Midwest Mooney 310HP STC conversion question

[Robert C.]

Looking at an Eagle that has the "Screaming Eagle" STC but declares it is the 280hp (up from 244hp) conversion.

 

I have seen other listings and discussions of conversions to 310hp and the Midwest Mooney website only mentions the 310HP conversion.

 

Are there indeed 2 versions of the STC?

 

Robert

[tascher]

Robert,

Yes, the 280hp STC on the Eagle bumps the redline up to the Ovation 1&2's 2500rpm limit. A 2700rpm STC pushes horsepower on Eagles and Ovations alike to 310 (the STC "included on the factory Ovation 3). I'd believe both STCs require a 3 blade Hartzell - either the standard top prop, the composite version, or the prop developed for the Acclaim S. The two latter props require additional STCs.

Regards,

Tom

[carusoam]

And it is nice to have the 310HP and TopProp.

Specifically for the shorter T/O distance for me...

My O started with 280HP.

Long Bodies come in a variety of HP from 240, 260, 280 and 310...

The 240 and 260 versions use a lot of runway...

A 280 HP O plans 1,200' T/O run...

A 310 HP O plans 800' T/O run...

These memories are from an old fuzzy memory bank... (Check your STC in your POH)

Best regards,

-a-

[Robert C.]

OK, Thanks, very helpful. Big difference on the T/O run between 280HP and 310HP!

[Cris]

The info above is correct and is what I initially had on my Eagle. However on the day of purchase I flew it to Midwest and had the 280hp upgraded to the 310 hp version. It required a new prop governor and tach as well as the paperwork but much cheaper than an a initial upgrade from the 244 hp version due to the fact that the three blade prop was retained. Depending on serial number you may or may not need a new prop gov. The cost at the time was 5k which I thought was a bit pricy but they were the only game in town and are great to deal with. I understand that the original STC developer/holder Bob Minnis of Minnis aviation (678-398-9781 cell 678-361-5696) who sold Midwest Mooney can also do this upgrade so maybe the costs will be less. And yes the performance difference is dramatic. Coming out of a J I did not want less T/O or climb performance not to mention the increase in useful load (1122 lbs) in my case and range.

[jhbehrens]

Not a new governor, an adjustment to your governor surely!

[Cris]

Not a new governor, an adjustment to your governor surely!

Nope It required a new governor don't know why.

[Guest]

The old governor is not designed to operate at 2700RPM.

Clarence

[StevenL757]

The old governor is not designed to operate at 2700RPM.

Clarence

Existing Eagle and Ovation McCauley and Hartzell governors alike will indeed run at 2700RPM, but will need a T20 upgrade to 2700RPM capability, which is essentially changing out a spring for about $150. Navaho Accessories in San Antonio does a very nice job with this and provides turnaround times within a week for no additional charge. If a full overhaul is needed, they will replace gaskets, replace the plastic front cover with a newer metal one (if you have a McCauley governor - not sure on Hartzell governors), and change out just about anything else showing wear. Happy to attach the invoice if anyone wants to see the breakdown of parts used. Labor was about $400 and parts $340 for $740 total. Full OH time was exactly a week and they replaced just about everything in mine.

[Txbyker]

Question- if you do the STC on an Ovation 2 GX then would you now officially have an Ovation 3 GX or would you just call it a modified 2 GX? Would you go as far as changing the decal?

Russ

[jetdriven]

Existing Eagle and Ovation McCauley and Hartzell governors alike will indeed run at 2700RPM, but will need a T20 upgrade to 2700RPM capability, which is essentially changing out a spring for about $150. Navaho Accessories in San Antonio does a very nice job with this and provides turnaround times within a week for no additional charge. If a full overhaul is needed, they will replace gaskets, replace the plastic front cover with a newer metal one (if you have a McCauley governor - not sure on Hartzell governors), and change out just about anything else showing wear. Happy to attach the invoice if anyone wants to see the breakdown of parts used. Labor was about $400 and parts $340 for $740 total. Full OH time was exactly a week and they replaced just about everything in mine.

A full overhaul is always required and there's always a grand in hard parts that need "updating" too. Just my experience. Prop and governor shops never seen a unit that didn't need a full overhaul.

[Txbyker]

No, just a governor spring and the paperwork I am told.

[M20S Driver]

My 280 HP STC could be converted to 310 HP by adjusting the prop governor. No overhaul is needed.

[Guest]

As well as governor modification and resetting to 2700, the fuel pump requires resetting to a new higher fuel flow and the propeller blade angles require adjustment.

Clarence

[carusoam]

So many choices...

You could call it an O3 powered O2... or..

Go with the IO550(N) and Top Prop.

Then get the decal that says Standing Ovation on it.

Only people in the know will understand what you did and why you did it...

(N) has the updated cylinder design with funky fins...

Or wait for the O4 to come out then install what they use...

Don't forget to update the RPM gauge with it's new red line...

Trying to aim at a moving target is too expensive for me.

Call it what it is. Avoid calling it what it isn't...

Expect the O4 to have the latest from Continental (60k), Hartzell (15k), and Garmin (or BK?)

How much for a G1000W?

If you really want to play a fun game...

Get run-out Eagle, add a pair of snails with matching cowl, get a decal that says 'Acclaim'

How much for the BMW paint design?

Just sayin',

-a-

[Cris]

My 280 HP STC could be converted to 310 HP by adjusting the prop governor. No overhaul is needed.

You might want to read again what Others have written above. You can't just change the gov to get 2700 rpm without all else that is required for the 310 hp STC including the requisite paperwork, tach and new gov or depending on serial number the adjustment you mention. Having done the upgrade from 280 hp to 310 hp required much more than a tach adjustment including about 5K. to make It legal.

