231

[kortopates]

  On 5/10/2019 at 2:08 AM, Pete M said:

Oh, I forgot to ask, what's crit alt on a 231?

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  On 5/10/2019 at 2:19 AM, anthonydesmet said:

240 is critical.  The highest I have been is 180 to 190 and I spend most of my time between 12K to 16K.  

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On a unmodified 231, the critical altitude is only 15,700' DA. A Merlyn raises that substantially and is the main benefit of adding the Merlyn - its still a manual wastegate, but now pneumatically controlled versus a real automatic controller like the modern hydraulically controlled wastegate in the 252.The intercooler doesn't affect critical altitude but it sure improves high altitude performance by lowering induction air which could otherwise reduce power available in the flight levels. 

The 252 airframe was cleaned up, especially in the cowling and is faster than the 231 - by 10 knots if you believe the POHs. 

The critical altitude of the -MB engine in the 252 and 262 conversions is 23K. Service ceilings are FL240 for the 231 and FL280 for the 252 as @gsxrpilot pilot 

[mike_elliott]

  On 5/10/2019 at 5:10 PM, Pete M said:

I'd love a Rocket...or a 252...buuuuuttttt.....there's that big, fat check up front:) Plus the fuel flow would offend my CB sensibilities:)

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Wait till you get a quote to insure a 231 as a trainer and comply with all the SB's and 100 hr schedules if you plan to use it as a trainer like eluded to in your first post.

[johncuyle]

  On 5/10/2019 at 12:19 AM, Pete M said:

Financially speaking,  I couldn't justify the added cost of a 252. A merlyn and an intercooler makes sense. What's the fuel capacity? Are later 231's any faster than earlier ones?  What changed on the model over the years?  My understanding is that most or all flying 231's should have the LB engine at this point. I'm really interested in a basic 231. I don't need lots of glass and all that. A couple of good radios and a working auto pilot is all I'm really interested in. I'll probably throw a G5 or two into it if it doesn't have an hsi. I have to check the instrument pts to see if I need an ifr certified gps for check rides. I actually don't mind having to do paint and interior. I kind of like making the plane my own in that regard. Do the 231's use a newer tank sealant that lasts any longer than the short body's or should I insist on a complete tank reseal be in the logs? 

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This is a pretty reasonable attitude going in.  It's the same one I had.  There are some practical difficulties.  Let me start at the beginning, though:

• Merlyn and Intercooler are great additions.  I installed the turboplus and it made a significant improvement in CHTs.  I'm having GAMIs installed and, as soon as an issue with my engine monitor gets worked out I'll do a post about my experience taking my 231 from mostly factory to actually flying right.  Turboplus installation is not cheap, so if you can buy a plane with the intercooler, it probably makes sense to do so.  They don't seem to carry much of a premium.
• 73 gallons usable.  Expandable up to something like 108 with the Monroy long range tanks.  In a plane that can do 155kt on 8GPH, the Monroy tanks would make it into a distance superstar.  More on that later.
• The big MY change on the K is 1986 where it went from the 231 to the 252.  There aren't a lot of differences from year to year within the 231 line, other than the LB that almost all of them have now anyway.  I think folding rear seats in '84, maybe, is the biggest one.
• Most of them should have the LB, yes.  Occasionally there's an old GB model for sale, though.  I'd worry about how much a GB equipped plane has flown.
• You want built in oxygen.  A 231 is just a much more expensive to maintain J model without oxygen.
• About basic.  I was fine with all the older BK stuff, regular six pack, KFC autopilot in mine.  That's the sort of panel I learned on and I was comfortable with it.  The problem is these planes are old.  Mine is a 1980.  Most of the original stuff turned out to be failing in some way or other.  My nav radios both died within a year of purchase, one of my coms did as well.  I have had a couple issues with my AI, the most recent being something with the FD or AP or something that has caused me to simply stop using the AP until I can replace it with a GFC 500.  A lot of these planes have King autopilots which are attitude based and depend on the AI.  The G5 cannot provide attitude info to these autopilots, so if you find one with a working KFC 200 or similar in it, that'll seem great... until one or another 40 year old component decides to fail.  My plane is going to end up with almost completely new avionics and instruments not because I really wanted to spend the money to replace them, but because dispatch reliability has been appalling thanks entirely to a radio failing or a gyro failing or an engine instrument failing. If you find one with an updated panel, that'll cost.  If you find one with an original, basic panel, there's a pretty good chance it'll end up costing you more.  At least you end up with the panel you want, though.
• Can't help you on the reseal.  It'll probably happen eventually.  I view it as the obvious time to add the long range tanks.

Someone might want to chime in with how excited they'd be about significant amounts of commercial training in their 231.  The performance descents are wear and tear I'd probably rather put on someone else's engine or just a cheaper engine. 

