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M20k vs M20J


cocolos

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There is a big price difference between 231's and 252's (both are M20K's).  I assume you are referring to the 231's?  If so, you have a point.

 

For example, a 1983 201 and 231 with similar equipment, engine times, etc. would probably be pretty close on price.  I think that is due to the perceived higher ownership costs of the 231.

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There is a big price difference between 231's and 252's (both are M20K's). I assume you are referring to the 231's? If so, you have a point.

For example, a 1983 201 and 231 with similar equipment, engine times, etc. would probably be pretty close on price. I think that is due to the perceived higher ownership costs of the 231.

yes exactly the 231. Anyone have some operating cost numbers for it?

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yes exactly the 231. Anyone have some operating cost numbers for it?

If you fly at the same altitudes in a 231 that you would in a 201 (12000 and below), you'll be burning more fuel and flying about the same speed.  I think it's something like 2 GPH more for about the same performance.  The overhaul on the motor costs more as well, depending on where you get it done (about 5-10K more).  If you fly at higher altitudes (>12000'), you'll really start to pull away from the J, and your fuel burn will remain about the same (a few GPH more... but you'll be at your destination faster).  In the 231, you alway have the option of flying higher, as well, and throttling back a little, to see comparable speeds and fuel burns (160kts, 10gph).

 

The turbo is the difference between the two.  The J is optimized for lower altitude flights (ie shorter duration), the K is better up high.  If your mission is <300-400NM, I'd go J.  If it's greater than that, I'd go K.  JMHO

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yes exactly the 231. Anyone have some operating cost numbers for it?

If you fly at the same altitudes in a 231 that you would in a 201 (12000 and below), you'll be burning more fuel and flying about the same speed. I think it's something like 2 GPH more for about the same performance. The overhaul on the motor costs more as well, depending on where you get it done (about 5-10K more). If you fly at higher altitudes (>12000'), you'll really start to pull away from the J, and your fuel burn will remain about the same (a few GPH more... but you'll be at your destination faster). In the 231, you alway have the option of flying higher, as well, and throttling back a little, to see comparable speeds and fuel burns (160kts, 10gph).

The turbo is the difference between the two. The J is optimized for lower altitude flights (ie shorter duration), the K is better up high. If your mission is <300-400NM, I'd go J. If it's greater than that, I'd go K. JMHO

ok thanks! sounds like it would be perfect for long cross countries.

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I have a 231 and know several people who have them.  It is a very nice airplane, normally has a good useful load for a Mooney, and is cost efficient.  Fuel flow at cruise is generally in the 12 something gallon range for 75% power (i.e. 12.5), for 165-175 kts true in the flight levels.  The issue or group of issues with the 231 is that it was Mooney's first foray into turbo's and high altitude flying (high for us lowly pistons).  There are a number of things in the aircraft that are underdesigned for this purpose and that were corrected in later aircraft.  The alternator is a direct drive, and the clutch is prone to failure.  I replace mine every 500 hours as a precaution.  There is one vacuum pump, although you can add a standby, it is also a 500 hr. item.  If you fly in the flight levels, the magnetos wear faster, and should be replaced or rebuilt at 500 hrs.  I love mine, however.  I am flying it to the Bahamas later this week - you guessed it, in the flight levels.  It is not uncommon on a west to east trip to see ground speeds of 230 kts, my fastest at level cruise was 275 from KPIA to KFDK.  The speed flagged of a little as I got to the east coast, but it was a short fast trip.  The turbo also allows flying above the popcorn cumulus and thus out of any turbulence.

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I really like the turbo planes and will have a big bore mooney turbo down the road. With that one thing to remember about the J is if you want to go faster, up high there is nothing wrong with running 2700rpm full prop forward at 80rop for max power (subject to keeping CHT 380 ish or lower) to get there faster.

It's cheaper to run a naturally aspirated engine at max power than pay for the added maintenance and upfront cost of the Turbo.

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I have a 231 and know several people who have them. It is a very nice airplane, normally has a good useful load for a Mooney, and is cost efficient. Fuel flow at cruise is generally in the 12 something gallon range for 75% power (i.e. 12.5), for 165-175 kts true in the flight levels. The issue or group of issues with the 231 is that it was Mooney's first foray into turbo's and high altitude flying (high for us lowly pistons). There are a number of things in the aircraft that are underdesigned for this purpose and that were corrected in later aircraft. The alternator is a direct drive, and the clutch is prone to failure. I replace mine every 500 hours as a precaution. There is one vacuum pump, although you can add a standby, it is also a 500 hr. item. If you fly in the flight levels, the magnetos wear faster, and should be replaced or rebuilt at 500 hrs. I love mine, however. I am flying it to the Bahamas later this week - you guessed it, in the flight levels. It is not uncommon on a west to east trip to see ground speeds of 230 kts, my fastest at level cruise was 275 from KPIA to KFDK. The speed flagged of a little as I got to the east coast, but it was a short fast trip. The turbo also allows flying above the popcorn cumulus and thus out of any turbulence.

