Name That Part #1

bnt83

bnt83

Final Approach
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Brian
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Hint: It's out of a Cessna 560XL
 
Air conditioning / pressurization turbo
 
Part of the Fuel pressurization system? Compressor/expander?
 
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I'll give the answer at the end of the day to give folks more time to respond
 
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Air handling machine. Ends up being used for AC by compressing air, cooling the (now hotter) air and expanding it to a cooler temp than originally there. No freon required!
 
Cessna calls the assembly an Environmental Control Unit (ECM) but Air Cycle Machine (ACM) is the same thing. This unit is not to be confused with a vapor cycle air-conditioning unit which is essentially the same type found in auto industry.

Bleed air off main engines or an APU powers the ACM. Then next time you sit on an airline take note of the cabin air momentarily cutting out as the crew starts the main engines. This happens because the bleed air powering the ACM is diverted to the main engine’s air starter system.

Due to the fact that most ACM’s don’t work well on the ground many aircraft also have a vapor cycle air-conditioning system which is usually electrically driven. An electrically driven system allows operation on the ground using external power, cooling the aircraft prior to engine start.
 
Little bit of trivia: The B787 uses electrically driven environmental control systems. In fact, engine bleed air is used for only two things on the 787 - engine nacelle anti-ice and hydraulic reservoir pressurization. Everything else is electric.
 
bnt83 said:
Due to the fact that most ACM’s don’t work well on the ground many aircraft also have a vapor cycle air-conditioning system which is usually electrically driven. An electrically driven system allows operation on the ground using external power, cooling the aircraft prior to engine start.
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Yeah, the Commander had an ACM (small one), and the air conditioning capabilities on the ground were poor. I think the main issue had to do with the lower engine speed (68% on the ground, as I recall).
 
Ted DuPuis said:
Yeah, the Commander had an ACM (small one), and the air conditioning capabilities on the ground were poor. I think the main issue had to do with the lower engine speed (68% on the ground, as I recall).
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Most likely due to low cooling airflow through the heat exchanger. In-flight ram air typically is ducted through the heat exchanger and on the ground a fan does a poor job of it.

Cessna 650 that pack cooling fan is actually hydraulic driven, kind of an oddball and scares the crap out of you when powering up a mule and hearing a loud unexpected whine.
 
Silvaire said:
Little bit of trivia: The B787 uses electrically driven environmental control systems. In fact, engine bleed air is used for only two things on the 787 - engine nacelle anti-ice and hydraulic reservoir pressurization. Everything else is electric.
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Reading up on the 787, being so dependent on electrical power, I wonder if there was a weight penalty for the "no bleed" design.
 
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bnt83 said:
Most likely due to low cooling airflow through the heat exchanger. In-flight ram air typically is ducted through the heat exchanger and on the ground a fan does a poor job of it.
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Might be a combination. Since we went to 100% as we were about to take off, the two happened simultaneously. Somewhere behind the cabin was where the airflow went through, so it would've been minimal on the ground.

bnt83 said:
Reading up on the 787, being so dependent on electrical power, I wonder if there was a weight penalty for the "no bleed" design.
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Well, you have to look at the whole system. Overall it ended up saving weight because the aircraft runs more efficiently, meaning that it requires less fuel to power the accessories than it otherwise would have. So while some of the components might add weight, that's offset by lower fuel weight.
 
What is shown is not a true air cycle machine.

the true air cycle machine uses a roots blower and a boot strap turbine. as pictured in the post above.

this one uses the engine exhaust or turbine compressor bleed air.

same function, different design.
 
Tom-D said:
What is shown is not a true air cycle machine.

the true air cycle machine uses a roots blower and a boot strap turbine. as pictured in the post above.

this one uses the engine exhaust or turbine compressor bleed air.

same function, different design.
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:rolleyes:



The types of air cycle machines may be identified as:
  • Simple cycle consisting of a turbine and fan on a common shaft
  • Two-wheel bootstrap consisting of a turbine and compressor on a common shaft
  • Three-wheel consisting of a turbine, compressor, and fan on a common shaft
  • Four-wheel/dual-spool consisting of a two turbines, a compressor, and a fan on a common shaft
I'm not even sure where came up with a roots blower being associated with modern jets :dunno: except the 787...
 
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I can identify the plastic wrap, if that helps.
 
Ted DuPuis said:
Well, you have to look at the whole system. Overall it ended up saving weight because the aircraft runs more efficiently, meaning that it requires less fuel to power the accessories than it otherwise would have. So while some of the components might add weight, that's offset by lower fuel weight.
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That's a really good point. I'm sure a lot of head scratching went into this, it's a pretty radical departure from the established standard but there must be a net gain in the end. The weight difference might be a wash and although eliminating the bleed systems gives the engine more thrust the generators still have to carry that load and the engines have to drive them. In the end I suppose the pneumatic just can't match the overall efficiency of the electrical system.
 
Silvaire said:
That's a really good point. I'm sure a lot of head scratching went into this, it's a pretty radical departure from the established standard but there must be a net gain in the end. The weight difference might be a wash and although eliminating the bleed systems gives the engine more thrust the generators still have to carry that load and the engines have to drive them. In the end I suppose the pneumatic just can't match the overall efficiency of the electrical system.
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Keep in mind also that a number of bleed air systems work by regulating on the exhaust side rather than the inlet side. So on many airplanes, pressurization receives a fixed amount of inlet air, and just vary the dump valve to determine cabin pressure. This means the engine is losing the same amount of energy regardless of what the plane needs. I think this has to do with operability dynamics.

By comparison, the electrical systems can be spooled up and down to the need. So you don't lose more than you need.

And if your engine is more efficient and you can carry less fuel because you burn less fuel, the people in control of the purses are happy.
 
bnt83 said:
I'm not even sure where came up with a roots blower being associated with modern jets :dunno: except the 787...
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Aircycle machines predate the jets by a long time.
 
Pretty sure that is a turboencabulator. http://www.turboencabulator.info/

In addition to CTAI and Hydraulic pressurization, bleed air is also used for engine stabilization during startup and power changes on 787.
 
Silvaire said:
Little bit of trivia: The B787 uses electrically driven environmental control systems. In fact, engine bleed air is used for only two things on the 787 - engine nacelle anti-ice and hydraulic reservoir pressurization. Everything else is electric.
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Ya mean like this one ???;)
 

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Ted DuPuis said:
Keep in mind also that a number of bleed air systems work by regulating on the exhaust side rather than the inlet side. So on many airplanes, pressurization receives a fixed amount of inlet air, and just vary the dump valve to determine cabin pressure. This means the engine is losing the same amount of energy regardless of what the plane needs. I think this has to do with operability dynamics.

By comparison, the electrical systems can be spooled up and down to the need. So you don't lose more than you need.

And if your engine is more efficient and you can carry less fuel because you burn less fuel, the people in control of the purses are happy.
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So at take off when you need the least pressure you get the most power?

Actually pretty slick
 
Skylane81E said:
So at take off when you need the least pressure you get the most power?

Actually pretty slick
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Right. The alternators will only pull as much power is as needed at any given time. Accessories not working as hard will produce a lower electrical load, ad so more power. More than anything, it means more efficiency and less fuel burned.
 
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