M20J 201 Model Speeds

[GOJAC]

I have had a similar problem with my M20J.  I was achieving a cruise speed of about 145kts TAS at 2,000ft with 75% power set.  I asked my A&P to take off the rocker covers and check the valve lift.  Two of the inlet valves had a lift of only about one third of the others due to cam wear.  The engine had less than 400 hours but was overhauled 11 years ago.  I had a similar problem in 2010 twelve years after an overhaul.  The aircraft has always been hangared, but this does not seem to stop corrosion of the camshaft.  The engine has now been overhauled and fitted with a new camshaft and I am achieving 160kts at 75% power.   It may also be worth checking the RPM indicator.  Mine has a 150RPM error.  Replacements do not seem to be available so I have fitted an EDM830 with RPM and MAP.

Roger

[1980Mooney]

On 5/24/2022 at 9:42 AM, Hank said:

No, he means the J model changed in 1978 from having a big-plane throttle quadrant to having the three control cable knobs sticking straight out of the panel for operation using pull and push motions.

Vernier controls came later.

All J models from Serial #0378 and up to the end of production had "push-pull" controls with Vernier adjustment on Mixture and RPM.  The Throttle "push-pull" had a screw friction adjustment.  All J prior to Serial # 0378 (except 0084) had the lever controls.  There are no "push-pull" Mixture and RPM controls without Vernier adjustment.  Below is a pic of a 1978 M20J 201 panel clearly showing the Vernier controls on Mixture and RPM.

[carusoam]

On 5/23/2022 at 5:09 PM, MooneyPilot145 said:

I have a 1977 M20J 201 with an IO-360-A3B6D. This model boasted 201 mph back in its time, but I average about 150 mph groundspeed (~135 kt true). It trims out nice in flight but just curious what others see.

I've also noticed the elevator has a natural downforce to it because of the bungee springs in the back. That tension decreases SOME when the tail is trimmed, but curious if anyone knows why those springs are there, and if it's possible it could be causing any drag in flight?

Any other mods or tweaks to improve speed or is what i am seeing normal?

Welcome aboard 145,

Sense a whole can of worms being opened?

 

You know… Mercury built a car called the Marauder…. I don’t think any actual Marauders bought the car…
 

You can select an arbitrary spring to discuss….

But, if you leave out 99 of YOUR more important details from aviation 101….

We’re gonna be here all night!

Have you compared your WnB to the marketing ads from 1977?

How are your power measurements being checked?

Does your T/O run match your POH?

Same for your climb rate?

Compare these to the marketing guy’s plane as well….

 

Any idea what the OAT was and what altitude they used?  Or YOU used?

 

Yes, you can get his speed number… but probably don’t want to go through the time and effort to do so…  it will work under a very narrow set of conditions…

Welcome to aviation 102… the next step up…  

Soooooo much to learn about Mooneys…. And marketing….

Best regards,

-a-

[ArtVandelay]

A bad cam will cause horsepower loss because valves aren’t opening fully, I think this can be checked by pulling valve covers.

[Shadrach]

On 5/23/2022 at 5:27 PM, Ragsf15e said:

Definitely need your power settings, but at anything “normal”, that seems wrong. I plan for 145ktas in my F when ROP and 138 LOP when between 7-10,000’. You should be 10kts faster.

Are you running 20° or 25° On the ignition timing?

[Shadrach]

On 5/25/2022 at 11:17 PM, 1980Mooney said:

All J models from Serial #0378 and up to the end of production had "push-pull" controls with Vernier adjustment on Mixture and RPM.  The Throttle "push-pull" had a screw friction adjustment.  All J prior to Serial # 0378 (except 0084) had the lever controls.  There are no "push-pull" Mixture and RPM controls without Vernier adjustment.  Below is a pic of a 1978 M20J 201 panel clearly showing the Vernier controls on Mixture and RPM.

 Pretty sure you guys are both saying the same thing. I read @Hank ’s last sentence as a reiteration of the previous statement not a suggestion that there were three different types of controls used on the J model’s production span. Pretty sure he knows that vernier controls in Mooneys preceded the 201 by decades.

[jetdriven]

Clean it up and you can get 159-160 KTAS LOP. 

