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Mooney M20C Vspeeds, IFR profiles, Procedures, etc...


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Hi there,

I'm seeking Vspeeds (VS0, VS1, VX, VY, VLMAX...ETC) for a mid-60s M20C equipped with the old school Johnson-bar landing gear,

Additionally, I'm interested in finding out what configurations and speeds are working for you fine folks in this make and model during both precision and non-precision approaches.

Last—does anyone have a document reflected Mooney vetted emergency procedures specific to the C model?  I was looking in the downloadable content, but maybe I missed something.  Will look again.

Thank you in advance.

Gratefully,

JN

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Welcome aboard Judas...

Let’s start with what you have...

1) Do you have an owners manual that matches the year of your plane?   (Legal issue / solution)

2) Do you have the latest POH ever printed for the model of your plane?  (Technical issues/ solutions)

 

These two document are the basis of many answers to the hundred questions you are going to think up...

Seek the download section of MS to see what comes close...

Then call your MSC to order what you don’t have...

 

The next step...

3) Look up MAPA... they are a great resource for all things speed related.  They sell great training and comes with a manual that specifically answers your question...

How was that for a speedy response? :)

Best regards,

-a-

 

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9 minutes ago, carusoam said:

 

Thank you for your prompt reply.  I have neither document, I'm afraid.  A friend recently acquired a Mark 21, and is interested in finishing his instrument rating.  I'm doing a little research to that end.  I've downloaded several of the different model-year information manuals from MooneySpace, but haven't bit the bullet and joined MAPA.

Edited by TheJudasNut
Bad formatting due to quote box
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IFR and MAPA are perfect together... a weekend in a nice place discussing Mooney flying at all levels tailored to your specific needs...

when you have done this a few times, you find new and interesting types of approaches to really hone your skills...

Ever done a PAR approach?

There is a pretty late model POH for the M20C in the download section of MS... 1977 is the last one written for the M20C.  I bought one direct from Mooney.  They might have digital copies by now... not very expensive, and highly filled with data.  Still 200 pages short of a modern POH...

Best regards,

-a-

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Ah, yes, Emergency Procedures . . . . The missing information in vintage Mooney Owners Manuals . . .

The Cessna i trained in had page after pagemof Emergency Checklists, seemingly a complete listmfor every possible emergency. My Mooney book has an Emergency Section, two whole pages--half of which is Emergency Gear Extension and Alternator Failure, all in paragraph form. It does kindly mention near the top "In the event of engine fire, close cabin vents" as the total advice, rather than step-by-step instructions.

Many of the V speeds are scattered through the Manual, rather than being listed all together. You just need to look for them in the relevant section. And I can't just give you mine because I don't have J bar gear or hydraulic flaps, so they are different. 

Just scroll through the Downloads section looking for the correct year and model, there's likely one there, then read the sections for Normal Procedures, Emergency Procedures and Limitations. Just don't look for checklists, it's all in paragraph form. Happy searching!

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According to the book, my Moony stalls dirty at 57mph, lean at 67.  Vx is 80, Vy is 105, with 120 being a fasts cruise/climb.  Gear speed is 120, flap speed is 105 (all in mph by the way, mine is a 62).  If mine has a maximum cruise speed I don't know what it is, I just try and keep it out of the yellow in rough air. Vne is 189.

For approaches and whatnot, hey, it's an airplane.  Fly it.

 

 

Edited by steingar
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Unless Im mistaken only a few speeds changed over time on the Cs, first in ‘68 and then again in ‘69.

In ‘68 Vfe went from 105mph to 125mph.

In ‘69 Vno went from 150mph to 175mph, Vne went from 189mph to 200mph.  These two changes were not accompanied by any structural alteration.

Other than that, I think speeds are identical for all C models?

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18 minutes ago, DXB said:

In ‘69 Vno went from 150mph to 175mph, Vne went from 189mph to 200mph.  These two changes were not accompanied by any structural alteration.

 

Hey @DXB , just curious- is this documented somewhere?  Particularly interested in Vno of 175 mph.

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16 minutes ago, Fred_2O said:

Hey @DXB , just curious- is this documented somewhere?  Particularly interested in Vno of 175 mph.

Sadly enough, it is documented in your Owners Manual . . . . No idea what if any changes were made to the aircraft structure / materials. Just glad that my C has the higher numbers, as it makes instrument approaches so much simpler:  Power back to 23/2300 and slow to 125 mph or less; add Approach flaps => slow from 120 to 105 mph (90 knots) if desired; drop gear when dot and a half above glideslope, the plane will start down centered pretty close.

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1 hour ago, Fred_2O said:

Hey @DXB , just curious- is this documented somewhere?  Particularly interested in Vno of 175 mph.

I think its been discussed extensively on here in the past, with some folks citing old time Mooney factory people as having stated it was purely a paperwork based change - no formal published source I can cite, though it may exist somewhere. I dont worry too much about the 150mph Vno on my ‘68 for this reason on a bumpy day - the thing loves to cruise in the yellow arc down low so I let it.  I’m not inclined to mess with Vne though- no need in routine flying - but if an emergency descent ever is needed, its nice to know a ton of extra margin is there. 

