S-tec 30 vs S-tec 55x

[Cris]

I am upgrading my autopilot from an S-tec 30 with manual electric trim to a 55x. I'd like to add the autotrim option available with the 55x and am wondering what is the differance in hardware between the two other than the computer? Is there an additional trim servo as an example? Also the S-tec 30 is coming out of an airframe with 490 hrs tt and is mint. I will be keeping the servo's so it is just the head and the pitch computer and It is 28 v so it would need a voltage reducer for the 14 v A/C. I might also have available the trim servo for the manual trim. S-tec charges $1600 for the STC to make it legal to be installed into another similar Mooney. PM me if interested.

[Marauder]

Hi Cris. I have the complete STEC wiring schematic at home and will look it up tonight if someone doesn't answer it beforehand. From memory (I have the 60-2 with autotrim), I believe it is just the computer that is different. It just automates the manual trim. Let me confirm for you.

[Cruiser]

your Eagle should have all the hardware needed for the upgrade. It will only require the System 55x and a new turn co ordinator plus the rewiring. I would strongly suggest you contact Mooney for the 830084 drawings. With this package you do not need the STC from S-Tec to make it legal. 

You will need to have the computer modified for the Mooney however.

 

contact me offline for more info, I am doing the same upgrade.

[John Pleisse]

Hi Cris. I have the complete STEC wiring schematic at home and will look it up tonight if someone doesn't answer it beforehand. From memory (I have the 60-2 with autotrim), I believe it is just the computer that is different. It just automates the manual trim. Let me confirm for you.

 

+1....I upgraded from a 30 to a 55X. There's more to it than just keeping the servos, swapping out the computer and adding auto trim. My net cost after finally arriving with the 55X was the same as if I had purchased it new. As with Chris above, I have the wiring schemes, paperwork, STC and log entries. Anything you need. Don't get it in your head that this is a 10 day thing and just swapping a few things. It is a full install and could take 3 biz weeks. It's a great upgrade, you'll be thrilled with it and a plane like yours deserves an AP that good.

 

The 830084 scheme, Tom mentioned, was not available when I upgraded. What a time saver if valid. I couldn't imagine dealing with Cobham.

[mike_elliott]

Hi Cris. I have the complete STEC wiring schematic at home and will look it up tonight if someone doesn't answer it beforehand. From memory (I have the 60-2 with autotrim), I believe it is just the computer that is different. It just automates the manual trim. Let me confirm for you.

 

Chris, I put the Stec service manual in the download section of MS a few months back that may help.

[Marauder]

Cris -- looks like you are getting some great help. Sorry we didn't get to see you at KLNS.

You are going to love the autotrim!

Sent from my iPad using Tapatalk

[Txbyker]

Cris and Tom, do you have WAAS and if so after the modification to the 55X will you be able to fly coupled VNAV approaches?  Just curious.

 

Russ

[Marauder]

Cris and Tom, do you have WAAS and if so after the modification to the 55X will you be able to fly coupled VNAV approaches?  Just curious.

 

Russ

 

I have the STEC 60-2 with the GPSS coming from the Aspen as opposed to the built in GPSS capability with the 55X. They should be able to fly pure LPV (precision)  & LNAV approaches as well as flying a GPSS overlay to a VOR or ILS approach.

[Cruiser]

what Chris said ^

 

Limitations are:

N/A above 185 KCAS

without or inoperative autotrim the use of flaps are prohibited

N/A coupled missed approach, you must disengage and then you can re engage after configuration changes.

Autopilot operation prohibited during take-off and landing

Category I operations only

N/A below 240' AGL

[Cris]

Wow folks, Thanks all for the info. Tom I'll look into the drawings and contact you off line. Stec seems to believe I must buy the STC from them so this could save me $1600. Mike thanks for the Stec manual. Chris I would appreciate the wiring diagrams. I have not been able to fly as I lost my medical but just got it back after the Feds decided to get back to work. Took my flight physical on Sept 30 th and then the Gov. shutdown but got it in the mail a few days ago so I will be able to get to the fly ins again. I'm still planning on a King KSN 770 and since it would require a complete wiring interface with my S-tec 30 I figure this is the ideal time to move to the 55X at minimal additional cost. This will all be installed by an S-tec/King shop. I do need the T & B for the 55x as well as a tray in case anyone has those available.

[skyking1]

Congratulations on the upgrade! Let me know how it works as I have an Stec 55 and thought the 55x would be a faster update ! Glad you are back flying!

[Cris]

Congratulations on the upgrade! Let me know how it works as I have an Stec 55 and thought the 55x would be a faster update ! Glad you are back flying!

So far as I know the 55x gives you GPSS built in and it is updated for Wass. Beyond that there are minimal differences but Sarasota Avionics has an upgrade program allowing you to trade the 55 for a 55x so you might check with them on details. I think the cost is 5k plus installation.

[John Pleisse]

I have two WAAS 430's. One feeds the FCS, the other to the FCS a-n-d an additional RS232 switched output, hard wired directly to the AP. If the FCS or other goes T-U, I have direct GPS feed to the AP's GPSS. Everything in the airplane can be turned off except GPS #2 and the Stec 55X. Hands off the AP could then fly and entire flight plan and lateral guidance for an approach. One simple back door connection.

[jhbehrens]

I upgraded the S-tec 30 that shipped in my Eagle to a 55x + autotrim a few years ago. You can indeed retain the servos and need to get a Mooney-adjusted computer from S-tec + a new turn coordinator and return to old computer to s-tec. The autotrim install is in the belly and requires a bit of work.

 

The 55x is a much more robust autopilot, can do VS descents and climbs and fly down a WAAS or ILS glidepath. Essentially, practically an s-tec 30 is an en-route autopilot only and a 55x is an en-route + approach autopilot. If you don't have an Aspen the 55x also adds GPSS for en-route turns, holds and course reversals.

 

If Aspen ever certify the DFC90 for the Mooney that would be the superior option. The 55x is rate-based and not completely rock solid when intercepting and ILS or VOR. S-tec support is also dreadful.