Supercharging - What's the catch?

Fearless Tower said:
I never said they were the most efficient.

But as someone who flies behind two supercharged engines, I'm genuinely curious about what is so horrible about them?

Can you weed out the emotion to explain why these engines are so insanely designed? I'm honestly attempting to understand how they were designed so incorrectly. The engines in use today seem to put in plenty of hours before overhaul and don't seem to be blowing up. My only real complaint about them is the fuel burn.

Why those engines are no longer produced has nothing to do with the supercharger va turbo argument. Keep in mind, those large supercharged engines were superseded by turbines. They were never replaced by flat engines with turbos.
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I'm willing to bet the older engines using superchargers versus turbo chargers may have been a materials issue as in the metals needed to survive the exhaust temps that those engines produced may not have been available or reliable for the application years ago.

I think superchargers are great designs, the only qualm I have is that I think they use more fuel for a given output versus a turbo charger. Applying a supercharger instead of a turbo charger as an after market option is probably a less expensive and less disruptive process to the original design of an aircraft.
 
mtuomi said:
Aren't they direct drive with no bleed/bypass? A popoff (if they have that) is not control, it's protection.
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I would think there is some type of over pressure protection via a bypass or maybe a clutch for the SC drive.
 
gsengle said:
Theoretically by not using exhaust to spin, they run cool...


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Not clear what you are stating here. Compress air at the same intake conditions to the same outlet boost pressure and it will be the same temperature going into the intake, regardless of whether the energy to do that came from an exhaust driven or engine mechanically driven source.
 
mtuomi said:
Aren't they direct drive with no bleed/bypass? A popoff (if they have that) is not control, it's protection.
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Perhaps reading the manufacturer's web site will help. They claim to have developed their own controller.
 
Turbos use excess engine heat and exhaust pressure that otherwise would be discarded in the exhaust to make the power to pressurize the intake air. Superchargers get their power from the engine via a pulley or other similar arrangement which takes away that power from powering the propeller. This difference makes turbochargers more efficient (use less fuel to obtain the same power). At least that is the way I understand it.
 
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coloradobluesky said:
Turbos use excess engine heat and exhaust pressure that otherwise would be discarded in the exhaust to make the power to pressurize the intake air. Superchargers get their power from the engine via a pulley or other similar arrangement which takes away that power from powering the propeller. This difference makes turbochargers more efficient (use less fuel to obtain the same power). At least that is the way I understand it.
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I can see that. My fuel consumption SUCKS...literally.

The one follow up question though would be....why were they still using superchargers and not turbos on the piston prop liners of the 50s? Unable to manage the heat?

45 GPH is the only thing I don't like about my aeroplane.
 
For a 182, this Supernormalized system seems perfect on paper..it is really designed to optimize performance for the 5000’ to 14,000’ density alt crowd... perfect for mountain flying in a 182... the turbo will win above 14,000 , but really how many folks cruise around above 14,000’ in a 182... don’t all raise your hands... the answer is almost nobody... on paper this makes a 230hp o470 more powerful and capable than a 300hp io550 (above about 4000’ DA ) and up to any altitude.... That is some impressive stuff...

my only gripe, is that it is not a self oiling unit... I’d prefer the engine oil System was not linked to the SC.. the magnuson supercharger in my car is self contained and I have over 100k on the SC.. I don’t know if a self contained oil system is a possibility in this setup...


Edit, correction , I called them today and back in 2012 they switched to a self contained oiling supercharger ... concern met.. awesome
 
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gsengle said:
Theoretically by not using exhaust to spin, they run cool...


Sent from my iPhone using Tapatalk
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Compressing the air heats it up, regardless of how. Some superchargers (and turbos are superchargers) are a bit more efficient and put is somewhat less heat (but even the screw-type/Roots blowers need intercooling on cars). Not having a turbine soaking up exhaust energy has got to help, as well. I believe that an axial compressor would run the coolest, and cost the mostest.
 
This is a brilliant system... power where you need it for mountain flying
 
coloradobluesky said:
Turbos use excess engine heat and exhaust pressure that otherwise would be discarded in the exhaust to make the power to pressurize the intake air. Superchargers get their power from the engine via a pulley or other similar arrangement which takes away that power from powering the propeller. This difference makes turbochargers more efficient (use less fuel to obtain the same power)...
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Correct. The downside of supercharging is parasitic horsepower loss to turn the supercharger; and beyond the max altitude the supercharger was designed to operate, power falls off more sharply than turbos with the effects of the parasitic loss compounding the issue. Superchargers make max boost relative to % of parasitic losses and generate progressively less power in relationship to the cost of HP needed to power them with each gain in altitude.

