M20k vs M20J

[M20F]

1 minute ago, Shadrach said:

What would be more interesting is seeing how a TN'd F or J would stack up against a 231. I think J Breda's 68 F will come with in spitting distance on speed.

A 231 is about 15-20 knots faster.  I get around 160-170 knots between 190 and 250 depending on temps.  It is about 30 mins to 190 and 50 mins to 250 and unless you are overcoming a huge headwind down low (as I did my last foray up high where I swapped 40kt headwind at 9000 for about 15kt headwind at 250 plus adding about 15-20KTS TAS) or a great tail wind up high, you are generally better off at 9000.  You also have to run rather ROP to keep cylinder temps down and to keep turbo from boot strapping.  LOP with the Rayjay on has been a no go in my experience and I run 10.5-11.8GPH depending on altitude.  

252 or even better Rocket is where the real separation begins at in my book.  I looked at a 231 when buying my F and just didn't feel the maintenance plus purchase price made sense for the $$$'s involved and down low the speed difference isn't that much between a K & F which is where most of my flying is.  The 252/Rocket were in range of my pocket book but aside from 2-3 trips per year most of my flying is 2hrs or less to where they don't make sense either.  Rayjay Comanches and E/F's are definitely a nice sweet spot from an economics point of view but you obviously aren't going to beat a plane 2x the price in a straight up race. 

All things being equal 400HP Comanche + Rayjay is where I would want to be, couple of them around but $$$.

[jetdriven]

i flew once from Kisimmee florida to Houston at 2400'. Any higher was slower and I could not make the trip nonstop.  For that flight it was 39 gallons,  776 NM, or 19.6 NM/gal.  that leg was done at 130 knots TAS.

[Steve Dietrich]

It is a great article .  A couple of comments  from 35 years ownership of an early 231  converted to 252 

Mag maintenance went way down with the introduction of the pressurized mags which were an early retrofit

The 252 was originally certified to 27,000  reduced to 25,000 by the FAA ,  That's about 10,000 feet more altitude than what's really usable in a 201 and offers weather and wind options not available to a 201 . 252 has no problem going to 30,000 if needed.  

The 252 turbo with its variable wastage  seems to require less turbo  maintenance thank the 231 but with both there is a lot of stuff under the cowl which glows in the dark.  

252 and converted 231's have much better cooling due to better cowl ( combustion air from nada duct which helps to prevent iced filter) better engine ducting and better cowl flaps including infinite adjustment. 

Very few 231/252's get to TBO without a top overhaul -  They are spending a lot more time at high power settings

If I had to guess   added maintenance of a 231/252   over a 201 is $15-$25/hour  (SPEED costs - how fast do you want to go) 

Can be nose heavy especially with a gravitationally gifted , short legged pilot.  Some tinkering with the Charlie weight can help as would an MT prop and a HD battery. 

Alternators should be overhauled mid time (primarily bearings) 

Without conversion to LED lights and perhaps more digital stuff , the 12v alternators are marginal and coupling failure not uncommon 

Speed brakes are nice but certainly not essential. You need to plan descents carefully to use the energy productively.  

The Mod Works conversion essentially consisted of a FWF (excluding prop) replacement of all parts from the 252 production line with the exception of a custom engine mount 

For single pilot business flying   250 - 750 NM the 252 is probably the ultimate non pressurized answer (especially with a relief tube) 

 

 

 

 

 

 

 

 

 

[dlthig]

I don't know how to set up a fillable excel sheet online, but it would be interesting to see real-world numbers for cruise for various Mooneys. I ran the numbers on the AOPA calculator, but it didn't appear to compensate for altitude, you just plugged in whatever for cruise speed, altitude and burn rate. If the Air Force wasn't so stingy they would have given me a T-37 to play with after they replaced them with the T-6.

