Original RayJay Turbo Normalizer v M 20 Turbo v Turbo Bullet

[Marauder]

Yves -- I entertained and spoke to John about his turbo system he has available. When I discussed it with my mechanic, he wouldn't install it. He walked me over to another Mooney in his shop which had one installed and began telling me about the issues that the owner was dealing with. I think they work but it appears they introduce other challenges.

I think Beard indicated it didn't change his plane's original service ceiling, just gave him more available power at altitude. 

[Guest]

10 hours ago, Beard said:

I own a 1984 J with the Turbo Bullet conversion. It still gives 38" of boost, but is placarded down to 33". I must admit that in the 6 years that I have owned it I have used the 38" for a very short period and it has performed quite well, good speed. However, when flying it at 33" in the lower altitudes, up to 7,000 ft, I am not as fast as a non turbo J. I have done a few comparisons with other stock 201s and they have left me in their dust. Maybe my engine is putting out less horse power that it should be at its close to 1800 hours, but I am not pleased with it performance. When climbing after take off I am at best getting 600 - 700 FPM on a warm day near sea level at 75 kts. It does climb well at higher altitudes when in cruise. I don't fly at higher altitudes so cannot report on them.

When my conversion was originally done it was for a true turbo so it had low compression pistons installed. It is very clear to me that my 201 with it's low compression pistons and max allowable boost of 33" makes it slower than if it was left stock.

I am starting to gather info on reverting it back to non turbo when it is time to rebuild the engine. I am not at all pleased with my Turbo Bullet conversion and wish I had not bought it.

I have been told that rebuilding the turbo would not be a difficult thing nor extremely expensive.

Other than only focussing on reliablity and cost of repairs, I would like to suugest that you fly this aircraft you are lookin at getting a share in and experience the climb out and top speed. Compare this to stock 201s. If it performs like mine it may be an eye opener for you.

Good luck.

Something sounds wrong with your engine, it should perform better than you're describing.  I'm over in Kitchener CYKF, I'd be happy to take a look at it with you.  We also have a good local engine shop who may have some ideas.

Clarence

[M20F]

13 hours ago, Beard said:

I believe it it is still the 200 HP. The bonus is keeping max HP at altitude. Not entirely sure.

Well if 38" is 200 HP and you are now limited to 33", it is definitely going to perform accordingly a lot worse.  You are probably only getting 70-75% power at 33/2700.  I would assume you have performance charts, what do they show?  

[KSMooniac]

38" is way more than 200 HP from what I've read. It never should have been certified to go that high. 33" should put it back down to 200, and I suspect something is amiss as Clarence pointed out.

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[M20F]

40 minutes ago, KSMooniac said:

38" is way more than 200 HP from what I've read. It never should have been certified to go that high. 33" should put it back down to 200, and I suspect something is amiss as Clarence pointed out.

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I don't know much about them and the only thing I found were these two articles article-1 /  article-2 and both seem to indicate it stays at 200HP but the  second states the compression ratio drops from 8:5 to 7:5 along with a RPM reduction to 2575 from 2700.  That would indicate to me 200HP is probably still the total which if you take 5 inches off probably is going to mean you are climbing at 75% power and that would reflect the climb rate the OP is seeing.  

I would personally do some TAS tests against the reference figures in the book, they actually list 33/2350 at 12500 as 155KIAS/189TAS so easy enough to see if you are close to that, if not definitely worth having somebody check out. 

Performance charts though would clear up a lot of the mystery, the fact there is almost nothing to be found on the Internet about the conversion would make me wary of buying one.

[KSMooniac]

Nice find with those articles!  I've previously searched for more coverage on the TB mod but never found those.  As I mentioned above, the conversion is no longer supported and it is hard to find any info about it at all.  I've heard if you call the vendor (the ADI principal is still in the business, but as a new company) and ask about the kit you'll get hung up on.   I've not tried that.

As an engineer in the industry, I can read between the lines a little bit.  For an STC project, if the horsepower or overall performance is substantially altered, then it triggers a LOT more testing and substantiation.  The first article mentions the "published" takeoff distance remains the same (ie they did NOT change POH performance charts) but the "unofficial" performance yields 11-20% reduction in takeoff distance.  That requires a lot more HP to generate that much of a reduction.  Ditto for the reported 1350 FPM climb rate in both articles... My stock J won't do that.    The first article mentions the TB J is faster than a stock 231 and 252, which have 210 HP.  To go faster in cruise with substantially identical airframes requires a lot more power, although the modified J is probably a little bit lighter than the K models.

I had forgotten about the 2575 RPM limit on this mod.  I wonder if the AD that restricts MP to 33" also allowed going back to 2700 RPM?  That would be something to verify as 33" and 2575 RPM is probably less than 200 HP.