Turbo's operate over a wider altitude range. My ship's Rajay turbo-normalized makes standard atmosphere to FL16 and certified to FL25 without robbing the engine of horsepower to accomplish the boost. Supercharger boost level is inversely proportional to altitude. Superchargers would require a dual stage feature like many of the WWII of that era employed.

I like flying 5,000 AGL over the Sierra's and Rockies, or higher on long flights for favorable winds & weather.

The big plus is immediate power and no turbo lag, plus lower installation cost to retrofit, and more compact package for tight spaces. With turbo-normalizing in aircraft turbo lag is a non-issue (the 1/2 second to spool-up power) and making boost into higher altitudes.
 
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While many like to quote theoretical designs... there is a practical application for each system...

Who flies a Cessna 182 to 16k? Almost no one... if you regularly are up above 14k’ , then a turbo will be a better option...

in the piston world :

Sea level to 3-5k’- naturally aspirated is best
5k-14k supercharged forced air system wins
above 14k - turbo normalized Is best

Choose the system for the altitudes you fly 80-90% of the time.. don’t worry about the 10-20%... unless it is a safety matter, the last 10% costs too much (money, heat, efficiency, performance etc..) to manage for...and the 90% will suffer for it...

If you study Aeromotive’s design and lack of heat, small boost for the specific design.. it is simple and elegant in its design, for 5-14k’, it’s by far the best answer.. turbos rob power as well.. contrary to popular fallacy..do you really think you are spinning a turbo will zero penalty? and this supercharger takes 4hp to run...I don’t own one, but I want to...

take your Rajay TN and this supercharged system and race to 13’k (from any altitude) ... you will be left in last place and your engine with the SC will take less punishment
 
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Davidl13 said:
While many like to quote theoretical designs... there is a practical application for each system...

Who flies a Cessna 182 to 16k? Almost no one... if you regularly are up above 14k’ , then a turbo will be a better option...
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Operating theory is critical for making a determination on equipment. Not only topology of solution but also the specific implementation. There are no fixed formulas.

The reality, there are no turbo retrofits available today I'm aware of currently. If someone would like a bolt-on forced air solution, then FAT supercharger is about the only choice. The only turbo option is buying a turbo-normalized aircraft. As an exception Rajay is ramping up to build kits again for Pipers. This system is nice as the engine is normally aspired until the waste gate is closed. Best of both worlds - boost when you want it and 100% off line when you don't.

The fact that Superchargers make power inversely proportional to altitude is the opposite of what many would like to have. Meaning the they make max boost at sea-level and low boost at altitude where it's needed.

How and where someone operates their aircraft should align with the system best for them. I think it's more complicated than just operating aircraft at altitude X, Y, or Z to pick a system. Other solutions are increasing engine displacement like P.Ponk option on Continental 182's.

However your idea of knowing the altitude for common operation is correctly part of the selection criteria.
 
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Compression by natural laws (Ideal Gas Law)....does create or add heat to the intake...and will increase CHTs, even without the exhaust heat. Also, you never get something for nothing....so the energy it takes to run the supercharger/pump will take fuel burn up 0.5 or 1.0 gph.
 
What I like about turbocharging is that it puts all the expanding exhaust gas to good use

There are pros and cons to both, but thermodynamically I appreciate what a turbo gives. It's crazy to let all that 1,000*+ exhaust gas go to waste. It does make your engine run hotter, but that can be managed

Granted, you could do like they did on the massive piston radials and do a combination of turbo and super charging, including a power recovery turbine that mechanically captures some of the energy from the expanding exhaust gases

Turbo seems to be the preferred method in cars as well towards the strive for higher and higher power and efficiency in smaller and smaller packages
 
Davidl13 said:
...turbos rob power as well.. contrary to popular fallacy..do you really think you are spinning a turbo will zero penalty?...
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Your knowledge of turbocharger thermodynamics is seriously lacking...
 
You mean that with turbos, all that weight and heat and pushing an impeller comes at zero penalty? Like magic? It’s all just free power?... Wow.. you must be a genius...

all power comes at a price.. all...

All Designs have certain parameters they are optimized For.. a Tesla is very efficient, but it completely inadequate for crossing a large region without charging ports .. where a 1979 ford pickup would do better...as an example...

turbos are great .. but they really shine and become efficient at altitude higher than a typical unpressurized aircraft flies... but is does make for a great marketing claim of 225knots (at FL250 in small print)... it takes owning them and flying them to realize, you rarely if ever get to that altitude as a practical Matter..

A great turbo system is the Vitatoe TN550 for the Cessna P210N... perfect for a pressurized plane who really will hang out in 16-23k’ due to pressurization.. that is a really good application.. or a piper Malibu...same reason...but a 182? Nah.. not a chance...