[Shadrach]

21 minutes ago, M20F said:

A 231 is about 15-20 knots faster.  I get around 160-170 knots between 190 and 250 depending on temps.  It is about 30 mins to 190 and 50 mins to 250 and unless you are overcoming a huge headwind down low (as I did my last foray up high where I swapped 40kt headwind at 9000 for about 15kt headwind at 250 plus adding about 15-20KTS TAS) or a great tail wind up high, you are generally better off at 9000.  You also have to run rather ROP to keep cylinder temps down and to keep turbo from boot strapping.  LOP with the Rayjay on has been a no go in my experience and I run 10.5-11.8GPH depending on altitude.  

252 or even better Rocket is where the real separation begins at in my book.  I looked at a 231 when buying my F and just didn't feel the maintenance plus purchase price made sense for the $$$'s involved and down low the speed difference isn't that much between a K & F which is where most of my flying is.  The 252/Rocket were in range of my pocket book but aside from 2-3 trips per year most of my flying is 2hrs or less to where they don't make sense either.  Rayjay Comanches and E/F's are definitely a nice sweet spot from an economics point of view but you obviously aren't going to beat a plane 2x the price in a straight up race. 

All things being equal 400HP Comanche + Rayjay is where I would want to be, couple of them around but $$$.

I know I've said it before, but I think if it were possible to get a RayJay'd IO360 to run LOP, it would be a real game changer.  I think one issue is likely that MP redline which was likely based on ROP power settings does not put enough air through the engine to get far enough LOP.  If you could run say 33" at 10GPH you would have some great economy.

[M20F]

18 minutes ago, dlthig said:

I don't know how to set up a fillable excel sheet online, but it would be interesting to see real-world numbers for cruise for various Mooneys. I ran the numbers on the AOPA calculator, but it didn't appear to compensate for altitude, you just plugged in whatever for cruise speed, altitude and burn rate. If the Air Force wasn't so stingy they would have given me a T-37 to play with after they replaced them with the T-6.

http://www.mooneypilots.com/mapalog/M20C%20Evaluation/M20C_Evaluation_Report.html

http://www.mooneypilots.com/mapalog/m20e.html

http://www.mooneypilots.com/mapalog/M20F%20Evaluation/M20F_Evaluation_Report.html

http://www.mooneypilots.com/mapalog/M20K231%20Eval%20Files/M20K231_Eval.htm

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

http://www.mooneypilots.com/mapalog/M20M%20Evaluation/m20m_eval.html

And so on...There F numbers match closely to mine thus probably the real deal.

Just now, Shadrach said:

 I know I've said it before, but I think if it were possible to get a RayJay'd IO360 to run LOP, it would be a real game changer.  I think one issue is likely that MP redline which was likely based on ROP power settings does not put enough air through the engine to get far enough LOP.  If you could run say 33" at 10GPH you would have some great economy.

If you ran at 33" you are basically doing a turbo bullet which swaps out to low compression cylinders and still has issues with the cylinders flying off.  Fuel is generally the least of my annual expense issues so 12GPH versus 9GPH on 100hrs a year isn't going to cause me much grief, I like to go fast.   

The main reason for the added fuel though is to keep the cylinders cool.  I don't remember my exact ROP numbers at 250 but want to say it was around 150-200 degrees.  In the teens I can run around 100ROP and trail the cowl flaps and keep cylinders below 380'ish.  Start getting higher though you need the gas to keep them cool in addition to trailing cowl flaps.  Yes LOP will make the cylinders cool as well but as you pull back power by leaning you pull it from the turbo as well so it just becomes a vicious cycle.  Dollar for dollar I think the IO360/Rayjay is a better solution than a 231 (speed, efficiency, useful load, etc.) but 252 on up is really where you want to be if 500NM+ is your life on a regular basis.  The E's with Rayjay's are certainly even more awesome.

I have always wanted to see performance charts with a 400HP Comanche and a Rayjay (think there is a guy in SD who owns one along with a M22).  I have heard though that 400's have cooling issues to begin with so not sure what happens when they get into thin air, maybe Clarence can add some insight.

