March Edition of THE MOONEY FLYER available

[mooneyflyer]

The March edition of The Mooney Flyer is available!

In this edition are:

• Insights into Mooney Stall Speeds & Characteristics
• A Mooney Factory Update
• Pre-Purchase or Pre-Annual Inspection when buying a Mooney
• My M20C Flys at 150 knots TAS
• How I got my Medical Back
• Out of the Clear Blue Western Skies
• Tales from the Right Seat to St. George, Utah
• Aeronautical Decisions

You can access this issue in either PDF or Flip Book versions by clicking here at http://TheMooneyFlyer.com

[rob]

Regarding the M20C speed article, I can find no such IAS / CAS chart in any of the various early M20C POHs that I've come across. That aside, relying on a single sample from the airspeed indicator to measure TAS is a fundamentally flawed exercise in my opinion.

[mooneyflyer]

Sounds like you may be stuck on basic definitions. Not unusual at all.

First it helps to have a simple understanding of how the ASI works. It doesn't really measure "speed" the way the speedometer on a car does. What it's really doing is comparing impact (or ram) air pressure coming through the pitot tube with static air pressure coming through the static port.

Indicated Airspeed (IAS). Some folks try to make this more complicated than it is. It's simply the speed that is shown on the airspeed indicator. Period.

Calibrated Airspeed (CAS). When you are in level flight at cruise airspeed, the pitot tube is aligned directly with the relative wind. But when you are, say, flying level slowly, the pitot tube is pointed up at an angle to the relative wind. It's not getting a direct flow, so the measurement is a bit off. This is what the book calls "position error".

Calibrated airspeed is indicated airspeed corrected for that error. As was already mentioned, there's a table in the aircraft manual that shows how to convert from one to another. Older Mooneys do not all have this data as they per-date modern POHs.

[rob]

I'm not confused about the definitions at all, not sure how you'd come to that conclusion based on the two sentences I wrote. I'm well aware of what IAS and CAS are; I just think that calculating TAS based on the indications from a 40 year old pressure instrument is futile, especially when there are more accurate ways to do so; as discussed many times over in threads here and on every other aviation forum. 

[carusoam]

The 1974 POH for the M20C includes a chart for calibrated air speeds at three different flap positions and gives an expected error range for AS indicators. Section 6-6 in the performance section.

The '74 POH was recommended to me by Bill Wheat at the factory in 2000 when I purchased my ’65C. It was the most complete POH for the C Model available.

It's pages are durable white plastic sheets and only half as thick as the more modern POH for my 90's O1.

The '65C 'POH' was an owners manual or booklet and was missing most information.

Of course, Use caution when assuming a manual will be appropriate to your model and year of production. We've covered this topic in other areas such as POHs for the J with different MGTOWs...

As usual YMMV...

Best regards,

-a-

[BigTex]

Would you by chance have a PDF version of the 1974 M20C POH version that you can share?

[carusoam]

Unfortunately, I no longer have access to copy machines or office machines of that level of technology.

Probably still available from Mooney at a fair price.

Best regards,

-a-