What's it useful load? also how much has your maintenance been? would you say $130/hr wet would cover most things?

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My useful load is just shy of 1,000 at 991.  If you have a 231 in good condition, your annuals should run 2-3,000 per year, but on a periodic basis there will be more costly repairs.  Alternator coupling is about $3,500, alternator itself is about the same.  Vacuum pump about $500.  Magnetoes a little more than that.  They have a reputation for needing a top at about 1200.  I did a field overhaul on mine at a little over 1200, I believe the need for it was there when I bought the aircraft at about 650 hrs., it had not been well managed by the prior owner.  A 231 requires a good deal of manual management of MP and mixture, even with a Merlyn (semi-auto wastegate), and good temp management.  The prior owner or whomever he loaned the plane to did not know what they were doing I don't think. 

 

If you want inexpensive, don't go turbo.  Buy a J.  But if you want not too expensive and a truly great aircraft for long distance travel, the 231 or a 252 would be your bird.  I am going to the Bahamas in a couple of days, from Minnesota, my third time in my aircraft.

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  Alternator coupling is about $3,500, alternator itself is about the same.  Vacuum pump about $500.  Magnetoes a little more than that. 

The clutch coupler? Overhauled units should be $700-1200. The labor is a few hours.

Brand new 28V alternator on my 252 ran me $595. No overhauled units available at the time.

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What's it useful load? also how much has your maintenance been? would you say $130/hr wet would cover most things?

The J itself will set you back 150 an hour wet for 100 hours a year.

I dont fly a K but I am guessing its going to be a bit more ..

Theres a 262 right now on controller.com for 65k or so.

Much better engine, cooling, better induction than the 231

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Theres a 262 right now on controller.com for 65k or so.

Much better engine, cooling, better induction than the 231

 

That 262 is getting close to TBO......a buyer should budget for an engine and prop overhaul.  Also sounds like it might be in need of a paint job before too long.

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That 262 is getting close to TBO......a buyer should budget for an engine and prop overhaul.  Also sounds like it might be in need of a paint job before too long.

I like aircraft close to TBO - the 262 is 250 hours from it. I get it for a discount, fly it on condition, rebuild the motor exactly how I want and then fly it exactly how I want.

Paint looks fine to me in the pics.

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  • 2 years later...

Bringing back an old thread... I've got three likely profiles/missions. They are 550NM, 400NM and 200NM. I need to be able to make the 550NM trip nonstop with IFR reserves and the family. My family is about 500lbs and should top out around 650 over the years. I have a boy and girl. I know the K will make the trips faster, but which will burn the least fuel and leave me with more flexible options WRT ALTs or WX, J or K? I wouldn't expect to need O2. I'd probably fly the J in the 6-8K and fly the K in the 8-12K range. I may eventually get my family to wear O2, but not out the gate. Thanks.

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A K at 12K versus a J at 9K is 5 knots difference at best.  Unless you get up into the FL's you aren't going to see that much of a speed advantage and generally to take advantage of getting above/around summer build ups you need to be in the teens at minimum.  Personally given the mission you list I would lean heavily towards the J.  K's are nice but it really doesn't bring any additional value to your mission over a J and brings a lot of negatives (2 more cylinders, turbo, generally less useful load, higher fuel burn, etc.).

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7 hours ago, dlthig said:

Bringing back an old thread... I've got three likely profiles/missions. They are 550NM, 400NM and 200NM. I need to be able to make the 550NM trip nonstop with IFR reserves and the family. My family is about 500lbs and should top out around 650 over the years. I have a boy and girl. I know the K will make the trips faster, but which will burn the least fuel and leave me with more flexible options WRT ALTs or WX, J or K? I wouldn't expect to need O2. I'd probably fly the J in the 6-8K and fly the K in the 8-12K range. I may eventually get my family to wear O2, but not out the gate. Thanks.

Almost any Mooney from an F forward will complete that mission easily. Mine would do it with large fuel and Useful load margins. Piece of cake. Unless you're in the mountains, I don't think you'd see even 15kts difference in block speed from F to K...on a 550NM trip that ~20 mins difference.

The conservative numbers for my 67F are as follows ~37gals of fuel for the trip ~3hr 40mn en route ~780lbs in the cabin plus 45 reserve fuel.

 

Edited by Shadrach
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DLT...

Our family of four uses a N/A Mooney.  Mostly flying the East Coast.

 Keeping alts under 12k' is just a comfort issue for them.

1000+UL, 100gal tanks, we typically make stops every 2-3 hours just after the halfway point in a long trip.

There is a lot of sleeping going on.  Sometimes taxiing before take-off...  Not much different than being in the car...

Best regards,

-a-

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