[Shadrach]

Just now, M20F said:

http://www.mooneypilots.com/mapalog/M20C%20Evaluation/M20C_Evaluation_Report.html

http://www.mooneypilots.com/mapalog/m20e.html

http://www.mooneypilots.com/mapalog/M20F%20Evaluation/M20F_Evaluation_Report.html

http://www.mooneypilots.com/mapalog/M20K231%20Eval%20Files/M20K231_Eval.htm

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

http://www.mooneypilots.com/mapalog/M20M%20Evaluation/m20m_eval.html

And so on...There F numbers match closely to mine thus probably the real deal.

If you ran at 33" you are basically doing a turbo bullet which swaps out to low compression cylinders and still has issues with the cylinders flying off.  Fuel is generally the least of my annual expense issues so 12GPH versus 9GPH on 100hrs a year isn't going to cause me much grief, I like to go fast.   

The main reason for the added fuel though is to keep the cylinders cool.  I don't remember my exact ROP numbers at 250 but want to say it was around 150-200 degrees.  In the teens I can run around 100ROP and trail the cowl flaps and keep cylinders below 380'ish.  Start getting higher though you need the gas to keep them cool in addition to trailing cowl flaps.  Yes LOP will make the cylinders cool as well but as you pull back power by leaning you pull it from the turbo as well so it just becomes a vicious cycle.  Dollar for dollar I think the IO360/Rayjay is a better solution than a 231 (speed, efficiency, useful load, etc.) but 252 on up is really where you want to be if 500NM+ is your life on a regular basis.  The E's with Rayjay's are certainly even more awesome.

I have always wanted to see performance charts with a 400HP Comanche and a Rayjay (think there is a guy in SD who owns one along with a M22).  I have heard though that 400's have cooling issues to begin with so not sure what happens when they get into thin air, maybe Clarence can add some insight.

I'm pretty sure the TAT turbo normalizers will run higher than SL pressure for LOP ops.  How else would Walter and George run their TN'd Bonanzas at 90% power while LOP.

[jetdriven]

LOP air cools engines pretty good, and its a little cheaper than gas, on a per pound basis.

Edited February 9, 2016 by jetdriven

[M20F]

12 minutes ago, Shadrach said:

I'm pretty sure the TAT turbo normalizers will run higher than SL pressure for LOP ops.  How else would Walter and George run their TN'd Bonanzas at 90% power while LOP.

90% power isn't 33" nor is 100% power 33", 33" is > than 100% power.  You are also talking about a different turbo, different engine, different cowl, different baffling, different induction, etc. in the TN Bonanza.

I can run 26/27 at 190 (190 is generally where I go below 26") which is 91% power but my cylinders would melt while doing it at anything shy of a lot more than ROP, can't say what a TN'd Bonanza is going to do.

[Shadrach]

1 minute ago, M20F said:

90% power isn't 33" nor is 100% power 33", 33" is > than 100% power.  You are also talking about a different turbo, different engine, different cowl, different baffling, different induction, etc. in the TN Bonanza.

I can run 26/27 at 190 (190 is generally where I go below 26") which is 91% power but my cylinders would melt while doing it at anything shy of a lot more than ROP, can't say what a TN'd Bonanza is going to do.

LOP peak, MP is cooling, FF is power.  

Edited February 9, 2016 by Shadrach

[jetdriven]

9 minutes ago, M20F said:

90% power isn't 33" nor is 100% power 33", 33" is > than 100% power.  You are also talking about a different turbo, different engine, different cowl, different baffling, different induction, etc. in the TN Bonanza.

I can run 26/27 at 190 (190 is generally where I go below 26") which is 91% power but my cylinders would melt while doing it at anything shy of a lot more than ROP, can't say what a TN'd Bonanza is going to do.

They run them LOP.  Strictly limited to LOP at high cruise, In fact, the TN Cirrus, also a Tornado Alley product, has FF limits when operating LOP.  If the CHT is acceptable, otherwise a little leaner.  They run cool. They come from the factory on a new airplane with a warranty, so theyre doing something right.

my io360 (not turbo of course) like 83% power lop, and runs 330 CHT like that.

