M20S horsepower increase STC

[Flymu2]

Is there an STC to go to 280 hp with the 2 blade prop? I believe the Ovation 1 had a 2 blade prop.

[kmyfm20s]

Maybe someone can scan there 280 hp Screaming Eagle STC? Are you looking for something different or just curious?

[Robert C.]

Hi neighbor (I'm at KDXR)

 

Nope, the STC requires a new (three-bladed) prop and governor.

 

If you're going to upgrade I'd suggest you go straight to 310hp. There is a less known 3 bladed prop that is like 7lbs lighter than the original STC prop. Look for the Bob Minnis/Hartzell scimitar prop PHC-J3YF-1RF/7498.

 

Found the thread (I started it - had forgotten that ), look for Steven's reply: http://mooneyspace.com/topic/12548-midwest-mooney-310hp-stc-conversion-question/page-2

 

Robert

[Flymu2]

I'm trying to avoid the 10K plus expense of the new prop. I'd love more performance, and would be happy to accept 280 hp. I also like the efficiency of the 2 blade. If I could upgrade using the 2 blade prop I'd do it in a heartbeat.

[Cruiser]

I don't believe the Eagles were ever upgraded from the original 244 HP. There were only 65 air frames produced over four years, the bulk of them in 1999 and 2000. They did add a 3 blade prop in 2001 but kept the horsepower the same at 244 HP.

 

The only STC is for the 310 HP version.

[Guest]

Is there an STC to go to 280 hp with the 2 blade prop? I believe the Ovation 1 had a 2 blade prop.

The Ovation type certificate shows a different 2 blade McCauley prop than your Eagle. It is rated at 280 horse power at 2500 rpm. Don't know if you could get approval to install this prop on your Eagle and turn up the engine to Ovation numbers. I have a spare prop if you can do it.

Clarence

[carusoam]

O1 came with a three blade MAC in 94 using 280hp @2500rpm...

The problem is the STC System...

The M20R is 'different' than an M20S.

What applies to one, does not directly apply to the other.

Good news.

You can go all in, TN 310hp with a TopProp on the S. Can't do that with an R!

Applying for a new STC probably costs more than getting the existing 310hp STC.

The extra HP is very useful.

There is no answer to 'is it worth it?'

Ya know?

-a-

[Cris]

There is no STC for a two blade prop that increases the HP on the Eagle. The 310HP STC 3 blade scimiter prop is used on the S/R for its performance which is better than the original 2 blade prop in both cruise and climb on the Eagle and the Ovation 2. That is why it is used but it is differant than the 3 blade prop that came on the Ovation 1's. There are now three different 3 blade props for that 310 HP STC but the STC does not use any of the original 2 blade or 3 blade versions. You might be able to find a used one at a lesser cost but you will still need an overhauled prop gov and new tach not to mention the paperwork.

[Flymu2]

I'm revisiting this topic because I was just told my 2 blade prop needs an overhaul.

Does anyone have a list of the approved props for the 310 hp STC?

Is anyone aware of a source for the prop other than new?

Thanks.

[Cruiser]

I have a complete two blade prop and hub as removed from my plane for the 310 HP STC if you are interested in it.

[Godfather]

I think you will be happy with the new hartzell propeller.  I'm pretty sure it comes in a standard, thin and composite versions.  You might be able to find a used al version from someone upgrading to composite.  IMO the hartzell 3 blade is a huge upgrade from the 2 blade ovation 2 prop...

 

this is page might help for the prop upgrades...LINK

Edited February 24, 2016 by Godfather

[StevenL757]

2 hours ago, Flymu2 said:

I'm revisiting this topic because I was just told my 2 blade prop needs an overhaul.

Does anyone have a list of the approved props for the 310 hp STC?

Is anyone aware of a source for the prop other than new?

Thanks.

I understand where your logic is, and agree there's nothing wrong with trying to save money.  To summarize others' comments (and my own), it's about complying with the details of an STC.  It's also about safety, peace-of-mind, and adhering to best practices and recommendations to maximize what your ship has to offer.  I appreciate there's a significant cost delta between a 2-blade OH and a used 3-blade Hartzell (much less a new one), but the benefits far outweigh the cons which I'm sure you know.  You'll spend the same amount of money on an STC-compliant prop to go to 280HP as you would to go to 310.  You can't mix-n-match...the STC is what it is.

The Hartzell 7693 DF-2 (80 pounds) and the 7498 (73 pounds) are the same cost at ~$12.5k (without TKS slinger hardware and boots).  The composite is ~$21.5k and gives the same performance numbers as the 7693.  The 7498 is used on the Acclaim Type-S conversions, and is approved for the Eagle and Ovation.  It's your best choice for all-around takeoff performance, climb performance, and cruise.  It adds 5 to 7 knots' increase out of the box over the 7693 and composite flavors.  From a value-add perspective, you really only have two choices:  O-haul your existing 2-blade and continue running as-is, or sell your 2-blade and put the cost against the 310 STC and a 7498 Hartzell.

Ping if you want to discuss further.  Happy to drop into HPN this weekend if you'd like.  A ride in my Ovation3 + coffee are on me.  If you haven't already experienced the IO550N + 7498 combo, you're in for an eye-opening ride.  When we're done, go crawl back into your Eagle, curse my existence for exposing you to that much power (out loud or under your breath - your choice), and start planning on spending that tax refund.  ;-)

Regards, Steve

[Seth]

Be like Erik - go for the four blade composite prop!  I overhauled my prop last year, however in six years/on condition, I plan to put the 4 blade prop on my Missile and lighten the nose by 30lbs.

As to Steve's quote, and since we are spending your funds, purchase the Typs S prop as indicated above, STC to 310 HP, and sell the 2 blade prop as is toward the cost of the upgrade.  Still pricy.

