M-20C Airspeed Indicator Replacement

[R Van Dyck]

Hello my fellow Birdmen/women. I am new to the group so please be gentle. I just purchased a 1975 M-20C. It has the standard MPH outer/ KTS inner ring style OEM Airspeed Indicator. I am looking for a KTS only style indicator (less clutter and easier  to read and not so cluttered). I know it can be done, the training M-20B I flew had a KTS only Ind.  I have only found a company that can make a new one with all the proper markings and limits. Starting at $800 and up!  My question is do any of you out in Mooney Land know of one that needs a good home or where to get one? Thanks in advance.

Fly Smart

Ryan

[Hank]

I think you're required to have fhe ASI marked in the same units that are in your Owners Manual. For my C, that's mph, but I do have knots on the inner ring. You're likely stuck with either mph & knots, or mph only for a clean look, in just about all vintage Mooneys. 

If you put in knots only, eventually one IA or avionics shop or another will require it to be changed out . . . . But it's your money, spend it how you want. Rescreening an existing ASI should not cost $800.

[StinkBug]

I find that the units used are somewhat meaningless. As you get used to the plane you figure out which numbers correspond to the phase of flight you're in. I actually use both scales for different things in my C. Basically I pick whichever primary marking matches what I'm doing so I can check it at a glance. After 700ish hours in my plane I'm not sure I could actually tell you what the exact speeds are, I can just tell at a glance if the needle is in the right place or not. 

When I got my G5 installed I could pick whichever units I wanted. I picked KTS at first, then quickly changed it simply due to being used to the original ASI, and scanning both. 

Edited September 26, 2017 by StinkBug

[Hank]

All I use the inner knot ring for is comparing against the GPS ground speed. This is handy for verifying which runway I want to land on, as well as determining the strength of head / tail winds.

[R Van Dyck]

Thanks guys for all the quick imput. I was born and all my upbringing in aviation all has been in KIAS. I am very new to the MPH thing. I will post a pick  of the panel below. I like the big Fisher Price letters and numbers that  are easy to read at a fast glance. I learned the quick ref 60,80,100, and 120 numbers for my M20 checkout, now I have to translate them in to MPH to see the big numbers on the outer scale.

[MBDiagMan]

Welcome to the forum.  I bought my C last February.  I also want to do something with my ASI, but mainly because it is foggy, probably from cigarette smoke from years past.  If you find a good source, please share the info and I will do the same.

looking forward to hearing more about your C.  It looks like an electric gear version.

[Hank]

5 hours ago, MBDiagMan said:

looking forward to hearing more about your C.  It looks like an electric gear version.

Mooney went all electric (flaps and gear) in 1969; before that, they were options for several years, with fewer and fewer buyers not opting for them.

[Raptor05121]

7 hours ago, Hank said:

All I use the inner knot ring for is comparing against the GPS ground speed. This is handy for verifying which runway I want to land on, as well as determining the strength of head / tail winds.

Hank, can you dive further into this? I'm perplexed

[N6758N]

1 hour ago, Raptor05121 said:

Hank, can you dive further into this? I'm perplexed

I'll try and explain for Hank- basically you can compare your GPS groundspeed (in knots) to your ASI inner ring, if you know what your actual TAS is, or if you are low enough to not make a difference, comparing the two will give you a rough idea of winds aloft. For example, your ASI says 120 knots, but your groundspeed is 140 kts. You can then approximate that you've got roughly 20kt tailwinds pushing you.

[carusoam]

Cleaning and re painting the face of the instrument goes a long way.  Instrument shops do this often.

They are also familiar the proper scales/paperwork/POH/OM that may be required...

Somebody went through this effort and posted Nice photos a while ago...

If you are fortunate... your manuals have both kias and mph in it.  

Many of the older ASIs were printed with mph in the most prominent areas, and KIAs were tiny on an inner ring.

Having one 're-screened' is all it would take.

Just a guess, check in with @Marauder, he may have updated his ASI.  Whoever did it, supplied nice photos.

Best regards,

-a-

[Bryan]

How about reconditioning the glass?  My ASI's glass seems to be kind foggy but the instrument works as it should.

[Marauder]

24 minutes ago, carusoam said:

Cleaning and re painting the face of the instrument goes a long way.  Instrument shops do this often.

They are also familiar the proper scales/paperwork/POH/OM that may be required...

Somebody went through this effort and posted Nice photos a while ago...

If you are fortunate... your manuals have both kias and mph in it.  

Many of the older ASIs were printed with mph in the most prominent areas, and KIAs were tiny on an inner ring.

Having one 're-screened' is all it would take.

Just a guess, check in with @Marauder, he may have updated his ASI.  Whoever did it, supplied nice photos.

Best regards,

-a-

I updated my ASI before I removed it a while later and sold it to Cyril. I just checked in with him and he says it is working fine although his plane is now a little nose heavy. I swore to him I thought I had cleaned all the fat off of it before I sent it to him. 

Mid-Continent did the rescreening and calibration of my ASI. I had the knots and MPH reversed. You can do that if your POH shows both. 

 

[carusoam]

It probably takes an instrument shop to wash the glass...

Best regards,

-a-

[Marauder]

[carusoam]

How is that for memory recall?  

-a-

[Raptor05121]

Marauder, I love that gauge. I wish our planes came with the TAS card like Cherokees

[StinkBug]

22 hours ago, R Van Dyck said:

Thanks guys for all the quick imput. I was born and all my upbringing in aviation all has been in KIAS. I am very new to the MPH thing. 

I did all my PPL training in planes with KIAS, and it felt a little weird when I got the Mooney, but that went away very quickly as I got used to the plane. Personally, unless there is something else wrong with the ASI I'd fly the plane for another 20-30 hours and see if it still bugs you. As for the 60, 80, 100 numbers, those are basically what I use in MPH, no need to translate. 

[flyboy0681]

I would prefer MPH. Whenever I fly with somebody and they ask how fast we are going, I always have to do the mental math - divide by ten, add half to that and then add it to the speed. I also don't like that OAT and EGT display in centigrade... lets see, 28 is 82, water boils at 100 and freezes at 0. It's displaying 18 so what is that in Fahrenheit?

If I wanted the metric system I'd order a Royale with cheese.

[Andy95W]

2 hours ago, daver328 said:

The big numbers on my gauge are MPH, and the limits in the Owners Manual are MPH. When I fly the Mooney, I think in MPH. There's just no getting around it for us.

Until we  ought our Mooney, with very few exceptions, everything I've flown has shown Knots. 

+1

[N201MKTurbo]

An instrument shop or the hangar fairies are required to clean the glass. The only problem is if the gasket cannot be reused the hangar fairies have to drag the instrument to the instrument shop with their head held low or put it back together and tell the instrument shop that it leaks and they need it fixed. 

[Bryan]

I am unsure my hanger fairy is competent enough to remove the glass and get it back together.  I might need an instrument shop.  At night, mine is almost unreadable because of the foggy lens.

 

[jetdriven]

On 9/26/2017 at 8:49 AM, Marauder said:

That looks fantastic who did the rescreen work 

[Marauder]

Mid-continent. Around $350

[outermarker]

I was informed that I need to have my ASI rebuilt and the cost will be around $350. At this point what options are there, rebuild, buy new or upgrade? I have to also consider the wing-leveler and autopilot(Brittain). Suggestions? It will go on a 65' E. thanks!

[65MooneyPilot]

Call aircraft quality instruments and ask them if they have a indicator face with knots. I just had them overhaul my airspeed indicator and the put a new face in it for 30.00 dollars I think it was.