FWIW, my Mooney mentors in college had the kit on their personal J.  I got a ride in it once, but didn't have enough Mooney experience at the time to notice performance differences... I was just in awe of the performance and loaded panel compared to the Cessnas I was used to.   They helped establish our flying club, and leased their J to a few experienced members now and then.  One of them crashed their plane in 1993 and unfortunately died, but at least his wife and 2 kids survived.  There was a power loss for undetermined reasons, and he made a mistake in not aborting a takeoff, and then in trying to return to the departure airport.  The AD limiting MP on the conversion came out in the wake of this accident, and I believe the kit was withdrawn from the market soon after.

[carusoam]

Starting to sound too complex to be usable...

1) Mooney TC'd engines have been evolving since the 231.

2) some planes simply got an add-on TN system.  Simply remove it when no longer wanted...

3) the turbo bullet got the complete change of hardware to lower the CR.  A little more challenging to simply remove.

4) the 231 went through improvements from the case to the inter coolers to the pressure controllers and became the 252.

5) was the TBullet built by the same guys in Florida that built the 262? A 252 copy?  

6) The simple idea of swapping out some pistons and adding a TC has fallen down here.  There just isn't enough pro Turbo Bullet owners with data to say 'it works for me'.  Who used the high compression helicopter Pistons with similar unappreciated results?

7) Compare to the Missile owners and rocket owners.  The data should be easy to find and readily available.

8) some things are just too hard for ordinary people to use.  Adding in a partnership increases the complexity.

9) is the TB engine being used succesfully in other airframes?

10) There are good ideas that have been bolted on Mooneys that have worked very well.  They get incorporated by the factory over time.  Speed brakes, inter coolers, TC controllers, the IO550...

11) when the engine management fails (pilot is responsible), what does it cost to fix?

These are the ideas that I had when looking at a plane to replace my C.  Hope that helps with your thought process.

Best regards,

-a-

 

[Beard]

I do not think the service ceiling of my TB 201 has changed. I suppose I should know, but I don't.

[M20F]

11 minutes ago, Beard said:

I do not think the service ceiling of my TB 201 has changed. I suppose I should know, but I don't.

Service ceiling is just when the plane stops climbing at 100FPM, it is a performance reference only and with a turbo it has changed for you.  The regulatory component is maximum operating altitude which is a limitation, that you can't go above as it is an operating limitation.  

This is from FAA perspective but would assume rules are the same in Canada.

Edited January 22, 2016 by M20F

[KSMooniac]

1 hour ago, carusoam said:

5) was the TBullet built by the same guys in Florida that built the 262? A 252 copy?  

No, it was done by an outfit in WA state...still in business with the same principal, but different company.  Started with Mooney mods and greatly expanded into others, and has been pretty successful.

Engine management is just like a stock 231...up to the pilot to manually control MP/boost vs. just firewalling it and forgetting it.

[carusoam]

Thanks, Scott. I think I did a fair amount of searching to find their version of speed brakes for somebody recently...

Best regards,

-a-

[aviatoreb]

Hey Yves, This seems like a really good airplane, and it is looking for a partner in Gatineau right by you!!!  What are the chances of that?!  A tks 262 is a really good airplane.  Much better than a turbo bullet I should think.

http://www.trade-a-plane.com/detail/aircraft/Single+Engine+Piston/1981/Mooney/M20K+231+Modified/1763132.html

Edited January 23, 2016 by aviatoreb

[yvesg]

Thanks Erik. I knew about this one. I do know the owner a bit and know it is a better airplane. I will go through annual for now (going in next week-end). It is due for 10 year mandatory prop overhaul so it will be in the shop for several weeks. This will give me the time to think about all this.

 

Yves

[aviatoreb]

2 hours ago, yvesg said:

Thanks Erik. I knew about this one. I do know the owner a bit and know it is a better airplane. I will go through annual for now (going in next week-end). It is due for 10 year mandatory prop overhaul so it will be in the shop for several weeks. This will give me the time to think about all this.

 

Yves

Well....if you need me to come up there and test drive that 262 with you!  Any time!

[rlinford1]

Just found this thread while looking for something else.  I own an M20J with the original engine and Turbo Bullet still installed. I have flown it since the early 80's.  No issues but I do run it carefully like any turbocharged engine.  Time on engine since last rebuild is about 2400 hours.  Annual last week compression test was good and a bore scope inspection revealed normal patterns on the valves and cylinder walls.  I will run the engine past TBO as long as compression and inspections show it to be sound, and I certainly wont take the turbo system off - it works really well.  And it's simple. Downside is you have to be careful not to over boost on takeoff but that's manageable if your on the ball.  There are some "scare stories' out there you shouldn't listen to. Over-boosting was a real issue but if you run it at 33" your not straining the engine.  Only issue is parts - my brother had to have the exhaust system rebuilt but that's what you deal with when your flying an old airplane. Also be darn sure your mechanic understands what they are looking at.  We had one shop decide the fuel servo was set wrong so they sent it back to the factory to be re-ported.  Took 6 months to get the STC information to straighten it out and get the plane flying again.  When the engine goes you wont be able to get Lycoming to rebuild it but any competent shop with the correct specs can rebuild it with the shorter pistons.