Edited February 9, 2016 by jetdriven

[Shadrach]

Just now, jetdriven said:

They run them LOP. IN fact, the TN Cirrus, also a Tornado Alley product, has FF limits when operating LOP.  They run cool. My non turbo 201 likes 83% power LOP,

Mine as well. Down on the deck I can run cooler for a given speed LOP than ROP.

[M20F]

Just now, jetdriven said:

They run them LOP. IN fact, the TN Cirrus, also a Tornado Alley product, has FF limits when operating LOP.  They run cool. My non turbo 201 likes 83% power LOP,

Again a different set up.  I can only tell you what happens with a RayJay + IO360 + M20F.  It won't run LOP with the turbo engaged due to bootstrapping and it needs fuel to cool the cylinders.  I can certainly run my IO360 LOP at 83% the same as yours at altitude X but mine isn't going to do that at FL20 (where I can get about 83% still with the turbo on) and you aren't going to get 83% at FL20.

Not really sure the point you and Ross are trying to make.

[Shadrach]

8 minutes ago, M20F said:

90% power isn't 33" nor is 100% power 33", 33" is > than 100% power.  You are also talking about a different turbo, different engine, different cowl, different baffling, different induction, etc. in the TN Bonanza.

I can run 26/27 at 190 (190 is generally where I go below 26") which is 91% power but my cylinders would melt while doing it at anything shy of a lot more than ROP, can't say what a TN'd Bonanza is going to do.

The tornado alley turbo is a TN system for the IO550. It runs standard 8.5 pistons.  30" will no way in hell provide enough Air to keep and IO550 LOP at 17GPH. They run higher than sea level MP while limiting FF to keep the engine form exceeding max rated power.  If I had a Ray Jay, I'd be attempting the same thing.  My stock F will break 155KIAS at 40LOP WOTRAO at DA's around 1000ft in the winter.  If I could emulate that with a turbo at 18K, I'd be doing quite a bit more than 170kts.  Once the TIT is below redline on the lean side, your MP limitation is really just engine roughness.

[jetdriven]

Does that rayjay conversion on the M20F have an intercooler?

[Shadrach]

8 minutes ago, M20F said:

Again a different set up.  I can only tell you what happens with a RayJay + IO360 + M20F.  It won't run LOP with the turbo engaged due to bootstrapping and it needs fuel to cool the cylinders.  I can certainly run my IO360 LOP at 83% the same as yours at altitude X but mine isn't going to do that at FL20 (where I can get about 83% still with the turbo on) and you aren't going to get 83% at FL20.

Not really sure the point you and Ross are trying to make.

The point is that I (we I think) are trying to discern if your LOP options are limited by how you're operating, the Rayjays output limits, lack of intercooler, etc.  The TAT set up is different, but it's also the same. Hi comp pistons with a turbo.  They run normalized engines at well above 30" without exceeding rated HP by limiting fuel.

In other words, how would your engine run at 18,000 on 11GPH and 33"? That would be roughly 170hp or 80%.

Edited February 9, 2016 by Shadrach

[M20F]

1 minute ago, Shadrach said:

 

1 minute ago, Shadrach said:

The tornado alley turbo is a TN system for the IO550. It runs standard 8.5 pistons.  30" will no way in hell provide enough Air to keep and IO550 LOP at 17GPH. They run higher than sea level MP while limiting FF to keep the engine form exceeding max rated power.  If I had a Ray Jay, I'd be attempting the same thing.  My stock F will break 155KIAS at 40LOP WOTRAO at DA's around 1000ft in the winter.  If I could emulate that with a turbo at 18K, I'd be doing quite a bit more than 170kts.  Once the TIT is below redline on the lean side, your MP limitation is really just engine roughness.

You can get @26" at 18K with a Rayjay, again as I said they Tornado Alley/Bonanza set up is a different animal which you seem versed in.  I can only tell you what the Rayjay will do both in experience and in terms of the actual performance charts/STC.  I think it is a well known fact that your stock F 40LOP is faster than a J at 50ROP from what I read on these forums.

