We are not dealing with the practicalities of converting twins to a single. NOTE: This example is for illustration purposes only. The article shows how we get the numbers we need from the turbo calculator to analyse turbo compressors maps. I'm guessing an IO-550 would also add weight to the nose over the stock engine, but don't know how much or if that's actually true.This article demonstrates how to use the turbo size calculator by using a BMW M4 turbo upgrade (S55 engine) as an example. ![]() The biggest downside is adding 35lbs to the nose of an already nose-heavy plane, and the price tag (but to be honest, the price tag seems reasonable compared to replacing the engine with an IO-550, which requires a new prop as well - we're talking $70k for that engine swap, which is crazy). I also don't really want the higher cruise fuel flows of a turbo'ed plane, and I suspect the FAT system will run a lot cooler and with a lot more reasonable fuel flows in cruise than the comparable turbo (this is partly due to lower power being produced, which is okay, but also because you shouldn't have as much cooling issues). I don't really want to run a hot turbocharger (been there, done that), and I don't really see myself operating much over 12,500, although the option would be nice. My main goal is to get better takeoff and climb performance (not cruise speed) and our DAs on bad days are usually not much more than 8,500' (where the stock IO-470 would get 188hp, the IO-550 would get 217hp, and the supercharged IO-470 would get probably about 245hp, for comparison's sake). It seems like a great solution for my use case. MP available at 12,000 feet would be equivalent to 5,000 feet, so roughly about 23-24"). After the critical altitude, MP decays as if 7,000' were your sea-level (i.e. So yes, it's a "turbo-normalizer" not a "turbocharger". I do believe there is a wastegate of sorts (popoff?) so you just go full throttle and that will maintain full sea-level rated MP (28" not 29" for what it's worth) through 7,000'. It'd have to be field approval, which when I first heard that I was like "yeah right that'll never happen," but I found out some other people have been successful working with them to get the field approval done and they say they've done some field approved IO-470S's, so maybe there's hope. They certainly don't seem to be too common, but from what I can tell it's a really nicely done system. Hopefully there's at least a couple of FAT supercharger owners here. It's worth asking FAT for the documentation on the system for your particular aircraft type to see what it'll get you. As you climb, you continue increasing the throttle to maintain 30"MP until you're at full throttle which happens at the critical altitude. I think they do tend to "supernormalize" rather than supercharge though, so you basically put the throttle up partway on takeoff, to get about 30" MP. With the Diamond one, they ended up optimizing the supercharger for ~12,000 feet because Diamond wouldn't cough up the engineering data to allow FAT to increase the ceiling of the plane from the existing 16,300 feet (5000m IIRC), so there was no sense in making it to allow a higher cruise than that. A normally aspirated plane can, thus, make 75% power up to 7000 feet and change, or 65% power up to 11,000 and change.Īh, cool! I followed their development on the supercharger for the DA40 but I don't know much about their other products. Look at the pressure ratio column, and that's about the max percent power you'll be able to get at that altitude. Here's the standard atmosphere up to 40,000 feet: What *exactly* are you trying to figure out? What airframe(s), what engines? We might be able to give you a more accurate answer with additional information. MP will drop a little more due to the air filter and possibly other intake quirks, mag timing may no longer be optimum, and plenty of other caveats. 5532 * 235, so the NA version could cruise with that much power at about 15,500. However, if you're talking about cruise at 65% for example, the Conti will make. ![]() 8511, so looking at the chart, somewhere around 4400 feet. If we assume that the crossover point is below the Conti's critical altitude, we just need to know where the Lyc will be developing 200hp. ![]() The NA version is a 235hp Lycoming O-540 while the turbo version is a 200hp Continental TSIO-360. When you're speaking of smaller turbocharged vs bigger NA, the plane that comes immediately to mind is the Dakota. Climb at all, and the NA one will start to lose some power while the turbo one will be able to maintain 100% power up to its critical altitude, after which it will start to taper off as well. Engines that are the same size and HP, the "crossover" is at sea level.
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