New Guy and an M20F with RayJay Turbo

[Brian Scranton]

Hi guys, first time caller, long time listener...

I'm at 200 hours and about halfway through my IR—I am looking for a fast efficient bird that can take me from western Colorado to CA, TX, WA. 

I just sold my 182L and was debating between a V-tail and an M20F. I think I can get more for my money with the F and have found one I have quickly fell in love with. Nice IFR flier, RJ turbo, Insight graphic engine monitor, 950 SMOH, 430, 3-axis AP, nice interior/exterior, same owner (and A&P) for last 26 years, just had its annual last week wth minimal squawks...any advice? 

Thanks! 

 

[Hank]

Have fun! The turbo should come in handy where you are. I'd recommend an experienced Mooney instructor to teach you the ins and outs of the F. There's a list at the back of The Mooney Flyer (www.themooneyflyer.com), as well as some here. Check out MAPA (www.mooneypilots.org) and see if there will be a Pilot Proficiency Program reasonably near you anytime soon. The MAPA website has a review posted of a non-turbo F, written by a former Mooney test pilot who rose to VP of Engineering for Mooney.

The F should run ~20 knots faster than your 182, on about 2/3 of the fuel. It's not as much of an SUV, but should still haul a decent load. Full fuel will be a lesser percentage of useful load, too.  

Before you buy, have a mechanic you trust review the logbooks. Visit and fly the plane. Then get a Pre-Purchase Inspection from an A&P with lots of Mooney experience. There will be many suggestions here, depending in where the plane is currently located.

Enjoy the search, and let us know how it goes!

[Brian Scranton]

Thanks Hank! I'm hoping for more than 20kts since my 182 is slow as shit. It has a great STOL kit, so I can fly her at 40mph all day long--but cruise was always around 125kts. The plane is 600 miles away, so I will most likely put my trust in a prebuy, fly up there on United with my CFI, and fly her home (if all goes well). I wish there were PPPs around Montrose--for sure in Denver, which is only a 1 hour flight. 

[Hank]

I fly a C, and can walk away from most 182s. Sounds like I could run away from your old one! Most Fs, even flown LOP, will walk or run away from me. They're generally good for 150-155 knots and have much more usable back seats than I do. Bigger, heavier  AND faster, there should be a law against that. At least they don't do it on less fuel.

[M20F]

I have a 67F with a Rayjay, happy to answer any questions.

[Brian Scranton]

Thanks Mike! I sent you a PM--hoping I can call you and ask some Qs.

[M20F-1968]

I have a 1968 F which has been completely rebuilt and which has a RayJay. 

I also have some parts:  new exhaust and wastegate for the original RayJay system (as you are considering) which have been rebuilt from one grade heavier stainless than the original as well as a beefier wastegate.  Aditionally, I have a good serviceable set of original RayJay exhaust pipes and other parts from the original RayJay system. You might consider having some of these parts as they are no longer available.  You can reach me here, or e-mail me at john.breda@gmail.com, or call me at (617) 877-0025.  You will find that the F with the RayJay system to offer a very nice combination of utility, climb, speed without much more in maintenance.

John Breda

[Brian Scranton]

Thanks John!!!! 

[jnisley]

I have a 69F that I've been flying for a number of years (550+ hours) if you have any questions.....I "might" be able to answer them.

[garytex]

I have a naturally aspirated F and sometimes wonder what the turbo'ed models' performance and cylinder longevity numbers are.  Anybody care to share?

[M20F]

2 hours ago, garytex said:

I have a naturally aspirated F and sometimes wonder what the turbo'ed models' performance and cylinder longevity numbers are.  Anybody care to share?

4500 / 144TAS (24.6/2500)

7000 / 146TAS (22.5/2500)

10000 / 146TAS (23/2400)

12500 / 151TAS (23.3/2400)

17500 / 155TAS (23/2600)

25000 / 162TAS (19.7/2700)

These were all done with 3 way ground test's with the exception of FL250 which I calculated (figures in my photo albums).  My non-turbo speeds align very closely to the speeds MAPA got in their M20F evaluation so should be typical speeds with turbo.  These are just some numbers I did awhile back that I had handy, should give you a flavor.  Fuel burn is around 11GPH, it needs gas for cooling (especially as you get higher) and to keep turbo from bootstrapping.  

I can get 26" till about 19000 feet so I could pick up some more knots but generally if I am going high it is a long flight and I try to balance fuel burn with TAS as stopping doesn't make the math work very well.  Climb rate is the same as you will see in your NA M20F so it  takes a while to get up into the FL's so if the winds don't favor you, the speed/length of the climb can make the trip longer even if you can pick up 15-20 knots.

One of these days I intend to make a more complete performance table but then again, I intend to do a lot of things....

[garytex]

Thank you for tailing the time to post.  In my dreams your airplane goes faster than that.  I thought that drag would fall off faster with altitude than it evidently does. Thats still blistering along, though.  And I bet it's nice at high airports.  And when you can catch some of those 50 kt tailwinds.

Gary

[M20F]

11 hours ago, garytex said:

Thank you for tailing the time to post.  In my dreams your airplane goes faster than that.  I thought that drag would fall off faster with altitude than it evidently does. Thats still blistering along, though.  And I bet it's nice at high airports.  And when you can catch some of those 50 kt tailwinds.

Gary

FL190-210 is the sweet spot, it gets really sloppy above that due to the thin air.  I suspect the scimitar prop isn't the greatest for the thin air as well so losing some thrust.  It gets between 160-170kts at that altitude at 75% ROP depending on temps/weight.

The biggest obstacle really is the climb speed.  What you make up in cruise is really offset by the slow and long climb up, but if the winds are there it works really nicely.  I come back from Wyoming each fall at 200+kts though the ride out is usually 100-120kts at all altitudes.  