And enough people have purchased them for big dollars so egos and Defense of resale dollars get involved...

This supernormalized FAT system Looks to
Me like a far better solution (than turbo or normally aspirated) for folks who spend most of your flight time in the 5000-14,000... and those levels cover a lot of regular territory for GA.. from a cost, performance, maintenance, engine wear, safety... it has it all.. bravo!
 
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Fearless Tower said:
I can see that. My fuel consumption SUCKS...literally.

The one follow up question though would be....why were they still using superchargers and not turbos on the piston prop liners of the 50s? Unable to manage the heat?

45 GPH is the only thing I don't like about my aeroplane.
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Because they were using the exahaust gas to run the power recovery turbines, rather than a turbocharger, would be my guess.
 
This is a super relevant thread to me, as I have recently been seriously considering the FAT supercharger for my plane. I fit the profile perfectly for its use case - mountain flying between DAs of 5k - 14k’, and the alternatives would be a swap to an IO-550, which would cost approximately $50k more and produce less power at all the altitudes I fly at, or sell my plane and buy a turbo 206, which would cost $100k more.

I have gone as far as interviewing a handful of current owners of 182s, 180s, and other field-approved planes that fly behind them, and they have been uniformly positive reviews. I have interviewed a couple installers and gotten mostly positive reviews (the negatives I did get were just that it’s not an easy install, they weren’t critical of the system per se).

Does anyone here on POA have direct first-hand experience with the FAT system? I would really like to hear more accounts and opinions from actual owners or users. There seems to be a lot of naysayers and heresay about this platform, but not necessarily from people with actual experience.
 
FWIW...

Somewhere in the rough neighborhood of about 1/3 of the energy in the fuel ends up in the exhaust system as waste heat. That energy can be used to spin a turbo to further expand / cool the exhaust and extract some of that excess energy and put it to work. Boosting is one use. Extracting it as mechanical power is another, but the problem with that is practical turbines tend to spin real fast. The easy thing is to either "normalize" (maintain sea level manifold pressure / power at altitude without large increases in load on the engine parts) or boost (increase manifold pressure above normal sea level values - more power per cubic inch. Grunt, Grunt, Grunt!). It does increase backpressure in the cylinders which increases temperatures... But turbos come about as close to a free lunch as you get when it comes to internal combustion engines.

A mechanical air pump (supercharger) sucks up power from the crankshaft and does not take advantage of the waste heat in the exhaust. But, it does not increase the backpressure and you don't have to make parts that thrive in the high temperature exhaust environment.

Turbo or Super chargers compress the air which a) requires work and b) heats up the intake charge. Depending on how much you heat the charge, the potential for bad things like detonation can increase. Better to dump the heat. Also, cooling the intake charge makes it more dense and makes it easier to get more air mass through the valves - which is the point of boosting - get more poop into the cylinders.
 
Capt. Geoffrey Thorpe said:
FWIW...

Somewhere in the rough neighborhood of about 1/3 of the energy in the fuel ends up in the exhaust system as waste heat. That energy can be used to spin a turbo to further expand / cool the exhaust and extract some of that excess energy and put it to work. Boosting is one use. Extracting it as mechanical power is another, but the problem with that is practical turbines tend to spin real fast. The easy thing is to either "normalize" (maintain sea level manifold pressure / power at altitude without large increases in load on the engine parts) or boost (increase manifold pressure above normal sea level values - more power per cubic inch. Grunt, Grunt, Grunt!). It does increase backpressure in the cylinders which increases temperatures... But turbos come about as close to a free lunch as you get when it comes to internal combustion engines.

A mechanical air pump (supercharger) sucks up power from the crankshaft and does not take advantage of the waste heat in the exhaust. But, it does not increase the backpressure and you don't have to make parts that thrive in the high temperature exhaust environment.

Turbo or Super chargers compress the air which a) requires work and b) heats up the intake charge. Depending on how much you heat the charge, the potential for bad things like detonation can increase. Better to dump the heat. Also, cooling the intake charge makes it more dense and makes it easier to get more air mass through the valves - which is the point of boosting - get more poop into the cylinders.
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Good summary, turbo = free lunch, supercharger= extra fuel used to generate boost . Turbo operates at insane speeds and insane temps (power generation side), supercharger operates cooler and more reasonable temps.
 
Davidl13 said:
You mean that with turbos, all that weight and heat and pushing an impeller comes at zero penalty? Like magic? It’s all just free power?... Wow.. you must be a genius...

all power comes at a price.. all...
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That's like saying that an investment that returns 30% annually is costing you something.

It's the NET gain that matters, and turbocharging offers a net gain.
 
