Willmar prefer 27" and 2400 RPM LOP. I detect no difference except noise. My instructor also preached that for high speed cruise to run 29"/2500 ROP as it was only a couple of knots slower than 30.5" and that 30.5 was hotter. Heat bad.

Recently, I have taken to flying at 29" 2500 RPM and LOP. As I said, cool and airplane seems to like it.

Finally, a word of caution. Watch the exhaust transitions into the turbos. They have a propensity to crack. Should be carefully inspected at each oil change. My airplane had one crack when relatively new, and again in the last year. I posted the story and pictures on this forum--search my name and you'll find it.

I think you can pull off two inches per minute in descent. I do, and (touch wood) no issues yet. That's what we did for years in the 340 too. And the Mojave (though little could hurt those big bad Lycs).

Best luck. Fly safe. Don't trust the speedbrakes--they fail just when you going to impress the Citation driver on the parallel approach.

 

[aviatoreb]

Quote: Daniel

First, in the Cessna 340 with Continentals we always flew ROP. Didn't help; the airplane was always a maintenance hog....

Best luck. Fly safe. Don't trust the speedbrakes--they fail just when you going to impress the Citation driver on the parallel approach.

 

[Joe Zuffoletto]

Daniel,

Thank you for your extensive reply. I also had a phone conversation with Bruce Jaeger who's also a LOP proponent at conservative power settings so I have a lot more to go by now. Tried his suggestions (which are similar to yours) during a 2-hour flight early this morning and really liked what I saw.

I'll keep an eye on those speedbrakes. My Encore had them as well and I was lucky enough to suffer only one failure in 11 years.

Keep the blue side up!

Joe

[Seth]

Joe-

Bruce had flown the Accliam Type S that was sitting in the hanger with the owner during the previous week from Washington (state, not DC).  Also, the owner was thinking of placing a four blade composite prop on it for testing and a possible STC.  Regardless, Bruce has experience in the Acclaim Type S - Also, just as mentioned in other posts, he showed that by backing off power and RPM, you lost maybe two knots but a lot of heat and fuel burn.  EDIT - Well we posted at the same time - I'm glad you spoke with Bruce.

George - I'll shoot you an email, but Tim Lunquist purchased the Wilmar sales depatment and now runs Strategic Aircraft LLC.  I can give you his number as he can be on the lookout for you, and usually has people interested in selling their aircraft if the right buyer comes along - those not listed on any of the avaition websites - controller, trade-a-plane, etc . . .  Tell him what you are intersted in, and who knows, the perfect bird may be waiting for you upon your return stateside.

Take care,

-Seth 

[Parker_Woodruff]

Quote: Seth

Tell him what you are intersted in, and who knows, the perfect bird may be waiting for you upon your return stateside.

Take care,

-Seth 

[Daniel]

Quote: aviatoreb

Hi Daniel,  Why did you always fly ROP in the 340?  Was it something special with that engine.  I ask because I have a rocket and you may know that the rocket conversion uses the exact engine and prop from the C340.

I hear you on the speed brakes.  My speed brakes are at the factory right now getting "retreaded" the rubber got old.

[aviatoreb]

Quote: Daniel

Hi Daniel,  Why did you always fly ROP in the 340?  Was it something special with that engine.  I ask because I have a rocket and you may know that the rocket conversion uses the exact engine and prop from the C340.

I hear you on the speed brakes.  My speed brakes are at the factory right now getting "retreaded" the rubber got old.

[Seth]

Quote: Parker_Woodruff

Yup.  Lots of his sales happen before the plane makes it to the online classifieds.

[Parker_Woodruff]

Quote: Seth

this was after the prebuy that had me walk away from a 252