Then again, there's nothing wrong with a $2500 overhaul, flying for another six years/on condition and upgrading then.  For all you know you may be in your M20U Ovation Ultra by then and you will not recoupe the money spent on the STC and prop as part of the sale/trade up for the M20U.  The next purchaser will complete the STC - you still have a very efficient and fast bird as is.

I'm usually of the opinion to do exactly what you are doing - when a piece needs to be overhauled/replaced, look at upgrade options and then weigh in the pros/cons for capabilities vs expense vs mission vs resale.

I didn't think about the four blade composite prop until after the overhaul, and now I kind of wish I should have.  When all was done between my prop overhaul and now governor issue just a year later, that's $5000 I could have put toward the new prop/governor combo - but the price difference is still around $15,000, so I'm fine not spending that now.  Next time, though, I may be in that position.  I also plan to keep the Missile a long long time, so I am fine spending money I will not recoup in the sale at this point.  I may build and RV-8 or get one like Joe, or get in a partnership on a pressurized aircraft, but I'll plan to keep my Mooney Missile as mine.

Do let us know what you end up deciding.  in the end regardless you still have a great plane.

 

-Seth

[Flymu2]

Does anyone have the STC number? My prop shop guy wants to look at it to see if he has a prop that complies.

[Cruiser]

SA02193CH for Hartzell  PHC-J3YF-1RF/F7693DF (B)-2

 

the STC is here: http://deltaaviation.com/Nav%20Page/ovation3/Ovation3%20STC.pdf

[Flymu2]

The prop shop looked into getting me a 3 blade prop. They have some units that were taken off Cirrus planes. Correct hub, incorrect blades.

The upshot is I'm going to have mine repaired for about $1600 and soldier on. I just can't justify $13k plus the STC plus the miscellaneous items for the hp increase. I'm sure it's great, but not worth 15-20% of the value of the plane.

Thanks for everyone's comments and information. 

[co2bruce]

I also own an Eagle (1999). I have looked at this upgrade for years, but we don't operate out of any short fields, fly 100% on the east coast ( no serious mountains ) and our flights are generally 1 - 3 hours. This 20 thousand dollar upgrade would save us 13 minutes on our long flights, and basicly no other benefit. I understand there are  missions that would totally utilize the benefits of the STC but we don't fly them. There is also the benefit of flying a de-rated engine that should "theoretically require less maintenance in the long run and fly way past TBO. Just my .02

[Flymu2]

For me the benefit would be better short field performance. As it is I'm not comfortable going to Block Island (2500') or Mattituck (2000'). I'm going to fly an O3 on Sunday. I'm curious to see what it's like.

The other cost issue is the tach and other accessories. My Moritz guages have seen better days, but to replace them would probably be major panel surgery which would not be cheap. It's a bit of "while I'm there" syndrome. Since I'm now not sure I'll keep the plane (wife wants a chute or a second engine) I think I have to stick with what I have.

[carusoam]

MU, I measured the 800' T/O run using an App and a WAAS SkyRadar...

It is a much better feeling than the 1200' standard of the 280hp O1.

Try it, you'll like it.  Use caution... If you don't want to spend the AMUs, It will take huge inner strength to say no after the flight.

I had my tach updated with new lines to match the new limitation requirements.  Realistically, I want to go JPI 930 over time... The Moritz solution was nice for it's time.

If you go with Steven, he is a wealth of knowledge on this topic. Before you buy the STC, take the opportunity to speak with it's originator. A brief conversation regarding the engine and the prop choices, you get a greater feeling of what the engine design limits are compared to where you will be running it.

My first flight in a 310 HP M20S was courtesy of Cris.

Don't be slow on the Pirep!

Best regards,

-a-

[Godfather]

Don't fly the O3...imo the difference you will feel will be similar to a 150 vs a 182.

[Shadrach]

9 hours ago, Godfather said:

Don't fly the O3...imo the difference you will feel will be similar to a 150 vs a 182.

Wow... Physics be damned, do tell?  A C182 climbs >100% faster than C150 and is about 50% faster in cruise.  How do the O3's numbers compare to the "lowly" Eagle?

[Godfather]

Nothing "lowly" about the eagle.  The OP was concerned about TO distance which is the period of time the average non-pilot can feel the difference in power.  So to answer your question a normal trip for a pilot might be visiting Denver in July.  Both m20s planes lined up on the runway mid day (avg temp 88f/31c).  Both planes loaded to 3200 lbs.  Going by the POH the TO distance for one is > 3000 feet and the other is <1500 feet.  This is coming from two planes that will have exactly the same operating expense (except for the 5 min of higher fuel burn).

Is the upgrade worth it when passing through 10k for a 4K pattern...no.  Will it save time to carry another 150lbs of fuel for flying cc at the same exact speed...it "might" save an hour to avoid a fuel stop.

I was being sarcastic with the 150/182 comparison but those two aircraft could have a slightly different operating expense as well.

[jclemens]

Everyone knows physics don't apply to aircraft.....

[Flymu2]

The 3 blade prop is slightly less efficient and weighs more, plus costs more to buy and overhaul. There's an increment in ops costs from that, probably a small amount compared to the total ops cost.

For me it's the 20K nut that holds me back. If I find a discounted prop or my mission changes I will revisit the issue.

[Godfather]

No question 20k is a lot to add to any aircraft.  Off memory I think the top prop conversion has increased in price ~40-50 percent, the used value of the takeoff prop has dropped a lot, and the price of the stc remains substantial.  

Im not too familiar with the m20s...do most people run a higher cruise power because the engine is de rated so much?  This would close the gap a lot if you fly in the 6-8k range.