[Txbyker]

Thanks guys.  Plane is with DMAX and he knows what to do.  I think I will chrome the pipes and landing gear and call it a Harley.

 

Russ

[M20S Driver]

My 280 HP STC could be converted to 310 HP by adjusting the prop governor. No overhaul is needed.

You might want to read again what Others have written above. You can't just change the gov to get 2700 rpm without all else that is required for the 310 hp STC including the requisite paperwork, tach and new gov or depending on serial number the adjustment you mention. Having done the upgrade from 280 hp to 310 hp required much more than a tach adjustment including about 5K. to make It legal.

 

My governor is already capable of operating up to 2700 rpm with a minor adjustment according to my mechanic.  I also checked with the local prop shop and they looked up the model number and confirmed it.  The additional costs are the STC and fuel set up and setting the Tac to red-line at 2700.

[LANCECASPER]

I just had this done this past week to an Ovation 2 that already had the correct 3 blade scimitar prop. It already had the Moritz gauges replaced with a JPI EDM 930.

 

It cost $6750 for the STC paperwork, $912 for a complete prop governor overhaul and to have the spring changed, it cost a couple hours labor for my A&P to communicate with JPI to get and install the new settings for the EDM 930 so that it now goes to 2700 rpm (it also shows the STC # next to the tail number at the bottom of the JPI 930 now) and a couple more hours for him to change the fuel flow settings, etc.

 

I have only had one flight so far, but you definitely notice the extra hp on take-off and climb out.

[carusoam]

Lance,

Which version of the prop do you have..?

Thick, thin, or composite?

Aka...

Heavy, lighter, too light

Best regards,

-a-

[LANCECASPER]

Lance,

Which version of the prop do you have..?

Thick, thin, or composite?

Aka...

Heavy, lighter, too light

Best regards,

-a-

 

Definitely not the really light (Acclaim) prop - the one that's designed to lighten your wallet at the same time.

 

The previous owner had installed the Hartzell PHC-J3YF-1RF prop. I'm assuming that this is the "thin" one that you are referring to. The original prop on this airplane in 2000 was the 2 blade McCauley which I understand was great for cruise but not for take-off and climb.

[carusoam]

The thick one allows for more OH potential.

The extra weight, way out front, would be nice to lose.

The composite one is so light it stops uncomfortably quickly. Goes against the feeling of a comfortable shut-down...

Best regards,

-a-

[StevenL757]

Just to clarify some specific propeller info, as I went throught this exercise a few months ago with Hartzell and Bob Minnis...both of whom were fantastic to work with. Apologies if the below is redundant...

The PHC-J3YF-1RF is a base designation for a three-blade Hartzell (the "3" in J3YF). Specific models are known by their suffixes as follows...

* The "standard" Ovation, Acclaim, and Eagle scimitar ("Top Prop" as referred to by some) is designated PHC-J3YF-1RF /7693DF-2. It's a 76-inch diameter prop reduced in diameter by 2 inches and weighs 80 pounds. This sounds like what Lance's previous owner had installed over the 2-blade McCaulay. It's the scimitar that is normally advertised and included as part of a conversion to 310hp

* The Bob Minnis/Hartzell scimitar is the PHC-J3YF-1RF /7498. It is a 76-inch diameter prop weighing 7 pounds less than the 7693DF-2, gives about 5 to 7 knots more speed "out of the box" over the 7693, and is used for the Acclaim Type-S conversion. As Tom A. pointed out, it is approved - via STC - for installation on the Ovation (obtained through Bob directly or Midwest)

* According to Bob and Hartzell, the 7693DF-2 and 7498 are the same price. As I was already installing an IO550N, plus paying for the 310hp STC, and replacing my McCauley 3-blade outright, it only made sense to buy the 7498 for its reduced weight and added speed advantages

* I don't have the specific designator on the composite scimitar, although I did price it before doing my conversion. When I checked in June 2014, price was $22,500 (without TKS slinger ring and accessories...add another $2500 for this kit)...compared to $15,500 for either metal option (TKS kit included)

* The composite option performs similarly to the 7693DF-2, so you're paying for only the increase in useable load without a speed advantage

Agree with Lance that all three of these props will lighten your wallet to some degree, but the composite option will do it much quicker.

Excluding Tom, myself, and other Ovation owners who I'm sure have the 7498, I'm not sure the large majority are aware that the 7498 prop even exists, much less know about its benefits. I'm not a spokesperson for Bob or Hartzell, but I know that Bob worked very hard on engineering and testing with Hartzell to bring his STC for the 7498 to fruition. Although it's been around for ~ 2 years, he's really trying to spread the word about its benefits to Mooney in general, and specifically to Ovation, Acclaim, and Eagle owners looking to convert from another model. Happy to share individual experiences as needed...

Steve

[Txbyker]

Just picked up my 2 GX (now an O3) from DMAX and brought it home.  2005 Ovation 2 GX required a governor adjust at a prop shop, placards, and resetting the G-1000 to choose O3 versus O2 so that the tach would register 2800 tops.  I had no idea the O3 was a selectable source in my G-1000 but it was hiding in there.  

 

I have the new POH supplement but it makes no mention of landing Prop RPM setting.  I guess its full prop, full MP, full mix?  I used to see 80 kts over the numbers at 13" and 2500 rpm.  Is everything full forward for landing with the O3?

 

Russ

[Robert C.]

Congrats!

Don't you love the extra acceleration and climb?

To your question: yep just push prop and mixture forward and forget about them till its time to lean for taxiing.