[Fly Boomer]

On 5/23/2022 at 4:09 PM, MooneyPilot145 said:

This model boasted 201 mph back in its time

Many excellent suggestions above, but "201" is a marketing number.  As a practical matter, in level flight, the 201 won't do 201, the 231 won't do 231, and the 252 won't do 252.  I don't doubt that a Mooney test pilot saw those numbers one time in a very light airplane with a new engine, but you and I are not going to get those numbers.  Mooney quit using numbers as marketing names after the 252,  Still, you can probably outrun most of your pals flying B, C, or P airplanes with similar power.

[Hank]

32 minutes ago, Fly Boomer said:

. . . you can probably outrun most of your pals flying B, C, or P airplanes with similar power.

My little C, with 180 hp, walks away from stock C182s with 235 hp and 50% higher fuel burn. Fueled for a long trip, I can carry just about as much baggage, too. . They need so much fuel!

[Ragsf15e]

2 hours ago, Shadrach said:

Are you running 20° or 25° On the ignition timing?

20 as base, but I have a SF mag on the left and generally fly high (I’m in the northwest), so MP is below 25” and there is some amount of advance happening.

Post SF, I did notice a (small) speed increase LOP.  I’m sure setting 25 deg advance is noticeable.

 

[N201MKTurbo]

On 5/24/2022 at 12:12 AM, 1980Mooney said:

l key modifications contributed to the increase in speed. Wheat said the engine cowl redesign added about 8 mph, the sloped windshield also added about 8 mph, the inboard gear doors added about 5 mph, and the gap seals, flap hinge and empennage fairings added another 1 mph compared with the M20F.

So, A J should go 21 MPH faster than a F ???

I have owned both and a J goes maybe 5-10 MPH faster.

[ArtVandelay]

Many excellent suggestions above, but "201" is a marketing number.  As a practical matter, in level flight, the 201 won't do 201…

It’s not a marketing number, it’s just performance under ideal conditions.

Removing all the extra antennas we add: ADF, ELT, GPS, etc.
Plane is clean, engine is making max power, gear doors are adjusted correctly, timing is correct.
Atmospheric temperature is standard, low humidity.
Weight in plane is balanced, it’s not all in the front seats.

And a few more tricks the engineers probably have to squeeze a few extra knots out of it.

[Fly Boomer]

58 minutes ago, Hank said:

My little C, with 180 hp, walks away from stock C182s with 235 hp and 50% higher fuel burn.

Oh, that's fun!

[201er]

44 minutes ago, bluehighwayflyer said:

I have owned both an early J and a lowly C.  Both for long periods of time.  The J cruised only 10 knots faster but, at the C’s cruise speed, it was remarkably more efficient.  Like 20 percent.  That is way more impressive than is the paltry 10 knots but no one ever talks about it.  Neither have ever made “book” numbers, even after the installation of a factory reman engine.  Neither have ever been rigged by a specialist such as @jetdriven, either.  I’m sure that that would unlock several more knots from both of them.  

E often outclimbs an equally loaded J. Not sure if this is the case with C?

[201er]

40 minutes ago, bluehighwayflyer said:

2900 pound gross late J’s are a striking 325 pounds heavier at gross than are Cs and Es.  We all know that is a lot for these airplanes and it has to negatively impact takeoff and climb performance.  

Well it’s the same wing and more weight, so obviously that’s gonna take a hit. It makes sense how the aerodynamic cleanup can make them faster at high speeds, but doesn’t help all that much at slow speed and climb. 20HP less vs a few hundred pounds may cancel out. But I do know for a fact that in formation flight, it’s hard to keep up with an E in the climb.

[jetdriven]

I would theorize a J and an E at the same weight will climb about the same. 

[mooniac15u]

3 hours ago, bluehighwayflyer said:

I have owned both an early J and a lowly C.  Both for long periods of time.  The J cruised only 10 knots faster but, at the C’s cruise speed, it was remarkably more efficient.  Like 20 percent.  That is way more impressive than is the paltry 10 knots but no one ever talks about it.  Neither have ever made “book” numbers, even after the installation of a factory reman engine.  Neither have ever been rigged by a specialist such as @jetdriven, either.  I’m sure that that would unlock several more knots from both of them.  