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44 minutes ago, DXB said:

I think its been discussed extensively on here in the past, with some folks citing old time Mooney factory people as having stated it was purely a paperwork based change - no formal published source I can cite, though it may exist somewhere. I dont worry too much about the 150mph Vno on my ‘68 for this reason on a bumpy day - the thing loves to cruise in the yellow arc down low so I let it.  I’m not inclined to mess with Vne though- no need in routine flying - but if an emergency descent ever is needed, its nice to know a ton of extra margin is there. 

Down low, my C will cruise happily 150-155 mph, but I don't fly that low much other than my 10.4 nm trips for fuel. It's fun, though. 

At altitude (mostly 7500 and up), she cruises in the mid-140s. But even descending from 3000msl cruise to 1700 msl pattern on a breakfast run, 500 fpm puts me right at 170 mph. Coming down from 9000-10,000 msl, this is fun for 50-60 nm! But my yellow arc runs 175-200 mph, and I only recall being there briefly a very few times (2? 3?).

Emergency descents at cruise speed with 45° bank are eye opening, and best practiced with a CFI a few times. But wow, it'll blow the bottom out of your VSI.

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Does you Mooney have an AS indicator.  Yellow band, green band , red tick for Vne that would be a start.  Gear speed Vlo ,  Vx and  Vy are not marked but in the POH verbage.  The one speed you should know is Va.  Good speed to be at in a mooney in turbulence with our wing loading;  it might even be placarded. 

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Va is never marked because it varies with weight. As weight goes down, Va goes down. The Manual will give one number, which is for gross weight. If you're worried about turbulence, fly slower than your published Va.

There should be a table or list giving Stall Speeds in various configurations and bank angles; it's worth studying. 

For Vintage Mooneys, there is only a single gear speed, so you don't need to worry about Opening Speed and Max Operating Speed being different; we just can't use them as speed brakes since we gotta slow down before putting them down. Depending on year, Flap Speed may be higher or lower than gear speed due to different construction methods for attaching the flaps to the wing.

Vx and Vy are in the Takeoff and Climb discussion, using descriptions like Best Angle and Best Rate of Climb. My Vy is 100 mph - Altitude in Thousands, there is even a chart showing Rate of Climb at two weights (gross, and solo with full tanks) and airspeed every 1000' from sea level to 18 or 20K. This makes the decreasing Vy very obvious. 

Study up! Have you found the correct Owners Manual yet?

Edited by Hank
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5 hours ago, TheJudasNut said:

Thank you all for your informative replies.  I appreciate it.

Still working on tracking down a '66 M20C manual, but this is all good info.

In the Downloads section, there is a file called "M20C POH" posted by @robert7467. While there is no year in the title (and I didn't download it to see), it appears that he has a 66C from some of his posts. This is part of why so many times people with questions are asked to populate their avatar with at least model designation and a hint of location.

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On 1/12/2019 at 9:09 AM, Hank said:

In the Downloads section, there is a file called "M20C POH" posted by @robert7467. While there is no year in the title (and I didn't download it to see), it appears that he has a 66C from some of his posts. This is part of why so many times people with questions are asked to populate their avatar with at least model designation and a hint of location.

 

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  • 2 weeks later...
  • 3 months later...

JN,

 

Here is the settings I came up with and use for approaches in my 77 M20C.   The beauty of this is how simple it is to use.  I am 2400 RPM, 18" Clean Approach Level at 100mph (about 90kts).  As soon as I intercept the Glide Slope - I do not touch RPM or MP,  I simply Drop the Gear,  Drop Flaps to TkOFf, and Pull Carb Heat.   Wait a few sec and I have a nice 500 FPM decent. 

image.png.07d152119708e6bc7d641e035342f04f.png

 

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  • 2 years later...

Some things to consider when talking V speeds.

1) Some V speeds are marked on the airspeed indicator by the bottom/top of the color bands, (published some stall speeds and some flap speeds for instance..)

2) The published V speeds vary according to your particular airplane serial number. (For example, our C model sn 2526 published Vy as 95mph with flaps at takeoff position. There is no mention of Vy with the flaps retracted.  (There are later C model pdf copies of flight manuals floating around the internet that show the Vy to be 105 with Flaps Retracted...)

3) All V speeds are published at MGTOW and SL Density Altitude. Regarding Vy, a decrease in GTOW results in a decrease in Vy. An increase in DA also results in a decrease in Vy. How much? We are not told, but by piecing together information from a variety of sources combined with experience I think a fair guess is that Vy in a C model decreases nearly 10mph at a very light takeoff weight and probably decreases another 2-4 mph at/near the service ceiling of the airplane.

Let's put this all together. The Vy at MGTOW with flaps at TakeOff position in a C model Mooney is about 95 mph.  After flap retraction it is around 105 mph. At mid weights, (2 people, light bags) the those speeds are probably closer to 90/100 mph.

I would be leery of not respecting the published Normal Operating envelope (top of the green arc) in anything but smooth air. Metal fatigue is cumulative; Just because there is no crack visible today does not mean no fatigue took place.

Ron - CFI/ATP/M20C sn2526

 

Edited by rc454
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Stall speeds according to POH  (1977, M20C)

1, clean 58 knots

2, Flaps TO+gear down 56 knots

3,  Full Flaps + gear down 49 knots.

 

Practically (tested yesterday- Weight 1017 kg, CoG 1188 mm, power off) 

Pictures below

1: clean

2: TO Flaps+ gear down 

3: Full Flaps + gear down

lg,m

clean.jpg

Flaps 15 + gear down.jpg

Flaps 33+ Gear down.jpg

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