The 231 is a great plane, but I cannot stress enough that unless you plan on being somewhere in the mid to high teens or low flight levels, sucking on oxygen approximately ALL THE TIME, the 231 might not be the best option for you.  The 231 has the worst short field performance of any Mooney, performs worse than a J model below about 8000 feet (draggier thanks to the six cylinder engine baffling design), and only goes faster above because the turbo lets it make more power.  It has nowhere near the speed of the big bore turbo Mooneys (but also nowhere near the fuel flow) but a big chunk of the maintenance cost.  In short, when you buy a 231 instead of a 201 you are paying a LOT of extra money for exactly one thing:  The ability to fly higher.  Be sure you're going to use it.

[Pete M]

i was worried about the autopilot thing. I figured it would break...dont they all? I'm not sure what the solution is there. Do all the servos need to be replaced or just the unit? Last time i had a kx155 repaired it was pretty reasonable. I'm not overly concerned about performance descents...not a big believer in shock cooling under normal operating temps. For training I'd be running pretty low power settings. Besides, I'm talking only about 5 hours a week or so. I'd never put one on the flight school line:)

[johncuyle]

  On 5/11/2019 at 2:21 AM, Pete M said:

i was worried about the autopilot thing. I figured it would break...dont they all? I'm not sure what the solution is there. Do all the servos need to be replaced or just the unit? Last time i had a kx155 repaired it was pretty reasonable. I'm not overly concerned about performance descents...not a big believer in shock cooling under normal operating temps. For training I'd be running pretty low power settings. Besides, I'm talking only about 5 hours a week or so. I'd never put one on the flight school line:)

It depends on what breaks. The BK autopilots, everything is expensive to have fixed. A couple gyro overhauls or a couple servos and you've paid for a pretty big chunk of a GFC 500. Other APs it depends. If you have something that doesn't require attitude information you can put a pair of G5 in. The BK not so much.

It's not shock cooling that concerns me with the 231, it's asking it to produce power when the engine (in particular the oil) is cold after you get to the bottom. It cools a lot in descents when still making some power, enough to drop temps out of the green sometimes. I'm planning to get my commercial in mine someday, after the panel is reliable enough to let me resume training. I just wouldn't want to have someone else doing it in my plane all the time. The throttle response is not linear, which doesn't help people who aren't used to flying one.



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[pwnel]

  On 5/12/2019 at 10:45 PM, johncuyle said:

It's not shock cooling that concerns me with the 231, it's asking it to produce power when the engine (in particular the oil) is cold after you get to the bottom. It cools a lot in descents when still making some power, enough to drop temps out of the green sometimes. I'm planning to get my commercial in mine someday, after the panel is reliable enough to let me resume training. I just wouldn't want to have someone else doing it in my plane all the time. The throttle response is not linear, which doesn't help people who aren't used to flying one.

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Did my Comm a few months ago in a rental 172 (now with the new rules this is fine).  Left my 231 in the hangar.  Just wasn't going to abuse it.

[gsxrpilot]

  On 5/16/2019 at 6:09 PM, pwnel said:

Did my Comm a few months ago in a rental 172 (now with the new rules this is fine).  Left my 231 in the hangar.  Just wasn't going to abuse it.

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I'm doing the Comm right now in my 252. Not abusing it at all.

[pwnel]

  On 5/16/2019 at 6:43 PM, gsxrpilot said:

I'm doing the Comm right now in my 252. Not abusing it at all.

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Yip, but you have the "proper" throttle :-)  

A chandelle is supposed to be a VFR maneuver - in the 231 I would need to spend too much time watching the MAP for over-boost.

[Marcopolo]

 

  On 5/17/2019 at 1:32 AM, pwnel said:

Yip, but you have the "proper" throttle :-)  

A chandelle is supposed to be a VFR maneuver - in the 231 I would need to spend too much time watching the MAP for over-boost.

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  I'm knee deep in the Commercial training in my 231 right now, its an excellent commercial platform.  The chandelle is entered at a pre-determined airspeed (~120KIAS) and the throttle isn't touched throughout the maneuver.  I have seen it done with throttle changes as the airspeed diminishes, but my instructor and the DPE that I'm using has no issue with my process in the maneuver, YMMV.  Now, spot landings in any Mooney....all bets are off! 

 

I think a 231 with long range tanks would be just the ticket for the OP!

 

Ron 

[Warren]

I live in Denver and am hangared at KBJC.  I have owned a 231 for three years and think the turbo is very beneficial in this environment.  Although you fly back and forth to Florida I am guessing you will want to explore all the wonderful mountain communities in Colorado.  The turbo really helps at altitude during the warmer summer days.  I flew to Telluride and was able to easily depart on a warm afternoon with a DA of 11,000’. The jets were all grounded and had to wait until evening or morning.

As others have said, the 252 is better but at a higher price.  A 231 with an intercooler and Merlyn upper deck pressure controller gives most of the performance of a 252 (agreed still a little less) but requires a little more pilot diligence.  It is not that significant once you come up the learning curve.