That's an interesting observation.  What was your metric for efficiency?  My J is faster in cruise at any fuel flow than my D was.

[mooniac15u]

2 minutes ago, bluehighwayflyer said:

Fuel flow.  And, yes, my J was faster at any fuel flow than my C is as well.  

I think I misread your post.  I thought you were saying that your C was 20% more efficient.

[mooniac15u]

2 minutes ago, bluehighwayflyer said:

No. The opposite.  My J was only perhaps 7 or 8 percent faster than my C at max cruise but it was around 20% more efficient if slowed down and flown at C speeds.  To me at least that is a greater evolutionary improvement than is the J’s improved top speed that so much is made of.  Two sides of the same coin, though, obviously.  

I agree.  The higher top speed is nice but the efficiency has made a bigger difference for me on long cross country flights by reducing or eliminating fuel stops.

[carusoam]

4 hours ago, ArtVandelay said:

It’s not a marketing number, it’s just performance under ideal conditions.
 

Let’s be nice to the marketing guys for a moment….  

They collected one data point, under ideal conditions, then left out the details, and then promoted it like crazy… 

 

For real reproducible numbers… under actual conditions… with an engine that wasn’t fresh from the factory…. With real UL and actual antennas on the roof….

Find the writings of the real Mooney engineer, who wrote reviews in the MAPALog…  (memory help anyone?)

 

Then take the interior out of the FireBird, empty most of the fuel tank, put on the racing slicks, then hit the 1/4 Mile…

YMMV…. 

 

Best regards,

-a-

[A64Pilot]

5 hours ago, Ragsf15e said:

20 as base, but I have a SF mag on the left and generally fly high (I’m in the northwest), so MP is below 25” and there is some amount of advance happening.

Post SF, I did notice a (small) speed increase LOP.  I’m sure setting 25 deg advance is noticeable.

 

You will not get a speed increase LOP, you will lose speed LOP compared to the same MP / RPM at ROP, but you will most likely burn much less fuel.

Your highest speed will be at low altitude and best power mix, but most of us would run full rich for concern that best power is a little lean (hot) at TO power, but assume the factory was going for every knot and may have risked it.

Best power mixture is called that because it’s the one mixture that gives best power, any leaner or richer will result in a power loss, power drops off faster going lean than rich of peak.

Depending on engine best power is usually around 100 ROP

[Ragsf15e]

2 minutes ago, A64Pilot said:

You will not get a speed increase LOP, you will lose speed LOP compared to the same MP / RPM at ROP, but you will most likely burn much less fuel.

Your highest speed will be at low altitude and best power mix, but most of us would run full rich for concern that best power is a little lean (hot) at TO power, but assume the factory was going for every knot and may have risked it.

Best power mixture is called that because it’s the one mixture that gives best power, any leaner or richer will result in a power loss, power drops off faster going lean than rich of peak.

Depending on engine best power is usually around 100 ROP

Dude, did you even read what I said?

If you’re not bothering to read what people say, then don’t bother to comment.

I said there was a slight increase in speed LOP after installing a SF mag which will increase the timing slightly at lower MP.  Increasing the timing results in very slightly higher temps and potentially more of the energy captured inside the cylinder.  The effects on my engine are not detectable ROP, but a slight increase in TAS LOP.  I never said LOP was faster than ROP.

[A64Pilot]

Dude, I quoted you word for word, but I do now understand what your saying that your new LOP speed is slightly higher than your previous LOP speed.

I’m trying to figure out why your airplane cruises at 135 kts, where most will cruise at 155 kts. That’s not a little bit, 20 kts is a whole lot. it’s a big number, one that might be at least partially explained by LOP operation.

135 kts is 182 or big motor Maule speed, a J Model ought to blow their doors off.

[mhrivnak]

10 hours ago, jetdriven said:

Clean it up and you can get 159-160 KTAS LOP. 

Can you elaborate on how to achieve that? Seems like a lot of Js settle from 145-150 KTAS LOP.

[ArtVandelay]

So, A J should go 21 MPH faster than a F ???
I have owned both and a J goes maybe 5-10 MPH faster.

But your J has turbo, so not apples to apples.