Question: Standard Turn-Coordinators and Panel tilt of 14 degrees... Will it work?

[Zippy_Bird]

Hi All,

The ancient 2" turn coordinator in my original Mooney shot-gun panel has died, and I need a replacement to finish my annual airworthy.

Got really excited about installing a R.C. Allen RCA2610-2 (2 inch) with Digital Turn & Slip Indicator in the existing 2" hole which would have put a digital horizon backup under the primary vacuum AI.  This is compliant via FAA AC91-75 which replaces a TC with a second AI having a different power source.  It would have been awesome, but unfortunately the bezel of the new instrument was too wide horizontally about 3/16 on each side, which conflicted with the adjacent altimeter and VOR/ILS instruments on either side.  Ended up returning it.  If others are considering this, it didn't fit in my M20E shot-gun panel.  I've looked into rebuilding this bad one or others found on eBay, but everyone I called said that was not viable.  Plus, aside from the RC-Allen that didn't fit, I have not found any 2" 14v replacements anywhere.

As of now, the plan is to move the 2nd VOR to the passenger side panel, slide the pilot side VOR/ILS one hole over to the right, and open 3 1/8 standard hole by the yolk.  There we plan to install a standard size T.C.

Question for the group is this... Will the 14 degree tilt on this bottom row of the panel cause problems with a standard TC?  I.E.  Will we need to install a 14 degree wedge to make it vertical OR, does the TC have the capability to function on a 14 degree tilt like this?  I have seen pictures of other Mooneys with a T.C. in this exact same location, but don't know if they are "wedged" or built to 14 degree purpose.

Any knowledge folks can pass along would be greatly appreciated!

Thanks,

Zippy_bird

[C.J.]

Your best bet would be to call and ask the manufacturer of the TC you're intending to buy. I had the same issue albeit with the original Garwin 2-inch T&B in my shotgun panel. It definitely had a 14-degree wedge, and I'd bet your failed TC had one too. Given my AI was also 59 years old, my solution was to completely re-do the panel into a standard 6-pack, so I bought an overhauled TC & am putting a wedge in. My TC was calibrated to zero degrees, so the wedge was necessary in the new panel. I also installed a new RC Allen AI built & calibrated to 8 degrees and it also required a wedge.

[Zippy_Bird]

Your best bet would be to call and ask the manufacturer of the TC you're intending to buy. I had the same issue albeit with the original Garwin 2-inch T&B in my shotgun panel. It definitely had a 14-degree wedge, and I'd bet your failed TC had one too. Given my AI was also 59 years old, my solution was to completely re-do the panel into a standard 6-pack, so I bought an overhauled TC & am putting a wedge in. My TC was calibrated to zero degrees, so the wedge was necessary in the new panel. I also installed a new RC Allen AI built & calibrated to 8 degrees and it also required a wedge.

Thanks C.J.

Exactly what I found as well. All analog TCs I researched are built to a specific mounting angle. Most being vertical mount only (0 degrees tilt). My original 2” Garwin is the dead instrument, and indeed had a 14 degree wedge installed to bring it vertical. I have a replacement 3 1/8 now, and am trying to sort how to obtain or make a wedge for it.

Any tips on wedge buying / making?

Thanks,
Z


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[bigmo]

There are lots of 8 degree options as lots of a/c (especially Cessna twins) have a 8 degree tilt. 14 is quite a bit - did you ask them if they (the OEM) could adjust it for 14 degrees? I have a bud with a Bo and he had one modified from 0 to 8. I do think it was RC Allen, but it’s been a while. Would make me think if they can make it work at 14.

Any electronic options that allow up to 14? I know they all have calibration options that allow 8…but the G5 installation guide doesn’t show the range of choices.

[C.J.]

On 9/6/2024 at 8:59 AM, Zippy_Bird said:

Any tips on wedge buying / making?

Thanks,
Z
 

You're welcome, Z.

My avionics technician made the two wedges using a 3D Printer. It's a very interesting fabrication process - just search for a YouTube video that explains it.

C.J.