My airplane is in annual right now but I am happy to talk further and take you for a ride if you find your way to Denver.  I think a 231 could be a good fit based on your mission.  Long range tanks also really open up long flights.  I flew to Florida a couple of months ago and could have made it with the favorable tail winds except weather forced me to stop short and overnight in southern Alabama.

Warren

[gsxrpilot]

  On 5/17/2019 at 2:04 PM, Marcopolo said:

 

  I'm knee deep in the Commercial training in my 231 right now, its an excellent commercial platform.  The chandelle is entered at a pre-determined airspeed (~120KIAS) and the throttle isn't touched throughout the maneuver.  I have seen it done with throttle changes as the airspeed diminishes, but my instructor and the DPE that I'm using has no issue with my process in the maneuver, YMMV.  Now, spot landings in any Mooney....all bets are off! 

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I'm working on my Commercial as well... in my 252. I find the power-off 180's to be pretty easy in the Mooney. I'm still working on the other maneuvers.

[Jeremy95]

  On 5/12/2019 at 10:45 PM, johncuyle said:

It depends on what breaks. The BK autopilots, everything is expensive to have fixed. A couple gyro overhauls or a couple servos and you've paid for a pretty big chunk of a GFC 500. Other APs it depends. If you have something that doesn't require attitude information you can put a pair of G5 in. The BK not so much.

It's not shock cooling that concerns me with the 231, it's asking it to produce power when the engine (in particular the oil) is cold after you get to the bottom. It cools a lot in descents when still making some power, enough to drop temps out of the green sometimes. I'm planning to get my commercial in mine someday, after the panel is reliable enough to let me resume training. I just wouldn't want to have someone else doing it in my plane all the time. The throttle response is not linear, which doesn't help people who aren't used to flying one.



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Looks like this new ka-310 with the ki-300 might be a decent replacement option if the ki-256 starts to go. https://www.bendixking.com/en/~/media/bendixking/files/n61-2019-000-000_aeroflight_electronic_attitude_indicator_autopilot_adapter-bro.pdf

[johncuyle]

  On 6/4/2019 at 1:43 AM, Jeremy95 said:

Looks like this new ka-310 with the ki-300 might be a decent replacement option if the ki-256 starts to go. https://www.bendixking.com/en/~/media/bendixking/files/n61-2019-000-000_aeroflight_electronic_attitude_indicator_autopilot_adapter-bro.pdf

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Except you're still stuck with the entire rest of the BK autopilot, which will still continue to break and be expensive to fix.  BK lost me as a customer.  I simply won't buy anything made by BK or Honeywell, ever again.

[CoffeeCan]

  On 6/2/2019 at 5:16 PM, Warren said:

 

As others have said, the 252 is better but at a higher price.  A 231 with an intercooler and Merlyn upper deck pressure controller gives most of the performance of a 252 (agreed still a little less) but requires a little more pilot diligence.  It is not that significant once you come up the learning curve

Warren

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Agreed.  I am 11 months into my 231 ownership adventure. To say that I have been pleased with my decision to buy a turbo Mooney would be a gross understatement. 

When I was shopping for my Mooney, I looked hard at a couple of 252's, but couldn't justify the price differential. In the end I bought a well-maintained 231 with recently rebuilt engine (with only 85 hrs on it), intercooler, Merlyn, and GAMIjectors, and upgraded panel, for substantially less than the  cheapest 252 on the market at that time.

As it happens, my hangar-neighbor bought a 252 about the same time as I bought my 231. I have flown his airplane quite a bit (about 25 hous) over the past 6 months while he's been out of the country. Aside from his panel being a bit cleaner and his interior newer, there's not much to choose between the two aircraft. As Warren says, once you learn the idiosyncracies of engine management in the 231 on takeoff and climbout, there's only a little less performance difference in the 252 and an upgraded 231 like mine. Would I buy a 252 if it was priced right? You bet! But an upgraded 231 like mine is a close second choice. 

As for turbocharged vs normally aspirated aircraft: the advantages are subtle but real, and in my view make a big difference, especially on long XC flights. The best reason for flying higher, in my view, is that there is far less traffic above 8000-9000 MSL, so your flights are safer. I fly regularly past KSAT, KAUS, and near/into the Bravo around KDFW  and KHOU.

Under 6000 MSL, there are a LOT of aircraft in these environs, and while most of them are talking to ATC a good percentage of them are VFR aircraft squawking 1200 and monitoring Guard only, if they're on the radio at all. Between 6000 and 10,000 MSL you'll find a lot of commercial traffic descending or climbing into/out of the Charlie and Bravo. But above 10,000, you'll be clear of almost all that traffic. Normally aspirated aircraft are almost all below 12,000 MSL, and commercial aircraft are almost all in the FL's... between 12K and 18K you'll find you're almost alone, in smooth air, often with very favorable tailwinds.  And maybe my experience at these altitudes is too short, but I've found that headwinds in the teens are less likely to be turbulent than they are below 6-8000', so even if I'm not seeing a bonus in groundspeed, I'm getting a much more comfortable ride and my engine temps and fuel flow are better than they are down low.