Dan Thomas said:
That's like saying that an investment that returns 30% annually is costing you something.

It's the NET gain that matters, and turbocharging offers a net gain.
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they both produce net gains... stupid example... numbers don’t lie if you don’t lie about the numbers
 
In theory, theory and practice are the same, in practice, they are not...

you can spout turbo theory all day long and it is worthless if not applied... the FAT system in a 182 will out climb and out perform a turbo in every mode of flight from 5000’ to 14,000... and probably from sea level to 14000’ simply perfect for a mountain 182...

How many 182 hang out above 14000 regularly... almost zero... FAT wins... oh and your engine will last much longer.. look at the actual specs...not the mirror of your mind...
 
AA5Bman said:
This is a super relevant thread to me, as I have recently been seriously considering the FAT supercharger for my plane. I fit the profile perfectly for its use case - mountain flying between DAs of 5k - 14k’, and the alternatives would be a swap to an IO-550, which would cost approximately $50k more and produce less power at all the altitudes I fly at, or sell my plane and buy a turbo 206, which would cost $100k more.

I have gone as far as interviewing a handful of current owners of 182s, 180s, and other field-approved planes that fly behind them, and they have been uniformly positive reviews. I have interviewed a couple installers and gotten mostly positive reviews (the negatives I did get were just that it’s not an easy install, they weren’t critical of the system per se).

Does anyone here on POA have direct first-hand experience with the FAT system? I would really like to hear more accounts and opinions from actual owners or users. There seems to be a lot of naysayers and heresay about this platform, but not necessarily from people with actual experience.
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go to Denver and take a test flight... they are at centennial airport...
 
@Davidl13 do you own one or have flown one?
 
AA5Bman said:
@Davidl13 do you own one or have flown one?
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I do not own one and I have not flown one... I have spent considerable time discussing the system with the designers. Everything about their design makes sense in performance, engine reliability, cost etc...I hope to take a test flight in one soon. As soon as I can get down to Denver. My wife is getting her PPL and she wants a bush plane for up here in Montana... so we will look to find a 182 and add this system.
 
Our King Air 65-A90 had a "Roots" type supercharger on the left engine. It robbed the left PT6-20 of 40'#s of torque. A very few here will know what it was used for.
 
Davidl13 said:
I do not own one and I have not flown one... I have spent considerable time discussing the system with the designers. Everything about their design makes sense in performance, engine reliability, cost etc...I hope to take a test flight in one soon. As soon as I can get down to Denver. My wife is getting her PPL and she wants a bush plane for up here in Montana... so we will look to find a 182 and add this system.
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Are the people trying to sell you that system also comparing their performance to turbo normalizing systems or only turbo charged a/c?
 
Tarheelpilot said:
Are the people trying to sell you that system also comparing their performance to turbo normalizing systems or only turbo charged a/c?
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I don’t know.. they are not trying to sell me the system..give them a call..

I have a turbine aircraft and am considering a 182 for Rocky Mountain camping and trainer for
My wife as she gets her Ppl.. I sought out the obviously better for the application technology.. I found them.. I’m impressed

Less heat, less boost, less weight, less parts, less complex,less expensive, simple and more reliable, more performance below 14,000’, elegant , simple, brilliant design for specific altitude purpose (5000-14000)

even if performance was the same as a turbo it’s a better system due to all of the above, for the typical unpressurized piston flyer
 
Tantalum said:
including a power recovery turbine that mechanically captures some of the energy from the expanding exhaust gases
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Napier Nomad was possibly the ultimate expression of this, at least in Aero engines. It was a post war design that was of course rendered hopeless by gas turbines and so was canned in 1955 at the flying experiment stage. These were giant engines of over 3,000 hp and were piston ported two stroke diesels which probably needed an external air pump to run.
https://en.wikipedia.org/wiki/Napier_Nomad
https://en.wikipedia.org/wiki/Napier_Nomad#/media/File:Napier_Nomad_Model_E._145_Diesel_Engine.jpg National Air and Space Museum has a Nomad 1.

800px-NomadSchematic_185kBpng360kB.png
 
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mtuomi said:
"designed correctly" and "well suited system", none of which are likely to apply to supercharged engines from the 30s/40s/50s.
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I understand that the Mathematics of superchargers was 'solved' in the late 1930's by Stanley Hooker at Rolls Royce. "notably the Merlin 45, improving its power by approximately 30%, ... The Merlin 45 was fitted into the Spitfire Mk V in October 1940"

I have no idea if this was held secret there or distributed or if others may have come to the same conclusions.

https://en.wikipedia.org/wiki/Stanley_Hooker

I have been meaning to get his biography for a while "Not Much of an Engineer".

 
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