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231 vs 252


GaryP1007

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12 minutes ago, GaryP1007 said:

 

Best bang for the buck? Thoughts and opinions please.

http://www.mooneypilots.com/mapalog/M20K252_evaluation_report.htm

If you can afford it, the 252 is much superior to the 231.  Read the above report. It's true the 231 can do almost everything a 252 can do... almost... and do it for about $40K less. But the doing will take more effort, attention, and care. Whereas the 252 will just DO it.

I flew a C for several years and always wished, in the back of my mind, that it was an E. So moving up to a K, I didn't want the same regret, so I waited until I could get a 252.

The ultimate pinnacle of speed and efficiency might well be the M20K Encore. A 252 can be upgraded to an Encore with a 300 lbs increase in useful load. The 231 can not be upgraded as such.

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What Paul said! But said another way, a 231 will do virtually anything you want to do, with only being a little careful. It doesn't take a genius.

But that being said, anyone would prefer having the 252. It will do it a hair better with less effort.

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The 252 is easily the best "bang for the buck" if you factor in resale and maintenance. The MB engine along with the improved cooling and airflow of the 252 means less maintenance and an easier/longer running engine. 231's can match the reliability but only if flown very carefully. 

The value of an airplane is more accurately measured by the difference of purchase price and eventual sale price, minus maintenance costs.

The 252 is the sweet spot for turbo Mooneys.

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2 hours ago, GaryP1007 said:

Best bang for the buck? Thoughts and opinions please.

Mooney made 889 231's from 1979-1985. They made 231 252's from 1986-1990 and just 35 Encores from 1997-1998. It's a challenge to find a 252 with the dual alternators in great shape that hasn't been converted to a Rocket (TSIO-520). It's nearly impossible to find an Encore. (The first eight '97 Encores were called 252's until the FAA approved the GW increase of 230 pounds, then they were called Encores.)

Model Chronology.pdf

 

My first Mooney was a 10 year old 231 (#759 - '83 model). New this airplane would have been probably a little over $100,000. I paid $83,000 for it 10 years later.

Later on in 2014 I owned a 17 year old spotless Encore (#12 - '97 model). There were a lot of upgrades from the 231 to the Encore, but by the time these were re-introduced in 1997 the price had gone up considerably. ($387,000 and the owner added TKS on top of that, so around $430,000). In 14 years from 1983 a loaded K model had gone from just over $100,000 to almost $400,000. Economy of scale was not working well for Mooney who had been producing a few airplanes a day in the late 70's down to 154 airplanes in total in 1983, down to 92 airplanes total in 1997.

N40FM FACTORY INVOICE.pdf

I took care of a few little things after I bought it during the year I owned it. When I sold it the buyer had a pre-buy done by Don Maxwell. Don went over it with a fine tooth comb and told me it was the first pre-buy he had ever done where he couldn't find one squawk. He was a little disappointed . . lol. I know, I probably should have never sold it.

5945dcb7a9cac_N40FMprofile.thumb.jpg.f3a483a31117e3c2ee2c3816e54f2356.jpg

 

But if we're talking best bang for the buck though (speed & value for the dollar) find the best, most well kept example of a later model 231 that has an aftermarket intercooler and a Merlyn wastegate. It will do almost everything that the 252 or Encore will do for considerably less money.

M20k_review_AvConsumer_Mar2010.pdf

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My understanding is the biggest improvements to the 252 were the intercooler and automatic turbo waste gate. It seems many 231 owners have made these upgrades. Best bang for the buck would be an upgraded 231 in my opinion. And there were significantly more 231s produced. 

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10 minutes ago, Bug Smasher said:

My understanding is the biggest improvements to the 252 were the intercooler and automatic turbo waste gate. It seems many 231 owners have made these upgrades. Best bang for the buck would be an upgraded 231 in my opinion. And there were significantly more 231s produced. 

Is there any echo in here . . lol?    

The 28 volt electrical system was also a nice upgrade on the 252's from the 231's.

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53 minutes ago, gsxrpilot said:

A cowl and cowl flap redesign between the 231 and 252 leads to better cooling of the engine which improves engine life and reduces maintenance.

The intake on the 252 is improved as well.

The infinite settings on the electric cowl flaps are great on late J, K models (252 and Encore) and M models . . until the cowl flap motor goes. I think the motors are more readily available than when I was trying back in '14.

