I've finally found an X-Plane 11 aircraft with which I can pretty realistically practice instrument approaches using a simulated airplane that fairly closely mirrors my real airplane. This Just Flight PA-28-181 Archer III is it. My problems with other Piper or Cessna airplanes I've tried in X-Plane 11 is the poor linkage between the RealityXP GTN 650/750 GPS plugin and the installed autopilot; if they can be linked at all. The stock S-TEC 55 X-Plane autopilot that is in most of the planes performs very poorly. You can't turn off Altitude Hold. The only way to release Altitude Hold is to touch the pitch trim. But anytime you touch the pitch trim or you try to retrim the pitch as you go through the various phases of arrival and approach the autopilot shuts off. At least the autopilot in this plane doesn't shut off. But it does disconnect NAV or HEADING like all of the rest of the airplanes. So you have to quickly reselect NAV or HEADING to keep the plane on course after you change pitch trim. In many of the other airplanes the RealityXP GTN 650/750 isn't linked to the autopilot at all. What's the use of having an autopilot and a very capable GPS if they aren't linked.
The glideslope works on RNAV approaches with the RealityXP GTN 650/750 in this airplane. Most of the other airplanes won't link properly to the VOR head which makes realistic approaches impossible. The RealityXP GTN 650/750 installs the Garmin 650/750 simulator which is quite realistic and was recently upgraded by Garmin with a nearly current database and almost all features available.
There is a bug in this version of the Archer III. Don't try to use the feature that allows you to pop up the autopilot window. It crashes X-Plane hard.
My airplane is a 1966 Piper PA26-180 Cherokee C that I've owned and flown for over 20 years. It is one of the older models in the Piper Cherokee/Archer series with the same 180 HP Lycoming engine. Mine has an S-TEC 30 ALT autopilot and a new Garmin GTN 650 GPS with roll steering that links the two. For situational awareness, weather, and approach plates Garmin Pilot on my iPad links with the GTN 650 via a Flight Stream 510 that allows downloading flight plans from the iPad to the GTN 650 and real time display of my location on charts and approach plates on the iPad. Garmin Pilot will link to X-Plane 11 for real time display of the X-Plane aircraft on charts and plates with Garmin Pilot in simulator mode. But flight plan download from Garmin Pilot to X-Plane is not available.
With such a modern GPS and autopilot setup VFR flight is easy. But is a lot to learn and practice for instrument flight.. So a realistic and capable sim airplane that can be used to practice all of the necessary procedures for instrument flight and to preview approaches into unfamiliar airports is my goal with a simulator. This Arrow III sim aircraft is usable to meet this goal. With a couple of fixes to the autopilot it would be a pretty close simulation and meet my needs well.
May 5, 2019 Update:
Well, on the surface everything seems right with this airplane. But there are some problems that need to be fixed to make it actually flyable.
* The center of gravity is too far forward. This makes it impossible to trim the plane for level flight at cruise power of 2450 RPM with 2 occupants and full fuel. Bring the CG back 13.5 inches and you'll see what I mean. It takes a lot of fiddling with Plane Maker to get the CG set right so you don't have to adjust it for every new flight.
* Fuel consumption is way too high, in excess of 13.5 gal/hr at cruise power in level flight. It should be about 10 gal/hr which is what my Cherokee 180C burns. I had to cut the Plane Maker settings almost in half to get the proper fuel burn. Full tanks of 25 gallons each should give you 4.8 hours of flying with calm winds.
* The plane is under powered. I had to jack the HP to 200 to get performance numbers close to my Cherokee 180. 105 kts in cruise at 4000 feet is just too low. My Cherokee 180 which is just the older version of the Archer is 53 years old with a high time engine and it gets better cruise numbers than that.
* The initial pitch trim setting is wrong. Pitch trim should be at neutral before takeoff. This plane has it set to full up. It's hard to see the pitch trim wheel between the front seats; there's no indicator on the panel. So having a proper starting trim is important.
* There is no disconnect button on the pilot yoke for either autopilot disconnect or altitude hold (ALT) shutoff. These are safety features that are in every airplane with an autopilot. The only way to turn off altitude hold is to momentarily turn off the autopilot which is totally unsafe and prone to unsafe airplane attitude. Touching pitch trim turns off the S-TEC 55 autopilot which is a bug in X-Plane. But the disconnect buttons should be there.
Fix these problems and you've got a good plane for practicing instrument flying and approaches.
August 11, 2019 Update:
With recent updates to the RealityXP GTN750/650 and to X-Plane 11.35 the localizer/glideslope no longer works in the Archer III. So until there is an update to the Archer III to truly enable the localizer/glideslope using either the stock GNS430 or the RealityXP GTN750/650 this plane is unusable for doing precision instrument approaches. The stock Cessna 172 works perfectly with the latest X-Plane update to 11.35. I've had to switch back to using the 172 for instrument approach practice since it's the only plane available in X-Plane that properly implements the RealityXP GTN750/650 with full capabilities for ILS and RNAV approaches.
Incidentally, the pitch trim autopilot disconnect issue has been addressed in X-Plane 11.30+ by adding "pitch trim up - mechanical" and "pitch trim down - mechanical" to the available commands. Using these commands for pitch trim up/down on the hat switch of the joystick allows adjusting pitch trim for climbs and descents without disengaging the autopilot.