1970 M20C Panel Upgrade

[tcal780]

My son and I just started the journey of updating the panel on my 1970 C! I'm super excited to do this with him as he has been working for the last 18 months at my local airport as an apprentice to gain his A&P cert. We're both going to learn a lot. His boss, the local IA, has agreed to oversee, and sign off on the project.

Going in:

Dual G5's

GNC255A

GMA345

GI106A (backup-only for Nav2)

JPI900

Cies fuel senders

Aera 760

 

Going Out:

Vac system

Century HSI

Intercom

Original Engine gauges

KI214

KX175B

 

The KX165, the STEC30 and the GNX375 will stay.

The pics will give you all an idea of where the panel was, where it's at, and where it's headed. This is the progress we made just this past weekend.

Best,

Tcal

[Utah20Gflyer]

That will be a nice set up!  Congratulations 

[DRH4249]

It looks like a great start to a very nice design

[tcal780]

I finished 95% of the old panel cleanup. The remaining wiring seen in the photo will stay.

A couple questions for the group:

First, panel mounting. Are there "standard" mounting brackets and avionics rails available for a new panel like this or will I need to have them fabricated? The avionics guy said vibration isolators are not needed anymore, citing Garmin avionics often don't work well with them. Is this the case?

Second, some advice on lighting. I am considering a combination of LED bezel ring lights for the 5 round instruments and an LED strip light on the underside of the glareshield for an overall flood.

I'd also like to have the toggle switches or switch labels illuminated. The original throttle quadrant/flap labels and compass are also illuminated with incandescent bulbs. Can these be converted to LED?

Ideally, I would like the avionics and the instrument ring lights to be on one dimmer and the remaining flood/panel lights to be on a second.

What would you recommend?

Thanks!

[PT20J]

I believe the GI 106A is has been replaced by the GI 106B. Are you purchasing a used GI 106A or did you find a new one on the shelf somewhere?

[Aerodon]

Some suggestions:

MaxDim Duo for panel and glareshield lights.  Nulites (incandescent work just fine, I think they make LED too but check that they are compatible with your dimmer)

KI206 or 209 for the KX165 to save a bit of money.  I think in the long run you will regret not doing 2 x GNC255's.

MD93 clock / OAT / USB C etc.

GI-275 engine gauge for space saving and symmetry.

Small vertical stack of circuit breakers like later model Mooney's on a separate panel.  It really helps to finish the power and grounds inn the airplane and have a quick connect like Mooney does on later models.

 

Aerodon

[Aerodon]

Here's a rough start based on my M20K panel.

I think your turn co-ordinator needs to be mounted vertically, or at least recalibrated for an 8 degree tilt to get a flat panel all the way across.  Or you can try doing a vertical panel all the way across?  I think a tilted panel will reduce the height of useable space in the radio stack because of interference?

Aerodon

 

 

 

M20C_R1.pdf

[tcal780]

Thanks for the suggestions Don.

I am planning to use the maxdim duo (or two single max dimmers). I prefer to not mix incandescent and LED, so I'm not sure what to do with the throttle quadrant lights.

This is (was) a vertical panel but the existing brackets and vertical rack rails are not suitable for reuse. I'll will need a new plan for those. This will be a two piece panel with the breakers all on the far right.

Tcal

[tcal780]

22 hours ago, PT20J said:

I believe the GI 106A is has been replaced by the GI 106B. Are you purchasing a used GI 106A or did you find a new one on the shelf somewhere?

I purchased a used 106A.

[tcal780]

Agonizingly slow, but making progress!

Question for those of you who are using the push to test LEDs from Lonestar for your gear warning lights...

The wiring diagram for the light shows  one 12v+ on pin #1. Pins #2 and #3 are grounds. When pushing to test, the light closes the circuit with #3. #2 is used for a switched ground (ie. gear position).

I thought it would take two 12v+ inputs with a common ground, but it's opposite. How did you make this work?

[jamesm]

Your Panel Looks nice.

Have you considered flush mounting G5's  ?