Just now, jetdriven said:

Does that rayjay conversion on the M20F have an intercooler?

No

 

[KSMooniac]

The TN Cirrus and Bo installations have a 30" MP redline.  They're not running more than that.

[Shadrach]

Just now, M20F said:

I think it is a well known fact that your stock F 40LOP is faster than a J at 50ROP from what I read on these forums.

Negative. During the winter here in MD, I regularly depart a 701' field elevation that has a DA of -2500'. Under those conditions, one can really explore high power LOP ops. I can be balls to the wall at 1000'AGL and still show 31" of MP because the DA at that altitude is almost -1000ft.  I would have to be wither LOP or full rich when operating this way.  If I were running a J in the same way, I'm sure it would be 5-10kts faster than my F. Most folks limit their LOP ops to 65%. I am happy running my engine Balls to the wall LOP because I can tell by the temps that it runs cooler for a given airspeed. 

[Shadrach]

Just now, KSMooniac said:

The TN Cirrus and Bo installations have a 30" MP redline.  They're not running more than that.

Then how does Atkinson run his A36 at 87%? He's mentioned it countless time on the red board. 

[KSMooniac]

5 minutes ago, Shadrach said:

Then how does Atkinson run his A36 at 87%? He's mentioned it countless time on the red board. 

WOT (30"), 2500 RPM and ~80-90 dF LOP @ 17.5 GPH.  That is the standard hi-cruise setting for those installations.  That is 190 KTAS +/- for an A36 at 17,500, with variances for temperature and weight.  87% power is the max LOP setting they can do and stay out of the red box on the lean side.  I'm not sure how fast the TN SR22 is with that setting.  

George Braly has a TN V-Tail IIRC that goes really, really fast.   

The only other engine installation that I envy is the IO-550R conversion with a new cowl that is done by Atlantic Aero IIRC.  It delivers similar performance below 15k' as the TN package but without a turbo.  It is a beautiful conversion.

[Shadrach]

22 minutes ago, KSMooniac said:

WOT (30"), 2500 RPM and ~80-90 dF LOP @ 17.5 GPH.

Thanks Scott, 30" just does not seem like it would provide enough CFM to get that far LOP.

Edited February 9, 2016 by Shadrach

[KSMooniac]

Just now, Shadrach said:

Thanks Scott, 30" just does not seem like it would provide enough CFM to that far LOP.

Without a doubt the TAT system has a thoroughly optimized induction system, including the intercooler.  I don't think any turbo Mooney (factory or aftermarket) gets close to that level of efficiency.  From the engineering perspective, it is impressive that such a result can be attained when looking at the entire system vs. just bolting-on various bits and hoping for the best.

[carusoam]

Ross,

The standard trip was only 1.5 hrs.  I know the longest time it took was 2.0 hours.  So, I would stay high and fight some wind. My mother would start calling on the cell phone at 1.5 hrs, no matter what....I could probably judge the wind speed by the number of messages I would have when I landed.  Better than filing a flight plan!

Another cool thing about flying the Mooney...  Climb until the air smooths out.  If you don't do this with the family of four, there are going to be some interestingly filled  Ziplocs.... Just be ready to have that conversation.  it can be made fun with preparation.  No room for the average guy to start testing out new stand-up material...

Moving up to the O. The standard trip was 1.25 hrs.  The new plane was much better cared for, and better equipped than the C.   The pilot was better equipped with an IR.   Flying a bit lower as we gained experience.  

The standard was an east-west trip.  Tail winds with the O made it feel worth it to visit the old home often.  There and back in one day. Unable to do that with an automobile and maintain sanity.

Thanks for asking,

-a-

[Shadrach]

14 minutes ago, carusoam said:

If you don't do this with the family of four, there are going to be some interestingly filled  Ziplocs....

We had a son 1 month ago to the day.  While he's not been flying yet, it seem he's practicing to fill ziplocs already...