 

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Hmmm...

Best bang for the buck...?

Usually implies getting the most of the basics, leaving out the expensive upgrades....

The basic K is pretty spectacular.

Adding intercooler, and MP controller or turning it into a Rocket are great ideas... but they are extras that cost.

Using logic is a hard way to set up a budget to shop for a plane.

Best regards,

-a-

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231 is your best bang for buck. I owned a very nice example with a merlyn controller and the more desirable airflow systems intercooler. I never had any cooling issues and had no trouble keeping the CHT's under 380 all the time on the LB engine. Typical temps were 330-360. Burned 9.5-13 gph in cruise depending on how you like to run it, 18 in cruise climb and 24.9 on take off. Cruised 160TAS with ease at Lower power settings and 170TAS up in the high teens. We saw 200 plus over the ground on many trips in mid teens. All in it cost me 170 bucks per hour over the span I owned it, less than most sky hawks rent for where I live. This is all in after sold, includes maintenance, upgrades, fuel, oil, hangar, etc.. It was and still is a great airplane for the money. You have any questions on costs, maintenance, operations on the 231, etc shoot me a message, happy to share my experience with the K model. I still have every receipt for every penny I spent on that bird and have some good cost to own spreadsheets if your curious. 

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231 with the 262 trophy upgrades is excellent value. Only major difference to a factory 252 is the 14V electrical system, which isn't really a limitation. Can still get dual alternators for them.

 

There is a great example of one for sale parked near to mine.  Owner may might be willing work out something as it has been for sale for a while.

 

https://www.controller.com/listings/aircraft/for-sale/1331645/1981-mooney-m20k-231

 

 

 

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There is no way i am aware of to put a second alternator in a 231.  The alternator is gear driven and a major engine modification would be needed.  the 231 alternator is a weakness.  The coupler is prone to failure, and the gearing is such that you either have to choose a fast taxi power setting, or put up with a Low Volts indication.  its not impossible to live wtih, but not as good as the 252 set up.

 

Edited by jlunseth
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Just to pile on:  I found that what I wanted and what I could GET were two completely different things.  As far as value goes, it doesn't matter what the rest of us think (to a point, as re-sale is always a factor), it matters what you find worthy.  Do you want speed, range, lift, load, etc...

When I started shopping, I wanted a 252.  Faster and easy to operate (due to the wastegate and intercoolers).  I couldn't find a nice one that didn't have really high time.  Had I been willing to wait for a couple of years, I'm sure one would have popped up.  I listed the things that mattered to me, and realized I could have those capabilities on a couple of different models.  In my own circumstances, I really valued speed, low time, and long range.  I ended up getting a 231 (with aftermarket wastegate and intercoolers) and couldn't be happier.  Were I shopping again, I'd still be starting with a 252, but I love the 231.  FWIW

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Same here.  My search in 1999-2000 was for a 252 with TKS.  Finding few planes and the ones I did were quite a bit higher priced than Rockets, I ended up with the Rocket.  If I was doing the same today, I would likely look for 252's first, and then at Rockets.  252's because I think they hold their value better than Rockets.  Rockets over 231's because I love 305 HP and 1,000 feet per minute climb to FL240.

Tom

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22 hours ago, Zwaustin said:

231 is your best bang for buck. I owned a very nice example with a merlyn controller and the more desirable airflow systems intercooler. I never had any cooling issues and had no trouble keeping the CHT's under 380 all the time on the LB engine. Typical temps were 330-360. Burned 9.5-13 gph in cruise depending on how you like to run it, 18 in cruise climb and 24.9 on take off. Cruised 160TAS with ease at Lower power settings and 170TAS up in the high teens. We saw 200 plus over the ground on many trips in mid teens. All in it cost me 170 bucks per hour over the span I owned it, less than most sky hawks rent for where I live. This is all in after sold, includes maintenance, upgrades, fuel, oil, hangar, etc.. It was and still is a great airplane for the money. You have any questions on costs, maintenance, operations on the 231, etc shoot me a message, happy to share my experience with the K model. I still have every receipt for every penny I spent on that bird and have some good cost to own spreadsheets if your curious. 