I really find it the right mix for me.  The vast majority of my flying is 2hrs or less so no need for a full time turbo.  On the longer trips though for speed or getting above weather it is a nice option.  It is cheap to maintain and doesn't impact useful load terribly or appear to have any real impact on speeds/fuel burn when it is off.

It seems rarer these days to see E/F's with a Rayjay for sale but when you do they don't have a real premium for it.  If I was shopping I would definitely pick one of these up as the utility is great for almost zero additional cost.

I have always thought a J with a M20/Rayjy set up from the factory would have been a really nice option.  Fast as a K with more useful load and lower fuel burn.    

 

 

[garytex]

Strictly a mental exercise, I wonder if an intercooler would make an appreciable difference in your heat loading. Thats what seemed to make the 232 really shine, as the 252. But lots of weight, plumbing, and complexity.

[M20F]

10 hours ago, garytex said:

Strictly a mental exercise, I wonder if an intercooler would make an appreciable difference in your heat loading. Thats what seemed to make the 232 really shine, as the 252. But lots of weight, plumbing, and complexity.

I think it would certainly help it to run leaner.  I don't think it would make a lot of appreciable difference in TAS.  A 231 is about 20kts faster at 8500 then I am and about 2kts faster at 17500 then I am.

My understanding is the M20 turbo has a intercooler and automatic waste gate on it, but I have never seen a write up by anyone who has one.  

[jnisley]

I recorded these numbers on a flight several years ago.

17,800' level flight

MP 24.5 (waste gate fully closed) (discovered later that it wasn't closing fully due to linkage needing adjustment, hence the lower MP)

RPM 2500

FF 11gph (needed to keep it at least 11 to keep cylinder temp in range)

IAS 124kts

TAS 169kts (according to TAS1000 fuel air computer)

GS 149kts

Oil temp 194 degrees

OAT 22 degrees F

#1-316 1407, #2-388 1270, #3-375 1377, #4-328 1405

I kept it set at 25/25 all the way thru 17,000, ( at 17,800 I still had 24.5mp) with fuel flow around 13.8 to keep cylinders below 385, my climb rate was around 250-350fpm @115IAS

It's the RayJay, installed just after leaving the factory in 1969, in the last 1100 hours we sent the turbo out once for overhaul, Approved Turbo Components from California overhauled it for $1051.57 (2007) I'm sure for that money they didn't need to replace any major components.

It has cost us very little but we don't use it much (flying mostly in the east) but I would expect heavy use would change that.

 

[Brian Scranton]

Thanks for the info guys...truly appreciate it. My offer has been accepted and I'll head up to check her out (and take her home) next week. Go Team!

[cliffy]

You will need to do a "turbo critical altitude" flight check. Find out what is listed as the Critical Altitude for the turbo, fly to above that altitude to check and see if the system is working properly. If the turbo can not make it to Critical Altitude without loosing manifold pressure you either have a worn out turbo, bad waste gate or intake system leaks. 

[N201MKTurbo]

I would think the Rayjay system with the manual waste gate system would hit critical altitude, with the waste gate closed, at something above 25000 ft. It will get pretty hot up there. I would say that if it can make full power at FL180 it is doing just fine.

[cliffy]

Are you saying that the RJ system has no critical altitude listed in its performance manual? 

That the RJ system wastegate never closes?  

I have no access to an RJ manual  but most every other turbo system I have ever worked on or flown had an altitude defined by the manual (when operating correctly) at which the waste gate was finally closed and above which the manifold pressure would begin to drop.   "Critical Altitude" for the turbo system. Any altitude lower (sometimes WAY lower) shows a turbo weakness, bad waste gate or system leaks that the turbo can't keep up with.

The question is, does the turbo system match what the book says it should do or not?  Guess work aside. 

If one is testing a system the "I would think" procedure won't cut it especially if it has financial risks like the cost of a turbo replacement after a purchase that the prebuy didn't find. If I'm doing your prebuy you can bet I'll check this so I don't get blamed for not finding a bad turbo system when your first annual rolls around and you won't be faced with that expense. 

Isn't this where we get into that high cost of the first annual business?

 

 

 

[Brian Scranton]

Good call cliffy...I am heading up this week to fly and buy. I'll take her high up and check it out. 

[M20F]

The Rayjay comes with a old school performance chart/graph that lists % HP through the range.  My POH is in the plane with it but you should get around 27" at 180.  You might see an inch or so less depending upon atmospheric conditions.  An exchanged turbo is $2800 as of last year from Main Turbo so even if it has some issues, they aren't expensive to get working correctly.

If you need some specific numbers Brian let me know and will try to remember to write them down.  

[N201MKTurbo]

No, I'm saying that the Rayjay system, with a wastgate that can be fully closed, will have a critical altitude so high that the engine heat will be the limiting factor, not the critical altitude.

It is essentially the same system that my plane has with a manual wastegate and no intercooler.

[M20F]

5 hours ago, N201MKTurbo said:

No, I'm saying that the Rayjay system, with a wastgate that can be fully closed, will have a critical altitude so high that the engine heat will be the limiting factor, not the critical altitude.

It is essentially the same system that my plane has with a manual wastegate and no intercooler.

Fully closed happens around FL180 which will be about 27".  CHT isn't an issue other than you need to run ROP to keep them down and prevent bootstrapping (I usually trail cowl flaps as well).  I would guess that 27/27 at 180 doesn't correspond to the same % of BHP at sea level due to CDT's but it isn't going to be a huge reduction.  

[N201MKTurbo]

Mine reaches critical altitude at about FL210 with a fixed wast gate that isn't closed all the way. It has the same turbo and the same engine. The only difference is the inter cooler. I didn't think it made that much difference, but apperently it does.