I also have all of the original STC documentation and drawings available.  Because of liability I don't want to give them to anyone who is contemplating adding a new system to their aircraft but I have no problem sharing if you can prove you own a TurboBullet already. Only cost would be to scan the documents.

Edited March 25, 2016 by rlinford1
Typo

[carusoam]

Welcome aboard RL.

Some people's scare stories are just another day at work for other people.  Thank you for the offer to share the hard to come by documents.

Engine management is the key to it's longevity.

Best regards,

-a-

[Beard]

Good to see that someone has something good to say about the Turbo Bullet. I have a 1984 J with this TB installed. I religiously keep below 33” so do not worry about stressing the engine. I just don’t feel like it performs as well as a stock M20J. I did some tests with a 1990 M20J and it out climbed me and was significantly quicker in cruise. My climb on a warm day can be 600 fpm at 1000 agl. At higher altitudes it performs much better.

 

My engine has about 1750 hours since new. When the TB was installed it was not overhauled, just the top end done. When the rebuild time comes I am contemplating going back to original. As there are so many negative comments about the TB on the internet it will be this that I have to deal with if I ever resell my Mooney. The paranoia about the TB may be unfounded, but perception is reality when I will be talking to a potential buyer.

 

Others on Mooney Space have told me that my lack of performance could be specific to my plane and I intend to have it looked at this summer.

 

I too have all the original STC documentation and drawings for the Turbo Bullet.

[kortopates]

When you compare your TB to the J what altitudes are use considering. If you compare at Sea Level and I can imagine the stock J out performing you. I have no time in the TB but the turbo itself doesn't add horsepower - in fact it generally robs you of it down low for the added overhead of spinning up the turbine - unless you can totally bypass it. But if you operate it altitude as turbos are designed for you should have no problem beating out a stock J. For example, you should do much better taking off from a high density alt airport such as Big Bear or Mammoth, and cruise much faster up in the middle to upper teens. But I wouldn't expect improved performance below 12K. Its important to know your birds critical altitude and take advantage of that when the winds aloft allow. But down low you are likely paying the overhead cost without any of the benefits.

If I had a performance concern the first thing I would likely do is fly it up to its critical altitude to very its performing as expected.

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[M20F]

My understanding is the Turbo Bullet is 200HP at 38" so when you limit it to 33" you are reducing BHP by quite a bit, hence the poor performance compared to a J (and probably F/G/E/C's) down low. 

[rlinford1]

My recollection is that the FAA and Lycoming determined that the engine was producing well over 200 hp at 38.5" hence their concern and the AD.  Been a long time so my memory is fuzzy. Supposedly 33" was calculated to produce 200hp but who knows.  I have not flown it sans turbo for 25 years so I don't have anything to compare it to but I would give up a little sea level performance for what I get at altitude.  Lots of tall hard mountains and weather around Spokane.  

Also the documentation I have came from the STC holder  and is not just the information that comes with the kit.  Probably not something anyone needs until they are looking at some major work - it's essentially what they submitted to the FAA to get the STC in the first place.  I never cataloged the whole thing but it's a lot of information - all I was looking for was servo porting info.

[carusoam]

One thing you may be able to compare...

Performance while running at peak or LOP.  

HP will have a direct relationship to FF and CR.  If you have the engine's compression ratio and a fuel flow instrument, the calculation boils down to multiply FF by a constant...

Do you know the CR of the TB's piston's/cylinders?

Best regards,

-a-

[M20F]

2 minutes ago, carusoam said:

Do you know the CR of the TB's piston's/cylinders?

7.5:1

[rlinford1]

Don't have the specs here at home, I'll look next time I'm at the hanger. Would be interesting to calculate it. 

 

[carusoam]

Borrowing from thread written by Dan Brown....

When LOP, the only way to know how much power you're making is to know fuel flow.  With 8.5:1 compression and LOP operations, fuel flow (in gph) * 14.9 = horsepower.  For the turbos that run around 7.5:1 compression ratios, the multiplier is different; I think I remember hearing 13.7, but I wouldn't bet on it.

 

Anyone know the name of this multiplier or how to look it up?  

Best regards,

-a-

[Beard]

Embarrassingly I am not sure what CR means.

I always lean for ROP, not LOP. I find that the for the best power when I lean ROP I get the FF called for in the Turbo Bullet specs. Examples are: 65% @ 11.8 GPH & 75% @ 12.9%.