Turbonormalized Cruise Climb
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Hi there!
I'm really looking forward to the upcoming Bonanza release, especially the turbonormalized version.While reading through the manual, I noticed the following. The Takeoff Power Chart for 5,000 and 7,500 feet lists 29.9 inHg (WOT), 2700 RPM, and a fuel flow of 200 PPH. Meanwhile, the Cruise Climb Chart at 6,000 feet shows 29.9 inHg (WOT?), 2500 RPM, but with a fuel flow of just 103 PPH.
Surely dropping the RPM from 2700 to 2500 wouldn’t cut the fuel flow by nearly half, right? So is the Cruise Climb Chart assuming leaning to reach those listed fuel flow values or am I missing something?
Also, shouldn't the turbine Bonanza be designated as B36TP rather than A36TP, since it was based on the B36TC (Baron wing) model?
Cheers
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Interesting point on the A36 vs. B36. While what you're saying makes sense, I have never encountered that identifier before, and a google search for "B36TP" only returns forklift parts.
I'll investigate the fuel flows later. In theory, nothing should get into that table unless I saw it in the virtual airplane, but with the months upon months of development while often being pulled in many different directions, who knows what could have transpired. Hopefully I just missed populating that part of the table, or something.
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Fair enough, I'm not exactly sure how or if the identifier was changed, or if it would still fall under B36TC (Edit: Yeah, they apparently still go with B36TC after the conversion. They marketed it as the "Turbine Air").
But I do know for a fact that it was based on the B36TC, the turbocharged Bonanza with Baron wings.
Unlike the Allison conversion, which is indeed based on the A36.I came across this neat little brochure that talks about this as well: https://rocketengineering.com/wp-content/uploads/2017/10/TurbineAir_Article_5-13-03.pdf
(It was never explicitly stated, but I assume your turbine Bonanza is based on the Rocket Engineering conversion) -
The only other turbonormalized aircraft I'm somewhat familiar with is the SR22TN (it also has the Continental IO-550), and its POH supplement mentions a cruise climb at lean of peak. A fuel flow of 17 GPH closely matches 103 PPH, so I assume that’s what’s going on here.
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It turns out there was actually an old post about the turbonormalized STC supplement in the Analog Bonanza section, and I was able to remind myself of what the situation was. I've corrected the numbers in the table.
The RPM does actually make a surprising difference (8% reduction in cylinder displacements per minute, plus knock-on effects of the turbocharger not needing to work as hard thereby reducing backpressure, plus leaning for best power resulted in some 15% reduction in fuel flow)
Also it's easy to forget (myself included) that the cruise climb table is not showing us the fuel flow at the target altitude, but rather the time-average fuel flow from sea level to our target altitude. In other words, the 25,000 foot target altitude line will show a much higher average fuel flow than the 25,000 foot maximum continuous power table, because it also includes all the time we spent at less efficient altitudes while climbing to 25,000 feet.