I did on my '67C  it looks  nicer in my opinion. I did have my G5's  sitting above panel for a  couple of years.  I changed mine because one of the RAM mount mounting option came real close to shearing off the knob of the G5. if I ever had to use full control input, highly unlikely but I decided to buy a little clearance so I flush mounted them.

The other reason to mount every thing from the one direction  is that  if you need remove the panel. and you have some  equipment the that mounts from the back and other equipment  mount from the front. you  have to disconnect pitot static lines and my understanding is technically  that you would need to pitot static check the system again since you had to disconnect the pitot static lines.

 

James

[tcal780]

4 hours ago, jamesm said:

Your Panel Looks nice.

Have you considered flush mounting G5's  ?

I did on my '67C  it looks  nicer in my opinion. I did have my G5's  sitting above panel for a  couple of years.  I changed mine because one of the RAM mount mounting option came real close to shearing off the knob of the G5. if I ever had to use full control input, highly unlikely but I decided to buy a little clearance so I flush mounted them.

The other reason to mount every thing from the one direction  is that  if you need remove the panel. and you have some  equipment the that mounts from the back and other equipment  mount from the front. you  have to disconnect pitot static lines and my understanding is technically  that you would need to pitot static check the system again since you had to disconnect the pitot static lines.

 

James

Thanks  jamesm,

You make good points, but if that panel ever must come out again, a pitot static test would be the least of my concerns.

I did consider flush mounting both G5's and the EDM900. Ultimately, I chose panel mounting only because flush mounting requires more space and this configuration would not have been possible.

It was important to me to have the EDM900 located there, on the left. A flush mount would have forced me to place it on the right side. I decided, if I couldn't flushmount both the G5's and the EDM900, they would all stay panel mounted.

[Ron McBride]

Looks great, but where is your gear switch?

[tcal780]

Dang. I knew I forgot something!

It's right under the backup CDI to the right of the switches. I didn’t put the cap on it yet.

[Hank]

19 hours ago, tcal780 said:

It's right under the backup CDI to the right of the switches. I didn’t put the cap on it yet.

Where are the Gear Safe / Gear Unsafe lights? They are usually above and below the switch.

[tcal780]

They will be right above the altimeter.

[Hank]

On 9/5/2024 at 7:10 AM, tcal780 said:

They will be right above the altimeter.

I see them now, with something in between. Should be very visible right in front of you!

[tcal780]

12 hours ago, Hank said:

I see them now, with something in between. Should be very visible right in front of you!

I'm adding a stall indicator light (red) between the two gear lights.

[tcal780]

I'm going to try switching the bulbs to incandescent and use the two ground pins as the switched 14v+ and a use the #1 pin as the common ground. The housing itself isn't grounded, so this should solve the problem with the push to test circuit mentioned in the above post.

[Dennis Pendergast]

On 3/9/2024 at 6:26 PM, tcal780 said:

I finished 95% of the old panel cleanup. The remaining wiring seen in the photo will stay.

A couple questions for the group:

First, panel mounting. Are there "standard" mounting brackets and avionics rails available for a new panel like this or will I need to have them fabricated? The avionics guy said vibration isolators are not needed anymore, citing Garmin avionics often don't work well with them. Is this the case?

Second, some advice on lighting. I am considering a combination of LED bezel ring lights for the 5 round instruments and an LED strip light on the underside of the glareshield for an overall flood.

I'd also like to have the toggle switches or switch labels illuminated. The original throttle quadrant/flap labels and compass are also illuminated with incandescent bulbs. Can these be converted to LED?

Ideally, I would like the avionics and the instrument ring lights to be on one dimmer and the remaining flood/panel lights to be on a second.

What would you recommend?

Thanks!

Nice looking panel work! Who did you have do it? I may want to work with them too.

