Out of curiousity, how does removing 380HP and replacing with a 375 or 350hp variant improve performance?
Few reasons. First off, that 380 HP rating was a bit optimistic. Meanwhile, the J2BDs tend to be strong performers. Add a bit one side, subtract it from the other, and...
For GTSIO-520s, you have the addition of an intercooler. This gets to be a big deal when you get up to the flight levels, where a non-intercooled engine is running some very high pressure ratios through the turbo and your induction air temperatures hit thermonuclear levels. So at altitude, you'd likely see an improvement.
No question on the support angle. Even if TIO-541s grew on trees, I would soon grow tired of the snickerings of my fellow pilots.
If they had the support they needed, I think they would be just fine. When they were built, the intent was the 541 to replace the 540, it just didn't work out that way. Teething problems and general poor performance/unpopularity of the Duke and P-Navajo meant that the things were quickly orphaned.
I always thought the efficiency of these and the Duke installation was poor from low ground clearance -- resulting in a stubby little prop turning at 2900RPM.
The engine was designed to spin fast, and engines that spin fast need stubby props. This does hurt propeller efficiency, and is another part of why you'd likely see equal to better performance from a J2BD or GTSIO install. However there's not a huge amount I'd expect you to gain there, probably mostly in takeoff and climb performance.
I never quite understood why they went with straight TIO-541s given the high-revving design of the engine. To me, it would've made much more sense to only stick to the TIGO-541s. For one, the 425-450 HP the TIGOs made would've made the Duke a significantly better performer, and the lower prop RPM would've made things much quieter and probably more popular. Of course, the geared engines had their issues, too.
I still lust for one of these, though. I have access to fuel, engine OH, and maintenance at cost, and it STILL scares the bejeesus out of me. I've tried to arrange a 3-way partnership in one a few times, as a "when you absolutely, positively, have to get to Vegas in 35 minutes" 2nd plane... no takers yet. They're all smarter than I am
We probably fall into one of the few groups that a 56TC would actually make sense for, given that the size and configuration of a Baron/310/Aztec is perfect for our mission and we do trips long enough that we can use the extra speed and would fly at the higher altitudes. If I wrecked the 310 tomorrow and we had to think about a replacement, we might consider it. I don't like the cramped front seat of a Baron, I really like the wing lockers on the 310, no pressurization, etc. So we'd probably end up looking at a 340-421, Aerostar, etc. Or maybe just get a RAM T310R and have pretty much the same performance with engines that are supported, a better interior, etc.
In the mean time, we'll just stick to flying the airplane that we have that fits our mission well, represents a good price point for us, and that is in great condition.
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