This is a great example of the capability of the 231 with an intercooler and merlyn wastegate: 

 

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1 hour ago, jlunseth said:

 

There is no way i am aware of to put a second alternator in a 231

 

jlunseth,

  I have seen both a belt driven and a shaft driven second alternator on the TSIO360 (GB,LB) in a 231 (unless my eyes deceive me, which they have been known to do).  The belt driven requires a set of bevel gears and new vacuum pump pad arrangement and the shaft driven just replaced the vacuum pump (B&C I think).  The B&C shaft driven I think would be considered a "stand by" where as the belt driven is a secondary unit, capable of supporting the full 60-70 amp load.  

 

Ron

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Curious, I just helped a friend get the B&N standby alternator added to his Bonanza. B&N makes a few different models, 2 of which are for Continental big bore engines which would work on the Ovation, but only with a field approval - since there is no STC for the Mooney.  These standby alternators are only 20 amps and need 2000+ rpm to do that. Of course they're better than single alternator, single battery configuration, but not nearly as a capable as a true second full output alternator such as on the 252's, and Bravo's. I have not heard of one fitting on the TSIO-360 engine vacuum pad - its too tight of a fit with the starter as far as I know. The belt driven true second alternator used on the Continentals require a different starter adapter configuration. Not sure if one is available for the GB or LB. But even on a 252 that lacks this option today, years ago you could get the required starter adapter for a few thousand dollars, swap out your old one and add the second alternator for a few thousand more but now (a few years ago actually) they were quoting $8K for the starter adapter alone, then add the cost for the alternator and re-wiring in the cockpit to the buss, load meter etc and you'll quickly be over $10K. Most people find it easier to find another air-frame that already has a second alternator rather than pay today's cost to add one. 

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22 hours ago, Marcopolo said:

 

jlunseth,

  I have seen both a belt driven and a shaft driven second alternator on the TSIO360 (GB,LB) in a 231 (unless my eyes deceive me, which they have been known to do).  The belt driven requires a set of bevel gears and new vacuum pump pad arrangement and the shaft driven just replaced the vacuum pump (B&C I think).  The B&C shaft driven I think would be considered a "stand by" where as the belt driven is a secondary unit, capable of supporting the full 60-70 amp load.  

 

Ron

I went looking for a solution a few years ago, and that included asking Willmar and, while I was in Ada one time, GAMI.  The answer was no, there is not a way.  There may have been a solution once upon a time.  There was an era where quite a bit of "modding" of the J's and K's was going on. But the companies and their STC's are gone.  I never saw one for a 231 alternator, but there may have been. But to my knowledge, today, there is not a way to put a second alternator on a 231.

PS I went on B&C's website, got all excited thinking there might be a way.  I saw STC's for Pipers and Cessnas, and solutions for experimentals, but nothing for the 231.  Wishful thinking I am afraid.  If someone knows of a way that would work for my certified aircraft please let me know, I will be all ears.  The 231 is a great, fast, economical aircraft, but that is a definite weakness.

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jlunseth,

 

  My apologies for leading you astray, was not my intention.  I am sure I've seen the mod, I cannot say I've seen the STC to perform the mod.  The B&C pad mount shaft driven unit would be my choice also,  Is there any precedence for a field approval on such a mod?  I've seen the 28v version on a Bravo with the whole emergency buss isolation process, would love to have the ability to do something similar on the 231 (after I'm done with the vacuum pump of course).

 

Ron

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No need for apologies, I am not astray.  I just got a little excited there might actually be a solution.  I think the problem is partly what Paul described, there is little room for a second alternator, and partly that there would need to be modifications of some kind to the engine case to adapt a second alternator somehow to the existing gear drive.  I will look the next time the cowl is off, but I don't think there is  a belt drive on the engine of any kind.  So adapting a belt driven alternator would involve somehow creating a belt drive system/engine driven pulley.  Its not a very big deal, it is as I said a very good aircraft.  However, there is no backup electrical source to support panel instrumentation, including engine and nav instruments, other than batteries, and it is not possible to add TKS because of the lack of a second alternator.  I know.  I had a mechanic improperly install an alternator coupler, resulting in the coupler coming off and falling into the sump in flight, resulting in no alternator power, resulting in me having to fly with the Master off to a landing spot, and then switching on for landing and radios.  My aircraft is equipped with a JPI 930 which is primary, meaning that all engine readouts (except vacuum) were dark, including RPM's, MP, all temps, etc., during the period the Master was off.  Fortunately it was VMC, so here I am to tell the tale.  Murphy's Law, what can happen, will.

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