Here are a few tips we have learned in our work on Mooneys in our avionics shop, perhaps you will find them useful:

• To my knowledge, there are no "standard" brackets available for the new panel. Most Mooneys we work on have the panel spaced out from the sub-structure using aluminum spacers to accommodate a #10 machine screw. The spacers are about 1/2" to 3/4" tall and guide the screw into a rivnut installed into the lower steel tube as well as the upper structure. These rivnuts are often stripped out and need replacement. Using a normal nut will make installation nearly impossible. We usually try to use the original provisions and mount the panel with hardware similar to what it originally had.
• Not all screws are equal. Remember that stainless hardware does not have the strength of most cad plated steel hardware. Use structural screws. Some inspectors will demand this and it is easily verified. Opinions vary widely on this, but instrument panel are sometimes considered to be "structural members."
• Make sure you maintain the original angle (fore and aft) of the panel. The spacer size will effect this.
• On the left and right side of the center stack, I notice that the vertical supports have been removed. I normally consider these to be structural members. Now, the panel which you are installing, if it is about .090" 2024T3 aluminum, will bring plenty of strength with it, but you might want to verify this. Much will depend upon the opinion of your local FSDO. Most reputable panel shops can also be very helpful with this and may have the paperwork to back it up.
• Some manufacturers actually require that the vibration isolators be removed since any movement of the panel can effect the accuracy of your digital instruments. Verify with the mfg's authorized documentation.
• I'm sure you've already done this, but remember to consider the structural steel tubes behind the center stack. I recently had to completely re-think a panel layout because of a mere 1/2" of interference the tubes brought to one of my deeper radios in the stack. Mooneys are famous for this as they have much less space behind the panel to fit everything where you want it.

Hope this helps

[tcal780]

5 minutes ago, Dennis Pendergast said:

Nice looking panel work! Who did you have do it? I may want to work with them too.

Here are a few tips we have learned in our work on Mooneys in our avionics shop, perhaps you will find them useful:

• To my knowledge, there are no "standard" brackets available for the new panel. Most Mooneys we work on have the panel spaced out from the sub-structure using aluminum spacers to accommodate a #10 machine screw. The spacers are about 1/2" to 3/4" tall and guide the screw into a rivnut installed into the lower steel tube as well as the upper structure. These rivnuts are often stripped out and need replacement. Using a normal nut will make installation nearly impossible. We usually try to use the original provisions and mount the panel with hardware similar to what it originally had.
• Not all screws are equal. Remember that stainless hardware does not have the strength of most cad plated steel hardware. Use structural screws. Some inspectors will demand this and it is easily verified. Opinions vary widely on this, but instrument panel are sometimes considered to be "structural members."
• Make sure you maintain the original angle (fore and aft) of the panel. The spacer size will effect this.
• On the left and right side of the center stack, I notice that the vertical supports have been removed. I normally consider these to be structural members. Now, the panel which you are installing, if it is about .090" 2024T3 aluminum, will bring plenty of strength with it, but you might want to verify this. Much will depend upon the opinion of your local FSDO. Most reputable panel shops can also be very helpful with this and may have the paperwork to back it up.
• Some manufacturers actually require that the vibration isolators be removed since any movement of the panel can effect the accuracy of your digital instruments. Verify with the mfg's authorized documentation.
• I'm sure you've already done this, but remember to consider the structural steel tubes behind the center stack. I recently had to completely re-think a panel layout because of a mere 1/2" of interference the tubes brought to one of my deeper radios in the stack. Mooneys are famous for this as they have much less space behind the panel to fit everything where you want it.

Hope this helps

Hi Dennis,

Thanks for your thoughts on this.

Superior made the panel.

In order to replace the rubber isolators and keep the panel in the same position/angle as the original, we machined 4 lower mounts out of 1/2 billet. Each is two pieces, that effectively clamp the 1/2" support via (11) 2" #8 screws and nuts. #10's would not fit in the existing holes. The outer mounts are about 7-1/2" long and the inner ones are about 3." The left side inner mount needed some additional work since there's a weld there to contend with. I've attached a photo of the mounts test fitted with the acrylic template.

[Dennis Pendergast]

Nice attention to detail.