Hey, Anybody have any experience (Flying, or owning/operating) an SA-26AT, or the TPE331 Merlin IIB. I see the II's were based on a Queenair fuselage, and a Twin Bonanza wing and land gear, so really a completely different aircraft than a Merlin III,IV, and Metroliner.
Cheers,
Doug

It is a great plane from what I’ve been told. My mechanic has worked on most of them over the years.

I like the Merlin IIb , performance and cabin are similar to B200 a little slower.
They are a collection of spare parts.
Lots of twin bonanzas sacrificed to build them.

I flew contract on one about 30 years ago. I only flew it maybe a total of 25 hours. Autopilot was inop, but it hand flew nicely, like a Beech, maybe lighter on the controls than a 90 King air. LARGE comfortable cabin, slightly complex systems. It liked to fly in the high teens,(small wings and 331-1 engines) and the cabin was close to sea level with 7.0 PSI cabin differential. Single engine climb rate could be increased with fuel dumping. ( limitation, do not dump with an engine fire, land overweight) Imagine that.
Not a speed demon, 220-230 as I recall.
I looked in the nose bays and thought.... that is a lot of OLD wiring. ( and now it would be 30 years older.)
I was trained by an instructor who mailed a manual to me, then did ground school at our airport, no sim, all in the airplane.

Not a queen air, all Swearingen design fuselage.. big and round.

I remember this thread had good info.

viewtopic.php?f=51&t=130470&hilit=Merlin

Yes Merlin IIB with TPE 331-1 engines, but better to go with -3 or -6 upgrade I think it is called Big Foot modification.usually done at hot section overhaul.

Nice flying plane kinda heavy on controls, cabin cooling was 1 electric driven York style air conditioning compressor with 2 evaporators in the cabin floor. Cooling was not very effective in Florida during the summer. Also airconditioning could not be operated unless the engines were running because the condensers located in the wing root did not have fans for airflow. There maybe some modifications to upgrade air conditioning system to better design that can be operated on the ground with ground power cart without running the engines.

An interesting issue encountered was a indication problem with some unit that compensated for altitude and temperature for the display of ITT gauge. The airplane I flew seemed very under powered for takeoff when Referencing ITT limitations.

As a result I requested maintenance to complete a Lebow check for engine torque on both engines. So this maintence company was not familiar with the TPE 331-1 engine as we learned. They did the check and their evaluation was that both engines were not producing rated power and needed to be overhaul, but engines were not anywhere near a TBO limit.

Weird analysis that both engines were shot. Next step was to get the airplane out of that shop and call in the experts at Garrett / Honeywell to trouble shoot.

What Garrett/ Honeywell found was those units for calculating ITT had developed small internal leaks to outside ambient temps and pressures which resulted in ITT being displayed about 20 to 30 degrees higher than actual. So they replaced those units and problem was fixed a lot cheaper than the misdiagnosis we were given.

I would recommend changing out the original (crystal type) radios because they are outdated and even if repaired will need repair again within a couple of months. Also I would definitely make sure the old carbon pile electric inverters / converters under the pilot and co pilots seats have been replace because they can catch your seat and other things like charts on the floor on fire. Once replaced with solid state units no more worries. I always enjoyed flying it with the big yoke and column rising up from the floor it gave you the feeling of flying something bigger.

Doug, you might want to check the Twin Bonanza thread. Go to “Merlin-Twin Bonanza Connection” topic (Sept, 2019). Sorry that I can’t supply the link.

MM